Audiology in Developing Countries

Review Review

AUDIOLOGY IN DEVELOPING COUNTRIES

Review

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AUDIOLOGY IN DEVELOPING COUNTRIES

BRADLEY MCPHERSON AND RON BROUILLETTE EDITORS

Nova Science Publishers, Inc. ReviewNew York

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CONTENTS

Preface vii Dedication ix Chapter 1 Introduction 1 Bradley McPherson and Ron Brouillette Chapter 2 Audiology: A Developing Country Context 5 Bradley McPherson Chapter 3 Demographics of Hearing Loss in Developing Countries 21 Andrew W. Smith Chapter 4 Education and Practice of Audiology Internationally: Affordable and Sustainable Education Models for Developing Countries 51 Helen Goulios and Robert Patuzzi Chapter 5 Screening for Hearing Loss in Developing Countries 75 Bradley McPherson, and Bolajoko O. Olusanya Chapter 6 Providing Diagnostic Audiology Services in Economically Challenged Regions 107 Jackie L. Clark and Valerie Newton Chapter 7 Rehabilitation of Hearing Loss: Challenges and Opportunities in Developing Countries 141 Ron Brouillette Chapter 8 Hearing Aid Provision in Developing Countries: An Indian Case Study 155 Vijayalakshmi Basavaraj Chapter 9 ReviewEducational Audiology in Developing Countries 167 Susie Miles and Wendy McCracken vi Contents

Chapter 10 Audiological Counseling in a Developing Country: A Journey through Guatemala 181 Patricia Castellanos de Muñoz and Sandra E. Sosa Chapter 11 Occupational Hearing Loss in Developing Countries 189 Geoffrey K. Amedofu and Adrian Fuente Chapter 12 Resources for Audiologists in Developing Countries 223 Bradley McPherson and Ron Brouillette Contributing Authors 231 Index 233

Review

PREFACE

In 1988, Sanford Gerber and I edited a book entitled “International Perspectives on Communication Disorders”. The first chapter discussed the World Health Organization General Assembly resolution of 15 May 1985 pertaining to hearing problems, in which it was stated: “… that the attainment of health for all requires increased activity for the prevention of hearing impairment” and further, that, “… in developing countries most of the hearing impairment, which occurs in excessive prevalence in some communities, results from causes that can be prevented at the primary health level” or is “… reversible or remediable”. That was twenty years ago! Since then much has been accomplished in documenting the incidence and prevalence of hearing impairment in both the developed and developing worlds, and in building hearing aids and drug therapy programs which can ease the economic, social and individual burdens resulting from hearing loss, especially in the developing world. Another of the key hearing health care advances of the past twenty years has been the introduction of universal systems for newborn hearing screening. We see such programs proliferating all over the developed world; but are those in the developing world any less needy? What is happening there? Of course, one of the most significant advances of the last twenty years is the growth, expansion and recognition of the profession of Audiology all over the world. With that change came an appreciation for the significant contribution audiology makes to improving hearing health care. We no longer hear questions about what an audiologist does. Now what we hear are complaints about the lack of audiologists and their services. For most of the developing world the presence of a barely adequate number of fully trained audiologists is still a dream. The good news is that we now have service/clinical standards and a model curriculum for training. These were developed through the good work of the European Federation of Audiology Societies and the International Society of Audiology. The bad news is that there are insufficient funds, programs and fully trained audiologists to put those standards in place or to apply the model curriculum in many parts of the world. But there is hope! I am delighted to report membership in the International Society of Audiology is growing rapidly and now represents 70 nations and every continent, and that our student membershipReview represents 10 nations as diverse as Australia, Iran, Mexico, Brazil, Sweden, China and the Philippines. I have no doubt that the next twenty years will continue to see major changes in service everywhere. Change is upon us, and yet it is slow in coming. Clearly the time has come when there is a tremendous need for a complete discussion and summary of “Audiology in Developing viii George Mencher

Countries”. Why? Because we need to know what we know, what we don’t know, what we are doing, what we are not doing, and what we should be doing to advance hearing health services in the developing world. Bradley McPherson and Ron Brouillette have taken on the task of developing such a work, and have made a powerful effort to answer these significant questions. Andrew Smith has been leading efforts to collect reliable international demographic data on hearing impairment, within the Prevention of Blindness and Deafness program at the World Health Organization. Who better than him to discuss the demographics of hearing loss in developing countries? Further, Bola Olasanya (Nigeria), Jackie Clark (USA), Valerie Newton (UK), Wendy McCracken and Susie Miles (UK), Geoffrey Amedofu (Kenya), Adrian Fuente (Chile), Helen Goulios and Robert Patuzzi (Australia), Vijayalakshmi Basavaraj (India) and Patricia Castellanos and Sandra Sosa (Guatemala) are internationally renowned persons with significant expertise in their topic areas who represent 6 continents and 8 countries. Each brings a maturity and world-wide perspective to their chapters. All have extensive experience throughout the world as they have charted new courses, established programs or provided much needed services to emerging countries and regions. This is a book which covers the theoretical, statistical, technical and practical aspects of Audiology in Developing Countries. I am delighted to invite you to enter its pages and to feel how far we have come in the past twenty years and to learn how far we need to go!

George Mencher, PhD Assistant Secretary General, International Society of Audiology Professor of Audiology, Dalhousie University Director Emeritus, Nova Scotia Hearing and Speech Centres Halifax, Nova Scotia Canada

Review

DEDICATION

This book is dedicated to the memory of Christopher Adrian Holborow MD FRCS OBE, former Chairman of the Commonwealth Society for the Deaf. Christopher Holborow was a compassionate pioneer in the field of hearing health care in developing nations and a firm believer in the importance of good hearing for everyone, wherever they were found. He was an inspiring mentor for many audiologists who carry on his passion for better hearing in developing countries. We believe he would have been pleased to see how the seeds of his knowledge and vision have grown.

‘Go in search of your people Love them Learn from them Plan with them Serve them Begin with what they have Build on what they know’

Ancient poem: From a Dispensary at Mansa Konko, The Gambia1 Review

1 Holborow, C. (1991). Hearing aids: Their production, delivery systems and effective use. A hospital based model. In Hearing aids: Their production, delivery systems and effective use (pp. 17-18). London: Royal National Institute for the Deaf. Review In: Audiology in Developing Countries ISBN 978-1-60456-945-2 Editors: B. McPherson and R. Brouillette © 2008 Nova Science Publishers, Inc.

Chapter 1

INTRODUCTION

Bradley McPherson1,* and Ron Brouillette2,* 1University of Hong Kong, Hong Kong, China 2Inclusive Education Consultant, Directorate of Primary and Mass Education, Bangladesh and "Affordable Hearing" and "Wings", Consultants for International Deafness and Development, United States of America

Audiology is the study of hearing disorders and the non-medical, non-surgical rehabilitation of people with hearing loss. For over fifty years audiology has advanced as a clinical speciality in the developed world. The past two decades, in particular, have seen a rapid growth in the numbers of audiologists and in the sophistication of audiology assessment techniques and rehabilitation procedures. Nowadays in industrialized economies most individuals with hearing impairment have access to appropriate screening programs, audiological diagnostic assessment, hearing aid fitting and support with the rehabilitation process. In developing countries this is not the case. Many children still have undetected hearing loss; many adults with hearing disorders struggle to fulfil their social and economic roles without the benefits that appropriate amplification could bring. At least two-thirds of the 278 million adults and children with significant hearing loss live in nations with less developed economies. Living in such countries, professional help may be scarce and often distant, and assessment equipment and hearing aids, or other amplification devices, unaffordable for most of the community. For example, it is estimated that only one million hearing aids are fitted in developing countries each year, when the actual need is for thirty million (Smith, 2007). However, there are many concerned individuals and organizations in both developed and developing countries who are now working to radically change this situation. Increasing attention is being paid to hearing loss in developing countries by international agencies such as the World Health Organization, Christian Blind Mission and Lions International. ProfessionalReview organizations in the developed world, such as the American Academy of Audiology, now regularly acknowledge the humanitarian work of their members with awards

* Correspondence: [email protected] * Correspondence: [email protected] 2 Bradley McPherson and Ron Brouillette and grants. Governments, private agencies and individuals in developing nations have commenced programs to detect hearing loss (Olusanya et al., 2007) and initiatives to create affordable hearing devices are now ongoing (McPherson & Brouillette, 2004). This work is beginning to have a widespread impact. At the same time, more audiology professionals and technicians (local and expatriate) are working in developing countries. The increasing wealth generated in many ‘emerging economies’ (The Economist, 2006) should ensure that funding for hearing health care in general gains increased attention over the next decade. There are many special challenges and opportunities faced by audiologists working in developing countries. For most practitioners in developing countries, the training they have received has been either undertaken in a developed nation or delivered from the perspective an advanced health care context. Very little information with a developing country perspective is available to guide audiologists. This publication is a first attempt to showcase both what has been done and what still needs to be done to improve hearing health care in developing countries. The book is primarily addressed to audiologists, other hearing health care workers, and policymakers who work in developing countries or who have an interest in working in developing countries. The Editors hope that this and future editions of Audiology in Developing Countries will serve to support audiologists who work in developing countries and motivate others to become involved in this rewarding field. This book is a beginning and not an end-point. There are no definitive single solutions to the many barriers to hearing health care in developing countries. Developing countries are inherently diverse and multifaceted societies and audiologists who work in developing countries bring with them a wide range of ideas and skills—all of which may be needed to provide effective client care. Audiology in Developing Countries provides a rich, diverse set of chapters that cover a broad range of audiology’s scope of practice. The chapter authors have been given the freedom to explore their chosen areas in their own unique way. This book is not designed to provide a detailed, prescriptive guide for clinical practice. Nor was it intended to give a solely academic account of audiological issues in developing countries. We have intended, however, to raise questions and stimulate interest in a remarkably rewarding field through the writings of an international group of professionals who have all made a significant contribution to hearing health care in the developing world. This book could not have been written without the generous contributions of our chapter authors. We have been privileged to work towards our publication goal with such a global network of dedicated colleagues. Some authors, such as Helen Goulios, Robert Patuzzi and Andrew Smith have contributed solid data and analysis that enhances our still limited knowledge of basic service needs and resource parameters in the developing world. Other authors, like Geoffrey Amedofu, Jackie Clark, Adrian Fuente, Valerie Newton and Bola Olusanya have provide scholarly reviews that have been thoughtfully framed to meet the needs of those working in developing countries. Vijayalakshmi Basavaraj, Patricia Castellanos, Wendy McCracken, Susie Miles and Sandra Sosa bring detailed and often inspiring reports of professional challenges and achievements in developing countries they are highly familiar with. We feel that every chapter in this book contributes in a unique way to a greater understanding of the issues involved in audiology as it relates to Reviewdeveloping nations. The Editors extend their sincere thanks and appreciation to Darren Bryant, Faculty of Education, the University of Hong Kong, for his careful proofreading and thoughtful advice on style and format. The support of the Centre for Communication Disorders, the University of Hong Kong has enabled us to publish this book. A generous grant from the Oticon Introduction 3

Foundation, Denmark, for the distribution of this book in developing countries is also very gratefully acknowledged. As mentioned above, Audiology in Developing Countries is best considered a working document that gives contemporary snapshots of issues that concern audiologists in developing countries and those who work with them. We welcome comments on this book and would value suggestions for future editions.

REFERENCES

Economist, The. (2006). The new titans. A survey of the world economy. The Economist, September 16, 2006. London: The Economist. McPherson, B., & Brouillette, R. (2004). A fair hearing for all: Providing appropriate amplification in developing countries. Communication Disorders Quarterly, 25, 219-223. Olusanya, B.O., Swanepoel, D.W., Chapchap, M.J., Castillo, S., Habib, H., Mukari, S.Z., Martinez, N.V., Lin, H-C., & McPherson, B. (2007). Progress towards early detection services for infants with hearing loss in developing countries. BMC Health Services Research, 7(14). Smith, A. (2007). Update on burden of hearing impairment, and progress of WHO/WWH hearing aids initiative. WHO/WWHearing Fifth Workshop on the Provision of Hearing Aids and Services for Developing Countries. November 8, 2007. Geneva: World Health Organization.

Chapter 2

AUDIOLOGY: A DEVELOPING COUNTRY CONTEXT

Bradley McPherson* University of Hong Kong, Hong Kong, China

ABSTRACT

This chapter provides a broad overview of the characteristics of developing nations that influence hearing health care. The varying ways that “development” can be defined are examined and listings of developing countries delineated by different criteria are provided. Developing nations have features that often make them unusual from a developed economy perspective. Such countries typically have a greater rural population, are less ethnically homogenous, are more linguistically diverse and have greater income inequality than populations in industrialized societies. Such factors impact on the abilities of societies and health agencies to provide services to many sectors of the community. Audiology arose in industrialized societies as a response to post-World War II hearing health issues and has not yet created models of service delivery that are entirely appropriate for developing nations in the 21st century. The costs generally associated with diagnostic and rehabilitative audiological services may be a barrier to all but the most privileged individuals in developing countries. This chapter discusses such barriers to service delivery and surveys possible options that could improve access to hearing health care in the developing world. The resources required to provide audiological services, such as personnel, diagnostic equipment and amplification devices, are related to the overall resources available in developing nations. Global efforts to improve hearing health, through institutions such as the World Health Organization and private agencies are outlined and future trends in funding for hearing health care envisaged.

Review

* Correspondence: [email protected] 6 Bradley McPherson

INTRODUCTION

We live in a world that is home to more than 6.5 billion people. The majority of these people, 5.3 billion, live in developing countries. Demographic projections suggest that, in the near future, the numbers of deaths will exceed the numbers of births in the world’s more developed countries. Already this trend of a declining population can be seen in developed economies such as Italy and Japan, with birth rates below 1.25 children per woman. A birth rate of 2.1 children per woman is considered necessary to avoid a long-term decline in population. Population growth estimates indicate that almost all future growth, perhaps 97% of net population increase (Todaro & Smith, 2006), will occur in the developing regions of Africa, Asia and Latin America. Along with population growth comes an increase in the number of children born with disabilities. In China, with 20% of the world’s population, it is estimated that one child is born every 40 seconds with significant handicap (Stratford & Ng, 2000). Of these children, at least 14% are born with hearing disorders. The World Health Organisation (WHO) has estimated that two-thirds of those with severe-profound hearing loss live in developing countries (Kumar, 2001). In the long term, global demographic changes will accentuate this pattern, further shifting the burden of hearing loss on to those living in developing nations. The burden is indeed a great one, as hearing handicap is very often a personal tragedy for individuals and their families. The educational, health care and social costs of hearing loss are also high. In the United States it has been estimated that the lifetime costs of severe to profound hearing loss average $297,0001 (Mohr et al., 2000), with 21% of these costs incurred in the provision of special education. Lifetime costs for those with severe to profound hearing loss of prelingual onset exceed $1 million. These figures indicate the high level of costs associated with reduced work productivity, hearing health care and education for persons with hearing loss in developed economies. These are costs that developing countries are ill-prepared to cope with. The vast majority of audiologists, and other professionals involved in hearing health care training, live and work in developed nations. They have been trained to prevent hearing loss and to assess, treat and rehabilitate persons with hearing loss – in the context of conditions found in industrialized countries. However, there can be deep economic, political, social, and health differences between developing countries and developed economies. All these contrasts may fundamentally impact on how an audiologist works –what she or he does in the clinic, in the school, in industry or in the community. Increasingly, hearing issues are gaining a place in the health care priorities of developing countries. Leadership from the World Health Organization and development agencies has given momentum to change and progress. More audiologists are now working in developing nations and establishing prevention, assessment and rehabilitation programs. Some developing nations, such as China (Zheng & McPherson, 2006), Columbia (Madriz, 2001), India (Karanth, 2002), the Philippines (Cheng, Olea & Marzan, 2002) and South Africa (Swanepoel,Review 2006), now have well-established professional training programs in audiology. The main objective of this chapter is to introduce the concepts of development and developing countries and summarize the key characteristics that distinguish developing

1 All dollar figures are in United States dollars unless otherwise noted. Audiology: A Developing Country Context 7

countries from those in the industrialized world. The chapter is divided into four main sections. The chapter initially discusses the various ways in which development level can be usefully viewed and quantified. Secondly, we consider the demographic, social and health factors that set developing countries apart from developed nations. The third section focuses on several specific audiology programs that have confronted development issues and their outcomes. Finally, the chapter summarizes the global initiatives that are underway and which may support the advancement of audiology services for the majority of adults and children – those who live in developing countries.

WHAT ARE DEVELOPING COUNTRIES?

Development in the present context was considered initially as an economic concept, equated to the process of industrialization. Developing countries have been defined as nations with low average annual income whose economies are mostly dependent on agriculture and primary resources and which do not have a strong industrial base. Typically, developing states are dependent on inflows of foreign capital and on international aid for their economic needs. For much necessary technology and expertise, developing countries depend on the industrialized world. “Less developed countries”, “emerging nations”, “the South” and “underdeveloped countries” are often used as synonyms for “developing countries”. Developing countries are found in Africa, Asia, the Middle East, Latin America and in the Pacific. According to certain criteria, some countries within Eastern Europe and the former Soviet Union are also classified as developing countries. There are many ways to attempt to quantify development and rank countries by level of development. The most common approaches have been to use income as a measure of development, or economic and social structure as a reflection of overall development, or to consider social or physical quality of life measures. Economic measures have the longest history of use and are the most widely reported, but all indices have their advocates and all are useful when considering an individual country’s level of development. By considering a range of measures a more sophisticated understanding of a country’s place in the world can be gained.

Income Measures

The oldest method of ranking nations for development is to compare their levels of per capita (per person) income. This is a straightforward measure and relative easy to calculate, as the required statistics are generally available. Per capita income can be measured in two ways. A country’s total income can be divided by its population and the resulting number for gross domestic product (GDP), nowadays usually termed gross national income (GNI), converted into an international reference currency (usually US dollars). This figure allows for ready comparison Reviewwith GNI figures for other countries. However, it can be misleading (Sanford & Sandhu, 2003). No one can survive long-term on one dollar per day in an industrialized economy but many people do live on such an average income in developing countries. This is partly because the price of many locally-produced commodities is low in developing economies and also because significant income may be generated from the informal 8 Bradley McPherson economy. On the other hand, a simple foreign exchange conversion GNI measure will give a good indication of the relative cost of imported goods and services. Hearing aids, assistive listening devices, and audiometric equipment are almost entirely imported from industrialized nations and comparing cost to local GNI will give a rough indication of affordability. A more complex measure of relative annual income seeks to compare the cost of the same standard basket of goods across nations. The purchasing power parity (PPP) method provides a more accurate comparison of relative standards of living. A person in a country with a PPP of $8,000 should have roughly the same standard of living as a person in the United States with an annual income of $8,000. There can be a wide disparity between GNI and PPP figures for the same nation, with India being a clear example. Rankings for 25 countries for both foreign exchange conversion GNI and PPP are shown in Table 1. The World Bank publishes foreign exchange conversion and purchasing power parity per capita income figures on an annual basis (World Bank, 2005). The World Bank uses GNI per capita to categorize states as low- income ($825 or less); middle-income ($826 to $10,065; and high-income ($10,066 and above). A simple criterion for a developing country is where GDP per capita is below this high-income GNI level. However, this benchmark leads to a very wide grouping of states being labelled as “developing”, from states such as Burundi with a GNI of $90 per person to recent European Union member states such as the Czech Republic, with a GNI per person of $9,150. The World Bank further divides middle-income countries into upper-middle-income and lower-middle-income economies, with a GNI per capita of $3,255 boundary between the two groups. Alternatively, lower-middle-income and low-income states may be collectively deemed “developing countries”.

Social and Political Measures

Economic measures of development have been criticized for ignoring the goals of the development process, which is to improve the quality of life of individuals. Many authors have argued that factors other than income must be considered when ranking relative standards of living. Basic societal factors should also be considered, including literacy levels, infant mortality, and life expectancy. A widely used ranking is the Human Development Index (HDI), published on a yearly basis by the United Nations Development Programme (UNDP). The HDI combines economic and social factors: life expectancy at birth, adult literacy, total school enrolment and GNI (using a PPP measure). The resulting index is a number that may range from 0 to 1. HDI rankings for selected countries are listed in Table 4.1 and show that quality of life is not always closely related to per capita income. Equatorial Guinea has a high GNI due to oil wealth ($19,780) but a relatively low HDI (0.655), in part related to poor life expectancy at birth (43 years). Cuba has a low GNI but has a comparatively high HDI (0.817), related to achievements in education and health care. The HDI is a relative index, and it is important to note that 50% of nations will always rank at the 0.5 level or below (Sanford & Sandhu, 2003). The relative position in the HDI table is of more practicalReview importance than the HDI figure itself. Countries with an HDI of 0.8 or more typically meet conventional expectations of a 'developed' country, and have achieved high levels of development, and those with an HDI between 0.5 and 0.8 (including many of the former Soviet and east European states) exhibit moderate development. Another common Audiology: A Developing Country Context 9

working definition of developing countries, in this case “countries with low human development”, includes all those with a HDI of less than 0.5.

Table 1. Development Indices for Selected Countries 2007

Country Gross Purchasing Gini Index Human Quality- National Power Development of-life Income Parity Index (HDI) index (GNI) per (PPP) per ranking capita capita Switzerland 48,230 35,370 0.13 0.947 2 United States 41,400 39,710 0.13 0.944 13 Japan 37,180 30,040 0.17 0.943 17 Ireland 34,280 33,170 0.11 0.946 1 Spain 21,210 25,070 0.31 0.928 10 South Korea 13,980 20,400 0.32 0.901 30 Mexico 6,770 9,590 0.34 0.814 32 Poland 6,090 12,640 0.19 0.858 48 Latvia 5,460 11,850 0.34 0.836 66 Argentina 3,720 12,460 0.22 0.863 40 South Africa 3,630 10,960 0.79 0.658 92 Russian Federation 3,410 9,620 0.14 0.795 105 Thailand 2,540 8,020 0.33 0.778 42 Dominican Republic 2,080 6,750 0.38 0.749 79 China 1,290 5,530 0.37 0.755 60 Ukraine 1,260 6,250 0.29 0.766 98 Indonesia 1,140 3,460 0.32 0.697 71 Zimbabwe ≤ 825# 2,180 0.30 0.505 111 India 620 3,100 0.56 0.602 73 Yemen* 570 820 0.73 0.489 not ranked Viet Nam 550 2,700 0.28 0.704 61 Tanzania 330 660 0.41 0.418 109 Cambodia* 320 2,180 0.28 0.571 not ranked Uganda* 270 1,520 0.50 0.508 101 Ethiopia* 110 810 0.83 0.367 not ranked * Least developed nations # estimate.

Another measure of social well-being is the manner in which income is distributed within a country. One commonly quoted index is the Gini index of inequality, or Gini coefficient. This statisticReview ranges from 0 (income distributed with complete equality) to 1 (income distribution “perfectly unequal”). The Gini index may be similar for countries that have very different income levels (for example, Italy and Sri Lanka both have a Gini coefficient of 0.23), indicating that there is no simple, direct relationship between GNI and income 10 Bradley McPherson distribution. For professionals in developing countries the Gini index is, however, useful. A high Gini coefficient in a country with a low GNI (for example, Nigeria with a Gini index of 0.53 and a GNI of $390 per person) suggests that there will be a proportion of the population with the financial resources to access developed nation standards of hearing health care services, along with a majority of people for whom such access is not generally possible. The current Gini index for a sample of developed and developing countries is shown in Table 1. These rankings can be found in the UNDP Human Development Report (and at http://www.undp.org/) and are updated annually. Many other rankings have also been devised and published, based on factors such as economic freedom (Miles, Feulner & O’Grady, 2005), corruption (Transparency International, 2006), freedom of the press (Reporters Without Borders, 2006), environmental quality (included in the “General Progress Indicator”, The Australia Institute, 2006), health quality (such as infant and child mortality, and life expectancy indices; World Bank, 2005) and overall quality of life. The Economist quality-of-life index ranks 111 states based on nine factors (Kekic, 2004). These variables are material well-being, health, political stability and security, family life, community life, climate and geography, job security, political freedom and gender equality. Quality-of-life rankings for selected countries are shown in Table 1.

Table 2. List of Least Developed Countries in 2006

1 Afghanistan 26 Madagascar 2 Angola 27 Malawi 3 Bangladesh 28 Maldives 4 Benin 29 Mali 5 Bhutan 30 Mauritania 6 Burkina Faso 31 Mozambique 7 Burundi 32 Myanmar 8 Cambodia 33 Nepal 9 Cape Verde 34 Niger 10 Central African Republic 35 Rwanda 11 Chad 36 Samoa 12 Comoros 37 São Tomé and Principe 13 Democratic Republic of the Congo 38 Senegal 14 Djibouti 39 Sierra Leone 15 Equatorial Guinea 40 Solomon Islands 16 Eritrea 41 Somalia 17 Ethiopia 42 Sudan 18 The Gambia 43 Timor-Lesté 19 Guinea 44 Togo 20 Guinea-Bissau 45 Tuvalu 21 HaitiReview 46 Uganda 22 Kiribati 47 United Republic of Tanzania 23 Lao People’s Democratic Republic 48 Vanuatu 24 Lesotho 49 Yemen 25 Liberia 50 Zambia Audiology: A Developing Country Context 11

Least Developed Countries

Non-industrialized nations can also be categorized as least developed countries (LDCs), usually based on their rankings for GNI and certain other factors. These are countries that in no sense of the word can presently be regarded as “developing”. A widely used classification is that of the United Nations, which identifies LDCs using three criteria: (a) low income – under $750 GNI per capita; (b) human resource weakness index based on indicators of nutrition, health, education and adult literacy; and (c) economic vulnerability index, calculated from data on instability of agricultural production and exports, share of manufacturing and service industries in GNI, diversity of exports, size of the economy and the effects of natural disasters. A list of current LDCs according to UN criteria are shown in Table 2. This classification is a very important one as many aid agencies target funding to countries that are “least developed” as defined by the UN. It should be kept in mind that countries may “graduate” from LDC status. Botswana has already done so and it is expected that Equatorial Guinea, Kiribati, Tuvalu and Vanuatu may do so in the near future.

IN WHAT WAYS ARE DEVELOPING COUNTRIES DIFFERENT?

Developing nations may be defined in various ways but all criteria in some way acknowledge low national income as a key factor. Low GNI is an indicator of widespread poverty, inequality and unemployment/underemployment. Developing countries, particularly least-developed states, generally struggle to provide minimum levels of education, health, housing and food to their citizens. In the developing nations of sub-Saharan Africa, 75% of the population lives on less than $2 per day (World Bank, 2005). At times developing countries have serious problems in maintaining a cohesive, functioning nation-state. Poverty and the effects of poverty impact on every area of a society, including hearing health care. Often developing countries share features that are not common in industrialized societies, such as a highly diverse ethnic/linguistic composition, limited physical resources and large rural-based populations, that create issues that need careful consideration by audiologists and other professionals. Some of the major features that make developing countries different to the developed world are highlighted below.

Agricultural Employment and Mainly Rural Populations

At the start of the 20th century over 40% of workers in the United States were involved in agricultural occupations (Ruben, 2003). Today, less than 1% of American workers are directly employed in agriculture. This is an outcome of the industrialization-development process. However, developing countries are still often heavily dependent on agriculture for economic survivalReview and the majority of workers and their families are based in rural areas. More than 65% of the population of LDCs is rural, compared to less than 27% in developed economies, and 58% of the workforce is agricultural (Todaro & Smith, 2006). Rural people are generally very much poorer than urban citizens, with an urban elite that derives a large 12 Bradley McPherson proportion of the national income. For example, in Ghana the incidence of poverty is 2% in the capital city, Accra, but 70% in the rural savannah (World Bank, 2005).

Young, Rapidly Growing Populations

As mentioned in the introduction to this chapter, many developed economies are now in transition to long-term population declines. The population of the European Union is projected to fall by 20 million by 2050. The population of Japan is predicted to decrease by 18 million, or 14%, by the same date. The opposite trend is apparent in many, but not all, developing states. The Indian population is expected to increase by 55% by 2050, making India the world’s most populous nation (Population Reference Bureau, 2006). Yemen, a nation with least-developed status, is projected to increase its population by more than 30 million– or 243%– by 2050. The population of sub-Saharan Africa will increase by perhaps 300 million by 2020. All these demographic projections are based on average fertility rates– lifetime births per woman. Fertility rates change over time and not all the projections mentioned may be met. However, fertility levels declined rapidly in many countries in the 1980s and 1990s and are at an average of 3.0 children per woman in developing countries. The rate of decline slows or stalls when nations reach lower fertility levels (Population Reference Bureau, 2006). Hence it is very likely that the developing world will have by far the largest share of the world’s children and young adults in the near future. Within developing countries populations are usually already skewed towards the young. Only 3% of West Africans are aged 65 years or more whereas 44% of the population is less than 15 years of age. In North America the percentages are 12% and 21%, respectively.

Ethnic and Linguistic Diversity

South Africa is a developing country with a population of 46 million people. Within South Africa there are eleven official languages, comprising English, Afrikaans and nine indigenous languages. This reflects the rich ethnic diversity found in many developing countries, where often a number of different tribal or religious groups may live in the same region or the same village. In many developing countries to be bilingual or trilingual is the norm (Kyiaga & Moores, 2003), unlike the majority of developed states where one national language prevails. Also, the “national” language in many developing economies may be a legacy of a previous colonial administration and only be used for communication by an educated elite in the society. Ethnic diversity may be a force for positive good within societies where majority and minority groups live a relatively harmonious existence. However, of the LDCs listed in Table 4.2, the majority are “fragile states” which have experienced serious ethnic conflict leading to political and social instability over the past twenty years. Such conflicts lead to lost opportunities for improved standards of living for the entire nation. Resolving competingReview needs and demands in a diverse society requires resources that are often lacking in developing states.

Audiology: A Developing Country Context 13

Limited Access to Education

Universal literacy is a long-established fact in the developed world. For nations with high and medium HDI rankings literacy rates are usually within the range of 80-90%. For developing countries literacy rates are typically much lower, particularly for women and for those living in rural areas. In Pakistan, 64% of urban boys complete primary school and only 50% of urban girls. Forty-two percent of rural Pakistani males complete primary school and 17% of rural females (World Bank, 2005). The overall literacy rate in Pakistan is 49% of those aged 15 years and older. Rates in some developing countries are far lower, with 38% of Gambian and 26% of Chadian citizens literate. Approximately 20% of the world’s children never experience any formal schooling (Grigorenko & O’Keefe, 2004). Children with disabilities compete for scarce educational resources with their able peers in developing nations. Statistics on the numbers of children with substantial degrees of hearing loss attending school in developing countries are lacking, although a number of excellent educational programs have been established (Moulton & Chinn, 2002).

Heavy Burden of Disease

One of the main consequences of low income in developing countries is poor health. Life expectancy, a key index of community health status, in low income developing countries still averages only 58 years, compared to 64 years among all developing nations and 78 years in industrialized countries (World Bank, 2005). Infant mortality rates (the number of children who die before their first birthday per 1,000 live births) also remain extremely high in many developing countries. The current life expectancy and infant mortality rates for selected countries are shown in Table 3. In addition to poor overall levels of health and health care, developing countries also must attempt to cope with diseases that are uncommon in the developed world and usually gain little international attention or resources. These include malaria, Chagas disease, lymphatic filiariasis, leprosy, and sleeping sickness (African trypanosomiasis). These tropical diseases cause especially high levels of physical and social impairment in developing countries, particularly amongst the poorest sectors in a community (WHO, 2005). The global tragedy of human immunodeficiency virus/ acquired immune deficiency syndrome (HIV/AIDS) has disproportionately affected the developing world. It is estimated that 39 million people now live with HIV infection (WHO, 2005). Of these people, over 90% live in developing countries (World Bank, 1997). AIDS is now the leading cause of death in sub-Saharan Africa and is prevalent at high rates in the Caribbean and some countries in the Asia-Pacific region. HIV/AIDS creates enormous strains on under-resourced health care systems and has profound social costs. In countries with very high HIV/AIDS prevalence rates, the number of orphans under 15 years of age can be as high as 17% of all children (WHO, 2005). Many of these children come from families affected by this pandemic, 12 million childrenReview in sub-Saharan Africa alone (UNAIDS, 2006).

14 Bradley McPherson

Table 3. Health Development Indices for Selected Countries

Country Life Infant Country Life Infant expectancy mortality expectancy mortality at birth (per 1000 at birth (per 1000 (years) live births) (years) live births) Switzerland 80.5 4 Dominican 67.2 29 Republic United States 77.4 7 China 71.6 30 Japan 82.0 3 Ukraine 66.1 15 Ireland 77.7 6 Indonesia 66.8 31 Spain 79.5 4 Zimbabwe 36.9 78 South Korea 77.0 5 India 63.3 63 Mexico 75.1 23 Yemen* 60.6 82 Poland 74.8 6 Viet Nam 70.5 19 Latvia 71.6 10 Tanzania 46.0 104 Argentina 74.5 17 Cambodia* 56.2 97 South Africa 48.4 53 Uganda* 47.3 81 Russian 65.3 16 Ethiopia* 47.6 112 Federation Thailand 70.0 23 * Least developed nations.

AUDIOLOGY IN DEVELOPING COUNTRIES

All of the factors mentioned in the previous section effect the ways that audiological services can be provided in developing economies. A division of hearing health care into four major activities is often made: preventive programs, screening programs, diagnostic services and rehabilitative hearing health care. Hearing health care providers need to consider many factors associated with work in developing countries, whatever type of work they are involved in. In this section two actual audiology programs in developing countries are discussed in relation to development issues.

The Gambian Hearing Health Care Project

The Gambia is a small West African nation of 1.5 million people. The country has LDC status with the United Nations and has a GNI of $290. The economy has for the past quarter century been based on agriculture (primarily peanut production) and tourism. Average life expectancy Reviewis 52 years for men and 55 years for women. Literacy levels are low, as were mentioned in the previous section. At present, the country is guided by a civilian constitution, reinstated in 1996 after two years of military rule. The economic infrastructure is poor. Banjul, the capital, experiences power cuts of up to 16 hours per day. Audiology: A Developing Country Context 15

In the early 1980s, The Commonwealth Society for the Deaf conducted a large scale survey of the prevalence of childhood hearing loss in The Gambia. The survey was completed over two years and involved population sampling in eight of the country’s local government districts (McPherson & Holborow, 1985). The project involved more than a simple count of hearing impairment. The survey team also attempted to discover the etiology of hearing loss in Gambian children, establish an ongoing audiology and primary ear health care clinic in the main government hospital, train local personnel in audiology and audiometry, and support a newly established school for the deaf near Banjul. The survey results found that the prevalence of severe to profound childhood hearing loss was double the rate of developed countries and provided new information on the causes of hearing loss in West Africa. Preventable infections such as meningococcal meningitis were found to be a major cause of childhood deafness and the project team advised a primarily preventive approach to reducing childhood hearing loss in The Gambia. The audiology clinic established during this time continued to function for a number of years, directed by Gambian personnel trained locally and in the United Kingdom. Equipment included otoscopes, audiometers and tympanometers. Some ongoing support was provided by the Commonwealth Society for the Deaf and Scandinavian aid agencies. The survey identified many children who later became some of the first student cohort at St John’s School for the Deaf, which was then under construction. The clinical infrastructure left by the project was not sustainable. Despite government support, in the form of salaries for the audiology and audiometry personnel, the hospital clinic had a fragile base. With only two trained staff, personnel transfers or resignations caused the clinic’s closure by the mid 1990s. This also reflects a global shortage of health care personnel that leads to further scarcity in developing countries. For example, another West African country, Ghana, saw over 3,000 nurses emigrate in the 1998 to 2003 period, while only 56% of these emigrants could be replaced by newly trained graduates (Munjanja, Kibuka & Dovlo, 2005). Audiologists are equally likely to emigrate for economic reasons, as there is a shortage of trained hearing health care professionals in many developed countries. The main Gambian hospital still had an audiometer in 2004 (Garner, 2005) but it had remained uncalibrated for a long period. No calibration facilities exist in the country and audiological equipment is usually sent to Europe for repair and calibration. Costs involved are high by local standards, as are the costs of new equipment purchase. A new diagnostic audiometer may cost a multiple of 15 times average annual income. This makes clear that future resources must be carefully considered prior to setting up an audiological facility in a developing country. Often, unforeseen barriers to hearing health care development include high customs tariffs for imported medical equipment (Bate, Tren & Urbach, 2006). For example, India taxes non-local hearing aids at 15.3% of the import price. Long-term, the Gambian Hearing Health Care Project did leave a number of positive legacies, aside from its scientific contribution. The country’s only school for the deaf is still functioning and now educating 150 pupils (Garner, 2005). The project disseminated information concerning hearing loss and treatment for hearing disorders to thousands of Gambians. Many individuals were treated with simple medicines by project workers and later by hospital Reviewpersonnel (Holborow & McPherson, 1986). The methods used by the survey team to successfully visit isolated rural regions of The Gambia later helped to inspire the Commonwealth Society for the Deaf to develop mobile hearing assessment and treatment clinics which have since been used in four other developing African nations (Sound Seekers – The Commonwealth Society for the Deaf, 2006). 16 Bradley McPherson

All Ears Cambodia

Cambodia, like The Gambia, is an LDC with low life expectancy and high infant mortality rates (see Table 4.3). Cambodia has a GNI of $320 (Table 1) and more than two- thirds of the population lives on less than $2 per day and one third lives on less than $1 per day (World Bank, 2005). This level of disadvantage is partly due to many years of political instability. One hospital in Cambodia, in the capital Phnom Penh, has an audiology unit capable of assessment and provision of hearing aids (Vaughan, 2005). All Ears Cambodia is a local non-governmental organization based in Phnom Penh that commenced in 2003. All Ears Cambodia seeks to help prevent hearing disorders within the country and to support treatment and rehabilitation activities. The organization has developed an independent, diagnostic and rehabilitative audiology clinic and supports the sole government audiology clinic through contributions of personnel and through training programs. This aid organization understands the need to reach rural as well as urban communities and has outreach programs in two provincial regions of Cambodia (Vaughan, 2005). Cambodia is a predominantly rural society; only about 18% of Cambodians live in urban areas. Health care and education workers in Cambodia are targeted for delivery of basic training in ear health care and in the effects of hearing loss. Adult literacy is comparatively high in Cambodia, at 74%, and programs that serve to increase an understanding of hearing health will have a wide audience. All Ears Cambodia also realises that to achieve sustainability the organization must generate income. It does this by charging fees for certain services, such as screening hearing in private schools and hearing aid prescription and fitting in the government hospital. In this way the organization may create a stable base for a long-term, positive role in Cambodia and improve the lives of many Cambodians with hearing disorders.

GLOBAL DEVELOPMENTS – IMPLICATIONS FOR AUDIOLOGY

Much of the discussion so far in this chapter has focused on the negative issues that surround developing countries. These certainly loom very large in the minds of those who work in or for hearing health care in developing countries. However, many positive trends can also be seen in general, and in health care specifically, in developing countries. Agencies such as All Ears Cambodia now exist in many countries, often promoted and sustained by individuals in developing nations with assistance from partners in the industrialized world. Projects such as the Gambian survey and service scheme are also to be found throughout the world. A wide range of funding agencies, foundations and individuals support the strengthening of hearing health care. Some of these are noted in Chapter 12 of this book. Two major, global developments that will impact on audiology in developing countries are discussed below.

United NationsReview Millennium Development Goals

In 2000, the member states of the United Nations made a commitment to eliminate extreme poverty and improve the health and social welfare of the world’s poorest people within 15 years. This commitment was known as the Millennium Declaration and from the Audiology: A Developing Country Context 17

declaration were developed eight time-linked goals (WHO, 2005). Achievement of many of these goals directly or indirectly will reduce the prevalence of hearing loss. Goal 4 aims to reduce child mortality and a key health indicator of success in achieving this goal is an increase in the proportion of children immunized against measles. Measles is a well-known cause of hearing loss in developing countries (Olusanya, 2006; Sharma, Dahal & Khadka, 2004). Immunization is a highly cost-effective strategy to reduce infant mortality and childhood hearing loss (Edejer et al., 2005). Millennium Goal 5 also impacts on hearing impairment. This goal is to substantially improve maternal health and a key health indicator is to increase the proportion of births attended by skilled health personnel (doctors, nurses or midwives). Better maternal health care is likely to lead to a reduction in the numbers of neonates with anoxia or birth trauma and hence improve hearing health outcomes in infants. Maternal and perinatal disorders, including birth trauma and asphyxia, may cause up to 20% of prelingual hearing loss (Smith, 2001). Millennium Goal 6 calls on member states to combat HIV/AIDS, malaria and other disease. Some developing countries have already achieved a reduction in their HIV/AIDS prevalence rates, including Kenya, Cambodia and Thailand (UNAIDS, 2006). Both HIV/AIDS (McNeilly, 2005; Newton, 2006) and malaria (Hinchcliffe & Prasansuk, 2006; Mackenzie, 2006) are responsible for many cases of hearing loss. Work by developing countries and the support of the developed world (through development assistance, debt relief, access to essential medicines and technology transfer) towards the Millennium Goals may lead to a significant reduction in the burden of hearing impairment in the developing world (WHO, 2004a).

World Health Organization Initiatives

In May 1995, the Forty-eighth World Health Assembly, passed resolution WHA 48.9. This resolution dealt with the needs of the many millions of adults and children with hearing loss. After stating that hearing loss was “largely preventable”, the preamble of the resolution went on to state that hearing loss was “a particularly serious obstacle to optimal development and education, including language acquisition” and noted “the persistent inadequacy of resources for hearing impairment prevention, despite the increasing commitment of international nongovernmental organizations”. The resolution (WHO, 1995) is important for audiologists because it urged member states to:

(1) prepare national plans for the prevention and control of major causes of avoidable hearing loss, and for early detection in babies, toddlers, and children, as well as in the elderly, within the framework of primary health care; (2) take advantage of existing guidelines and regulations or to introduce appropriate legislation for the proper management of particularly important causes of deafness and hearing impairment, such as otitis media, use of ototoxic drugs and harmful exposureReview to noise, including noise in the work environment and loud music; (3) ensure the highest possible coverage of childhood immunization against the target diseases of the Expanded Programme on Immunization and against mumps, rubella and (meningococcal) meningitis whenever possible; 18 Bradley McPherson

(4) consider the setting-up of mechanisms for collaboration with nongovernmental or other organizations for support and coordination of action to prevent hearing impairment at country level, including the detection of hereditary factors, by genetic counselling; (5) ensure appropriate public information and education for hearing protection and conservation in particularly vulnerable or exposed population groups.

WHO, through this resolution, committed itself to fully supporting these goals. WHO has worked steadily since resolution WHA 48.9 to collect reliable data on the prevalence of hearing loss in developing countries and to develop strategies for the prevention of hearing impairment (Djelantik-Soejoto, 2004; Smith, 2001). Recently, WHO has also carefully considered the appropriate means to provide hearing aids in developing nations and developed guidelines for the provision of hearing technology (WHO, 2004b). Working in conjunction with the Christian Blind Mission, the WHO has supported the publication of high quality health education materials in the area of hearing loss and hearing handicap (WHO, 2006) for village health workers. A new independent international agency, WWHearing - World Wide Hearing Care for Developing Countries, is also being fostered by WHO and the Christian Blind Mission. WWHearing now sponsors pilot projects in six developing countries that demonstrate a variety of service delivery models (Nemes, 2005). The project procedures call for measures of client satisfaction, the impact of the service on individual quality of life as well as cost effectiveness. After learning from pilot project outcomes, WWHearing plans to set up full scale service delivery centers, through local partnerships in developing countries (Garms & Smith, 2004). Throughout the developing world dedicated professionals are working to improve hearing health care services. Countries such as Angola, China, Dominican Republic, India, Mozambique, Viet Nam — to name a few — are benefiting from improved audiological clinics and expanded hearing aid fitting programs. Audiologists and other professionals now have access to funding from a variety of non-government agencies to support prevention, treatment and rehabilitation programs. With greater international focus on hearing impairment, the future for many children and adults with hearing loss in developing nations is more positive than it has ever been.

REFERENCES

Bate, R., Tren, R. & Urbach, J. (2006). Still taxed to death: An analysis of taxes and tariffs on medicines, vaccines and medical devices. Washington, DC: American Enterprise Institute-Brookings Joint Center for Regulatory Studies. Cheng, W.T., Olea, T.C.M. & Marzan, J.C.B. (2002). Speech-language pathology in the Philippines: Reflections on the past, perspectives for the future. Folia Phoniatrica et LogopaedicaReview 54, 79-82. Djelantik-Soejoto, B. (2004). World Health Organization to address the problems of deafness and hearing impairment on a larger scale. In J.Suzuki, T. Kobayashi & K. Koga (eds.) Hearing Impairment. An Invisible Disability. How You Can Live With a Hearing Impairment, pp. 322-328. Tokyo: Springer-Verlag. Audiology: A Developing Country Context 19

Garms, C. & Smith, A. (2004). Alliance faces worldwide realities of hearing loss. Hearing Health 20 (2) http://www.drf.org/hearing_health/archive/2004/sum04_ alliancefacesrealities.htm Garner, M. (2005). Deaf children in the Gambia. ENT News, 14(5), 62-63. Grigorenko, E.L. & O’Keefe, P.A. (2004). What do children do when they cannot go to school? In R. J. Sternberg & E. L. Grigorenko (eds.) Culture and competence: Contexts of life success, pp. 23-53. Washington, DC: American Psychological Association. Edejer, T.T., Aikens, M., Black, R., Wolfson, L., Hutubessy, R., & Evans, D.B. (2005). Cost effectiveness analysis of strategies for child health in developing countries. British Medical Journal, 331, 1177-1182. Hinchcliffe, R. & Prasansuk, S. (2006). Infectious diseases and hearing in the tropics. In Newton, V.E. & Vallely, P.J. (eds.) Infection and hearing impairment, pp. 217-237. Chichester: John Wiley & Sons Holborow, C. & McPherson, B. (1986). Simple treatment for the infected ear. Tropical Doctor, 16, 31-32. Karanth, P. (2002). Four decades of speech-language pathology in India: Changing perspectives and challenges of the future. Folia Phoniatrica et Logopaedica, 54, 69-71. Kekic, L. (2004). The World in 2005, p. 86. London: The Economist Newspaper Limited. Kiyaga, N.B. & Moores, D.F. (2003). Deafness in sub-Saharan Africa. American Annals of the Deaf, 148(1), 18-24. Kumar, S. (2001). WHO tackles hearing disabilities in developing world. Lancet, 358(9277): 219. Mackenzie, I.J. (2006). Malaria and deafness. Community Ear and Hearing Health, 3,14-15. Madriz, J.J. (2001). Audiology in Latin America: hearing impairment, resources and services. Scandinavian Audiology, 30 Suppl 53, 85-92. McNeilly, L.G. (2005). HIV and communication. Journal of Communication Disorders, 38, 303-310. McPherson, B. & Holborow, C. (1985). A study of deafness in West Africa: The Gambian Hearing Health Project. International Journal of Pediatric Otorhinolaryngology, 10, 115- 135. Miles, M.A., Feulner, E.J. & O’Grady, M.A. (2005). 2005 Index of Economic Freedom. Washington, DC: Heritage Foundation and Dow Jones & Company, Inc. Mohr, P.E., Feldman, J.J., Dunbar, J.L., McConkey-Robbins, A., Niparko, J.K., Rittenhouse, R.K. & Skinner, M.W. (2000). The societal costs of severe to profound hearing loss in the United States. International Journal of Technology Assessment in Health Care 16(4): 1120-1135. Moulton, R. & Chinn, K. (2002). International deaf education teacher-training projects. Journal of International Special Needs Education, 5, 36-40. Munjanja, O.K., Kibuka, S., & Dovlo, D. (2005). The nursing workforce in sub-Saharan Africa. The Global Nursing Review Initiative, issue paper 7. Geneva: International Council of Nurses. Nemes, J. (2005).Review Some imagine a world where hearing care is available to all. Hearing Journal, 58(2), 19-25. Newton, P.J. (2006). The causes of hearing loss in HIV infection. Community Ear and Hearing Health, 3,11-14. 20 Bradley McPherson

Olusanya, B. (2006). Measles, mumps and hearing loss in developing countries. Community Ear and Hearing Health, 3,7-9. Population Reference Bureau. (2006). http://www.prb.org/ Reporters Without Borders. (2006). Worldwide press freedom index 2005. http://www. rsf.org/rubrique.php3?id_rubrique=554 Ruben, R.J. (2003). Valedictory—why pediatric otorhinolaryngology is important. International Congress Series, 1254, 69-80. Sanford, J.E. & Sandhu, A. (2003). Developing countries: definitions, concepts and comparisons. New York: Novinka Books. Sharma, B., Dahal, M.P. & Khadka, B. (2004). Hearing impairment in Nepal. In J.Suzuki, T. Kobayashi & K. Koga (eds.) Hearing Impairment. An Invisible Disability, pp. 70-77. Tokyo: Springer-Verlag. Smith, A.W. (2001). WHO activities for prevention of deafness and hearing impairment in children. Scandinavian Audiology, 30 Suppl 53, 93-1000. Sound Seekers – The Commonwealth Society for the Deaf. (2006). http://www.soundseekers.org.uk Swanepoel, D. (2006). Audiology in South Africa. International Journal of Audiology, 45, 262-266. Stratford, B. & Ng, H. (2000). People with disabilities in China: changing outlook-new solutions-growing problems. International Journal of Disability, Development and Education, 47(1), 7-14. The Australia Institute. (2006). Genuine Progress Indicator. http://www.gpionline.net/index. htm Todaro, M.P. & Smith, S.C. (2006). Economic development. 9th ed. Boston: Pearson Addison Wesley. Transparency International. (2006). http://ww1.transparency.org/ UNAIDS. (2006). 2006 Report on the global AIDS epidemic. New York: Author. Vaughan, G. (2005). Audiology services in Cambodia. Community Ear and Hearing Health, 2,9-11. World Bank. (1997). Confronting AIDS: Public priorities in a global epidemic. New York: Oxford University Press. World Bank. (2005). World Development Report 2006. New York: Oxford University Press. World Health Organization. (1995). WHA48.9 Prevention of hearing impairment. http://www.who.int/pbd/publications/wha_eb/wha48_9/en/print.html World Health Organization. (2004a). WHO and the Millennium Development Goals. Geneva: WHO. World Health Organization. (2004b). Guidelines for hearing aids and services for developing countries. 2nd ed. Geneva: WHO, Prevention of Blindness and Deafness. World Health Organization. (2005). Health and the Millennium Development Goals. Geneva: WHO. World Health Organization. (2006). Primary Ear and Hearing Care Training Resource. Geneva:Review WHO. http://www.who.int/pbd/deafness/activities/hearing_care/en/index.html Zheng, V.W. & McPherson, B. (2005). Audiology in China: then and now, Audiology Now, 21, 19-21.

Chapter 3

DEMOGRAPHICS OF HEARING LOSS IN DEVELOPING COUNTRIES

Andrew W. Smith* International Centre for Eye Health, London School of Hygiene and Tropical Health, London, United Kingdom

ABSTRACT

The burden of hearing impairment and disability is high and growing. Moderate or worse hearing impairment affects 278 million people in the world and adult onset hearing impairment ranks 3rd amongst contributors to Years lived with Disability, a component of the Global Burden of Disease. Hearing impairment and disability have profound individual, societal, and economic consequences. In high income countries, hearing impairment has been shown to have very large financial costs and these are also likely in low and middle income countries. Hearing impairment is a cause and consequence of poverty, especially in low and middle income countries. Despite the size and effects of the burden, there are widespread deficits in awareness, programmes and resources in relation to hearing impairment in developing countries. A key need for planning and raising awareness is the assessment of the existing situation including the collection of population-based data on prevalence, causes, and needs. This chapter will address the estimation of hearing impairment and disability in populations, and why this is important. It will describe the various methods in use and the difficulties in using them in developing countries. An overview of recent World Health Organization (WHO) estimates and why these are increasing will be followed by a review of available data in developing countries. The collection of data should never be an end in itself, so using the results of surveys will be demonstrated for the key tasks of raising awareness, and programme development. The value ofReview accurate data for the construction of regional and global databases, and contribution to classification, burden estimates and economic analyses, especially from the point of view of WHO, will be emphasized.

* Correspondence: [email protected] 22 Andrew W. Smith

The final section will attempt to assess future needs and developments in this field.

INTRODUCTION

In this chapter, the term hearing loss, used by itself, denotes any or all levels of severity of hearing difficulty. These levels of hearing impairment comprise mild (26–40 decibel hearing level, dBHL), moderate (41–60 dBHL), severe (61–80 dBHL), and profound (81 dBHL or greater). The term deafness denotes profound hearing impairment (World Health Organization (WHO), 1991, 1997). Disabling hearing impairment in adults is defined as “a permanent unaided hearing threshold level for the better ear of 41 dB or greater; for this purpose, the hearing threshold level is to be taken as the better ear average hearing threshold level for the four frequencies 0.5, 1, 2, and 4 kHz.” Disabling hearing impairment in children under the age of 15 years is defined as a permanent, unaided hearing threshold level for the better ear of 31 dB or greater; for this purpose, the hearing threshold level is to be taken as the better ear average hearing threshold level for the four frequencies 0.5, 1, 2, and 4 kHz (WHO, 1997). This categorization of hearing impairment (Box 1) was originally developed for a speech- based performance test where pure-tone audiometry was not available and the ISO dB equivalents were later included (WHO, 1986). This definition of disabling hearing impairment is currently used in WHO surveys1 and in the estimation of global deafness and hearing impairment for the global burden of disease rankings.

Table 1. Main Causes of Hearing Loss, by Proportion of Total Burden

High proportion Moderate proportion Low proportion Genetic causes Excessive noise Nutritionally related Otitis media Ototoxic drugs & chemicals Trauma-related Presbycusis Antenatal & perinatal problems Menière’s disease Infectious causes Tumors Wax and foreign bodies Cerebrovascular disease

Hearing loss is grouped according to International Classification of Diseases and Related Health Problems, 10th revision, version for 2003 (ICD-10) (WHO, 2003) into conductive and sensorineural loss and other hearing loss, ICD-10 codes 90–91. The main causes are shown in table 1 according to the proportion that these contribute to the total burden (Cook et al., 2006; WHO, 1986).

Review

1 In some surveys in the field and as recommended by the WHO Ear and Hearing Disorders Survey Protocol, testing was only done at 1,2 & 4 kHz but not at 0.5 kHz, because of the likelihood of false-positive results when 0.5 kHz is included. Demographics of Hearing Loss in Developing Countries 23

Box 1. WHO Grades of hearing impairment

GRADES OF HEARING IMPAIRMENT

Grade 0 25 dB or less No/slight problems None Hears whispers

Grade 1 26 - 40 dB Hears/repeats words Slight in normal voice at lm

Grade 2 Child 31 - 60 dB Hears/repeats words Moderate Adult 41 - 60 dB in raised voice at 1m Disabling Grade 3 61 - 80 dB Hears words shout- hearing Severe ed into better ear impairment Grade 4 81 dB or more Cannot hear/under- Profound stand shouted voice [Average 0.5, 1, 2, 4 kHz in better ear]

1. ESTIMATION OF HEARING IMPAIRMENT AND DISABILITY IN POPULATIONS

Why Is it Important?

Hearing loss is a chronic and often lifelong disability that, depending on the severity and frequencies affected, can cause profound damage to the development of speech, language, and cognitive skills in children, especially if commencing prelingually. That damage, in turn, affects the child’s progress in school and, later, his or her ability to obtain, keep, and perform an occupation. For all ages and for both sexes, it causes difficulties with interpersonal communication and leads to significant individual social problems, especially isolation and stigmatization. All these difficulties are much magnified in developing countries, where there are generally limited services, few trained staff members, and little awareness about how to deal with these difficulties. In addition to its individual effects, hearing loss makes a large contribution to the burden of disease (see section 2, this chapter) and it substantially affects social and economic development in communities and countries. Ruben (2000), taking into account rehabilitation, special education, and loss of employment, estimated the cost to the U.S. economy in 1999 of communicationReview disorders (hearing, voice, speech, and language disorders) at between US$176 billion and US$212 billion (2004 dollars; 2.5–3 percent of the gross national product of the United States in that year). Hearing loss accounted for about one-third of the prevalence of these communication disorders. A 2005 study in Australia showed that the real financial costs of hearing loss were approximately US$9.6 billion, (1.4% of gross domestic 24 Andrew W. Smith product for the country). 57% of the costs were due to productivity loss (Access Economics, 2006). Accurate measurement of the size of the problem of hearing loss in populations will enable comparison of the burden in the same population at different times or different populations at the same time, and hence help to assess the progression of the impairment and the effectiveness of interventions. These data are essential for the prioritization of interventions, selection of strategies for implementation, and monitoring of programmes both at national and global level. The information will also form the foundation of economic analysis studies which can show the huge costs, and perhaps more importantly compare the cost-effectiveness of different interventions against hearing impairment, and in comparison to interventions against other health conditions. Resources to act against hearing loss are much more likely to be allocated by Governments if the condition is shown to be a huge cost to society and for which there are comparatively cost-effective interventions.

Methods

To help to address this need for accurate data, especially from developing countries where there is little information available, WHO in 1999 published a protocol, developed by an expert group, for a standard method of conducting population-based, random sample surveys on the prevalence, causes and needs for ear and hearing disorders (WHO, 1999). The protocol comprises a section on survey methods, a questionnaire to record information on demographics, audiometry (by pure-tone audiometry and more recently by testing otoacoustic emissions, OAE, and auditory brain-stem response, ABR), ear examination, family history, diagnosis of ear diseases and cause of hearing impairment and actions needed, and a set of coding instructions to go with the questionnaire. The protocol recommends a cluster sampling method which may be multi stage, and stratified, with a minimum sample size of approximately 6,000 individuals randomly sampled from 30 clusters. Rigorous quality- control methods are recommended. The method can be used at national or district level. It is strongly recommended that the data that are collected and the actual methods of collection, as set out in the ear examination form (part 2 of this protocol) and coding instructions (part 3), should not be changed independently by users of the protocol. If they were changed independently it would not be possible to use the data for inter-country or inter- regional comparisons. If other data are thought to be essential, they could be collected in addition to the data required by the protocol. However, in order to avoid overloading the survey teams, only additional data on topics of immediate interest should be collected and the temptation to collect opportunistic data should be resisted. A survey needs multidisciplinary expertise and the survey investigators should comprise from the outset an epidemiologist and biostatistician as well as an audiologist and otolaryngology specialist. They should all plan the study together from the beginning. The WHO protocol should be adapted to make a specific local protocol with clear objectives since these will determineReview the type, size of the survey and personnel and other resources required. In any survey, it is essential to plan in detail and well in advance all aspects of study design, sample size, personnel required, training, remuneration, resources including vehicles, equipment and supplies, accommodation and subsistence. A smoothly run survey depends on Demographics of Hearing Loss in Developing Countries 25

detailed and properly worked-out timing of all its aspects, and a small pilot study may be needed to provide timing estimates. The protocol will continue to be developed and improved by a process of consultation and field testing, coordinated by WHO.

Difficulties

The data collected by these methods is often time consuming, expensive and sometimes difficult to collect but it is much superior to clinic or school-based data which do not give a true picture in the whole population, and hence are much less useful to health planners and governments. There are particular difficulties in developing countries, due to lack of adequate resources, equipment, and trained staff, and difficulties of access to remote areas. Sampling errors and quality control is one area that is often forgotten in survey work. Sampling error is the difference between the values derived from the sample population and the true values in the population. It is partly due to random sampling error which can only be minimised by increasing the sample size, and non-random errors which are potentially more serious and less easily quantifiable. Non-random errors can be grouped as follows:

(1) Coverage errors. These occur when population elements which are not part of the target population are sampled, or when those that should be part of the sample are not sampled. Non-response due to refusal or unavailability of the subject is also in this category. (2) Observational errors. These are caused by errors in making and recording the observations and can be attributed to observer, respondent or instrument errors. Inter- and intra-observer error should be measured and corrected during the survey. (3) Processing errors. These are mainly clerical errors that occur during coding, entering or analysing the data.

Various quality-control measures can be taken to minimise non-random errors:

1. Sampling units should be clearly defined at all levels within the survey. 2. Clear and detailed training and operations manuals should be developed for each survey. 3. All field staff should be carefully trained under actual field conditions, in all aspects of their duties, and all office staff in data coding and entry. 4. Survey staff should sign each form and enter their survey staff number when they have finished completing the form. This encourages good work and makes checking of records much easier. 5. Inter- and intra-observer variation should be measured and quantified. Thus at the beginning and at several points during the survey, the performance of team members shouldReview be assessed by comparing different team members testing the same subject, and comparing a particular team member testing the same subject on different occasions. 6. Validation of the tests used, both audiometric and otoscopic, should be carried out and their sensitivity and specificity should be measured. This can be done by 26 Andrew W. Smith

comparing a number of subjects, with normal and abnormal hearing or otoscopic findings, with a gold standard. Sensitivity is the proportion of truly abnormal subjects who are found to be so by the survey test, and specificity is the proportion of true normals who are found to be so by the test. 7. Supervisors should make daily checks of that day's mapping and enumeration, and of the completed forms and also make regular, announced and unannounced checks on performance of all survey procedures carried out by survey teams. 8. A sub-sample of households should be re-checked by supervisors on a regular basis. 9. Every effort should be made to find non-responders. There may be a higher prevalence of hearing loss amongst non-responders, and if they are not found the results of the survey could be biased. If subjects are not at home when the team makes its first visit, a second visit should be made at an appropriate, arranged time to find these subjects. 10. Audiometric equipment should be regularly calibrated by a laboratory at the beginning and end of a study, and on a daily basis by team members using self- calibration against their known hearing levels. 11. Supervisors should provide field and office staff with regular feedback of their performance, and provide refresher training if necessary. 12. Data should be double-entered into the computer programme used for entering and analysing the data.

It is also important to consider ethical issues when conducting surveys. From the outset, good relations should be established with community leaders and other prominent people. They will help improve community relations and can often give valuable advice and assistance. Team members must always respect local customs, and schedule visits for the convenience of subjects if possible. For a successful survey it is essential that the community and its leaders understand why the survey is being conducted, what are the benefits for them, and that they give their fully- informed consent. In addition, arrangements must be made for appropriate treatment or referral for survey subjects found to have survey-related or other diseases. The survey should not be started if this cannot be done. However, since the main purpose of the visit is to conduct the survey, there probably will not be time to provide full-scale clinical services at the time of the visit. In any case, such services can only be properly planned by using the full results of the survey. Surveys using the protocol have so far been conducted in the following countries (with prevalence of disabling hearing impairment in parentheses): Oman (2.1%); Indonesia (4.6%); Myanmar, Sri Lanka, India (5.9-8.8%); Nigeria (three states: Akwa Ibom 4.4%, Benue 6.1%, Katsina 7.6%); Viet Nam (three Northern provinces 7.8%, three Southern provinces 4.7%); southern Brazil (Canoas 6.8%); Madagascar (Antananarivo Province 6.9%); and four provinces in China (Jiangsu 6.4%, Sechuan 4.9%, Guizhou 6.1%, Jilin 4.5%). All the surveys included all ages, generally from 6 months of age upwards, except that the most recent surveys (Vietnam,Review Brazil, Madagascar, China) have used oto-acoustic emission testing to include infants younger than 6 months of age. In addition to measuring the burden and assessing the cost and benefits of prevention, this data will be useful to planners at national and regional level to raise awareness about the size Demographics of Hearing Loss in Developing Countries 27

of the problem, to predict needs, to determine programme priorities, to select targets and strategies for prevention, and to monitor and evaluate achievements.

2. SIZE OF THE PROBLEM IN DEVELOPING COUNTRIES

Growing Size of the Problem Worldwide

WHO estimates of the global number of persons with disabling hearing impairment has increased substantially in the last 15 years. This number was originally estimated at 42 million in 1985, and then increased to 120 million in 1995 at the time of the last World Health Assembly Resolution on Prevention of Hearing Impairment (WHO, 1995). The most recent figure is 278 million in the year 2005 which is approximately 4.2% of the world’s population (Mathers, 2006). The increase in the WHO estimates since 1985 is most likely due to a combination of improved diagnosis, earlier detection, longer survival of elderly people who have the highest prevalence of deafness and hearing impairment and probably increased incidence due to causes such as noise-induced hearing loss and ototoxic drugs. Three-quarters of these people have adult-onset hearing loss2. 364 million persons have mild hearing loss, adult and child-onset (See table 2 which shows year 2005 estimates). At least ⅔ of the burden of hearing loss is found in developing countries (WHO, 2001b). This is proportionately slightly less than the proportion of the total population in the developing world and is probably accounted for by the larger numbers of elderly people in the developed world having deafness and hearing impairment. Eighty percent of the burden is found in low and middle income countries as defined by the World Bank (see Annex Table 3).

80 70 India Indonesia Myanamar Sri Lanka 60 50 40 30 20 Prevalence (%) Prevalence 10 0 0-4 5-14 15-29 30-44 45-59 60-74 75+ ALL Age in years

Figure 1. Prevalence of disabling hearing impairment by age in surveys in 4 countries conducted 1998 – 2000 using the WHO Ear and Hearing Disorders Survey Protocol.

2 Review Prevalence of adult onset hearing loss was estimated by subtracting from prevalences at ages 20 and over, the estimated prevalence of hearing loss for teenage children (15-19 years) or the nearest similar age group for which prevalences available. It is assumed that the incidence of adult-onset hearing loss associated with otitis media and other infectious and non-infectious causes included elsewhere in the GBD 2000 cause list is negligible compared to the incidence of adult-onset hearing loss associated with age-related hearing degeneration or noise-induced loss. (Smith, 2006). 28 Andrew W. Smith

Table 2. Estimated global prevalence of hearing loss by sex and level of severity. Note that figures at each level include those in more severe levels (Mathers, 2006)

Severity (dBHTL) Males Females Persons Mild or greater (26+) Prevalence (millions) Adult-onset 241 220 461 Child-onset 92 90 181 Total 332 310 642 Moderate or greater (41+) Adult-onset 106 104 210 Child-onset 33 34 68 Total 140 138 278 Severe or greater (61+) Adult-onset 24 28 52 Child-onset 4 4 7 Total 27 32 59 Profound (81+) Adult-onset 4 5 9 Child-onset 3 3 6 Total 7 8 15

Current Global, Regional and National Estimates

Age Prevalence of disabling hearing impairment increases markedly with age (see figure 1) which is mainly related to the effect of presbyacusis.

Geographical Burden The current shortage of data particularly in developing countries prevents accurate assessment of the distribution of the prevalence and causes geographically by region. This is being addressed by conduct of surveys using the WHO Ear and Hearing Disorders Survey Protocol, the compiled results from which will be made available soon.

Gender Burden Burden Reviewby gender and WHO subregion is shown in Table 5 [Adult-onset hearing loss (41+ dBHTL): age-standardized incidence and prevalence estimates for WHO epidemiological subregions, 2000]. Male/female ratios of age-standardized adult-onset prevalence rates were found to be greater than 1 in most studies in all WHO regions, Demographics of Hearing Loss in Developing Countries 29

(Mathers, Smith, & Concha 2005; Mathers & Smith 2008). This may be related to occupational noise-induced hearing loss differentially affecting men.

Mortality There is evidence that adults with post-lingual onset of deafness have higher mortality than non-deaf adults (Barnett & Franks, 1999). A ten year longitudinal analysis of the USA National Health and Nutrition Examination Survey (NHANES I) survey participants aged 55- 74 years at baseline found that hearing loss predicts mortality: RR = 1.17 (Mui et al., 1998). Other studies have reported that after controlling by age the association disappears and, in any case, no relationship is large enough to show figures greater than 0 in WHO estimates of deaths by cause (WHO, 2004, Annex table 2) and by years of life lost (YLL; Mathers et al., 2005) in any region. A very small number of deaths are recorded for otitis media, 6,000 globally in 2001, but these would be mainly due to infective complications, mostly not directly related to hearing loss.

Prevalence of Child- and Adult-onset HL Estimates of the prevalence of childhood hearing loss up to age 15 years and adult-onset hearing loss from age 20 years (Mathers, et al., 2005) have recently been used to estimate the burden of this disability in adults, according to the 17 WHO sub-regions used in all WHO work on the Global Burden of Disease (see Annex tables 1 & 2). The sources of data on which these estimates are based are shown in table 3 (children) and table 4 (adults). All the surveys in these tables were population-based and used audiometric measurements, (there are relatively few surveys that fulfil these 2 criteria) generally using the WHO definition. Where non-WHO thresholds were used, the prevalence of hearing impairment at the WHO thresholds was interpolated assuming the log of the cumulative prevalence is linear with threshold. This relationship holds reasonably well in most studies. Prevalence rates of disabling hearing impairment were obtained for the 17 WHO subregions by means of a model based on the data from the countries listed in tables 3 & 4. Standardised prevalence rates from country level were used to calculate the sub regional prevalence rates. The prevalence rates from countries in the same WHO subregion were taken as representative data of the sub region. When there were several available data sources, average prevalence rates weighted on sample size were calculated and then used for the sub regional estimates. For sub regions where there were no population-based surveys available, the prevalence rates were estimated to be the same as for other sub regions with similar health level indices. Prevalence of adult onset hearing loss was estimated by subtracting from prevalences at ages 20 and over, the estimated prevalence of hearing loss for teenage children (15-19 years) or the nearest similar age group for which prevalences were available. This prevalence data for adults is shown in figure 2 and table 5. It should be noted that this work is still in an interim phase; as more accurate data becomes available, especially from developing countries, the estimates will be refined and updated. Review

30 Andrew W. Smith

Table 3. Prevalence studies for hearing impairment: children

Country Study Ref. Years Definition used Sample Age range Prevalence population size % Developed Review Davidson Review 41+ dBHL better ear Childhood 0.05 – 0.23 1988 UK Trent Fortnum 1985- 40+ dBHL better ear at 552,558 0-9 0.133 birth region 1997 1993 0.5, 1, 2, 4 kHz prevalence3 USA Atlanta Van 1991-93 40+ dBHL better ear at 255,742 3-10 0.11 Naarden 0.5, 1, 2 kHz 1999 USA NHANES Lee 1996 1982- 31+ dB HL better ear 7,888 6-19 II and 1984 African-Am. 0.78 Hispanic Cuban Am. 1.21 HANES Mexican Am. 0.60 White, non-H. 0.38 USA NHANES Niskar 1998 1988-94 16+, 26+ dB HL at 0.5, 6,166 6-19 0.7 (16+) III 1, 2 kHz better ear 0.4 (26+) Developing Review Davidson Review 41+ dBHL better ear Childhood 0.2-0.42 1988 Thailand Bangkok Prasansuk ? 41+ dBHL better ear 10,242 School age 3.9 schools 2000 2,153 Children 6.1 Rural schools Sierra Leone Panguma Seely 1995 1992 26+, 41+, 61+ dBHL 2,015 5-15 2.58 (26- better ear 40) 0.65 (41- 60) 0.50 (61+) Angola Luanda Bastos 1993 1981-82 31+ dBHL better ear at 1,030 Schoolchildren 2.0 .5, 1, 2 kHz Zimbabwe Primary Jones 1974 1972 31+ dBHL better ear 885 Schoolchildren 3.2 schools, SE highlands Kenya Kiambu Hatcher 1992 31+ dBHL better ear at 5,368 Primary school 2.2 district 1995 2 & 4 kHz age Tanzania Northern Bastos 1995 31+ dBHL either ear at 854 Primary school 3.0 inland .5, 1, 2 kHz age district Severe/profound 0.35 South Africa Poor rural Prescott 1990? 21+, 31+, 41+ dBHL 401 6-13 2.0 (31+) district in 1991 better ear 0.5 (41+) Western Cape Swaziland 1st year McPherson school- 1997 children Saudi Arabia Riyadh Zakzouk 1997 20+dBHL, Air cond at 6421 2m – 12y 7.7 2003 .25-.8kHz & .5-4kHz bone cond, unilateral or better ear bilateral Review

3 This figure refers to what the authors call “permanent childhood hearing impairment”– that is mainly sensorineural hearing loss and includes 16% who had post-natally acquired loss. The prevalence rate for congenital hearing impairments was 0.112%. The figures are not directly comparable with data from the WHO studies, which include all conductive loss. Demographics of Hearing Loss in Developing Countries 31

Table 4. Data sources for prevalence estimates of adult-onset hearing loss (Mathers et al., 2004)

Country Study Ref. Years Definition used Sample Age range Prevalences population size available by UK Four cities Davis 1989, 1980-86 25+, 45+, 65+ dBHL in 2,910 17-80 Age, sex 1994 better ear Italy Milan, Padua, Quaranta 1989 25+, 45+, 65+, 90+ 2,170 18+ Age Florence, 1996 dBHL in the better ear Bari, Palermo Denmark Copenhagen - Parving 1997 1976 25+dBHL in better ear 300 49-69 Age males 0.5,1,2,4) Denmark Jutland (rural) Karlsmose Early 25+ dBHL 1,397 31-50 Age x sex 1999 1990s 35+ dBHL 45+ dBHL, Finland Northern Uimonen 1997 21+, 40+, 70+, 95+ 5,400 5-75 Age Ostrobothnia 1999 dBHL in the better ear (0.5,1,2,4) USA Framingham Moscicki 1985 1979 25+ dBHL (0.5,1,2,4 2,293 57-89 kHz) in better ear USA Beaver Dam, Cruickshanks 1993-95 26+, 41+, >60 in 3,753 48-92 Age x sex Wisconsin 1998, 1998 WORSE ear (0.5,1,2,4 (26+ only) Dalston 1998 kHz ) >25 dBHL in better ear (0.5,1,2,4) USA Beaver Dam, Popelka 1998, 1987-88 26+, 41+, >60 in 48-92 Wisconsin 2000 WORSE ear (0.5,1,2,4 kHz ) USA NHANES 1 Reuben 1998, 1971-75 25+ dBHL in the better 2,506 55-74 Age x sex national 1999 ear (HFPTA scale 1,2,4 kHz) USA HHANES Lee 1991 1982-84 26+, 41+ in WORSE 2,751 20-74 Age x sex Hispanic ear (0.5,1,2 kHz ) Americans Brazil Residents of Beria 2003 2003 26+,41+, 61+, 81+ 3,858 All ages Age, sex Canoas City, dBHL or, better ear RS, Brazil Australia South Wilson 1999 1996? 25+, 35+, 45+, 65+ 9,027 15+ Age x sex Australia dBHL in better ear0.5,1,2,4) Oman National Khabori 1996 1996-97 26+, 41+ dBHL (1,2,3 11,402 All ages Age kHz bilateral/better ear) India Vellore, WHO 1997-98 26+,41+, 61+, 81+ 5,432 All ages Age Taluk, Tamil SEARO, 1997 dBHL or, better ear Nadu Joseph, 2003 India Lucknow Singh 1980 1975-76 15+, 30+, 60+ dBHL, 904 All ages Age x sex rural bilateral deafness and (15+) unilateral deafness Age (30+,60+) India Lucknow Pal 1974 1970 15+, 30+, 60+ dBHL, 904 All ages Age x sex urban bilateral deafness and (15+) unilateral deafness Age (30+,60+) Sri Lanka KandyReview district WHO 1998- 27+, 41+, 61+ 81+ 4,858 All ages Age (41+ SEARO, 1997 2000? dBHL, better ear (1,2,4 only) Joseph, kHz bilateral/better ear) 2003

32 Andrew W. Smith

Table 4. Continued

Country Study Ref. Years Definition used Sample Age range Prevalences population size available by Nepal Two regions Little 1993 1990? 31, 51+, 81+ dBHL, 15,845 5+ years Age better ear (1,2,4 kHz bilateral/better ear) China Sichuan Liu 1993, Bu 1986-87 27+, 56+, 91+ dBHL, 126,876 All ages Age, sex 2002, 2003 better ear (27+ only) Korea Community- Kim 2000 1994-97 27+, 41+, 56+, 71+ 39,004 25+ Age x sex based and dBHL, both ears; Age (56, 71) health clinics presbycusis only Thailand 17 provinces Prasansuk 1988-90 41 dBHL, better ear 7,499 All ages 2000 Thailand Bangkok + 5 Prasansuk 1986-87 41+, 61+, 81+ dBHL, 1,797 All ages Total only provinces 2000 better ear (0.5, 1, 2 kHz bilateral/better ear) Indonesia Bandung WHO 1997-98 26+, 41+, 61+ 81+ 5,604 All ages Age (41+ municipality SEARO, 1997 dBHL, (1,2,4 kHz only) & district Joseph, 2003 bilateral/better ear) Myanmar Yangon WHO 1997-98 26+, 41+, 61+ 81+ 5,604 All ages Age (41+ SEARO, 1997 dBHL, (1,2,4 kHz only) Joseph, 2003 bilateral/better ear) Vietnam 6 selected Dung 2003 26+, 41+, 61+ 81+ 13,120 6 months Age x sex provinces (3 dBHL, (1,2,4 kHz and older north, 3 south) bilateral/better ear) Nigeria 3 states: Akua Nwawolo 2000- 26+, 41+, 61+ 81+ 8,975 All ages Age (41+ Ibom, Benue, 2003 2001 dBHL, (1,2,4 kHz only) Katsina bilateral/better ear)

Table 5. Adult-onset hearing loss (41+ dBHTL): age-standardized incidence and prevalence estimates for WHO epidemiological subregions, 2000. For list of countries in each WHO subregion see Annex 1

Age-std. Incidence/100,000 Age-std. prevalence/100,000 Subregion Males Females Males Females AFRO D 213.8 167.8 3466.8 2919.3 AFRO E 203.9 169.2 3451.1 2976.7 AMRO A 323.1 189.0 4351.5 2643.0 AMRO B 264.7 150.1 3500.9 2119.8 AMRO D 260.3 150.8 3498.1 2107.9 EMRO B 324.2 281.3 4829.5 4200.5 EMRO D 322.8 279.1 4829.0 4241.4 EURO A 234.9 190.0 3337.6 2795.5 EURO B1 233.8 189.7 3301.7 2803.7 EURO B2 273.0 228.9 4037.9 3557.5 EURO C 274.8 235.0 4078.6 3561.7 SEARO B 421.8 336.7 6390.3 4901.9 SEARO D 363.2 360.0 5870.1 5827.1 WPRO A 243.1 187.7 2859.6 2685.9 WPRO B1 159.5 127.4 2567.5 2056.6 WPRO B2 430.7 346.4 6352.3 4506.2 WPRO B3 326.8 278.1 5081.0 4163.0 World Review271.5 220.1 4036.3 3326.7 Demographics of Hearing Loss in Developing Countries 33

Prevalence - Males Prevalence - Females

AFRO D - 1 AFRO D - 1

AFRO E - 2 AFRO E - 2

AMRO A - 3 AMRO A - 3

AMRO B - 4 AMRO B - 4

AMRO D - 5 AMRO D - 5

EMRO B - 6 EMRO B - 6

EMRO D - 7 EMRO D - 7

EURO A - 8 EURO A - 8

EURO B1 - 9 EURO B1 - 9

EURO B2 - 10 EURO B2 -10

EURO C - 11 EURO C -11

SEARO B -12 SEARO B -12

SEARO D -13 SEARO D -13

WPRO A -14 WPRO A -14

WPRO B1-15 WPRO B1-15

WPRO B2-16 WPRO B2-16

WPRO B3-17 WPRO B3-17

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000

Age-std prevalence/100,000 Age-std prevalence/100,000

70000 60000 A Regions A Regions Males Fe m ale s AMRO BD AMRO BD 60000 EURO BC 50000 EURO BC EMRO EMRO 50000 SEARO SEARO 40000 WPRO B WPRO B 40000 AFRO AFRO

30000 30000 Prevalence/100,000 Prevalence/100,000 20000 20000

10000 10000

0 0 0-4 5-14 15-29 30-44 45-59 60-69 70-79 80+ 0-4 5-14 15-29 30-44 45-59 60-69 70-79 80+ Age groups Age groups

Figure 2. Estimated adult-onset hearing loss prevalence rates, 41+ dBHTL, by region and sex, GBD 2000 VersionReview 2. For list of countries in each WHO subregion see Annex 1.

34 Andrew W. Smith

Impact on the Poor Little data is available to document this but it is evident that poor persons who also have hearing loss are doubly disadvantaged and could be called the "poorest of the poor".

Box 2. Uses of data collected using tools such as the WHO Ear and Hearing Disorders Survey Protocol

1. Accurate, population-based information on the population prevalence, main causes and interventions required in the country or part of the country where the survey is being conducted. 2. Information to raise awareness among opinion leaders, decision makers and the general public on the size of the problem. 3. Information for selecting and prioritizing strategies for prevention, and predicting needs programme planning and resource allocation. 4. Linkages to infrastructure and health services surveys. 5. Baseline data for comparison with subsequent similar surveys to measure changes in the problem and assess the effectiveness of interventions. 6. Information for determination of costs of hearing impairment, costs and benefits of prevention, and comparisons of cost-effectiveness of interventions. 7. Accurate, standardised information to compare prevalence and causes of hearing impairment between different countries and regions. This can only be done when a standard methodology is used, such as in the WHO protocol. 8. Essential data for estimation of the burden of hearing impairment, as part of Global Burden of Disease work.

3. USES OF THE DATA

Despite the improvements in estimation of the burden of deafness and hearing impairment, there remains a widespread scarcity of appropriate data, particularly from developing countries. More, and more accurate, data is urgently needed in order to raise awareness, prioritize interventions, predict needs, monitor outcomes, and underpin credible economic analyses, such as in cost-of-illness and cost-effectiveness studies. The latter could be included in the menu of estimates of cost effectiveness of a wide range of health interventions that WHO is compiling which are intended to be used by governments to determine good investments for health. This is the WHO-CHOICE project (WHO, 2007a). The uses for this data are summarised in box 2 and are described in more detail in the following sections.

Awareness

A majorReview problem in addressing this field is the general lack of awareness about issues related to deafness and hearing impairment in all parts of society. The population as a whole is generally not aware of the specific effects this problem has on individuals. They may not know about its huge cost to society or that there are good opportunities for intervention for Demographics of Hearing Loss in Developing Countries 35

prevention and management. Since the true size of the problem is not accurately known, there is a lack of political will to deal with it which leads to a lack of resources for programmes. The collection of accurate data will help to raise awareness amongst opinion leaders, decision makers, health planners, and the general public.

Need for a Public Health Approach

In order to prevent deafness and hearing impairment on a large scale and help hard of hearing people around the world, it is essential to develop a public health approach to this problem. Health professionals and health planners need to re-orientate their thinking and activities along a public health route to addressing the situation. We need to find ways to make a difference in the population in addition to treating people on an individual basis. Conditions should be selected for targeting on a massive scale according to whether they have at the same time a high prevalence in the population together with cost-effective means of prevention or control. Unfortunately, there is a shortage of appropriate and effective interventions in this field not only at the basic scientific level, but also in terms of programme implementation. Good data will be essential in determining the conditions that should be targeted and assessing the cost-effectiveness of new interventions.

Construction of Regional and Global Databases

The monitoring of the global trends of prevalence and causes of hearing impairment and the estimates of the current burden can be achieved only with recent and comparable epidemiological data. The WHO Programme for the Prevention of Blindness and Deafness and Hearing Impairment (PBD/PDH) has created a Data Bank of Hearing Impairment with the purpose of collecting and storing the available data and of determining the extent of the global and regional burden. WHO is preparing to use the data collected using the WHO Ear and Hearing Disorders Survey Protocol to make a major contribution to the Data Bank. As a first step there has been a systematic search of available epidemiological data from sources such as Medline (National Library of Medicine), LILACS (Latin American and Caribbean Center on Health Sciences Information), African Index Medicus, reports from ministries of health, doctoral dissertations, and other published and unpublished data available at the Programme for Prevention of Blindness and Deafness of the World Health Organization (WHO/PBD), including from surveys conducted. Studies were selected according to rigorous criteria, the foremost being that the studies have randomly selected samples, are population- based and representative of a country or an area in a country. Only such data can allow accurate, up to date estimation of prevalence in the general population (see box 3 for further criteria). So far 51 studies from 31 countries from all WHO regions have been found to meet the selection criteria and tables for each WHO region, will report prevalence of slight and disabling hearingReview impairment and other details from the studies. The study will be published soon and details will be posted on the WHO PBD web site (http://www.who.int/PBD/ deafness/en/). A new edition of the WHO Ear and Hearing Disorders Survey protocol and software will be ready soon. 36 Andrew W. Smith

Economic Analysis As well as the assessment of the size of the problem, there is an urgent need to use this epidemiological data to help carry out economic analysis of deafness and hearing impairment, especially in developing countries. All the data on the costs and cost-effectiveness of interventions related to hearing loss (including school-age screening, treatment of COM, surgical interventions, hearing aids, and cochlear implants) come from developed countries. Although they can be summarized quite readily, it is not clear whether and how they relate to the costs that would be experienced in developing countries. WHO has recently completed a review of the evidence on the burden of both blindness and deafness and the available data on the cost effectiveness of various interventions. The next steps in this initiative will be to develop and test instruments for economic analysis in developing countries and then use them to measure the burden including health status and costs and evaluate cost effectiveness of various health interventions. These interventions can also be included in the list of estimates of cost effectiveness of various health interventions that WHO is compiling which will be useful for governments to determine good investments for health.

Assessment of the Global Burden of Hearing Impairment and its Contribution to the Global Burden of Disease

In 2005 WHO estimated that adult onset hearing loss accounted for 1.9% of total global burden of disease as measured by "Disability-Adjusted Life Years" (DALYs) and it ranked twelfth among leading causes of the global burden (see table 6). Since 2001, WHO has included adult-onset hearing loss in the tables of the global burden of disease (GBD) in the World Health Report (WHO, 2001a). The causes of the global burden of disease are assessed according to the percentage of total disability adjusted life years (DALYs) in the world attributable to each cause. DALYs are a measure of the years of healthy life lost due to premature mortality (YLL), and the years lived with disability (YLD), hence taking much more account of the burden of chronic conditions than was the case with previous indicators that focused only on mortality. One DALY can be thought of as one lost year of ‘healthy’ life and the burden of disease as a measurement of the gap between the current situation and an ideal situation where everyone lives up to the age of the standard life expectancy, free of disease and disability. YLL for hearing loss is assumed to be zero so all the DALY burden comes from YLD. The data required to estimate YLD are: disability incidence, disability duration, age of onset, and distribution by severity class, all of which must be disaggregated by age and sex. These in turn require estimates of incidence, remission, case-fatality rates or relative risks, by age and sex. A specific software tool, DisMod, has been produced to assist in the development of internally consistent estimates. The basic calculation for YLD is the product of the number of incident cases in the reference period, the disability weight and the average duration of disability in years. Disability weight reflects the Reviewseverity of the disease or condition on a scale from 0 (perfect health) to 1 (death). It is planned to use results from the new World Health Survey (WHO, 2007b), currently being conducted, to comprehensively revise the disability weights. Demographics of Hearing Loss in Developing Countries 37

In general, the results of measurement surveys contribute more to YLD calculations than self-reported interview surveys; population-based epidemiological studies provide the most useful information (Mathers et al., 2004). The WHO Ear and Hearing Disorder Survey Protocol (WHO, 1999) was developed to encourage countries to fulfil these needs by conducting population-based, random cluster sample surveys. In the majority of cases, routine data on consultations by diagnosis is not helpful in estimating burden since this is almost always based on samples of the disability present in the community and does not give a true picture of the situation in the whole population. However it may be possible to use hospital data to measure some conditions where the coverage is good—those relevant to hearing loss may include perinatal conditions and meningitis (Mathers et al., 2004). Adult-onset hearing loss ranked 12th amongst the leading causes of the DALY burden in the year 2005 (see table 6), coming after perinatal conditions, lower respiratory infections, HIV/AIDS, unipolar depression, ischaemic heart disease, diarrhoeal disease, strokes, road accidents, tuberculosis, malaria, chronic lung disease, in that order of ranking (Mathers et al., 2004). However on a regional basis these rankings vary considerably—thus in 2002 adult- onset hearing loss ranked 6th, 10th and 11th in the WHO European, Western Pacific, and South-East Asian regions respectively. It does not rank at all in the first 15 places in the African region, which includes most sub-Saharan African countries, which are dominated by infectious diseases and trauma.

Table 6. Leading global causes of disability (YLD) and burden of disease (DALYs), 2005

Years lived with disability (YLD) Burden of disease (DALYs) Percent Percent of of total total Cause YLD Cause DALYs

1 Unipolar depressive disorders 12.1 1 Perinatal conditions 6.3%

2 Other unintentional injuries 4.8 2 Lower respiratory infections 5.7%

3 Hearing loss, adult onset 4.8 3 HIV/AIDS 5.5%

4 Cataracts 4.7 4 Unipolar depressive disorders 4.7%

5 Alcohol dependence 3.3 5 Ischaemic heart disease 4.1%

6 Schizophrenia 2.8 6 Diarrhoeal diseases 4.0%

7 Osteoarthritis 2.7 7 Cerebrovascular disease 3.4%

8 Age-related vision disorders 2.6 8 Road traffic accidents 2.8%

9 Bipolar affective disorder 2.5 9 Tuberculosis 2.4%

10 Chronic obstructive pulmonary 2.0 10 Malaria 2.3% disease 11 Asthma 2.0 11 Chronic obstructive pulmonary 2.1% disease 12 Cerebrovascular disease 2.0 12 Hearing loss, adult onset 1.9%

Review 38 Andrew W. Smith

Table 7. Childhood and adult-onset hearing loss: YLD, YLL and DALY estimates by subregion and region, 2000

Sequela: Deafness Seq No. YLD/ YLD/ YLL/ YLL/ Total Total Total % Total WHO % total 100,000 100,000 100,000 100,000 YLD YLL DALYs DALYs region DALYs Males Females Males Females ('000) ('000) ('000) by WHO region R01 AFRO D 807,7 847,9 0,0 0,0 2764 0,0 2764 8,3 AFR 16,8 R02 AFRO E 825,9 858,5 0,0 0,0 2843 0,0 2843 8,5 R03 AMRO A 499,1 379,7 0,0 0,0 1357 0,0 1357 4,1 AMR 8,9 R04 AMRO B 346,5 288,7 0,0 0,0 1404 0,0 1404 4,2 R05 AMRO D 303,8 251,5 0,0 0,0 198 0,0 198 0,6 R06 EMRO B 507,0 459,2 0,0 0,0 675 0,0 675 2,0 EMR 4,1 R07 EMRO D 482,4 498,0 0,0 0,0 677 0,0 677 2,0 R08 EURO A 470,0 451,7 0,0 0,0 1893 0,0 1893 5,7 EUR 12,1 R09 EURO B1 354,6 358,9 0,0 0,0 592 0,0 592 1,8 R10 EURO B2 421,1 448,5 0,0 0,0 221 0,0 221 0,7 R11 EURO B3 509,8 576,8 0,0 0,0 1340 0,0 1340 4,0 R12 SEARO B 735,3 598,9 0,0 0,0 2631 0,0 2631 7,9 SEA 37,0 R13 SEARO D 700,5 738,5 0,0 0,0 9694 0,0 9694 29,1 R14 WPRO A 354,7 467,9 0,0 0,0 616 0,0 616 1,8 WPR 21,2 R15 WPRO B1 418,6 379,0 0,0 0,0 5423 0,0 5423 16,3 R16 WPRO B2 725,1 644,3 0,0 0,0 972 0,0 972 2,9 R17 WPRO B3 667,7 604,3 0,0 0,0 44 0,0 44 0,1 Total 559,2 543,9 0,0 0,0 33344 0 33344 100,0 100

If mortality is excluded and disability considered alone using the assessment of years lived with disability (YLD), adult-onset hearing loss ranked third in 2005 at 4.8% of total YLD. Unipolar depressive disorders ranked first with 12.1% of the total (see table 6; Mathers et al., 2008). Preliminary estimates have recently been made to show the burden of childhood and adult onset combined for the 17 sub-regions and the proportions in the 6 regions (see table 7). These show that the total global burden in 2002 is 33.344 million DALYs with the largest proportions of this burden in the South East Asian and Western Pacific regions. These figures will be updated as more recent, accurate data becomes available and is assessed for inclusion.

4. FUTURE NEEDS AND DEVELOPMENTS

A large number of studies of the epidemiology of deafness and hearing impairment have been performed in many countries; however many of these have deficiencies in methodology that make the data unsuitable for insertion in databases. It is very important to improve data gathering methodsReview because databases are essential for the assessment of the total burden of hearing loss and its contribution to burden of disease estimates. Demographics of Hearing Loss in Developing Countries 39

There is thus a huge need for more acceptable data, especially from developing countries. Data that would be acceptable for incorporation in the WHO data bank should be collected according to rigorous criteria (see box 3). Research needs to be done on identifying better methods for field testing in remote areas, especially on testing of young children, on eliminating the effects of background noise, and on better methods for ascertaining the cause(s) of hearing loss. This last need is a prerequisite for determining the individual burdens of the different causes of hearing loss. It would be very useful to devise rapid assessment methods for particular causes as has been done in studies estimating the burden of other conditions such as cataracts.

Box 3. Criteria for conduct and selection of surveys for WHO Data Bank (Pascolini & Smith., 2008)

• Data should be population-based and collected by random sampling with adequate sample size and quality control. • Hearing levels should be measured by audiometric testing or other objective test of hearing, before removal of wax but without the subject wearing a hearing aid. • Test instruments should be calibrated and background noise measured and controlled • Definitions of hearing impairment should be clearly stated and hearing levels and frequencies should be reported. • Data should be analysed by hearing loss in the better ear and not by individual ears. • Conformity to the provisions of the WHO Ear and Hearing Disorders Survey Protocol (WHO, 1999), which addresses all the above criteria in more detail.

For WHO, there is a need for the burden of disease estimates on conditions with hearing loss sequelae to be disaggregated so as to indicate the contribution the hearing loss makes to the burden of that condition (e.g., various infectious causes such as measles, mumps, rubella and other perinatal infections, and other major causes such as congenital causes; Smith & Mathers, 2006). However this may not come about until more data is available and collected according to the criteria listed above. Better and more comprehensive epidemiologic data will also be needed in order to carry out economic analysis studies in developing countries, especially of costs of the burden of hearing impairment and the cost-effectiveness of different interventions against it. This will encourage, assist and justify the allocation of increased resources by more developing countries toReview this neglected field. 40 Andrew W. Smith

ANNEX TABLE 1. REGIONAL EPIDEMIOLOGICAL ANALYSIS CATEGORIES FOR GLOBAL BURDEN OF DISEASE 2000 PROJECT: GBD REGIONS AND 17 SUBREGIONS

GBD Mortality Region WHO Member States Reporting region stratum code subregion AFRO D 1 Algeria, Angola, Benin, Burkina Faso, Cameroon, Cape AFRO D Verde, Chad, Comoros, Equatorial Guinea, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Madagascar, Mali, Mauritania, Mauritius, Niger, Nigeria, Sao Tome And Principe, Senegal, Seychelles, Sierra Leone, Togo, Djibouti, Somalia, Sudan EMRO D AFRO E 2 Botswana, Burundi, Central African Republic, Congo, AFRO E Côte d'Ivoire, Democratic Republic Of The Congo, Eritrea, Ethiopia, Kenya, Lesotho, Malawi, Mozambique, Namibia, Rwanda, South Africa, Swaziland, Uganda, United Republic of Tanzania, Zambia, Zimbabwe AMRO A 3 Canada, United States Of America AMRO A AMRO B 4 Antigua And Barbuda, Argentina, Bahamas, Barbados, AMRO B Belize, Brazil, Chile, Colombia, Costa Rica, Dominica, Dominican Republic, El Salvador, Grenada, Guyana, Honduras, Jamaica, Mexico, Panama, Paraguay, Saint Kitts And Nevis, Saint Lucia, Saint Vincent And The Grenadines, Suriname, Trinidad And Tobago, Uruguay, Venezuela Cuba AMRO A AMRO D 5 Bolivia, Ecuador, Guatemala, Haiti, Nicaragua, Peru AMRO D EMRO B 6 Bahrain, Cyprus, Iran (Islamic Republic Of), Jordan, EMRO B Kuwait, Lebanon, Libyan Arab Jamahiriya, Oman, Qatar, Saudi Arabia, Syrian Arab Republic, Tunisia, United Arab Emirates EMRO D 7 Egypt, Iraq, Morocco, Yemen EMRO D EURO A 8 Andorra, Austria, Belgium, Croatia, Czech Republic, EURO A Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Israel, Italy, Luxembourg, Malta, Monaco, Netherlands, Norway, Portugal, San Marino, Slovenia, Spain, Sweden, Switzerland, United Kingdom EURO B1 9 Albania, Bosnia And Herzegovina, Bulgaria, Georgia, EURO B Poland, Romania, Slovakia, The Former Yugoslav Republic Of Macedonia, Turkey, Yugoslavia EURO B2 10 Armenia, Azerbaijan, Kyrgyzstan, Tajikistan, EURO B ReviewTurkmenistan, Uzbekistan EURO C 11 Belarus, Estonia, Hungary, Kazakhstan, Latvia, Lithuania, EURO C Republic of Moldova, Russian Federation, Ukraine

Demographics of Hearing Loss in Developing Countries 41

GBD Mortality Region WHO Member States Reporting region stratum code subregion SEARO B 12 Indonesia, Sri Lanka, Thailand SEARO B Malaysia, Philippines WPRO B Brunei Darussalam, Singapore WPRO A SEARO D 13 Bangladesh, Bhutan, India, Maldives, Nepal SEARO D Afghanistan, Pakistan EMRO D WPRO A 14 Australia, Japan, New Zealand WPRO A WPRO B1 15 China, Mongolia, Republic Of Korea WPRO B DPR Korea SEARO D WPRO B2 16 Cambodia, Lao People's Democratic Republic, Viet Nam WPRO B Myanmar SEARO D WPRO B3 17 Cook Islands, Fiji, Kiribati, Marshall Islands, Micronesia WPRO B (Federated States Of), Nauru, Niue, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu, Vanuatu

ANNEX TABLE 2. DEFINITIONS OF MORTALITY STRATA USED TO DEFINE WHO SUBREGIONS FOR THE GBD2000

Mortality Child mortality Definition Adult mortality stratum st A Very low child mortality (1 quintile 5q0 < 0.0122 Low adult of 5q0) mortality nd rd B Low child mortality (2 and 3 0.0122< 5q0 < Low adult quintile of 5q0) 0.062 mortality nd rd C Low child mortality (2 and 3 0.0122< 5q0 < High adult quintile of 5q0) 0.062 mortality th th D High child mortality (4 and 5 0.062< 5q0 High adult quintile of 5q0) mortality th th E High child mortality (4 and 5 0.062< 5q0 Very high adult quintile of 5q0) mortality

For geographic disaggregation of the global burden of disease, the six WHO regions of the world have been further divided into 14 subregions, based on levels of child (under five years) and adult (15-59 years) mortality for WHO Member States. The classification of WHO Member States into the mortality strata were carried out using population estimates for 1999 (UN PopulationReview Division 1998) and estimates of 5q0 and 45q15 based on WHO analyses of mortality rates for 1999 (WHO, 2000).

ANNEX TABLE 3. COUNTRIES GROUPED BY REGION AND INCOME LEVEL ACCORDING TO THE WORLD BANK CLASSIFICATION

Classification of Economies by Income and Region, 2000 [Web addresses at end of table]

Income Subgroups Sub-Saharan Africa Asia Europe and Central Asia Middle East America groups and North Africa East West East South Eastern Rest of Middle North and South Africa Asia and Asia Europe Europe East Africa Africa Pacific and Central Asia Low-income Angola Benin Cambodia Afghanistan Armenia Yemen, Rep. Haiti Burundi Burkina Faso Indonesia Bangladesh Azerbaijan Nicaragua Comoros Cameroon Korea, Dem. Rep. Bhutan Georgia Congo, Dem. Rep. Central African Republic Lao PDR India Kyrgyz Republic Eritrea Chad Mongolia Nepal Moldova Ethiopia Congo, Rep. Myanmar Pakistan Tajikistan Kenya Cote d`Ivoire Solomon Islands Turkmenistan Madagascar Gambia, The Vietnam Ukraine Malawi Ghana Uzbekistan Mozambique Guinea Rwanda Guinea-Bissau Somali Liberia Sudan Mali Tanzania Mauritania Uganda Niger Zambia Nigeria Zimbabwe Sao Tome and Principe Senegal Sierra Leone Togo Review

Middle-income Lower Namibia Cape Verde China Maldives Albania Turkey Iran, Islamic Rep. Algeria Belize Swaziland Equatorial Fiji Sri Lanka Belarus Iraq Djibouti Bolivia Guinea Kiribati Bosnia and Herzegovina Jordan Egypt, Arab Rep. Colombia Marshall Islands Bulgaria Syrian Arab Rep. Morocco Costa Rica Micronesia, Fed. Sts. Kazakhstan West Bank and Tunisia Cuba Papua New Guinea Latvia Gaza Dominican Republic Philippines Lithuania Ecuador Samoa Macedonia, FYR (a) El Salvador Thailand Romania Guatemala Tonga Russian Federation Guyana Vanuatu Yugoslavia, Fed. Rep.(b) Honduras Jamaica Paraguay Peru St. Vincent and the Grenadines Suriname Upper Botswana Gabon American Samoa Croatia Isle of Man Bahrain Libya Antigua and Mauritius Malaysia Czech Rep. Lebanon Malta Barbuda Mayotte Korea, Rep. Estonia Oman Argentina Seychelles Palau Hungary Saudi Arabia Barbados South Africa Poland Brazil Slovak Rep. Chile Dominica Grenada Mexico Panama Puerto Rico St. Kitts and Nevis St. Lucia Trinidad and Tobago Uruguay Venezuela, RB Review

ANNEX TABLE 3. CONTINUED

Income Subgroups Sub-Saharan Africa Asia Europe and Central Asia Middle East America groups and North Africa East West East South Eastern Rest of Middle North and South Africa Asia and Asia Europe Europe East Africa Africa Pacific and Central Asia High-income OECD Australia Austria Canada countries Japan Belgium United States New Zealand Denmark Finland France (c) Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Non-OECD Brunei Slovenia Andorra Israel Aruba countries French Channel Islands Kuwait Bahamas, Polynesia Cyprus Qatar The Guam Faeroe Islands United Arab Emirates Bermuda Hong Kong, Greenland Cayman China (d) Liechtenstein Islands Macao, Monaco Netherlands China (e) Antilles New Virgin Caledonia Islands (U.S.) N. Mariana Islands Singapore Taiwan, China Total 207 25 Review23 35 8 27 27 14 7 41

a. Former Yugoslav Republic of Macedonia. b. Federal Republic of Yugoslavia (Serbia/Montenegro). c. The French overseas departments French Guiana, Guadeloupe, Martinique, and Réunion are included in France. d. On 1 July 1997 China resumed its exercise of sovereignty over Hong Kong. e. On 20 December 1999 China resumed its exercise of sovereignty over Macao. 2000 table at: http://www.worldbank.org/depweb/english/beyond/global/classification.html Most recent classification at: http://web.worldbank.org/WBSITE/EXTERNAL/DATASTATISTICS/0,,contentMDK:20420458~menuPK:64133156~ pagePK:64133150~piPK:64133175~theSitePK:239419,00.html

Review 46 Andrew W. Smith

When these mortality strata are applied to the six WHO regions, they produce 14 mortality subregions. These are listed in Annex Table 1, together with the WHO Member States in each subregion. For the purposes of burden of disease epidemiological analyses, 2 of these regions have been further subdivided: EURO B into EURO B1 and EURO B2 – the latter including the central Asian states; and WPRO B into WPRO B1 (mainly China), WPRO B2 (south east Asian countries) and WPRO B3 (Pacific Islands). Additionally, some Member States have been reclassified into subregions with similar epidemiological/geographic/ethnic patterns in order to maximise the epidemiological homogeneity of the subregions for the purposes of epidemiological analysis. These subregions are used for analysis in the GBD 2000, but the resulting estimates are mapped back to the 14 subregions defined in Annex Table 1 for all reporting purposes.

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WHO (World Health Organization). (1999). WHO Ear and Hearing Disorders Survey: Protocol and Software Package, WHO/PBD/PDH/99.8. Geneva: WHO. Available from PBD, CPM, World Health Organization, Avenue Appia, 1211 Geneva 27, Switzerland. (Email: [email protected] ). WHO (World Health Organization). (2003). International Statistical Classification of Diseases and Related Health Problems, 10th rev. Geneva: WHO. http://www3.who. int/icd/ vol1htm2003/fr-icd.htm. WHO (World Health Organization). (2004). Changing History: The World Health Report. Geneva: WHO. WHO (World Health Organization). (2007a). WHO-CHOICE: CHOICE = CHOosing Interventions that are Cost Effective. Geneva: WHO. http://www.who.int/choice/en/ Accessed 27 December 2007 WHO (World Health Organization). (2007b). World Health Survey. Geneva: WHO. http:// www.who.int/healthinfo/survey/en/ Accessed 27 December 2007. WHO-Regional Office for South-East Asia. (1997). Multicentre Study on the Magnitude and Etiology of Hearing Impairment. Report of a Meeting of Principal Investigators. Colombo, Sri Lanka: WHO-Regional Office for South-East Asia. Wilson, D.H., Walsh, P.G., Sanchez, L., Davis, A.C., Taylor, A.W., Tucker, G., & Meagher, I. (1999). The epidemiology of hearing impairment in an Australian adult population. International Journal of Epidemiology, 28, 247-252. Zakzouk, S.M. (2003). Epidemiological study of childhood hearing impairment in Saudi Arabia. Informal Consultation on Epidemiology of Deafness and Hearing Impairment in Developing Countries and Update of the WHO Protocol, March 2003. Geneva: WHO.

Chapter 4

EDUCATION AND PRACTICE OF AUDIOLOGY INTERNATIONALLY: AFFORDABLE AND SUSTAINABLE EDUCATION MODELS FOR DEVELOPING COUNTRIES

Helen Goulios* and Robert Patuzzi University of Western Australia, Perth, Australia

ABSTRACT

The recognition by societies of the problems caused by deafness and hearing impairment has led to a significant increase in the need for hearing health care worldwide. In developed countries, an ageing population and advances in hearing services have placed greater pressure on governments, academic institutions and professional associations to increase graduate numbers, and to broaden their knowledge and competencies. This has resulted in longer, more expensive education programs for hearing health care professionals. In developing countries, deafness and hearing impairment may not be seen as a high priority, and preventative and rehabilitative solutions to address hearing disorders are often unaffordable. Furthermore, the profession of audiology has evolved from many related areas of expertise resulting in diversity in the education of hearing health care professionals internationally. Yet despite these educational differences, there is significant overlap in the scope of practice of the many hearing health care workers. The differences in level and breadth of education involve wide-ranging costs in training of professionals which ultimately result in a variation in the cost-effectiveness of service provision. Collectively, increased demand, wide diversity, low cost-effectiveness and increasing globalization all highlight the need to evaluate current audiology education programs from an international perspective. This chapter profiles the profession of audiology, based on the results of a recent international survey ofReview audiology education and practice of over 60 countries, representing 80% of the world’s population. It compares hearing health care professional resources, educational levels and scope of practice between countries. It also presents a conceptual model which describes the interactions between the main issues involved in the provision of hearing

* Correspondence: [email protected]

52 Helen Goulios and Robert Patuzzi

services. The model can be used to make comparisons between countries and examine efficiencies for hearing health care education. It provides a first step in the development of affordable, cost-effective and sustainable hearing health care education models that can be adapted for local environments.

INTRODUCTION

Increasing awareness of the problems caused by deafness and hearing impairment has resulted in a rising need for hearing health care worldwide. The World Health Organization (WHO, 2006a) has estimated that there are 278 million people with bilateral moderate to profound hearing loss, with two-thirds of them in developing countries, and a half with a hearing loss that is avoidable. In developed countries, improvements in hearing technologies and service provision, and an ageing population have contributed to greater community demand for hearing services. As a consequence, there has been greater pressure placed on governments, academic institutions and professional associations to increase the number of students trained, and to broaden their knowledge and competencies. There are many different professionals that currently provide hearing health care services. Patients with active medical conditions may be seen by otolaryngologists, general medical practitioners and nurses, whereas the non-medical care of patients with hearing impairment is more often provided by other professionals, including audiologists, audiometric technicians, hearing aid acousticians, teachers of the deaf and speech pathologists. Audiologists are increasingly becoming the primary contact for the non-medical management of hearing, tinnitus and balance disorders (International Society of Audiology, 2004; European Federation of Audiological Societies, 2001; Bess and Humes, 2003). As the profession of audiology has evolved from many other related areas fields, including engineering, medicine, physiology, psychology, speech pathology and teaching (Burkhard, 2002; Bess and Humes, 2003), there is a broad diversity in audiology education, both within countries and internationally. Furthermore, the issues around education of audiologists in developing countries are different from those in developed countries. In most developed countries with established audiology education programs, education of audiologists is at a tertiary level. However there is significant variability in the minimum entry level requirement for clinical audiologists. Depending on the country, training may involve a four-year undergraduate Bachelors degree (Brazil, South Africa, and United Kingdom), a two-year postgraduate Masters degree (Australia, Canada, and New Zealand) or a four-year postgraduate Doctorate in Audiology (USA) or, as in many European and some South American countries, a medical degree followed by postgraduate training in audiology. Despite these differences, there is considerable overlap in the scope of practice amongst the many hearing health care workers with different levels of training, suggesting a variation in the cost-effectiveness of service provision. This diversity in training has been acknowledged by the International Society of Audiology (ISA, 2004) and the European Federation of Audiology SocietiesReview (EFAS, 2001), with both organizations supporting a move to long-term international equivalency, while maintaining contributions by the many professions currently involved in audiology. Apart from curriculum diversity, there are other issues facing the education of audiologists. Closer examination of courses within countries highlights problems common across countries in providing appropriate and cost-effective programs. For example,

Education and Practice of Audiology Internationally 53

Florian (2002) has highlighted the situation in the United States, where there were 123 university level audiology programs producing an average of only six graduates per program per year. He concluded that having so many programs producing so few graduates has caused concern about the financial viability of courses and the quality of graduates. The issues in developing countries are different. Given the many other health priorities, deafness and hearing impairment may not always be seen as a significant problem, and preventative and rehabilitative solutions to address hearing disorders are generally thought to be unaffordable (WHO, 2004). Furthermore, the large manufacturers of hearing devices have increasingly focused on sophisticated products yielding high profit margins in the developed world, with little work on low-cost devices appropriate in developing countries. The WHO (2004) has reported recent hearing aid production to be one tenth of global need, with only one quarter of these aids being distributed to developing countries. Even if hearing aid issues were resolved, developing countries lack appropriately trained individuals to perform basic hearing assessment, device fitting and/or rehabilitation. In 1998 the WHO also found that in developing countries there were between 1 audiologist per 0.5 million people to 1 per 6.25 million. In contrast, the number of audiologists in developed countries was reported to be closer to 1 per 20,000 people. This further highlights the need for a sustainable cost-effective model for education of audiologists. Additionally, increasing globalization links the problems in developing countries with those in the developed world, further supporting the need to view the education of audiologists from an international perspective. As Frenk et al. (2001) point out, health care is a “global good”, and an increase in the hearing health needs of industrialized countries has resulted in an inadequate supply of providers. There are already examples of international movements of audiologists and audiology services from country to country, with graduates from some developing countries in particular (including Brazil, South Africa, India and the Philippines) migrating to developed countries (including the United Kingdom, Canada and Australia) to seek better employment opportunities. The permanent relocation of audiologists to developed countries compounds the difficulties in providing hearing care for developing countries, who suffer the added burden of other major health problems and malnutrition. Increased demand for audiology services, a wide diversity and low cost-effectiveness of current education programs, and increased world globalisation have highlighted the need to evaluate established audiology education programs from an international perspective. This chapter profiles the profession of audiology, based on the results of a recent international survey of audiology education and practice of over 60 countries representing over 80 % of the world’s population (Goulios and Patuzzi, in press). It compares hearing health care professional resources, educational levels and scope of practice between countries. It also presents a conceptual model describing the interactions between the main issues in the provision of hearing services, and provides a basis for comparison and discussion of different countries and regions. The model is one step in the development of affordable, cost-effective and sustainable hearing health care education models that can be adapted for local environments. It is clear that the development of effective education models will need to consider theReview range of clinical services, the different hearing professionals required to provide these services, and the nature of the education systems needed to provide their training.

54 Helen Goulios and Robert Patuzzi

50 41% 40 32% 30 20 10% 10% 10 5%

% Respondents 2% 0 Non- education health and health Hospital Government Professional Associations departments government Research Insititutes and charities organisations Private clinics Private Audiology and Audiology Departments of Departments Otolaryngology Universities and

Figure 1. Types of organizations completing survey as a percentage of total returns.

INTERNATIONAL SURVEY OF AUDIOLOGY EDUCATION AND PRACTICE

Between February 2005 and May 2007 a survey aimed at obtaining quantitative and qualitative data on audiology education and practice was distributed worldwide (Goulios and Patuzzi, in press). The survey was designed in English and translated into five additional languages: Arabic, Chinese, French, Russian and Spanish, and was sent to representatives of each country’s professional body for providers of hearing health care services. In countries where there was no known professional body for audiologists, the questionnaire was sent to organisations involved in education, practice or research in audiology. Every effort was made to obtain contact details for individuals working in hearing health care for as many countries as possible. In total, 63 countries completed and returned the questionnaire, representing 80% of the world’s population. Returned questionnaires were largely completed by individuals representing national professional bodies, or universities and research institutes (72%). Only 3% of returns were from individuals working in private clinics. A breakdown of the proportion of various organisation types completing the questionnaire is shown in Figure 1. The reliability of the data was well supported, given the national standing and independence of the respondent organizations.

Professional Hearing Health Care Resources

Table 1 shows the distribution of hearing health care providers in respondent countries, with countries ordered from lowest to highest per capita Gross National Income (GNI) in InternationalReview Dollars ($Int), as determined by the World Bank (World Bank, 2007). International Dollars are derived by dividing local currency units by an estimate of their Purchasing Power Parity (PPP) compared to the US Dollar, (i.e., the measure which minimizes the consequences of differences in price levels between countries, WHO, 2006b).

Education and Practice of Audiology Internationally 55

Based on the World Bank classifications, countries have been grouped into low income, lower-middle income, higher-middle income and high income countries. Lower-middle income economies and low income countries are most often referred to as “developing countries”. The first two columns in Table 1 provide figures for each country's per capita GNI ($Int PPP) and population, so that country comparisons for hearing health care may be made. The following columns show the estimated numbers of professionals involved in hearing health care in each country, including the total number of audiologists and otolaryngologists, the number of audiologists and otolaryngologists per million people, and the total number of other hearing care providers. In some cases the respondents did not know the numbers, and this is indicated by “not available”. The lack of otolaryngologists was evident in many developing countries in Asia and Africa (including Bangladesh, Myanmar, Pakistan, Madagascar, Mali, Namibia and Nigeria), with several countries having less than one otolaryngologist per million people. These countries were also very poorly resourced with respect to all other hearing care professionals. The majority of countries classified as having low and lower-middle incomes reported having no audiologists, or less than 4 audiologists per million persons. Most respondent countries indicated having more otolaryngologists than audiologists per million persons, except for the English-speaking countries, Belgium and the countries with a combined audiology and speech pathology profession. The data shown in Table 1 are consistent with those reported earlier in several small studies in specific world regions. Madriz (2001) examined audiology resources and services in Latin America by surveying each country’s Ministries of Health, Education and Social Security, and official institutions and NGOs associated with hearing and deafness. The professional resources and training programs reported by Madriz closely matched numbers reported by the Latin American countries responding to this survey, after population increases between 2001 and 2006 were taken into account. Given the limited material and human resources, the scarcity of audiology services, and the high cost of technology by regional standards, Madriz concluded that hearing impairment was seen as a low priority by the national health systems of most Latin American countries. The data from Table 1 were also used to generate Figures 2A and 2B. Figure 2A shows the number of ear, nose and throat (ENT) surgeons per million people, as reported by 49 of the 63 respondents, plotted against per capita GNI ($Int) PPP. Figure 2B shows the number of audiologists per million people against per capita GNI ($Int) PPP, as reported by 39 countries. One fifth of these countries, all of which had very low per capita GNI, reported having no audiologists. They included Bangladesh, Indonesia, Laos, Guatemala and Tonga. Most respondent countries indicated having more ENTs (Figure 2A) than audiologists (Figure 2B), with the exceptions being the English-speaking countries, Belgium, and the countries with a combinedReview audiology and speech pathology profession.

Table 1. Estimated numbers of Hearing Health Care Professionals for low, middle and high income countries

Country GNI $Int Pop. Auds Auds/ ENTs ENTS/ Aud Aud H/A SLT TOD PPP (000s) Mil. Pop. Mil. Pop. Phys Tech Tech Madagascar 950 17404 N/A N/A 5 0 1 2 0 0 20 Nigeria 1050 124009 N/A N/A 60 0 1 50 15 N/A 150 Mali 1130 13007 N/A N/A 7 1 N/A N/A N/A N/A N/A Myanmar 1480 49485 N/A N/A 50 1 N/A 2 N/A 1 N/A Low India 1568 1065462 1000 1 N/A N/A N/A N/A N/A 700 N/A Income Laos 2050 5657 0 0 N/A N/A N/A N/A N/A N/A N/A Bangladesh 2340 146736 0 0 275 2 2 40 18 40 100 Pakistan 2500 153578 7 0.1 200 1 7 N/A 30 4 105 Cambodia 2920 14144 N/A N/A 50 4 0 0 0 0 0 Indonesia 3950 219883 0 0 606 3 N/A N/A N/A 1 N/A Nicaragua 4010 5466 3 1 20 4 0 3 6 6 6 Libya 4400 5551 2 1 40 7 2 5 2 N/A N/A Lower Egypt 4680 71931 110 2 N/A N/A N/A N/A N/A N/A N/A Middle Guatemala 4800 12347 0 2 50 4 0 5 7 100 50 Income Philippines 5980 79999 21 0.3 400 5 0 N/A N/A N/A N/A Jordan 6200 5473 10 2 130 24 3 10 10 20 1 Belize 6640 256 N/A N/A N/A N/A N/A N/A N/A N/A 10 Colombia 7620 44222 480 11 1000 23 N/A N/A 20 3000 N/A Panama 7680 3120 124* 40 71 23 N/A 3 N/A 3 1 China 7730 1311709 N/A N/A 20000 15 200 5000 5000 N/A 10000 Namibia 8110 1987 7 4 3 2 N/A N/A 2 7 40 Dominican Rep. 8290 8745 2 0.2 52 6 0 2 2 N/A N/A Tonga 8580 104 0 0 1 10 0 0 1 0 2 Brazil 8800 178470 25600* 143 6000 34 0 0 10 1000 27500 Thailand 9140 62193 50 1 750 12 10 0 10 20 400 Romania 9820 22334 N/A N/A N/A N/A 5 N/A N/A N/A N/A Costa Rica 10770 4173 N/A N/A 75 18 N/A 25 15 N/A 120 Taiwan 10981 22894 150 7 N/A N/A 5 N/A 20 300 50 Upper Chile 11260 15806 174* N/A N/A N/A N/A N/A N/A N/A N/A Middle Malaysia 11300 24425 90 4 N/A N/A 3 N/A N/A 120 N/A Income Mexico 11330 103457 400 4 4500 43 15 150 N/A 3000 1000 Russia 11670 143246 300 2 N/A N/A N/A N/A N/A N/A N/A South Africa 11710 45026 1000* 22 N/A N/A 0 0 1000 N/A N/A Review

Botswana 12240 1785 6 3 5 3 N/A 3 N/A 3 31 Croatia 13670 4428 40 9 220 50 40 90 7 60 40 Poland 14530 38587 N/A N/A 1500 39 120 1000 250 300 Lithuania 14930 3444 N/A N/A 320 93 N/A N/A N/A N/A N/A Argentina 15390 38428 7000* 182 N/A N/A N/A N/A N/A N/A N/A Saudi Arabia 16620 24217 104 4 460 19 8 12 78 116 285 Slovak Rep. 16910 5402 N/A N/A 400 74 N/A 40 N/A N/A N/A Portugal 20850 10061 180 18 N/A N/A N/A 140 N/A N/A N/A Slovenia 23980 1984 N/A N/A 70 35 N/A 120 15 125 50 Israel 25470 6725 600 89 1200 178 N/A N/A 50 800 100 New Zealand 26470 3875 173 45 65 17 N/A N/A N/A N/A N/A Spain 28420 41060 N/A N/A 2000 49 50 300 700 2000 1000 Italy 29840 57423 N/A N/A 4500 78 650 1200 500 300 250 Germany 31280 82476 N/A N/A 4000 48 300 1500 1000 2000 1000 Australia 31860 19731 1300 66 350 18 0 N/A 400 6000 300 France 32130 60144 N/A N/A 2500 42 N/A N/A N/A N/A N/A Japan 33730 127654 N/A N/A N/A N/A N/A N/A N/A 10000 N/A Belgium 34460 10318 500 48 500 48 N/A 100 500 N/A N/A High Canada 34610 31510 1100 35 N/A N/A N/A N/A N/A N/A N/A Income Singapore 34700 4253 20 5 50 12 N/A 9 N/A N/A N/A Sweden 34780 9041 750 83 542 60 N/A 60 45 N/A N/A Austria 35300 8116 N/A N/A 520 65 N/A N/A N/A N/A N/A Netherlands 35500 16149 60 4 350 22 0 200 400 200 100 Ireland 35540 3956 50 13 N/A N/A N/A N/A 50 N/A N/A United Kingdom 35690 59251 2250 38 520 9 40 1700 N/A N/A N/A Denmark 36110 5364 N/A N/A 350 65 35 200 0 500 100 Hong Kong 38180 6980 70 10 118 17 N/A 15 N/A 600 25 Switzerland 40630 7169 N/A N/A 230 32 40 50 250 N/A N/A Norway 43920 4533 N/A N/A 300 66 0 150 N/A N/A N/A USA 44260 294043 15000 51 12000 41 N/A N/A N/A 130000 N/A GNI $Int PPP: Per Capita Gross National Income in international dollars; Pop. (000s): Population (000s); Auds: Total Audiologists; Auds/Mil. Pop: Audiologists per million people; ENTs: Total ENT surgeons; ENTs/Mil. Pop: ENT surgeons per million people; Aud Phys: Audiological Physicians; Aud. Techs: Audiological Technicians; SLT: Speech-Language Therapists: TOD: Teachers of the Deaf; * indicates combined Speech-Language-Hearing qualification

Review 58 Helen Goulios and Robert Patuzzi

Countries fell into clusters in both Figures 2A and 2B which could be grouped according to low and high numbers of hearing health professionals and low and high per capita GNI. Four clusters of countries are seen in Figure 2A, and these are shown as Groups 1-4. Group 1 is comprised almost entirely of developing countries with low per capita GNI and low numbers of ENTs per million people. Group 2 are developing countries with low per capita GNI but numbers of ENTs per million people similar to countries with a much higher per capita GNI. Group 2 countries (including Lithuania, the Slovak Republic, Croatia, Poland, Mexico and Brazil) tended to have health care systems that were government-funded to a greater extent than countries with higher per capita GNI. There was also a large variation in the numbers of ENTs in countries with higher per capita GNI. Countries clustered within Group 3 had greater numbers of otolaryngologists, and were mainly European countries with primarily government-funded health systems. Audiology in these countries tended to be a post-medical specialization in ENT. Group 4 countries were wealthier with fewer ENTs per million people, had more privately funded health insurance systems, and were supported by larger numbers of audiologists. A similar picture is seen in Figure 2B, although in this case Groups 1 and 2 fell into a single cluster, with all countries with low per capita GNI reporting low numbers of audiologists. Group 3 countries had higher per capita GNI and larger numbers of audiologists. The profile of audiology in all these countries was a university qualification that did not require prior medical training. Group 4 comprised countries with high per capita GNI and few audiologists. Most of these countries were also represented in Group 3 of Figure 3A, with higher numbers of ENTs, audiology as a post-medical specialization, and health care systems that were predominantly government-funded. Argentina, Brazil and Panama were omitted from Figure 3B because their audiology professionals had a combined audiology/speech and language qualification, and it was not possible to differentiate personnel or time devoted to audiology per se. Although South Africa also has a combined qualification, a separate value was provided for audiologists in the returned survey and so they are included in this figure.

100 Madagascar Nigeria Lithuania 90 Mali Myanmar Group 3 80 India Italy Slovak Rep. 70 Bagladesh Group 2 Pakistan Austr ia Denmark Norway 60 Cambodia Sweden Indinesia Croatia Nicaragua Spain Belgium 50 Germany Libya Mexico France 40 Guatemala Poland USA Philippines Slovenia Brazil Switzerland 30 Jordan

Ents per million persons Panama Group 4 20 Netherlands China Colombia Saudi Arabia Austr alia Hong Kong Thailand 10 Group 1 New Zealand Singapore Tonga Botswana Namibia UK 0 0Review 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 per capita GNI ($Int) PPP

Figure 2A. ENTs per million persons versus per capita GNI.

Education and Practice of Audiology Internationally 59

100 Madagascar Nigeria 90 Mali Israel Myanmar Sweden 80 India Laos Bangladesh Group 3 70 Pakistan Cambodia Austr alia 60 Indonesia Nicaragua Libya USA 50 New Zealand Belgium Egypt Guatemala 40 Philippines UK Jordan Canada 30 Namibia Groups 1&2 Domincan Rep Group 4 Tonga South Africa Audiologists per million persons million per Audiologists 20 Thailand Portugal Russia Ireland Romania Chile Hong Kong 10 Mexico Croatia Singapore Netherlands Taiwan Italy Botswana Saudi Arabia Spain Germany Switzerland Norway 0 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 per capita GNI ($Int) PPP

Figure 2B. Audiologists per million persons versus per capita GNI ($Int) PPP.

Table 2. Hearing health care professionals world-wide

Audiological Physician (European countries) Audiological Scientist (United Kingdom and some Asian countries) Audiological Technician (European and South American countries) Audiologist (title used in many countries world-wide) Audioloog (Netherlands) Audiometrist (English speaking countries) Audio-Prothetist (France, Romania) BSc Audiometrist (Norway) ENT Technician (Mali) Hearing Aid Acoustician (European countries) Hearing Aid Dispenser (English speaking countries) Hearing Aid Technician (European and African countries) Hearing Therapist (United Kingdom, New Zealand and Scandinavian countries) Fonoaudiologo (Argentina, Panama) Phonoaudiologist (Brazil) Otorhinolaryngologist/Ear Nose and Throat Surgeon (world-wide) Speech Language Therapist/Pathologist (titles used in many countries world-wide) Surdologist (Russia) Teacher of the Deaf (title used in many countries world-wide) TechnicianReview in Audiometry (Costa Rica); Technolog Medico con Mencion en Otorrinolaringologia TMORL (Chile)

60 Helen Goulios and Robert Patuzzi

Another difficulty in reporting the data is in the definition of the different hearing health care professionals in each country. In many cases there are similarities across countries. For example, the ENT surgeon was similarly described in all respondent countries, while large differences existed for audiologists. These differences between professionals across countries are discussed below. The gap in hearing care resources between developed and developing countries was most obvious in the numbers of hearing health professionals. European countries were best resourced with ENT surgeons, however few of these countries reported having university qualified graduates in audiology without prior medical training. The exception was the United Kingdom which reported 100,000 persons per ENT surgeon, who were also supported by audiological physicians and non-medically qualified audiologists. At the other extreme were the professional numbers found in most developing countries, mainly in the African and Asian regions, with between 0.5 and 3.4 million people per ENT surgeon. These countries had access to even smaller numbers of audiologists, and several (including Bangladesh, Indonesia and Laos) reported having no audiologists at all. These findings are consistent with earlier reports of limited numbers of hearing professionals in African countries (Olusanya, 2000; Eleweke, 1997), Eastern Europe (Farkas and Ribari, 1997; Salmivalli and Sorri, 1997), Latin America (Madriz, 2001) and Asian countries (Alauddin and Joarde, 2004; Suwento, 2004).

Professionals Working in Hearing Health Care One of the difficulties in collating and reporting these results was the definition of the range of hearing health care professionals in different countries. Table 2 shows the various professional titles cited by respondents, and lists countries in which they are most commonly used. The survey asked respondents to list the professionals primarily responsible for hearing health care in their country, with responses not required to be exclusive. Most countries indicated a variety of providers, with over half of the countries surveyed indicating ENT surgeons (58%) and audiologists (52%) as their main providers of hearing care. ENT surgeons were present in all countries surveyed, although their scarcity (particularly in developing countries) necessitated contributions by other professionals. Audiologists were strongly represented in the Americas, Asia and the Pacific countries, in addition to all countries that had English as their national language. A combined qualification was obtained for speech-and-hearing professionals in several countries in Central and South America. These professionals were referred to as Fonoaudiologo in Argentina, Colombia and Panama, and phonoaudiologist in Brazil. In addition to having 26,500 phonaudiologists, Brazil also had 600 “certified audiologists” who specialised in hearing care. The dual university qualification in audiology/speech-pathology was also a requirement for audiologists educated and practising in South Africa. Mexico also reported audiologists as the primary hearing care professional, however in this instance the audiologist needed a general medical qualification, which was followed by a 3-year (soon to become 4-year) specialisation in audiology. This qualification enabled professionalsReview to diagnose and manage communication problems, whereas ENT referral was made for disorders requiring specialist medical treatment. The situation was different again in Costa Rica, with three profiles for the practice of audiology, including otolaryngologists, physicians in audiology and technicians in audiometry, with the survey respondent specifying that in answering the questions relating to audiology they were strictly referring to University

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educated technicians in audiometry. Professionals in Chile had a similar educational background, and used the title Technolog Medico con Mencion en Otorrinolaringologia (TMORL). Most African countries had very small numbers of ENTs relative to their populations, and these were supplemented by small numbers of hearing aid and audiometric technicians without tertiary qualifications. The exceptions were South Africa and Egypt with university- educated audiologists. Asian countries (including China, India, Japan, Malaysia, Philippines and Thailand) generally had a wide range of hearing care professionals, although again their numbers were small relative to population. The exceptions were Hong Kong (surveyed separately from China) and Singapore who were serviced by a wide range of professionals, including ENT surgeons, audiologists and audiometric and hearing-aid technicians in relatively higher numbers. In most European countries audiology was a specialisation after professionals had completed their ENT training. This was the case in Austria, Croatia, Denmark, France, Germany, Italy, Norway, Poland, Slovak Republic, Slovenia and Switzerland. Although these countries used the term audiologist (and in Russia, the title surdologist), it was the otolaryngologists that was seen as the primary hearing care professional, and they were complemented by audiological physicians and audiological scientists. In addition, Belgium, Germany, Ireland, Portugal and Sweden were in various stages of adopting university- educated audiologists without medical training. The title of Audioloog was used in the Netherlands, but this only applied to graduates with a Masters degree in Physics, followed by a 4-year post-specialisation in audiology. Larger numbers of other professionals undertaking a narrower range of clinical activities were also active in European countries, with their titles closely connected to their clinical practices. These professionals included ENT technicians and audiological technicians who supported otolaryngologists with audiometric assessment, hearing-aid acousticians and hearing-aid dispensers who selected and fitted hearing instruments, and audiometrists whose scope of practice have included a range of assessment and/or hearing-instrument fitting activities. Hearing therapists, speech-therapists/pathologists and/or teachers-of-the-deaf were largely responsible for managing aural rehabilitation programs.

World-Wide Need for Audiologists In the past there have been numerous anecdotal reports regarding a shortage of audiologists worldwide, and this was confirmed in the international survey with 87% of respondent countries indicating they needed more audiologists, including countries from the lowest to the highest income groups. All countries that indicated they had sufficient numbers of audiologists (including Argentina, Belgium, Denmark, Germany, Italy, The Netherlands and Poland) were in the upper-middle to high income groups. Three percent of countries were undecided. There were several reasons identified for the shortage of audiologists (and these were not exclusive), with the main reasons being: (i) a lack of government funding for hearing health care as a result of other health priorities (80%), (ii) a lack of awareness about the professionReview of audiology (76%), (iii) a lack of public awareness about deafness and hearing loss (60%), and (iv) a lack of audiology education programs (50%). Some countries reported that student intakes were small, and a related reason for low intakes was the difficulties programs had in obtaining suitable clinical placements for students. Half of the respondent countries also indicated poor pay and conditions as a major reason for the shortage. Some

62 Helen Goulios and Robert Patuzzi

countries also gave poor workforce planning by governments as the reason for the resignation of audiologists, or for their tendency to seek better employment conditions overseas. Employment opportunities are closely linked to the level of audiology resources, and the survey asked about employment opportunities in each country. Figure 3 shows how countries reported the employment opportunity for audiologists. The results are consistent with the reported shortages, with 66% of countries describing local work opportunities as excellent or very good. Only 3% of countries indicated that opportunities were poor. The availability of professional resources can often be linked to work-place settings, and countries were asked to identify the work environments for their audiologists. Again the responses were not exclusive. Seven countries indicated the question was not applicable to their situation (including Austria, Cambodia, Guatemala, Mali, Romania and Tonga). Hospital settings were the most common environment (89% of countries), while other common work environments included private clinics (64%), universities (62%) and hearing- aid manufacturers (53%). Government clinics (34%) and non-government organizations (26%) were less common. Specialist audiological centres, schools for deaf children, and other regular educational settings, occupational health settings, military and war veteran centres, and hearing aid dispensing clinics were also common.

Education of Audiologists There are not only differences in the levels of audiological resources across countries, but a wide variation in education and scope-of-practice for audiologists across countries. Using the results from the international survey, the educational level of audiologists could be grouped into one of four clusters: (i) medically qualified practitioners who had completed specialisations in ENT and/or additional study in audiology; (ii) non-medically qualified university-educated practitioners who had completed a degree in Audiology; (iii) practitioners who had completed some formal studies in audiology, through a technical or vocational training college or school (but not at university level), or (iv) other practitioners, who had completed University studies in another non-medical field, and who undertook some hearing health care practice as part of their role.

45 40 39% 35 30 27% 23% 25 20

% Countries 15 10 8% 5 3% 0 Excellent Good Fair Poor Not Applicable ReviewEmployment opportunity

Figure 3. Employment opportunities for audiologists.

Education and Practice of Audiology Internationally 63

30 27% 24% 25

20 15% 15 13%

10 8% % Countries 5% 5% 5 3%

0 University University University University Technical University University Other Bachelors Post- Bachelor Masters College Bachelor, Master or Degree graduate or Masters Degree Master or Doctorate Medicine Doctorate

Figure 4. Educational level of audiologists across countries.

Figure 4 highlights the degree to which the educational level varied in the 67% of respondent countries who reported having audiology programs. The majority of these countries were in the upper-middle and high income groups. Audiologists were educated at university level, with most (60%) having university degrees focussed on audiology, and in a small proportion of cases, qualifications in combination with speech, language and communication therapies. Combination qualifications were mostly offered in South American countries, but were also established in South Africa. Some countries had a single educational entry level for the practice of audiology. For example, a Bachelors degree was the minimum requirement in 27% of countries, and a Masters degree in 13% of countries with established programs. Twenty percent of countries with established courses had multiple entry level courses, including Bachelors, Masters and Doctorates. In most countries with established courses the entry level requirement for the practice of clinical audiology was a university-level Bachelors degree in audiology, whereas in 24% of countries with courses any clinical practice involved a medical degree and, in most instances, further qualifications in otolaryngology followed by various levels of a post-graduate specialisation in audiology. These countries also tended to have a wide range of other professionals with differing levels of technical training in specific tasks, including audiometric assessment and/or hearing aid fitting. In 8% of countries with formal audiology education programs, the minimum entry level was a technical college course, usually of two to three years duration. This varied from informal, on-the-job training, through to countries where a vocational or technical college diploma was required. Data on the level and number of programs in each country were also collected. Japan, Brazil and the United States of America offered the largest number of courses, but it was India that was the largest supplier of audiologists, with 1200 graduates per year. These graduates were at both Bachelor and Masters level, and it was estimated that 70% of the postgraduate audiologists emigrated from India within 2 years of graduation. At the time of the survey the United States reported producing a total of 550 graduates per year from a total of 90 programs.Review This suggested that the average number of graduates per course was 6.1 annually. China, Brazil and South Africa, who produced between 50-60 graduates per year, had the largest programs. While most audiology classes had between 10-20 students, many courses (including courses outside the United States) had classes of only 5-6 students.

64 Helen Goulios and Robert Patuzzi

At the other end of the spectrum were the 37% of respondent countries who reported no formal courses in audiology, and these are summarised in Table 3. Almost all of these were developing countries in the low to lower-middle income groups, and they often depended on support from non-government organisations for both direct provision of hearing health care services and for funding for training of local residents to undertake programs offered in other countries. The exceptions to this were Singapore and Switzerland, who had relatively higher per capita GNI, but depended on education of their audiologists through programs in other countries. These audiologists included both expatriates and local residents who had completed their training in other countries There were also countries that produced disproportionately small numbers of graduates given their population bases. These included Croatia, Ireland, China, Malaysia, The Philippines, Thailand and Egypt.

Table 3. Countries without established audiology courses and their support agencies

Country Support countries Funding sources Europe Lithuania Sweden Charity, Individual self-funding Slovak Republic Not available Not available Switzerland Germany Individual self-funding Asia/Middle East Bangladesh India, Thailand Charity, WHO Cambodia Not available Not available Indonesia Not available Not available Laos United Kingdom, Italy Sweden Libya United Kingdom, Italy Government Myanmar Thailand, India WHO, Government Pakistan United Kingdom, Australia Individual self-funding Singapore Malaysia, Australia, UK, USA Government Africa Botswana South Africa, USA Government Madagascar Norway, France Charity, Individual self-funding Mali Not available Not available Namibia Not available Not available Nigeria Not available Not available Americas Belize USA Charity Dominican Republic India, Thailand Charity, WHO Guatemala USA, Mexico, Colombia, Argentina Individual self-funding Nicaragua Colombia, Mexico, USA Charities and NGOs Aust/PacificReview Tonga Not available Not available

Education and Practice of Audiology Internationally 65

Table 4. Percentage countries in which professionals perform clinical activities listed

Clinical Activity Audiologist ENT Audiological Audio- Speech Other Not Physician metrist Therapist Professional Performed Audiometry 48% 12% 0% 21% 2% 13% 2% Tympanometry 50 10 0 21 2 11 4 Play Audiometry 51 5 1 11 8 13 9 Behavioural 59 7 2 11 8 1 11 Observation Visual 54 7 2 10 7 6 13 Reinforcement Hearing Aid 50 11 2 24 2 7 2 (Adult) Hearing Aid 52 10 2 21 2 8 3 (Paed.) Speech Tests 46 9 0 14 3 16 10 OAE 50 12 3 19 0 4 12 ABR 51 18 4 10 0 6 8 ECoG 45 19 2 4 0 3 25 Other 47 16 3 7 0 3 21 Electrophysiology 51 21 2 4 3 2 16 Cochlear Implant Assess. Cochlear Implant 37 9 1 1 18 16 16 Rehab. Rehabilitation 41 6 0 10 20 8 11 Tinnitus 50 30 2 7 1 2 7 Assessment Tinnitus 45 32 2 2 2 0 15 Management Impression 44 8 0 28 2 14 2 CAPD Assessment 43 13 2 7 4 5 24 CAPD 40 14 2 2 11 3 26 Management Neonatal Screening 40 10 1 9 2 19 15 Other Paed. 45 11 2 11 2 15 12 Screening Balance 42 27 0 11 0 3 14 Assessment Balance 38 22 0 2 0 13 22 Management Hearing 42 9 2 11 0 13 21 Conservation Noise Management 38 8 2 5 0 19 26 Vibrotactile Aid 36 7 2 2 3 5 43 Educational 35 7 0 7 8 34 7 Audiology Review Mould make-up 22 5 0 27 2 34 5 Wax Management 14 76 0 2 0 6 0

66 Helen Goulios and Robert Patuzzi

Scope of Practice Despite the wide variation in educational levels, there was significant overlap in the scope of practice of audiologists educated in different countries. Countries were asked to indicate which professionals performed 30 pre-defined audiological clinical activities. Respondents were also given the opportunity to include other activities performed by audiologists in their country. These results (Table 5) show that there were primarily three professionals that undertook most activities, that there were many other professionals involved in some aspects of audiological practice, and that there was a significant proportion of countries (mainly developing) in which many of these activities were not performed. The three main professionals were (i) the audiologist (including all professionals with a non- medical university qualification in audiology in addition to audioloogs, fonoaudiologists, phonoaudiologists and professionals with a combination audiology/speech language qualification), (ii) the ENT surgeon and (iii) the audiometrist (including audiological and ENT technicians and hearing-aid acousticians, and dispensers without a university qualification).

Learning Pathways in Hearing Health Care Education It is evident from Table 4 that hearing health care is provided by a wide range of professionals, with a large overlap in their scope of practice. The time, complexity and costs involved in education and training of ENT surgeons, would suggest their time is best spent undertaking medical and surgical activities. Less time and money is required to train audiologists, and the focus of their work is the assessment and management of the non- medical aspects of hearing impairment. Over the last 50 years, the ratio of audiologists to ENTs in Australia has grown from almost zero to over four audiologists per otolaryngologist. We suggest that this rise is an indicator of the maturation and improved cost-effectiveness of the Australian hearing health care system (although there are still problems). The complex interaction between issues makes it difficult to determine the optimal mix between highly trained audiologists and other hearing care providers with less training. Rapidly advancing technologies and some complex hearing disorders require complex diagnostic tests, and many aspects of audiological practice require highly skilled professionals. Other aspects of audiological work require a lower level of skill and training, and this survey highlights the many categories of hearing care professionals that undertake a narrower range of clinical activities and, most often, assessment of non-complex hearing disorders and the fitting of hearing aids in adults. However, in developed countries adult hearing aid cases are often the most profitable, leaving the more highly-trained audiologists to perform the most complex, the most time-consuming and least profitable tests (including electrodiagnosis and paediatric testing). It has been suggested that the shortage of highly trained audiologists in developed countries might be solved by “upskilling” other less trained hearing care workers. Assuming that such a move would be (financially) attractive to such workers, it is not clear whether it is possible. The concept of a “learning pathway” for hearing care professionals may seem attractive, butReview it assumes that students can progress from vocational training through to a university qualification. Universities all set their entry requirements to accept students with a proven ability and commitment to complete a course at a university level, whereas (in developed countries) students who undertake vocational or technical training often do so because they have not met the minimum university entry requirements. This can lead to a

Education and Practice of Audiology Internationally 67

mismatch between students and courses in such an upgrade process. Consideration also needs to be given to the economics of implementing such a 'learning pathway', and its impact on the long-term sustainability of the highly specialized university programs required for more complex cases.

Evolving Educational Requirements for Hearing Health Care According to the International Society of Audiology (ISA), “Audiology deals with the knowledge, protection and rehabilitation of human hearing”, although the profession of audiology in many countries also includes assessment and rehabilitation of balance and other related disorders. The European model of hearing health care has been traditionally based on medically qualified practitioners, and supplemented with non-medically qualified personnel and/or non-university personnel. However, there have been rapid development and expansion of audiology into scientific and clinical fields over the last few decades, and this was recently acknowledged by the European Federation of Audiological Societies (EFAS, 2001), which then proposed the model of a “General Audiologist” as the primary contact person for hearing-impaired people (supported by other professional groups already providing some audiological services). This model has also been accepted by the ISA (2004), which proposed a four-year undergraduate curriculum in audiology, primarily targeted at countries without established audiology programs. Both societies agreed that the “General Audiologist” model should produce graduates in audiology, while maintaining contributions by the many other related professions currently involved in the field. The model also recognised the considerable variation in the way audiology was organized within each country’s health system. Overall, the intention of the “General Audiologist” model was to provide a framework (including a curriculum outline) for countries without established programs, while understanding that the timeframe for implementation in many countries was likely to be gradual. However this model did not consider economic or operational issues associated with running a course or a health care system, and this may impede its acceptance by many countries. The design of audiology courses is complicated even further by relatively rapid changes in the profession, offering a moving target for planners. For example, even in countries with longstanding programs, audiology courses have evolved in recent years. The United States currently has the longest training program for audiologists without prior medical training. In the 1960’s the entry-level qualification for audiology in the US was a Masters degree, which varied from an 18-month to a two-year postgraduate program. The profession in the United States argued that the changing and widening scope of practice necessitated educational changes, and raised the minimum requirement to a four-year postgraduate professional doctorate (Harford, 2000). The objective was to address advancements in technology by upgrading to a four-year clinical doctorate; however, the viability of such courses has been questioned. The US already has the largest number of audiology courses in the world, with this survey reporting 90 programs producing a total of 550 graduates per year. This compares with Florian’s (2002) report of 123 university level programs producing an average of only 6 graduates perReview program, which even then drew into question graduate quality and long term sustainability of the programs. The evolving educational requirements are different again in countries that offer combination audiology and speech-and-language pathology qualifications. There are also competing influences on course design. While advancing technologies and broadening scopes

68 Helen Goulios and Robert Patuzzi

of practice in developed countries place pressures on educational institutions to specialize and/or lengthen programs, the community needs in developing countries place pressures in the opposite direction (with shorter courses and higher student output). Swanepoel (2006) outlined the recent changes in South Africa, which has a four-year combined program for both audiologists and speech-language therapists. Institutions have begun offering a choice of either audiology or speech-language therapy, but there has been resistance to this. As a developing country, South Africa has a primary health care system reliant on generalist professionals who are able to attend to a wide range of communication disorders. To encourage this, the public system in South Africa prefers to employ professionals with the combined qualification. The opposite is seen in the private sector, where the professions tend to be practised separately to keep up with increasingly specialised services. Swanepoel has also pointed out that to meet the audiology needs of the broader South African community, hearing care service delivery has moved towards preventative community-based models that provide basic care, rather than more specialized institution- based services that are more common in developed countries. This highlights the problems faced by course designers and educational funding agencies in a single country, when they are expected to develop and fund a single course or service for multiple communities with different needs. This problem is not exclusive to developing countries, but also exists in many developed ones.

Multiple Communities within Single Countries This chapter has largely focused on hearing health care practice and education for individual respondent countries, with each description presumed to be representative of the whole country. However, there are different communities within all countries, and the social and economic environments for hearing care are not homogenous within any country. For example, Swanepoel (2006) has pointed out that, for the majority of South Africans, there are insufficient audiologists. The audiologists are unequally distributed between the public and private sectors, and are more easily accessed by the more affluent minority who speak their language. There are similar situations in other developing countries, where a wealthy minority has access to the highest quality services, and the majority has little or no access to a poor service. Such disparities also exist in many developed countries, and in particular those where the indigenous populations have become the minority groups, with significantly poorer health and living standards. For example, the highest prevalence rates in the world for chronic otitis media are present among the Aboriginal and Torres Strait Islander people of Australia, the Inuit people of Canada, and the Native Americans in the United States (WHO, 1996). Many of these communities are remote, economically disadvantaged, and have cultural and language differences with the majority. All of these factors compound their difficulties in accessing appropriate hearing services, and need to be taken into consideration in designing education models and hearing care services. Future strategies and programs tailored to groups of countries may also apply to sub-populations within any single country.

A ConceptualReview Model for Hearing Health Care Education While the design of models for hearing health care services and education is already complicated by the 'simple' problem of multiple professions serving multiple communities, the 'design problem' is complicated even further by many other interacting issues. In order to open the discussion on the efficiencies of hearing health care education, we have developed a

Education and Practice of Audiology Internationally 69

model of the hearing health care service provision and training, as shown in Figure 5. The model has education as its focus and refers to all levels of hearing health care education. The discussion below walks the reader through this model. Referring to Figure 5, education of hearing health care service providers produces local professionals able to provide appropriate hearing services. This pool of local professionals is built primarily by education programs, but can be changed by migration, and depends on an environment that provides competitive employment opportunities and conditions for graduates. Because of the need for intensive clinical teaching and the use of complex equipment, the education model needs to be built around and supported by the existing public and/or private health infrastructures (including NGOs). The foundation of the model is the economy of the country, itself shaped by its history and politics, which influence both the mix and complexion of the private and public economies. For this discussion we have shown the education system/s as separate from the public/private hearing health care infrastructures which themselves interact, with public seeding money building private systems, and private philanthropy feeding public systems. These in turn impact on the public and private infrastructures that support the country’s health system.

Figure 5. ConceptualReview model of hearing health care.

70 Helen Goulios and Robert Patuzzi

Again referring to Figure 5, once the public and private infrastructures are established, the efficiency of service provision (including prevention and rehabilitation) determines the disease burden of hearing impairment, and ultimately affects a country’s economy. At the same time, the prevalence of hearing loss, its recognition, and its diagnosis determine the “perceived need” for hearing health care services, and consequently the demand for hearing health care graduates. This places pressure on educational institutions to produce more or less professionals. The perceived need for services also contributes to the level of demand and resulting public pressure placed on governments, public services and/or private service provision. Education of professionals is also influenced by the level of public health awareness of the consequences of hearing impairment. This public awareness hopefully affects the provision of hearing services through non-professional personnel working in decentralized, community-based environments (possibly separate from the formal public and private infrastructures). The efficiency of such (informal) non-professional interventions also impacts on the burden of disease. The model presented in Figure 5 provides a simple basis for discussing the factors that may influence the provision of services, and the possible strategies for the developing appropriate education models. The model also formalizes the feedback loops which may affect the success of possible interventions within a given system. For example, tracing around the model of Figure 5, it is clear that an increased output of trained graduates should lead to increased service provision, and a drop in disease burden, and ultimately the number of graduates required. That is, one goal of a health care system is to ultimately put its graduates out of work by eradicating disease. In a rapidly expanding health care system, it is possible for the heath care workers to be so effective that their success either threatens their own job security, or requires a change in the nature and output of the education process. This is important in considering the sustainability and adaptability of a hearing health care service system and its associated education process. As another example of a feedback loop within the model of Figure 5, graduates need to be presented with a clear and sustainable career path. If either the public or private infrastructure is absent or underdeveloped, not only will effective service provision be reduced, but graduates are unlikely to stay within their country or region. The success of an education program requires concurrent development of infrastructure, and presumably hearing health care markets. In this context, the private sector is clearly a necessary component of the development of a hearing health care system, and alliances and synergies need to be developed in a timely way. As one final example of a feedback loop, a successful private sector leads to increased profits being re-invested in both infrastructure and education. Unless governments make private companies welcome and successful, no private infrastructure will prosper, and an important contribution to the overall hearing health care would be lost. In this context, the sizeable middle class in many developing countries or regions may serve as a nucleation site, allowing ultimate growth of, first, a private health care system, but later (or concurrently) a public system. The existenceReview of feedback loops within a hearing health care system is also important in terms of the dynamics of change. For example, it may be that the production of many effective graduates may ultimately reduce ear disease, but the time required for such a feedback loop to produce secondary effects varies enormously between countries and regions. In China for instance, it will take many years with the present system to produce any

Education and Practice of Audiology Internationally 71

significant impact on hearing health care. In Zhejiang province, with a population of 40 million, there are 60 audiology graduates per year from one of China’s most successful programs. This graduation rate would require at least 40 years to produce a level of service provision approaching that in Australia. Conversely, in Australia, although doubling the number of audiology graduates from its courses would reduce shortages that presently exist, within a few years the hearing health care needs would be satiated, and a crisis in the profitability of audiology courses may emerge. The difference between China and Australia is not so much a difference in systems, but one of system size and system starting point. For example, a limiting factor in increasing the rate of graduate production is the availability of clinical placements within a community. This would be an even greater issue for countries without established programs and existing hearing health care infrastructure, and alternative mechanisms to supplement and/or replace traditional clinical practica would be needed. The development of cost-effective and sustainable audiology programs (hearing health care and education) will require due recognition of the existence and time scale of the feedback loops evident in Figure 5.

Possible Solutions We hope that the data and the conceptual model we have provided in this report may help others in developing their own strategies. For the remainder of this paper we offer our view on possible solutions. The lack of public and professional awareness was one issue shared by both developed and developing countries, and it is perhaps the most easily addressed. It would be relatively simple and economical for professional societies to contribute both nationally and internationally through programs to increase public awareness of the impact of hearing impairment, and of the profession of audiology. In developed countries the issue of cost-effectiveness of audiology education programs was identified. This is primarily a result of the complexity of audiology, the high cost of equipment, and the low student-staff ratios. A possible solution would be for institutions to increase student fees and lengthen their courses, largely shifting the burden of an inefficient education process onto the students themselves. Although this may solve the problem in the short term, it seems unlikely to work in the longer term if the salary expectations of graduates are not met. At best, graduates would pass the cost of their education to clients. Inefficiencies in the education systems could be addressed if a small number of problems were overcome. For example, courses could enroll larger numbers of students in fewer programs to improve the student-staff ratios and reduce salary costs. However, there are at least three hurdles to overcome: (i) geographical isolation, requiring multiple courses across large countries; (ii) limits to increases in supervised clinical placements, especially during chronic shortages of and large workloads for existing audiologists; and (iii) an unwillingness of academic institutions to sacrifice courses that might be profitable or prestigious. Courses in developed countries will need to use more cost-effective teaching techniques, including national and international exchange of course material and resources, the development of less expensive teaching equipment,Review the use of new communication technologies to overcome problems in distance and time, and more inventive ways to provide high level clinical supervision to students. The issue of language barriers will need to be addressed, but the translation of international courses is probably a simpler problem to resolve than developing local courses de novo.

72 Helen Goulios and Robert Patuzzi

Of particular importance to the initiation of courses in developing countries is the issue of clinical supervision. A solution of this same problem in developed countries may provide some help to new courses in developing countries. However, strategies for developing countries will also need to focus on a parallel development of hearing health care infrastructure. Given the other major health priorities of these countries, it is likely that funding will need to come from a mix of public and private sources, probably based on development of markets for the middle class. The issue of course equivalency also needs to be a high priority if there is any chance of pooling resources (including graduates) to address the international shortage of hearing care services and education. World globalization already affects hearing health care, most often as the permanent migration of professionals from developing countries to developed ones with better employment conditions. Perhaps programs could be designed to allow temporary movement of students or recent graduates to more developed systems where they could gain experience that they could bring back to their countries of origin.

CONCLUSION

It is clear that most countries need more audiologists, with these shortages greatest in developing countries. In future, the ageing population and more advances in technology are likely to place further pressures on hearing health care service provision. There is already evidence that wealthier countries try to fill their needs by attracting graduate audiologists from the developing world. This pattern of movement is likely to continue in the short term, and is consistent with increasing trends in health globalisation. It is also evident that the dominant reasons for these shortages are different for developing and developed countries, but there are some shared problems. For developed countries with established audiology programs, courses need to become more cost-effective by sharing resources, by adopting more inventive methods for course delivery, with less expensive equipment for teaching. Developing countries must initially concentrate on strategies that allow the initiation of education programs. As we have argued, this will depend on the establishment of strong alliances within and between countries involving governments, private industry, educational institutions, professional bodies and, wherever possible, consumer organizations. This chapter introduced a conceptual model that can be used to discuss the interactions between the main issues involved in the provision of hearing services, and subsequently examined the efficiencies of hearing health care education. It is one step in the development of affordable, cost-effective hearing health care education models that can be adapted for local environments, and produce graduate numbers to ensure a steady-state supply of services.

ACKNOWLEDGEMENTS The authorsReview would like to thank Dr Andrew Smith from the World Health Organisation for his assistance with locating worldwide contacts for hearing health care organizations. The authors also convey their thanks to the following people for their time and contributions to the international survey: Ms. L. Abano, Ms. Anneli Ahlers-Cuadra, Prof. J. Attias, Mr. D. Akinyemi, Asociación Argentina de Logopedia Foniatria y Audiología (ASALFA), Prof.

Education and Practice of Audiology Internationally 73

A.G. Mohamed Alhousseini, Prof. M. N. Amin, Dr. P. Berruecos, Dr. D. Bouccara, Mr. J. Brown, Dr. P. Castellanos, Dr. B. Christensen, Prof. Xingkuan Bu, Ms. D. Carkeet, Dr. Sheng Hwa Chen, Dr. Qasem Daraiseh, Prof. W.A. Dreschler, Dr. A.M. Dugdug, Ms. M. Escobar, Dr. C. Farfan-Reyes, Dr. U. Froeschl, Dr. V. Gladstone, Dr. P. Govaerts, Mr. S. Govil, Ms. M. Gunn, Dr. T. Gvelesiani, Dr. H. Hendarto, Assoc. Prof KM Holgers, Ms. C. Lalonde, Prof. E. Laukli, Prof.T. Lenarz, Mr. K.T. Ling, Dr B. McPherson, Dr J. Madriz, Dr. N.V. Martinez, Dr. H. Meister, Ms. O. Otto, Dr. T. Pitt, Mr. J. Parsons, Dr. S. Prasansuk, Prof. M. Profant, Dr. T. Randrianarisoa, Ms. M. Redzuan, Dr. D. Reed, Dr. L.C.P. Russo, Dr. Lei Saafi, Dr. E. Salesa, Dr. M. Serrano, Prof. M. Shiroma, Dr. I. Siddiqui, Dr. T. Spillmann, Dr. DeWet Swanepoel, Prof. S. Tawfik, Dr. T. Thepsomphon, Mr. Erlett Thomas, Dr. P.M. Towle, Dr. R. Trotic, Dr. G. Tejada, Prof. T. Tun, Dr. B. Walter, Prof. V. Uloza, Dr. J. Vatovec, Mr. G. Vaughan, Dr. K. Welzl-Mueller, Prof. Wieslaw, Prof S. Zakzouk and Dr D. Zanetti.

REFERENCES

Alauddin, M. & Joarde, A.H. (2004) Deafness in Bangladesh. In J. Suzuki, T. Kobayashi and K. Koga (Eds.), Hearing Impairment: An Invisible Handicap (pp. 64-69). Tokyo: Springer-Verlag. Bess F.H. & Humes L.E. (2003). Audiology: The fundamentals. (3rd Edition) Baltimore, MD: Lippincott, Williams and Wilkins. Burkhard R (2002). Educating Audiologists: Diversity or homogeneity? American Journal of Audiology, 11, 4-7. Eleweke, C.J. (1997) Provision of audiological services in Nigeria: what future? Scandinavian Audiology Supplement, 45, 47-53. European Federation of Audiological Societies (2001). Audiology in Europe. The General Audiologist – A proposal for a model training program in general audiology for Europe. http://www.efas.ws/download/GA%20Revision%204.1.pdf retrieved 15 May, 2005. Farkas, Z. & Ribari, O. (1997). Some data on the audiological situation and ear care in Hungary and in some central and Eastern European countries. Scandinavian Audiology Supplement, 45, 55. Florian J (2002) The proliferation of AuD programs: Is it too much of a good thing? The Hearing Journal, 55 (2) 23-32. Frenk, J., Gomez-Dantes, O., Adams, O. & Gakidou, E.E. (2001). The Globalisation of Health Care. In M. McKee, P. Gamer, & R. Stott (Eds.). International Co-operation in Health (pp. 31-47). Oxford: Oxford University Press. Goulios, H. & Patuzzi, R.B. (in press). Audiology education and practice from an international perspective. International Journal of Audiology. Harford E.R. (2000). Professional Education in Audiology. In H. Hosford-Dunn, R.J. Roesser & M. Valente M (Eds.). Audiology Practice Management (pp. 17-40). New York: Thieme. InternationalReview Society of Audiology (2004). Curriculum in Audiology. The General Audiologist – A proposal for a model training program in general audiology. Madriz, J.J. (2001). Audiology In Latin America: hearing impairment, resources and services. Scandinavian Audiology, 30 (suppl. 53), 85-92.

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Olusanya, B.O. (2000). Hearing impairment prevention in developing countries: making things happen. International Journal of Pediatric Otorhinolaryngology 55, 167-171. Salmivalli, A. & Sorri, M. (1997). Ear care programs for Estonia. Scandinavian Audiology Supplement, 45, 41-42. Suwento, R. (2004). Hearing health infrastructure in Indonesia. In J. Suzuki, T. Kobayashi and K. Koga (Eds.), Hearing Impairment: An Invisible Handicap (pp. 45-48). Tokyo: Springer-Verlag. Swanepoel, D. (2006.) Audiology in South Africa. International Journal of Audiology. 45, 262-266. World Bank (2007). Country Classification Data. http://siteresources.worldbank. org/DATASTATISTICS/Resources/GNIPC.pdf. Retrieved 10 August 2007. World Health Organization. (1996). Prevention of hearing impairment from chronic otitis media. Report of a WHO/CBM Workshop. Geneva: World Health Organisation. http://www.who.int/pbd/deafness/en/chronic_otitis_media.pdf. Retrieved 20 August, 2007. World Health Organization. (2004). Guidelines for hearing aids and services for developing countries. Second Edition. Geneva, World Health Organisation. http://www.who.int/ pbd/deafness/en/hearing_aid_guide_en.pdf. Retrieved 20 August, 2007. World Health Organization. (2006a). The World Health Report 2006: Working together for Health. Geneva: World Health Organization. (http://www.who.int/whr/2006/en) Retrieved 20 August, 2007. World Health Organization. (2006b). WHO Statistical Information Systems. http://www. who.int/whosis/whostat2006HealthFinancing.pdf. Retrieved 20 August, 2007.

Review

Chapter 5

SCREENING FOR HEARING LOSS IN DEVELOPING COUNTRIES

Bradley McPherson1,* and Bolajoko O. Olusanya2 1Centre for Communication Disorders, University of Hong Kong, China 2Department of Community Health and Primary Care, University of Lagos, Nigeria

ABSTRACT

Hearing loss is often undetected in all age groups in developing nations as routine hearing screening is uncommon, especially for children. The limitations of current preventive programs make hearing screening activities a high priority component of a hearing health care program in some developing countries. Infant hearing screening allows for the prompt detection of congenital and early onset hearing loss, and is essential for timely intervention within the period most crucial for optimal speech and language development. This chapter considers the basic requirements for infant and other hearing screening programs in situations where personnel and financial resources are limited and describes programs that seek to overcome such obstacles. The ethical standards that should govern screening activities are described. Priority populations for screening are suggested and appropriate techniques for screening in developing countries are outlined. The use and examples of culturally appropriate screening strategies are discussed, particularly for environments where a significant proportion of births occur outside regular hospital facilities. Possible challenges and recommendations for effective screening programs are also highlighted. The value of preschool surveillance is discussed in view of the adverse impact of hearing loss on educational achievement. Primary school enrolments are expanding in many developing nations and schools provide an important and convenient venue for screening. School-based hearing screening, especially at school entry, is common for the identification of childhood hearing loss in many developing countries.Review Other hearing screening programs may consider adults, particularly for those groups at known risk of hearing impairment, such as workers exposed to industrial hazards that affect hearing and those with illness associated with hearing loss.

* Correspondence: [email protected]

76 Bradley McPherson and Bolajoko O. Olusanya

INTRODUCTION

Both children and adults in developing countries are often at high risk of undetected hearing loss. Current attempts to curtail the burden of this condition through primary prevention are inadequate and sometimes ineffective. This leads to a need to consider screening programs to identify individuals with hearing loss. The present chapter provides an overview of current issues in general screening audiometry relevant to the particular hearing health needs of people in developing nations. A number of present day screening programs in developing countries are then reviewed and possible future screening procedures discussed. About 50% of the burden of hearing loss is believed to be preventable or avoidable (Smith, 2003). Current activities aimed at preventing hearing loss include the promotion of immunization against known causes of hearing loss such as measles, mumps and rubella; improved care of mothers before and during child delivery; and education on the use or misuse of ototoxic drugs. However, the healthcare systems in many developing countries are unable to maintain these standards of care. Even if it were possible to attain these standards, the remaining 50% of the burden of hearing loss is unavoidable. This includes childhood hearing loss attributable to hereditary and genetic factors. For this reason it becomes necessary to identify cases of hearing loss promptly through “secondary” prevention in order to minimize its consequences. Screening is the best known secondary prevention process for hearing loss.

DEFINITION AND PRINCIPLES OF SCREENING

Screening for the early detection of health problems is an integral part of a public health care system (Reynolds, 1982). Screening has been defined by the World Health Organization (WHO, 1971, p. 10) as a “medical investigation that does not arise from a patient’s request for advice for specific complaints. The term covers all types of examinations and does not refer to their speed or accuracy”. This definition points to the routine, public health managed nature of the process in which an investigation is triggered by an administrative system and not a patient initiative. In this way “screening is a process by which individuals are identified who may have diseases or disorders that are otherwise undetected” (Harford, Bess, Bluestone, & Klein, 1978, p. 4), i.e., the “finding of asymptomatic cases” (Haggard & Hughes, 1991, p. 235). Screening usually implies the examination of large population groups—“mass screening” is a commonly used term. Thorner and Remein (1982, p. 408) make this explicit when they state that the:

“basic purpose of screening for disease detection is to separate from a large group of apparently well persons those who have a high probability of having the disease under study, so that they may be given a diagnostic workup and, if diseased, brought to treatment.”

Within Reviewthis statement is the implication that the main purpose of screening is to benefit the individuals being examined (Wald, 1994). Wilson and Jungner (1968) make explicit ten basic principles that screening programs should adhere to. These are:

Screening for Hearing Loss in Developing Countries 77

1. The condition to be screened for should be an important health problem. 2. There should be an accepted treatment for cases identified. 3. Facilities for diagnosis and treatment should be available. 4. There should be a recognizable latent (early, asymptomatic) stage in the condition. 5. There should be a suitable test to employ in screening. 6. The test should be acceptable to the population. 7. The natural history of the condition should be understood. 8. There should be an agreed policy on whom to treat as patients. 9. The cost of case-finding (including diagnosis and treatment of those diagnosed) should be non-wastefully balanced in relation to expenditure on medical care as a whole. 10. Case-finding should be an ongoing process and not a ‘one-off’ project.

Hearing screening programs, in industrialized societies and developing countries, should always be considered in relation to these ten principles, which encompass political, economic, social, and health issues as well as the technical characteristics of the screening test itself.

ETHICS OF HEARING SCREENING

In selecting an appropriate screening procedure, a logical approach is to initially consider those aspects of ear disorder and hearing loss in a community that impact on the application of Wilson and Jungner’s principles of screening (1968). These principles can be used as a basis to consider the ethics of a proposed program. Screening programs should only commence if they can provide satisfactory assurances that they can meet all these criteria.

1. The condition to be screened for should be an important health problem. A case could be made that hearing loss caused by middle ear disorder in some parts of the developing world is a serious health concern. Otitis media with effusion is a major cause of hearing loss in some developing countries (Smith & Mathers, 2006) and may lead to dangerous intratemporal complications such as chlolesteatoma or mastoiditis. Hearing loss in general also assumes importance when the associated long-term social, educational and economic disadvantages are considered from a public health perspective (Access Economics, 2006; Mohr et al., 2000). 2. There should be an accepted treatment for cases identified. Effective medical, surgical or rehabilitative treatments are known to improve the thresholds of children with hearing loss. For example, there are “accepted treatment” protocols that can be used as a rationale for the detection of school children with hearing loss. Ethically, it is essential that appropriate treatment is available for children identified with hearing disorders. Controversy can exist over what is “acceptable” treatment in developing countries. Some audiologists may argue that thisReview encompasses at least primary health care for ear disease and provision of hearing devices for those in need of amplification. Others, such as McPherson and Holborow (1988) argue that identification of hearing loss can be a positive event in the life of children, even if provision of hearing aids is not feasible. They consider that raising the awareness in teachers and parents of children’s disabilities may in itself improve

78 Bradley McPherson and Bolajoko O. Olusanya

a child’s educational opportunities. This view was supported by Braveman and Tarimo (1994, p.101) in their recommendations for hearing screening in developing countries. 3. Facilities for diagnosis and treatment should be available. There can be great disparities in health service delivery among different developing countries and among regions within developing countries. In particular, there are inadequacies of many rural health systems (World Bank, 2005). The exact nature of local services that can assist in the diagnosis and treatment of school children with hearing loss and ear disorder needs to be ascertained prior to establishing any identification program. This is especially important if medical treatment alone does not prevent the disorder and ongoing tertiary prevention of an audiological nature is required. Many audiologists consider no form of screening should be conducted unless facilities for diagnosis and treatment are available (Gell et al., 1992). Some professionals do, however, consider that screening with a primary focus on collecting information on the prevalence and nature of hearing disorders is also justifiable (Jauhiainen, 2001). However, such programs are better labeled as ‘prevalence studies’ rather than screening programs. 4. There should be a recognizable latent (early, asymptomatic) stage in the condition. If looked at from a holistic, developmental perspective, hearing screening can be justified as averting long-term social and academic handicap if carried out, for example, before or during periods of critical language acquisition or the early, formative years of primary school education. 5. There should be a suitable test to employ in screening. This principle refers to the need for a screening test that is relatively simple to perform, and has sensitivity/specificity characteristics that minimize over-referral to diagnostic centers. There are well-established procedures for screening hearing, such as pure-tone audiometry, that may be appropriate in developing countries. 6. The test should be acceptable to the population. In the context of hearing screening, this principle leads to the consideration of the cultural appropriateness of the screening procedures used. The appropriateness of a procedure may vary according to the population being served. For example, screening of school children at a community hospital may result in poor compliance in a community where hospitals are viewed as places only for the sick (Olusanya & Okolo, 2006). To be ethically sound, a test procedure used in screening should be acceptable to the target community. 7. The natural history of the condition should be understood. The natural history of diseases associated with hearing loss has been scientifically studied for many years. Although gaps in our knowledge of some conditions’ pathogenesis and natural history are still apparent, there is usually adequate information on which to base screening programs. Exceptions might be where hearing loss is associated with new or emerging diseases such as Lassa fever (HinchcliffeReview & Prasansuk, 2006). 8. There should be an agreed policy on whom to treat as patients. Clear pass/fail criteria need to be established and acted upon in a consistent manner for any hearing screening program to function effectively (WHO, 2004a).

Screening for Hearing Loss in Developing Countries 79

9. The cost of case-finding (including diagnosis and treatment of those diagnosed) should be non-wastefully balanced in relation to expenditure on medical care as a whole. This is an economic and, ultimately, political question for health service managers. The sensitivity/specificity, speed and simplicity of a screening test, will contribute to the final decision on the procedure’s overall cost and possible introduction. However, complex decisions need to be made regarding the ability of the health care system to manage patients with hearing loss and the competing needs of other health care programs (Olusanya, McPherson et al., 2006 and White, 2006 provide a highly relevant discussion of such issues). 10. Case-finding should be an ongoing process and not a ‘one-off’ project. There is little point in creating the complex procedural system necessary to implement school hearing screening and referral, or to initiate the training of screening personnel, or purchase screening equipment, unless the program is to be of a significant duration. To be ethically sound, screening programs in developing countries should, at all times, be viable and make a long-term commitment to their community (Miles, 1984).

INFANT HEARING SCREENING

Significance of Prelingual Hearing Loss

Hearing loss before or during the development of speech and language is referred to as prelingual hearing loss. It includes permanent congenital and early-onset hearing loss. Congenital hearing disorder could manifest postnatally as late-onset, progressive or acquired hearing loss, with varying degrees of severity. “Early-onset” refers to the first twenty-eight days of life. The ability to read and write is predicated on a solid foundation in language skills. The effect of hearing loss on language development is intricately linked to the sensory development of the infantile brain and nervous system (Hannon, 2003; Ruben & Schwartz, 1999; Sininger, Doyle & Moore, 1999; Stockard-Pope, 2001). The human fetus can hear by 27 weeks gestation and the auditory sensory mechanism of the human neonate is fully functional at birth. In addition newborns have been observed to demonstrate selective response to their mothers’ voices. The experience of listening to the same voice in-utero has been advanced as a possible reason for this observation. From the knowledge of neural plasticity it is understood that the compensatory and reorganizational possibilities of the brain are significantly greater in very early childhood than in later life. This is applicable to the auditory system as well as other structures of the central nervous system, which underpin cognitive development. In fact, infants less than 6 months of age are superior to adults in their ability to discriminate speech sounds from languages other than those to which their family is exposed. However,Review the second half of the first year of life reflects a preference for the sounds and pattern of their native language, signifying the beginning of cortical maturation. Similarly, it is suggested that the individual sensory organs only reach their full development or in the case of hearing loss, their maximum functional potential if they are intensively

80 Bradley McPherson and Bolajoko O. Olusanya

stimulated before neural maturation. This has led to the concept of a sensitive or critical phase, which refers to the optimal period for the required sensory stimulation. The period from birth to five years is considered as the critical/sensitive phase for the development of language, while hearing during the first year of life is crucial for normal acquisition of language (Carney & Moeller, 1997). Studies have demonstrated that the detection of prelingual hearing loss and the provision of amplification within a family- oriented intervention program in the first year of life are associated with favorable outcomes in speech and language development (Kennedy et al., 2006; Moeller, 2000; Yoshinaga-Itano, Sedley, Coulter & Mehl, 1998). In contrast, children not detected or detected late may never catch up with their normal-hearing peers in their academic, social and emotional development even with the best of rehabilitation. Hearing loss in infancy is considered as significant if the degree is such that it would interfere with normal speech and language development. Moderate-to-profound bilateral permanent hearing loss (>40 dBHL) in early childhood can impede speech, language and cognitive development (Ramkalawan & Davis, 1992; Robinshaw, 1996). Language delays resulting from hearing loss usually hinders development of literacy skills. Even children with mild or unilateral permanent hearing loss may experience difficulties with speech, language, educational and psycho-social development (Blair, Peterson & Viehweg, 1985; Culbertson & Gilbert, 1986; Keller & Bundy, 1980). Developmental delays in language therefore have adverse effects on social, emotional and academic development with a high cost to society (Bess, Dodd Murphy & Parker, 1998; Davis, Elfenbein, Schum & Bentler, 1986; Mohr et al., 2000; Schroeder et al., 2006).

Prevalence of Hearing Loss in Early Childhood

Epidemiological data on early childhood (0-5 years) hearing loss in developing countries is scarce or of limited value due to the lack of infant hearing screening programs. Available studies are predominantly among school-aged children in schools for the deaf or mainstream schools. In developed countries, the incidence of congenital hearing loss is 2 to 4 per 1000 live births (White, 2004). If the poorer health and socio-economic conditions in developing countries and the significant proportion of births occurring outside hospitals were considered, the incidence of permanent congenital and early-onset hearing loss (or prelingual hearing loss) is likely to rise to at least 6 per 1000 live births in this region (Olusanya, Ruben & Parving, 2006). Of the 133 million annual live births in developing countries, about 798,000 are likely to have permanent congenital and early-onset hearing loss based on the latest estimates by the United Nations Children’s Fund (UNICEF, 2005). These data demonstrate that prelingual hearing loss is perhaps an even more significant health problem in developing countries than in developed countries where newborn hearing screening is now a standard aspect of neonatal care. Review

Screening for Hearing Loss in Developing Countries 81

The Significance of Early Detection

Prior to the advent of objective hearing screening tests in developed countries, the median age of identification varied from 10.4 months to 43.2 months depending on the degree of hearing loss (Harrison, Roush & Wallace, 2003; Marttila & Karikoski, 1996; Parving, 1999; Watkin, Baldwin & McEnery, 1991). Parents were usually the first to suspect hearing loss but confirmation was always considerably delayed, sometimes by the physicians’ doubts about the possibility and efficacy of hearing screening in newborns and infants (Kittrell & Arjmand, 1997). In developing countries parental suspicion prompted by a child’s inappropriate response, or lack of response, to sound is still the predominant mode of detection and occurs usually at a mean age of 22 months (Gopal, Hugo & Louw, 2001; Mukari, Vandort, Ahmad, Saim & Mohamed, 1999; Olusanya, Luxon & Wirz, 2005). The development of reliable screening instruments and higher prospects of mainstreaming severe-to profoundly hearing impaired children through improved amplification options in the last decade has stimulated the trend towards early detection and intervention through newborn or infant hearing screening. An ideal screening test would be simple to apply, safe and valid. It is valid if it detects the majority of subjects with the target disorder (high sensitivity) and excludes most subjects without the disorder (high specificity) and if a positive test indicates the presence of the disorder (high positive predictive value). Two objective screening tests currently available for detecting infants with hearing loss are otoacoustic emissions (OAE) and auditory brainstem response (ABR). Screening with OAE – either as transient evoked otoacoustic emissions (TEOAE) or distortion product otoacoustic emissions (DPOAE) – is an electro-physiologic measure of the integrity of the outer hair cells in the cochlea. OAE, also known as cochlear echoes, are low intensity sounds originating from the outer hair cells and can be elicited in response to clicks presented to the ear through a light weight probe that houses both a transducer and microphone/receiver. The emissions are recorded and displayed in a waveform for interpretation in diagnostic instruments or simply produce a ‘pass’ or ‘fail’ result in OAE screeners. The test is relatively quick, non-invasive and does not require sleep or sedation, which makes it readily tolerable by babies and acceptable to parents. The recording often takes about one minute and can be administered without audiological expertise. The test has high sensitivity (>90%) and specificity (>96%) based on two stage screening (Davis et al., 1997; JCIH, 2000) in developed countries. One disadvantage with this test is that it is sensitive to conductive hearing loss, which may result within the first day of life due to a vernix plug in the external ear canal. It is also sensitive to peripheral impairments but will not detect auditory neuropathy. The DPOAE differs from click stimulus TEOAE in that it is stimulated by two continuous pure tones introduced to the ear simultaneously and produces frequency-specific signals across the range 500 to 8,000 Hz. However, this advantage is not critical for screening newborns and young children. Besides, DPOAE may miss mild hearing loss due to the higher level of the stimulus signals. ABR is an electrophysiologic measure of the function of the eighth cranial nerve and the auditory pathwayReview in the brainstem. The electrical response to auditory stimuli is recorded with three surface scalp electrodes and it is not state-dependent as recordings can be obtained when babies are sleeping or sedated. In addition, the response is significantly correlated with the degree of hearing loss. In general, the click-evoked threshold predicts behavioral audiometric threshold in the 1,000 to 4,000 Hz range within 10 to 15 dB HL. It is valuable as a

82 Bradley McPherson and Bolajoko O. Olusanya

confirmatory test in infants. The automated ABR (AABR) is designed as a screener to simply produce a ‘pass’ or ‘fail’ result. It has high sensitivity (>90%), high specificity (>96%) and low positive predictive value (19%) (Vohr et al., 2001; Watkin, 2001). When only TEOAE is used for screening, babies with auditory neuropathy will be missed, while AABR may fail to detect babies with mild sensorineural or exclusively low frequency hearing loss. The combination of TEOAE and AABR tests in a two-stage screening has been found to have the most favorable combination of specificity, sensitivity, acceptability, and high coverage in hospitals with a wide range of birth rates (Kennedy, Kimm, Thornton & Davis, 2000; Vohr et al., 2001). Evidence from ongoing infant hearing screening programs has shown that these tests are acceptable to parents because they are non- invasive, painless and quick to administer. They are currently employed in developed countries and in a growing number of developing countries. Since the screening tests can be conducted in newborns, screening of babies before hospital discharge is recommended.

Hospital-based Hearing Screening

Screening babies in hospitals before discharge is also desirable for at least two main reasons. First, it eliminates the need to ask mothers to return specifically to have their babies tested. Parents are likely to be less enthusiastic to seek detection of an invisible and non life- threatening handicap in their apparently normal babies. Besides, taking an apparently well child to hospital for any “check-up” is viewed as socially and culturally inappropriate in many communities because of the notion that hospitals are established only to cater for the sick. Secondly, it helps healthcare professionals to satisfy an important ethical obligation of ensuring that babies have been examined and tested for a hidden abnormality prior to discharge. A common protocol is a two-stage screening, first with transient evoked otoacoustic emissions (TEOAE) followed by auditory brainstem response for those referred from the first stage (i.e., TEOAE) screen. This protocol is often associated with minimal false-positive rates (specificity >90%) without significant reduction in sensitivity (Hall, Smith & Popelka, 2004; Kennedy et al., 2000). Most screening instruments are simple to use, allowing screening to be conducted after a brief period of training by any person without prior audiological expertise. It is advisable to entrust the screening to a dedicated team because adding this responsibility to the workload of nurses could be counter-productive in many settings where such workers are likely to view this task as being less important compared to other routine clinical duties. Screening is often recommended to be performed as close to discharge as possible to minimize referral rates from vernix plugs. Hospital-based screening may pose some challenges in many settings. Given the low prevalence rates for congenital hearing impairment, the majority of babies are expected to pass the first-stage screen. Excessive ambient noise level at the screening site may unduly increase referral rates. Finding a suitable section within the ward may therefore be necessary to minimizeReview false-referral rates. Where there is a long queue of babies awaiting screening, some mothers may be too impatient to wait thereby compromising optimal uptake of screening services. In addition, the widely promoted UNICEF baby friendly hospital initiative for exclusive breast-feeding—which prohibits the use of artificial milk or water for newborns—often makes it difficult to test babies who are unsettled because their mothers

Screening for Hearing Loss in Developing Countries 83

have not yet established lactation. Moreover, hospital-based programs are inadequate where a significant proportion of births occur outside regular hospitals, which are typical in many developing countries (UNICEF, 2005). For instance in South Asia the proportion of births performed with skilled attendants (a proxy for hospital deliveries) varies from as low as 13% in Bangladesh to 43% in India, compared with about 99% in developed countries. Consequently, many babies in these regions will be missed by hospital-based programs. The obvious challenge then is to locate where the majority of babies are born within the communities and establish effective ways of attracting their caregivers to hearing screening services.

Community-based Hearing Screening

In many developing countries home births and deliveries at private maternity homes run by traditional birth attendants account for majority of babies born outside hospitals (WHO, 2004). The rest are delivered in church premises or before arrival at hospitals. Contemplating newborn hearing screening programs at these various locations may be a logistical nightmare. However, the experiences in most of these countries show that mothers from all birthing locations take their babies to immunization clinics at designated community health centers. Routine childhood immunization is perhaps the most well-established public health program globally, due to the substantial technical/financial support it receives yearly from UNICEF, WHO and several donor agencies/partners. Its popularity is derived from its preventive value for most childhood killer diseases and because it is offered free to parents. Consequently, immunization clinics have been utilized as platforms for delivering new child health intervention packages, especially in the developing world (WHO, 2002). They equally offer a ready framework for introducing infant hearing screening (Olusanya & Okolo, 2006). However, community-based screening is not limited to immunization clinics and may be implemented during infant welfare clinics and other child health programs (Lin, Huang, Lin & Wu, 2004; Kapil, 2002; Bantock & Croxson, 1998).

Table 1. Risk factors for hearing loss in newborns (JCIH, 2000)

1. Family history of sensorineural hearing loss. 2. In-utero infections such as rubella, cytomegalovirus, syphilis, toxoplasmosis and herpes. 3. Craniofacial anomalies. 4. Birth weight less than 1,500g (3.3lbs). 5. Hyperbilirubinemia at levels requiring exchange transfusion. 6. Bacterial meningitis. 7. Ototoxic medications. 8. Mechanical ventilation lasting five days or more. 9. StigmataReview or other findings associated with a syndrome known to include a sensorineural and/or conductive hearing loss. 10. Birth asphyxia with Apgar <5 at 1 minute or <6 at 5 minutes.

84 Bradley McPherson and Bolajoko O. Olusanya

A typical national immunization schedule for developing countries offers a number of options within the first year of life for infant hearing screening. BCG immunization often records the highest uptake of all the vaccinations administered in the first year in many developing countries (UNICEF, 2005). However, the age at which babies are presented for various immunizations varies widely within and across communities. For instance, the age at presentation for BCG immunization in Nigeria typically ranges from 1 to 136 days (percentile: 75th – 24 days; 95th – 61 days). A similar variation has been reported in South Africa for the first DPT immunization at 6 weeks (Swanepoel, Hugo & Louw, 2006). This variation in age/timing has the advantage of facilitating early detection for a significant number of infants with progressive/delayed-onset congenital hearing impairment and those from acquired causes that would have been missed under hospital-based newborn hearing screening. These categories of hearing impairment are commonly associated with prevailing adverse perinatal conditions in many developing countries. In addition, this platform provides the chance to screen sick babies (now recovered) who could not be tested or immunized while admitted to hospital. Occasional hiccups may occur when routine immunization programs are interrupted because of vaccine shortages or some extraneous reasons. For instance, a recent controversy on polio vaccination in some Nigerian states would have disrupted any other adjunct programs, as would have occurred in some developed countries that were once engulfed in controversies on the safety of MMR vaccinations. However, the experiences in many countries suggest strongly that routine immunization programs are still the most effective platform for integrated child health intervention globally. Another major challenge arises when screening cannot be completed and babies would require follow-up visits outside scheduled immunization clinics. It may then be useful to ascertain any likely difficulties the affected parents may encounter in keeping follow-up appointments and offer appropriate support such as compensation or reimbursement for transportation fares. Moreover, a register of babies with incomplete screening tests may be maintained at subsequent immunization clinics for tracking purposes.

Targeted or Universal Newborn Hearing Screening

An important ethical requirement for infant hearing screening is the provision of equitable access to all babies. However, due to resource constraints in some settings, limiting screening to babies who exhibit some risk factors for hearing loss is often suggested. A typical list of risk factors is those recommended by JCIH (2000), which is shown in Table 1. Such targeted screening has been found to identify about 50% of babies with moderate to profound hearing loss (Vohr et al., 2000; Watkin et al., 1991). This is because not all babies with hearing loss exhibit at least one of the known risk factors. In addition, some of the risk factors may not be easily detectable at birth or shortly thereafter, especially those associated with genetic factors. Another major limitation arises from the fact that the causes of hearing loss may be unknown in up to half of the babies with hearing loss, especially in developing countries (Derekoy,Review 2000; Elango, Chand & Purohit, 1992; Gray, 1989; Holborow, Martinson & Anger, 1982; Minja, 1998; Sellars & Brighton, 1983). Notwithstanding, targeted screening could serve as a good take-off point for universal newborn screening and is certainly better than no screen. It may be useful to establish predominant risk factors in a given country or community initially through well-designed pilot studies of universal infant hearing screening,

Screening for Hearing Loss in Developing Countries 85

to help devise a subsequently more effective and culturally-appropriate, targeted hearing screening program.

Possible Challenges of Infant Hearing Screening

The dearth of audiologists and speech pathologists in developing nations is one major challenge in many countries. While screening can be conducted by non-specialists with minimal training, the confirmatory tests and the provision of amplification are more complex and require the skills of qualified audiologists. Hearing aids are mostly manufactured in developed countries, where they are quite expensive to purchase and maintain. Moreover, the ability of government to provide routine and universal access to infant hearing as currently practiced in developed countries is doubtful in many developing countries. For these reasons some reservations about the propriety of introducing infant hearing screening in developing countries have been expressed even among ear care professionals (Mencher & Devoe, 2001; White, 2006). However, the rationale for withholding screening for prelingual hearing loss where resources are limited has been contested more recently in view of its especial significance (Olusanya, Luxon & Wirz, 2006). This is because the detection of prelingual hearing loss of congenital and early-onset is inevitable and is likely to occur late in the absence of newborn screening. Parents would prefer to know early enough that their apparently well-babies have hearing loss. Such knowledge will minimize uncertainties regarding the special needs of these children and reduce possible recourse to the unorthodox therapies which are prevalent in many traditional communities (de Andrade & Ross, 2005). In the last five years, several initiatives are evident that seek to reduce some of these constraints. For instance, WHO has issued guidelines for the development of audiological services to facilitate capacity building at different levels of healthcare delivery to address the current resource gap (WHO, 2004a). Recognizing the constraints due to high costs of hearing aids, WHO has also taken various steps to stimulate production of affordable hearing aids for developing countries. Private-sector initiatives to manufacture solar-powered hearing aids at affordable running costs (McPherson & Brouillette, 2004; Parving & Christensen, 2004) have also begun. Experiences from developed countries clearly demonstrate that services will develop more rapidly as the healthcare system is being taxed by unmet demands. Consequently, failure to screen due to current temporary shortages in service delivery may be counterproductive for requisite capacity building. It is pertinent to observe that health interventions and ancillary services are rarely provided free in many developing countries. In low income countries, governments contribute less than 40% of total health expenditure. Over 90% of the 60% balance spent by the private sector comes from out-of-pocket spending by individuals. So the notion that government has to provide hearing services to make them justifiable for developing countries is at variance with the current realities in many countries. It would therefore be inappropriate to deny such vital, time-bound, intervention services to those who are in a position to afford them. Review

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SCHOOL HEARING SCREENING

Development of School Hearing Screening

There is a long history in industrialized countries of school hearing screening. By the end of the 19th century there was a general trend within the medical profession to consider the preventive aspects of health care, including the prevention of disorders in those under the educational care of the State (Hatch, 1986). In 1890 the London School Board appointed a school medical officer and other English educational authorities soon followed. By 1907 the Education (Administrative Provisions) Act made it the duty of local education authorities to provide for the medical inspection of elementary school children. Similarly, groups within North American, Australian and European medical professions began to call for the regular health examination of school children. For example, school health services were introduced in Australia in the early years of the 20th century. In the United States formal school health examinations developed early in the 20th century and hearing screening programs were routinely implemented by 1927 (Northern & Downs, 2002, p.259). Such activities fulfilled the definition of screening programs in that they were involved in the large scale examination of a population that usually had not requested medical intervention for any particular complaint. Children with sensory disorders were a particular concern to the school health services from their inception. Henderson (1975) cites the Chief Medical Officer’s 1911 report to the British Board of Education which stated that: “Among the requirements of a satisfactory scheme of medical inspection is that of applying a hearing test to every child who is old enough to respond”. School medical services in many other industrialized nations also incorporated a hearing assessment component. By 1943, twenty American states had laws requiring school screening for hearing loss (Wall and Bührer, 1987). School screening is not confined to industrialized nations, with programs reported in many developing countries. Examples include Columbia, Costa Rica, Cuba, Nicaragua and Panama (Madriz, 2001); slum schools in Kenya (Macharia, 2003); secondary school children in Ghana (Amedofu, Awuah, Ocansey & Antwi, 2003); and in schools in Jamaica (Lyn et al., 1998). School screening audiometry has concentrated on the detection of possible disorders in primary (elementary) school children. This has been due to: (a) an underlying rationale for screening being that there is an advantage in the earliest possible treatment of the condition detected (Paradise & Smith, 1979); (b) the common finding that there are a number of children with previously undetected hearing losses entering the primary school system (Roeser & Clark, 2004). This may be particularly so in developing countries, in the absence of neonatal or infant screening programs (McPherson & Holborow, 1988); (c) the generally higher prevalence of otitis media with effusion related hearing loss in the earlier school grades. However, programs for secondary (high) school children have also been implemented in many areas (e.g., Hodges, 1983). School Reviewscreening audiometry is also known by other terms at times. The American Speech-Language-Hearing Association (ASHA) publishes recommendations for identification audiometry procedures, with “identification” being used nowadays as a synonym for “screening” (American Speech-Language-Hearing Association, 1985; American Speech-

Screening for Hearing Loss in Developing Countries 87

Language-Hearing Association, 1997). Chaiklin, Ventry, and Dixon (1982, p. 405) however, consider that there is some degree of difference between these two terms, with identification emphasizing “the principle that the primary goal of hearing screening tests is to find (i.e., identify) persons who have significant or potentially significant hearing problems” whereas in most health professions screening refers to “brief tests applied to large populations in an effort to locate individuals who may have specific disorders”. Chaiklin and colleagues appear to imply in this statement that identification reflects a more directly accurate procedure than does screening. If so, this is perhaps a dangerous definitional approach since school-based hearing tests are usually conducted under conditions that of necessity limit their accuracy. In this chapter screening audiometry and identification audiometry are regarded as synonymous terms and used interchangeably, with both referring to activities conventionally known as screening procedures. Research studies, particularly in the North American literature, also at times describe school screening programs as “school hearing conservation programs” (Wall & Bührer, 1987). However, school hearing conservation programs are generally regarded as involving the education and counseling of children, parents and teachers and the habilitation of hearing impaired children in addition to the screening of audition (Alpiner, 1978). Hearing screening is a necessary first step for a school hearing conservation program (Roeser & Clark, 2004). More generally, hearing screening is often the prerequisite for any hearing health measures involving individual treatment or habilitation.

Issues in School Hearing Screening in Developing Countries

Screening audiometry is an established aspect of audiological practice. A number of present-day issues in hearing screening need to be discussed in this section, as they impact on the identification of hearing loss in school children in developing countries.

Goals of Screening A screening program requires clear goals to be effective (Lescouflair, 1975). There has been a long debate among hearing health professionals, however, concerning the precise goals of school screening. Should hearing screening be concerned with the detection of ear pathology, auditory disability or both entities? In most school health programs throughout the developed world, the day-to-day administration of screening tasks soon devolved from medical personnel to nursing or paramedical staff with training, and was often limited to the application of formal screening protocols. Screening staff often do not have skills in ear examination that would enable them to identify ear pathology as such, other than through gross visual examination for disorders such as pinna abnormalities, discharge or impacted wax. In this situation screening for auditory disability, rather than ear disorder, became the paramount goal for school programs. With the advent of practical methods of acoustic immittance measurement in the 1970s, it became possible for trained screening staff to identify possibleReview middle ear disorders in school children. Authors such as Brooks (1971; 1977), Ferrer (1974) and Keith (1974) became early advocates of the use of immittance technology to screen primary school children for ear pathology. When immittance techniques are employed the goal of the screening process becomes that of “identification of ear disease that can be managed medically, surgically or though rehabilitation” (Johnson, 1984, p. 153)

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rather than solely of auditory impairment. The absence of immittance testing in many school screening programs is an indication that the use of this procedure remains controversial (Johnson, 2002). Roush (1990) summarizes the history of debate in this area, and mentions the 1984 recommendation by a US expert panel that acoustic immittance screening should be limited to special populations known to be at high risk for complicated sequelae of otitis media. Later expert panel have also recommended against the general use of immittance procedures in a mass screening context (American Academy of Pediatrics Committee on School Health, 1987; Rosenfeld et al., 2004). Despite the Bluestone et al. (1986) and American Academy of Pediatrics (1987) recommendations, many suggested school screening protocols in industrialized nations have included an immittance testing component. Influential examples include the American Speech-Language-Hearing Association guidelines (1997) for screening for hearing impairment and middle ear disorders, the American Academy of Audiology (1997) recommended identification program, and the Johnson (2002) suggested screening program. In developing countries most screening programs have concentrated on auditory disability. Few programs are known to routinely include immittance techniques. Gell et al. (1992) advise that tympanometry is not appropriate in developing countries where the prevalence of chronic serous otitis media is high as (a) ear discharge can be better noted through a visual inspection of the ear, and (b) identification of moderate to severe hearing loss is a priority. Olusanya, Okolo and Adeosun (2004) suggested that routine otoscopy, rather than tympanometry, of primary school children and referral of those found to have impacted cerumen would effectively identify many children with conductive hearing loss.

Hearing Loss Criteria Lescouflair (1975) made a strong case that many hearing screening programs in the developed world failed, at that time, to identify large numbers of children who have significant hearing loss. This was partly because screening intensity levels were set to standards of normalcy devised for the compensation of adults with industrial hearing loss. In Lescouflair’s view, children may well be disadvantaged by hearing loss at lower levels than the > 25 dB HL standard for “hearing loss” often set at that time. One primary rationale for not using this standard was the finding of Boothroyd (1970) that children require greater intensities in speech recognition tasks to achieve equivalency with adult scores. This is thought to be due to their lack of sophisticated strategies in speech recognition. More recent hearing screening procedures, such as the ASHA guidelines, have tended to use > 20 dB HL as a cut-off intensity (Roush, 1990). Haggard and Hughes (1991) point out that this cut-off criterion is often set on practical rather than purely audiological grounds. Ambient noise can often make testing below 20 dB HL impossible, particularly for low frequencies (Harrison, 1971; Johnson, 1984). There is now a growing tendency for many audiologists, including those in developing countries, to consider that a “hearing loss” begins at > 15 dB HL, and an advocacy of screening criteria that reflect this point of view (Olusanya, 2004a). If the primary goal of a hearing screening program is “to screen out pupils with deviations in hearing that affect classroomReview communication” (Downs, Doster, & Weaver, 1965, p. 363) then the criteria set for such “deviations in hearing” needs to be carefully considered. The current WHO criterion for “priority for hearing aids” in children is an average hearing loss in the range 31 to 80 dB HL in the better ear (WHO, 2004a). However, this does not preclude screening that also targets milder degrees of hearing loss, if there is a local capacity to provide appropriate

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hearing health care. Even very basic intervention, such as preferential seating in classrooms, may improve educational outcomes for children with slight and mild hearing loss (McPherson & Holborow, 1985; Olusanya, Okolo & Adeosun, 2004).

Referral Pathways in Screening Programs “The best screening program is useless without definitive criteria for referral” (Johnson, 1984, p. 171). Programs are also inappropriate and, indeed, unethical (World Health Organization, 1971) if there is not a sufficiently well-developed medical, educational and audiological infrastructure to cope with the cases of hearing loss or ear disorder found. Lescouflair (1975) considered that the ineffectiveness of referral and follow-up procedures was one of the main factors contributing to the failure of many school screening programs in developed countries. A major part of this problem is the long time delay between failing a screening test and further diagnostic testing that is often experienced. This may adversely impact on the audiological habilitation process or may give rise, in the case of fluctuating hearing loss, to inconsistencies between screening and diagnostic results. Another aspect is the concentration of some programs on medical treatment rather than on the overall communicative needs of the child (American Speech-Language-Hearing Association, 1985). Effective programs must work actively to ensure prompt review of cases failing the screening and have in place a range of referral and case review options appropriate to the range of disabilities found (Amedofu, Opoku-Buabeng, Ose-Bagyina & Antwi, 2003).

School Screening Audiometry Techniques in Developing Countries

Nowadays, screening techniques used with school children in developed countries are almost exclusively based on combinations of pure tone audiometry and immittance audiometry. These techniques are also used in many school aged populations throughout the developing world. Despite their popularity, they do have disadvantages and other procedures may enable a greater number of disadvantaged children to been screened in a manner that meets Wilson and Jungner’s (1968) principles for effective screening. This section summarizes audiometric screening techniques that have been developed for school aged children and may be feasible in developing nations. All screening tests should be relatively simple to perform (Thorner & Remein, 1982), with “minimum preparation by the patient, depend on no special appointments, and be inexpensive” (Fletcher & Fletcher, 2005, p. 157). This is particularly the case in developing nations, where human and financial resources are scarce.

Pure Tone Audiometry Screening In this procedure pure tone stimuli are presented at predetermined frequencies and at fixed intensity levels. The tested child is instructed to respond to a perceived signal by raising a hand, pressing a response button or in some other manner. For younger children, a conditionedReview play response is typically used, such as placing a peg in a board in response to each perceived sound. Earphones are the sound source and a practice tone is presented to the child at a level well above the test tones (often at 40 or 60 dB HL) to acquaint the child with the type of sound to be listened for. Test stimuli are presented first to one ear and then another

90 Bradley McPherson and Bolajoko O. Olusanya and the presence or absence of a child response is recorded for each tone. No attempt is usually made to find the hearing threshold for a signal if the child fails to respond (Roeser & Clark, 2004). Pure tone screening audiometry was found to accurately assess hearing status in children six years and older, when trained community health workers in a rural Bangladeshi village used a simple play response procedure (Berg, Papri, Ferdous, Khan & Durkin, 2006). All aspects of pure tone screening audiometry have been subject to investigation at some time, including the intensities and frequencies used, the pass/fail criteria chosen, the environment parameters required for testing, and the means of delivering the acoustic signal. Various intensity levels have been advocated for use in this form of audiometry, ranging from 15 dB HL to 25 dB HL, and even higher intensities are in clinical use (Wall, Naples, Bührer & Capodanno, 1985). Intensity levels also sometimes vary according to the test tone presented (e.g., Mencher & Alfano, 2000; Swart, Lemmer, Parbhoo & Prescott, 1995) although this makes for a more complex test and is discouraged. Test frequencies also vary, with various combinations of 500, 1000, 2000, 3000, 4000, 6000 and 8000 Hz having been recommended. A general consensus is (a) 500 Hz should only be used in conditions of low ambient noise; (b) there is no advantage in using 3000 or 6000 Hz instead of, or in addition to, 4000 Hz (Katt & Sprague, 1981); (c) test-retest variability due to placement effects makes use of 6000 Hz inadvisable; and (d) 8000 Hz is not required if the goal of screening is to detect hearing loss that will interfere with speech communication. ASHA (1997) guidelines for screening audiometry recommend screening at 1000, 2000 and 4000 Hz, at 20 dB HL. It should be kept in mind that such recommendations were developed primarily with a view to the identification of children with sensorineural loss. They are not necessarily appropriate for children with otitis media related loss. For example, Silman, Silverman, and Arick (1994) found that 500 Hz was an important frequency for assessing the auditory impact of otitis media with effusion in children. This group found a 31% increase in the number of children with otitis media with effusion related loss who were identified when 500 Hz was included in their screening test protocol. However, background noise conditions in schools in developing countries can make screening at 500 Hz, or with low intensities at any pure tone frequency, impractical (Amedofu, Opoku-Buabeng et al., 2003; Berg et al., 2006; Gell et al., 1992) despite a WHO (1997) recommendation that this frequency be included in screening programs. Pass/fail criteria have also varied widely in audiometry screening programs. Wall et al. (1985), in a large survey of American professionals involved in school screening, found that failure to detect a signal at two frequencies was deemed a test failure for about one-third of respondents, others used one frequency (29%), more than two frequencies, two consecutive frequencies or a pure tone average greater than a predetermined level as a criterion for ‘failure’. Pass/fail criteria will be influenced by the aims of the screening program and the conditions under which the program operates. As mentioned previously, a working definition of ‘hearing loss’ will be based partly on the philosophy underlying each program. For example, in a locality where chronic serous otitis media is common, children with a >15 dB HL loss in either ear may be targeted for referral (Olusanya, 2004b). However, in an area where middleReview ear disorder is rare and where hearing instruments are available for children with identified hearing loss, screening programs may wish to target according to WHO (2004a) recommendations for priority pediatric hearing aid candidates. Audiometry instrumentation will have some influence on the manner in which testing is carried out. The type of earphone used affects test parameters, with noise-excluding,

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circumaural earphones (Berger & Killion, 1989; Poulsen, 1988; Wall & Tillis, 1977) or insert earphones (Sklare & Denenberg, 1987) enabling screening to take place in non-soundtreated rooms at lower intensity levels than would otherwise be possible. Screening programs in developing countries often make use of circumaural earphones (e.g., Mencher & Alfaro, 2000; Olusanya, 2004b; Swart et al., 1995). These can provide attenuation of background noise, when properly fitted, of up to 44 dB (Westerberg et al., 2005). Since ambient noise levels in school rooms used for screening may be very high–43 dB SPL in classrooms in Ghana (Amedofu, Awuah et al., 2003) and up to 56 dB A in a study in rural India (Rao, Subramanyam, Nair & Rajashekhar, 2002)–noise-excluding earphones are advisable. Even background noise levels in isolated village or rainforest locations may exceed 40 dB A (Counter, 1986). Insert earphones are seldom used in developing countries due to the considerable expense of proprietary foam inserts and because the small diameter sound bore is easily occluded by wax or discharge, with a consequent loss of the test tone. One alternative, albeit costly, way to reduce background noise problems is to create a mobile hearing screening facility. An example of this is the use of large 4x4 vehicles in the HARK Project of South Africa (Ogilvy & Michelson, 2003). Such purpose-built vehicles incorporate a sound-treated environment for hearing screening and have also been successfully used in Lesotho and Uganda and will soon be used in The Gambia. A mobile facility is also used in school screening in Jamaica (Lyn et al., 1998). Low cost, hand-held screening audiometers have been designed, such as the Liverpool Field Audiometer (McPherson & Knox, 1992), the Welch-Allyn Audioscope™ (Frank & Peterson, 1987) or the Otoscreener™ (Alvord & Davenport, 1992). In such ‘miniature’ audiometers the earphone is directly coupled to the audiometer and the tester manually applies the device to the ear. These instruments are designed to provide sound output at selected frequencies and intensities only, making them simpler to operate and less expensive to manufacture than conventional audiometers. However, the utility in field conditions for such equipment needs to be carefully evaluated. For example, the Liverpool Field Audiometer was found to have high test-retest variability at 500 Hz, when a 30 dB HL screening intensity was used (McPherson & Knox, 1992), although variability was acceptable at higher test frequencies. Other hand held devices have been found to have unacceptably high false positive rates at low intensity levels (Bess et al., 1998). Pure tone audiometric screening cannot be reliably performed without quality operator training. Roeser and Clark (2004) noted that the success of any screening program depends on test personnel and recommended a minimum training program for ‘paraprofessionals’ of no less than five days. Berg et al. (2006) trained community health workers in Bangladesh over a two week period in pure tone screening audiometry, as well as in otoacoustic, tympanometric and questionnaire-based screening techniques. The WHO recommends an initial three-week training program (WHO, 2004a) for ‘primary ear health workers’, whose role could include hearing screening activities. However, it must be remembered that successful screening involves clear tester-child communication and a sophisticated understanding of pediatric behavioral responses–subtle skills that are not always easily attained. Review Immittance Audiometry Screening The most common immittance audiometry test used in screening programs in developed and developing countries has been tympanometry. Modern tympanometry testing can often be carried out in less than one minute per ear and provides important information on middle ear

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status. However, it is not an accurate predictor of actual hearing loss in children, and as mentioned previously, its use is not advised for screening programs in developing countries. Although tympanometry is not recommended for routine use the technique has been employed as an adjunct to pure tone audiometry (Chadha, Agarwal, Gulati & Garg, 2006) and otoacoustic emission screening (Berg et al., 2006) in developing countries.

Speech Audiometry Screening Speech audiometry is a fundamental part of the audiological diagnostic test battery and was at one time advocated as a pediatric screening technique. Several screening tests using speech material were developed, with the Verbal Auditory Screening Test (VASC Test) gaining popularity in the United States in the 1960s (Roeser & Northern, 1981). Evaluative research carried out on this test concluded that the use of speech stimuli should be avoided, as tests based on such stimuli were not sensitive to mild hearing loss or high frequency hearing loss (Mencher & McCullock, 1970). Very little research has been conducted on speech screening techniques in developing countries. In some environments a screening test that uses speech stimuli, in an appropriate local language, may be suitable. McPherson and Holborow (1988) describe a screening procedure that made use of simple auditory-only commands to gauge whether a child may be disadvantaged at school by hearing loss, for use in an area where audiometry and amplification devices were unavailable. Wirz and Winyard (1993) give advice to community based rehabilitation (CBR) workers on dealing with communication disorders in developing countries with limited resources. They suggest CBR workers systematically observe a child’s responses to speech as well as environmental sounds, to determine whether or not the child is likely to have hearing loss. World Health Organization (2006a,b) resources also give advice on informal behavioral observation techniques that can be used with children. However, such techniques have not been shown to be effective as part of a formal screening program.

Questionnaire-based Screening Teacher identification of hearing loss, based on the use of questionnaires, has a long history in the screening of school children in developed countries. Early studies by Curry (1950) and Kodman (1956) in the United States found classroom teachers accurately identified, at best, 25% of the hearing impaired children in their classrooms. Kodman reported that teachers failed to identify the six most severe hearing loss cases in the group he studied. Nodar (1978), in a reevaluation of teacher identification, found improved teacher accuracy if teacher ratings were compared to testing that was carried out immediately following rating. Nevertheless, teachers still missed over 50% of the children who failed hearing screening, including 12% classified by Nodar as having a moderate or severe hearing loss. A consequence of these disappointing results was that few screening programs used teacher questionnaire techniques. Work in developing countries has usually had the same outcome. The Ten Questions Screen (Zaman et al., 1990; Table 2) for childhood disability has good utility with CBR workers as a rapid, low-cost screen for serious cognitive, motor and seizure disabilities, Reviewbut not for vision or hearing disability (Durkin et al., 1994), despite four questions relating to hearing loss or its potential consequences. A study of South African preschool pupils (Chambers & Anderson, 1997) found that teachers accurately identified only one out of seven children who failed audiometric screening. For a number of reasons questionnaire-based teacher identification may prove difficult in developing nations. Class

Screening for Hearing Loss in Developing Countries 93 sizes are often very large in developing countries–often 60 students or more in African urban areas and 100 students in some classes in Guatemala (ILO, 1996)–and teachers may have little opportunity for close observation of individual children. Families with few resources may withdraw their children from school on a regular basis, if they are unable to meet the costs of attendance, reducing opportunities for contact with teachers. Children (and teachers) may come to school with a variety of first language backgrounds and communication difficulties may be ascribed to language factors rather than hearing loss (Chambers & Anderson, 1997). Teachers may lack a solid foundation of professional training and be unaware of the normal developmental milestones associated with hearing. The studies mentioned above typically used a simple teacher yes/no response rating for hearing loss or a very limited number of questions. More sophisticated questionnaires, based on physical and behavioral characteristics common in hearing impaired children, may provide a better framework for teacher decision making and improve the accuracy of teacher identification, particularly if targeted to detecting children with greater degrees of hearing loss. An example of this approach is the Newton, Macharia, Mugwe, Ototo and Kan (2001) study of Kenyan preschool children. An eight item questionnaire (Table 3) was given to teachers of preschool children. The questionnaire had 100% sensitivity and 75% specificity in detecting bilateral hearing loss >40 dB HL. The authors noted that no single questionnaire item was positive for all cases of hearing loss. An Australian study of teacher identification of hearing loss in indigenous, rural, primary school children (McPherson, Preston, Canuto & Kimber, 1992) found teachers correctly identified 82% of children with an average hearing level >30 dB HL, using a detailed 12 item questionnaire. In situations where pupil numbers are reasonably low, classes have stable student cohorts and there is a regular class teacher, this method holds promise and deserves further study. Teacher questionnaire screening is relatively low-cost and has the additional benefit of raising teacher awareness of childhood hearing impairment and its consequences. Teacher training in the screening procedure can be linked with practical advice on how to support children with hearing loss in the classroom (such provided in WHO, 2006a,b). It should be noted that primary school attendance is not universal in developing countries. For example, 10% of Zimbabwean children have never attended or did not complete primary school (Westerberg et al., 2005). Globally, approximately 20% of children never attend school (Grigorenko & O’Keefe, 2004). This reality means that school hearing screening in many developing countries will not equate to a universal screening procedure. Inequality in access to education also means that children with more severe degrees of hearing loss are less likely to attend school because parents are less likely to invest scarce resources in children with disabilities. Also, some studies (e.g., Chadha et al., 2006, Rao et al., 2002) but not all (Olusanya, Okolo et al., 2004) note a correlation between lower socioeconomic class and higher prevalence of ear disorder and hearing loss. Poorer families are less likely to be able to send their children to school. Rural families are typically poorer than those in urban areas. Minja and Machemba (1996) noted almost a doubling in prevalence of sensorineural hearing loss among rural school children in Tanzania compared to their urban peers. AlternativesReview to teacher identification via a screening questionnaire do exist. Community health workers and/or parents can be targeted for a questionnaire-based approach to screening. The Ten Questions Screen discussed earlier is one example. This procedure was developed to alert community health workers to a range of disabling conditions and to facilitate appropriate referral. A recent Brazilian project (Gomes & Lichtig, 2005) used a

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parental report questionnaire to detect hearing impairment in children aged 3 to 6 years. Results were disappointing as the 33 item questionnaire failed to differentiate between children with normal hearing and those with hearing loss. However, the study group was comprised of children with slight or mild hearing loss only. Further research that considers the utility of community health worker or parental questionnaires for children with more severe hearing loss is warranted in developing countries.

Table 2. Ten Questions Screen for childhood disability (Zaman et al., 1990)

The ten questions, which follow, require only a “yes” or “no” response 1. Compared with other children, did the child have any serious delay in sitting, standing or walking? 2. Compared with other children does the child have difficulty seeing, either in the daytime or at night? 3. Does the child appear to have difficulty hearing? 4. When you tell the child to do something, does he/she seem to understand what you are saying? 5. Does the child have difficulty in walking or moving his/her arms or does he/she have weakness and/or stiffness in the arms or legs? 6. Does the child sometimes have fits, become rigid, or lose consciousness? 7. Does the child learn to do things like other children his/her age? 8. Does the child speak at all (can he/she make himself/herself understood in words; can he/she say any recognizable words)? 9. For three to nine-year-old children ask: Is the child’s speech in any way different from normal (not clear enough to be understood by people other than his/her immediate family)? For two-year-old children ask: Can he/she name at least one object (for example: an animal, a toy, a cup, a spoon)? 10. Compared with other children of his/her age, does the child appear in any way mentally backward, dull or slow?

Table 3. Hearing loss screening questionnaire for Kenyan preschool children

1. Can the child hear a loud noise, e.g., a door banging? 2. Does the child respond when his/her name is called? 3. Do people have to shout for the child to hear? 4. Can the child hear a dog barking? 5. Does the child ask people to repeat what they have said? 6. Does the child speak as well as other children of the same age? 7. Does the child hear quiet sounds? 8. Do you have to raise your voice to get the child’s attention? (Newton et al., 2001).

OtoacousticReview Emissions Screening Otoacoustic emissions (OAEs) are a routine procedure in neonatal and infant hearing screening. The cost of hand-held OAE screening devices is reducing over time and both McPherson and Smyth (1997) and Nozza, Sabo and Mandel (1997) found that OAE screening

Screening for Hearing Loss in Developing Countries 95 was feasible in the school environment in developing countries and well accepted by children. However, test results below 2000 Hz can be adversely affected by high levels of ambient noise in the school environment (Nozza, 2001) and, with current equipment, sensitivity and specificity for hearing loss is not as high as conventional pure tone audiometry. For primary school children the costs associated with OAE screening were found in one study to be slightly greater than those incurred using a conventional pure tone protocol (Driscoll, Kei & McPherson, 2000). OAE techniques may have a more important role in future in screening preschool children. In an important study, Berg et al. (2006) found that a combined OAE and tympanometry protocol was very effective in screening Bangladeshi children in the two to five-year-old age range. Only 8.9% of children in this age range could not be tested by community health workers using this protocol. Older children were more readily assessed using a conventional pure tone audiometric screen. In areas where there is a high prevalence of hearing loss associated with middle ear disorder OAE-based screening may also be worth consideration. OAE recordings are sensitive to middle-ear status as well as cochlear function. OAEs are only elicited if (a) a stimulus is of sufficient signal intensity to trigger cochlear activity, (b) cochlear function for the stimulus frequency is normal, and (c) the OAE activated in the cochlea is not attenuated by the middle ear to a level where it can no longer be measured by the OAE instrumentation. These characteristics cause OAE measures to be sensitive to middle ear disorder as well as cochlear hearing loss. Indigenous primary school children in Australia have very high prevalence rates of middle ear disorder. In this population, McPherson and Smyth (1997) found that OAE screening held promise as a tool to screen for conductive hearing loss related to middle ear disorder. OAE screening may also be appropriate for children studying in special schools, who are not developmentally able to perform pure tone audiometry (Driscoll, Kei, Bates & McPherson, 2002). It is worth remembering, however, that OAE screening suffers from similar disadvantages to immittance audiometry. OAE recording is not a test of hearing per se, but of middle and inner ear function, and in regions where children have high rates of impacted cerumen or aural discharge the probe tip is readily occluded and testing adversely affected. Other screening options include otoscopic examination to rule out impacted cerumen. Impacted cerumen is one of the commonest ear diseases and a frequent cause of hearing impairment, with prevalence rates between 7.4% - 63% (Rao et al, 2002; Lyn et al, 1998; Swart et al, 1995; Mourad, Farghaly & Mohammed, 1993) but its pathophysiology is still not well established. For instance, it has been suggested that the aggressive or improper use of cotton swabs or other objects to clean the external ear canal or to relieve itching increases an individual’s susceptibility to excessive/impacted cerumen (Macknin, Talo & Medendrop, 1994). Given the high prevalence of impacted cerumen in many developing countries, the prompt detection of children with this disorder should lead to the identification of significant proportion of hearing impaired children. Identifying children with impacted cerumen routinely for audiometric evaluation may not require a great deal of expertise beyond basic training in otoscopy. It is useful, at least, to refer a child when no part of the tympanic membrane can be visualized due to occlusion of the external auditory meatus by cerumen during routineReview ear examination. The use of medical or audiology personnel in hearing screening is usually discouraged because it is an expensive option. Hearing screening is usually conducted by trained audiometrists, school health nurses, community health workers or other appropriate groups. However, a number of developing countries are microstates–often island nations–with very

96 Bradley McPherson and Bolajoko O. Olusanya small populations. Examples include Samoa, with a population of 177,000 and Sao Tome and Principe, with 193,000 inhabitants. In such nations it may be possible to use regular short- term visits by overseas health personnel to meet hearing screening needs. If there is a commitment to regular screening, formal screening protocols and the availability of diagnostic assessment and follow-up rehabilitation, then such visits may meet ethical standards for screening programs. Similarly, if screening is targeted to a specific area and a stable, long-term program can be arranged that involves assistance from abroad, then such a program may be worthwhile. Screening programs in developing countries may also need to carefully consider their target populations. Although neonatal screening is optimal, in many countries it may not be possible to gain access to large cohorts of children soon after birth. In developing countries, only 59% of births are attended by a doctor, nurse or midwife (UNICEF, 2006). Many births occur at home and infants registered with authorities at a later date or not at all. However, Elahi, Elahi, Elahi & Elahi (1998) noted nearly universal immunization coverage in school- age children in rural Pakistan. Programs that use immunization events as an opportunity for associated hearing screening of school age children may be considered. In some settings it may be very desirable to screen secondary school children, for example in areas that are recovering from the effects (including noise trauma) of civil warfare. An initial survey in Ghana that found hearing loss in 6% of secondary school students, with the majority having sensorineural hearing loss (Amedofu, Awuah et al., 2003).

OTHER POTENTIAL SCREENING ACTIVITIES

Most developing countries have a population structure that is skewed towards the young. Hearing health care services for children are often given priority in developing nations. Few studies are reported that have looked at the needs of the elderly with hearing impairment. Bunnag et al. (2002) found a 52.4% prevalence of hearing loss in elderly persons living in Bangkok, with 9.5% having a bilateral moderate to severe hearing loss. A Nigerian study (Ologe, Segun-Busari, Abdulraheem & Afolabi, 2005) found high rates of impacted cerumen, hearing loss and middle ear disorders in elderly hospital patients. Also in Nigeria, Olusanya (2004a) noted favorable rehabilitative outcomes following hearing aid fitting in adult, often elderly, clients. As hearing devices become more affordable in developing countries demand is likely to increase amongst elderly individuals. Screening programs that focus on elderly citizens may become an important means of delivering hearing health care. Adults exposed to noise or chemical causes of hearing disorder also require consideration for routine screening programs. Occupational hearing loss screening for developing countries is discussed in detail in Chapter 11. HIV/AIDS is widely prevalent in many developing countries and people living with HIV/AIDS need careful consideration for targeted hearing screening. Both adults and children with HIV/AIDS are at greatly increased risk of otitis media with effusion, associated with conductive Reviewhearing loss (van Hasselt, 2003). Sensorineural hearing loss due to direct HIV virus infection, ototoxic medication, opportunistic nervous system infections and cerebral atrophy has also been reported (Chidziva, 2003). In one study, conductive losses were noted in 50% of HIV-positive children and 5% had severe to profound sensorineural hearing loss (McNeilly, 2005). In particular, there is a need in developing countries for regular school “at

Screening for Hearing Loss in Developing Countries 97

risk” screening that identifies hearing loss in children known to have HIV/AIDS, if no universal school screening program is in operation.

CONCLUSION

Permanent hearing loss is a significant health problem in the developing world. Current efforts aimed at primary prevention are inadequate and ineffective in addressing the major causes of hearing loss. A significant proportion of hearing loss is of unknown cause, making primary prevention unattainable for this sector of individuals with hearing loss. Screening at various levels of a healthcare delivery system as a secondary prevention strategy is necessary and efficacious. Evidence from on-going pilot programmes in developing nations demonstrates that infant hearing screening is feasible. The inability of governments to provide free screening services should not preclude efforts that can facilitate the systematic introduction of this vital healthcare service through public-private partnerships involving multilateral institutions such as WHO and relevant non-governmental organizations. Hearing screening of neonatal and/or school age populations can be provided ethically using conventional procedures in developing countries. There is also great scope for research into innovative, low cost hearing newborn and school-based screening procedures in developing regions. No ethical priorities are served by withholding hearing screening and time-bound intervention for potential beneficiaries, where resources can be gathered for a sustainable program.

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Sellars, S., & Brighton, P. (1983). Childhood deafness in southern Africa. An etiological survey of 3064 deaf children. Journal of Laryngology and Otology, 97, 885-889. Silman, S., Silverman, C. A., & Arick, D. S. (1994). Pure-tone assessment and screening of children with middle-ear effusion. Journal of the American Academy of Audiology, 5, 173-182. Sklare, D. A., & Denenberg, L. J. (1987). Interaural attenuation for Tubephone™ insert earphones. Ear and Hearing, 8, 298-300. Sininger, Y.S., Doyle, K.J., & Moore, J.K. (1999). Auditory system development, experimental auditory deprivation, and development of speech perception and hearing. Pediatric Clinics of North America, 46(1), 1-14. Smith, A. (2003). Preventing deafness – an achievable challenge. The WHO perspective. International Congress Series, 1240, 183-191. Smith, A., & Mathers, C. (2006). Epidemiology of infection as a cause of hearing loss. In V.E. Newton & P.J. Vallely (Eds.). Infection and hearing impairment (pp. 31-66). Chichester: John Wiley & Sons. Stockard-Pope, J.E. (2001). Auditory development and hearing evaluation in children. Advances in Pediatrics, 48, 273-299. Swanepoel, D.W., Hugo, R., & Louw, B. (2006). Infant hearing screening at immunization clinics in South Africa. International Journal of Pediatric Otorhinolaryngology, 70, 1241-1249. Swart, S.M., Lemmer, R., Parbhoo, J.N., & Prescott, C.A.J. (1995). A survey of ear and hearing disorders amongst a representative sample of Grade 1 schoolchildren in Swaziland. International Journal of Pediatric Otorhinolaryngology, 32, 23-34. Thorner, R. M., & Remein, Q. R. (1982). Principles and procedures in the evaluation of screening for disease. In J. B. Chaiklin, I. Ventry, & R. F. Dixon (Eds.), Hearing Measurement. A Book of Readings (pp. 408-421). Reading, Massachusetts: Addison- Wesley Publishing Co. United Nations Children’s Funds (UNICEF). (2006). Delivery Care. http://www.childinfo. org/areas/deliverycare/ accessed 1 August 2006. United Nations Children’s Funds (UNICEF). (2005). State of the world’s children 2006. New York: Oxford University Press. van Hasselt, P. (2003). Otology in Botswana and Malawi. ENT News, 12(2), 46-48. Vohr, B.R., Oh, W., Stewart, E.J., Bentkover, J.D., Gabbard, S., Lemons, J. et al. (2001). Comparison of costs and referral rates of 3 universal newborn hearing screening protocols. Journal of Pediatrics, 139, 238-244. Vohr, B.R., Widen, J.E., Cone-Wesson, B., Sininger, Y.S., Gorga, M.P., Folsom, R., & Norton, S.J. (2000). Identification of neonatal hearing impairment: characteristics of infants in the neonatal intensive care unit and well-baby nursery. Ear and Hearing, 21, 373-382. Wald, N. J. (1994). Guidance on terminology. Journal of Medical Screening, 1, 76. Wall, L. G., & Bührer, K. (1987). Hearing identification of the preschool child: A proposed trainingReview program. Folia Phoniatrica, 39, 145-152. Wall, L. G., Naples, G. M., Bührer, K., & Capodanno, C. (1985). A survey of audiological services within the school system. Asha, 27(1), 31-34.

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Wall, L. G., & Tillis, C. H. (1977). The value of noise–excluder shells in reducing overreferrals from a school audiometric screening program. Clinical Pediatrics, 16, 530– 532. Watkin, P.M. (2001). Neonatal screening for hearing impairment. Seminars in Neonatology, 6, 501-509. Watkin, P.M., Baldwin, M., & McEnery, G. (1991). Neonatal at risk screening and the identification of deafness. Archives of Disease in Childhood, 66, 1130-1135. Westerberg, B.D., Skowronski, D.M., Stewart, I.F., Stewart, L., Bernauer, M., & Mudarikwa, L. (2005). Prevalence of hearing loss in primary school children in Zimbabwe. International Journal of Pediatric Otorhinolaryngology, 69, 517-525. White, K.R. (2006). The role of the JCIH in the global expansion of newborn hearing screening [letter]. Journal of the American Academy of Audiology, 17, 295-296. White, K.R. (2004). Early hearing detection and intervention programs: opportunities for genetic services. American Journal of Medical Genetics, 130A, 29-36. Wilson, J. M. G., & Jungner, G. (1968). Principles and practice of screening for disease. Geneva: World Health Organization. Wirz, S., & Winyard, S. (1993). Hearing and Communication Disorders. A manual for CBR workers. London: Macmillan Press. World Bank. (2005). World Development Report 2006. New York: Oxford University Press. World Health Organization (WHO) (1971). Mass Health Examinations. Public Health Papers No. 45. Geneva: World Health Organization. World Health Organization (WHO). (1997). Report of the First Informal Consultation on Future Programme Developments for the Prevention of Deafness and Hearing Impairment. Geneva, 23-24 January 1997. Geneva: WHO, Prevention of Blindness and Deafness. World Health Organization (WHO). (2002). State of the world’s vaccines and immunizations. Geneva: Author. World Health Organization (WHO). (2004a). Guidelines for hearing aids and services for developing countries. 2nd ed. Geneva: Author. World Health Organization (WHO). (2004b). Reproductive Health Strategy. Geneva: Author. World Health Organization (WHO). (2006a). Primary Ear and Hearing Care. Training Resource. Student’s Workbook. Intermediate Level. Geneva: Author. World Health Organization (WHO). (2006b). Primary Ear and Hearing Care. Training Resource. Advanced Level. Geneva: Author. Yoshinaga-Itano, C., Sedey, A.L., Coulter, D.K., & Mehl, A.L. (1998). Language of early and later–identified children with hearing loss. Pediatrics, 102, 1161-1171. Zaman, S., Khan, N., Islam, S, Bsanu, S., Dixit, S., Shrout, P. et al. (1990). Validation of the ‘ten questions’ for screening serious childhood disability: results from Bangladesh. International Journal of Epidemiology, 19, 613-620. Review

Chapter 6

PROVIDING DIAGNOSTIC AUDIOLOGY SERVICES IN ECONOMICALLY CHALLENGED REGIONS

Jackie L. Clark1,*and Valerie Newton2 1University of Texas at Dallas, United States of America and University of the Witwatersrand, Johannesburg, South Africa 2University of Manchester, United Kingdom

ABSTRACT

Accurate diagnostic assessment is a prerequisite for providing appropriate treatment or effective management of a hearing impairment. In the context of developing countries, often the facilities for carrying out assessment may be limited due to a paucity or absence of technological assistance for equipment calibration and/or repair, limitation of stable and dependable electricity for equipment, and other factors. Yet, knowledge of basic audiological principles and methods involved can ensure optimal use of such resources that are available. This chapter examines the concept of diagnostic assessment and the importance of: 1) attention to the test environment and instrumentation used; 2) careful observation and history-taking; 3) appropriate selection and rigorous performance of test methodology; 4) determining the appropriate inclusion of physiologic measures; 5) sensitivity to the culture and language of those being served. In addition, this chapter will also incorporate current World Health Organization recommendations and guidelines with the purpose of seeking to raise awareness, support and training for professionals in developing countries.

INTRODUCTION ThoughReview limited epidemiological data exists regarding the prevalence of hearing impairment in developing countries, the World Health Organization estimates that the burden of disabling hearing impairment in developing countries is potentially twice that of developed

* Correspondence: [email protected]

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countries (Smith, 2001). In fact, it is estimated that 80% of hearing impaired and deaf individuals in the world come from developing countries (World Health Organization, 2006). Developing countries are often faced with few, if any, skilled hearing health care workers and/or a meager budget on which to base an intervention program. Yet, hearing disability is one of the most common communication disorders. Initiation and implementation of programs to identify, remediate and prevent ear disease and hearing loss can easily tax even developed countries with a well-established infrastructure. It could be argued that a country would be best served to wait for infrastructures and for more critical/fatal health issues to be adequately addressed before beginning a hearing health assessment program. However, deferring audiological management and intervention programs until health conditions improve would likely force many developing countries to wait indefinitely for infiltration of resources into their infrastructure to the detriment of many who are deaf and hearing impaired. A preferable approach is to utilize the resources currently available to increased effectiveness. This chapter is written for the experienced audiologist/hearing health care provider. Consequently, the reader desiring more theory and in-depth procedural explanations of diagnostic services than described within the confines of this chapter may find a number of academic textbooks that will facilitate that goal. This chapter instead focuses on the progression of audiological tasks to completion, with issues, suggestions, and considerations for a practicing clinician when performing diagnostic audiometric measures in developing countries (see Figure 1). In order to maximize those limited resources for equipment and training within a developing country, a great deal of attention should be focused within the context of five “A”s: affordable for the economics of the population; accessible to everyone regardless of language, background or economic status; acceptable to everyone needing services; appropriate for the culture while still helping the person with her/his problems; lastly and most importantly, service provision that raises awareness within the community. Raising awareness about hearing impairment and prevention within the general and medical community at a national, provincial and local level can be achieved while, at the same time, promoting overall public health. By increasing awareness on these multiple levels, there is a greater chance that those with hearing impairment will be encouraged to seek help for remediation of their disability and/or alternative modes of communication. Prior to implementing identification audiometry, there is a critical need to determine local cultures and attitudes about hearing loss. For instance in some regions, deafness is quite prevalent and not considered a disability and many community members communicate bilingually, in oral and sign languages. In such a community, there may be no immediate need for a remediation plan or intervention audiometry. WHO defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” The audiological/hearing health care practitioner is equipped with a clear rationale for pursuing remediation of those non-fatal, yet disabling health problems. An understanding of the etiologies directly and indirectly resulting in hearing lossReview in a developing country becomes a critical component to the assessment phase. Knowledge of which etiologies, such as ototoxicity, neonatal infections, chronic otitis media, malaria, meningococcal meningitis, syphilis, measles, or genetic factors, are particularly prevalent in a specific region or country will facilitate in planning a feasible course of action.

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Case history

Otoscopy

Hearing tests Tympanometry Speech test

Normal Conductive Sensorineural/mixed loss hearing loss

Tests for site of lesion

Cochlear Retrocochlear

Figure 1. Suggested order of presentation for diagnostic audiological evaluation.

Implementation of an "identification audiometry" program should encompass more than solely locating individuals with hearing impairment. As mentioned in a separate chapter within this book, hearing screenings can be viewed as the general process by which groups of people are separated into those who manifest some defined trait, or those who do not. A hearing screening becomes the entry point to identification of those with a defined disorder who would otherwise not be identified nor receive remediation or monitoring. When there is very little infrastructure or only limited audiological/otolaryngological services, it is wholly appropriate to have a designated primary health care worker trained to function as an audiology technician.

PATIENT INTAKE

Having failed a hearing screening, the patient will be seen for a full hearing assessment either immediatelyReview or on a subsequent day. It is important to appreciate that there will be some accompanying anxiety. To help allay this then, after a friendly greeting, an explanation should be given of the planned procedure. This will usually start with taking a clinical history and then performing otoscopy followed by the appropriate hearing test, tympanometry and

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speech tests. The results of these tests will determine what other investigations to perform. If a hearing loss is found then tests which identify the site of lesion will be necessary in order to make the appropriate management decisions.

History Taking

Information gained from a careful history may provide an indication of the degree, type and likely cause of a hearing impairment. It is, therefore, important to take the time needed to ask questions of the client or—in the case of a child—the caregiver, and to keep a written record of the information obtained. Records are important and help to indicate any changes in hearing occurring over time. Questions need to be phrased in terms which can be understood by the person being questioned and should take into account cultural background. They should relate to the following areas:

1. General information (a) Full name and address: Full names often include the family or tribal name which can be useful in detecting family connections and identifying an inherited hearing loss. (b) Age and sex: Some causes of a hearing impairment are more likely at some ages than others and more likely in one sex than the other. (c) Occupation: Certain occupations (e.g., those where there are high noise levels) can be associated with a hearing loss particularly affecting the higher frequencies. When a very noisy occupation is indicated then the length of time spent in that occupation is useful to know, as well as the availability of any devices to protect hearing. 2. Information about hearing (a) How long the problem has been noticed? (b) One or both ears? If both, does it seem to be the same in both? (c) Onset—sudden or gradual? (d) Hearing loss stable, fluctuating or improved since onset? (e) Any associated problems (e.g., tinnitus, balance disturbance, excessive loudness sensitivity)? (f) Has there been any earache or aural discharge? (g) Has there been any previous treatment? 3. Information relating to causative factors: (a) Family history indicating a permanent hearing impairment (b) Birth history—was a child born early, very small, in need of special care? (c) Maternal history during pregnancy—any significant illness and treatment? (d) History of previous infections (e.g., meningitis, measles, mumps) (e) History of head injury and its severity (f) Review Exposure to loud noise—at work, leisure, exposure as a result of conflict? (g) Previous medical conditions and their treatment.

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Information from the case history may indicate that the audiologist should refer the patient to other professionals for further treatment or management. The WHO guidelines (1998) suggest referral when patients present the following “Red Flag” conditions:

1. Pain not responding to treatment; 2. Pus discharge not responding to treatment; 3. Pain in discharging ear; 4. Pain with or without pus discharge associated with a tender swelling; behind the ear (mastoiditis) 5. Any symptoms or signs suggesting intracranial infection such as drowsiness, confusion or loss of consciousness, especially when there is neck stiffness and fever, vomiting or convulsions; 6. Giddiness, dizziness (vertigo) with either vomiting or nausea; 7. Lame face/facial nerve palsy; 8. Sudden loss of hearing.

A major question in defining the overall purpose of any program in the context of a developing country is deciding whether to attempt to identify only those with significant auditory impairment or to have an additional purpose of preventing auditory impairment and ear disease. Information from each case history can be important not only for the individual concerned, but as a step towards accumulating population data which is useful to inform health authorities of the size of the problem, resources needed and facilities necessary to monitor program effectiveness. However, patients need to have confidence that all health information provided will be held in utmost confidence. Consequently, the facility and key personnel conducting assessments must have a means of organizing and maintaining confidential audiological data.

INFECTION CONTROL CONSIDERATIONS

Communicable and infectious diseases when combined with malnutrition, overpopulation, and scarce health care access have become serious health issues. Unfortunately, most of those diagnosed with infectious diseases live in developing countries (Archibald & Reller, 2001). When considering that antimicrobial drug resistance pathogens are on an increase while infectious diseases are identified as the leading cause of death in many developing countries (Hart & Karuiku, 1998; Hinman, 1998), there is a greater call for hearing health professionals to implement infection control measures with their diagnostic measures. Physical contact of any instrument used with the patient in the audiological evaluation can result in the spread of infection and/or disease. Supra-aural and, especially, insert earphones must be cleaned and disinfected between patients. Response switches/buttons should also be given the same attention. As the clinician will come in physical contactReview with each patient during audiometric testing, hand washing should occur between patients. Transient bacterial skin flora that are most likely to colonize on the superficial layers of health-care worker’s skin are easily removed by routine hand washing (Boyce & Pittet, 2002). Transmission of pathogens by health-care workers (HCW) from one patient to another

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requires the following sequence of events: bacterial skin flora present on the patient or shed onto inanimate objects in close proximity to the patient transfer to the hands of HCWs; pathogens that are capable of surviving for at least several minutes on the hands of personnel; inadequate or entirely omitted hand washing or hand antisepsis by the worker; inappropriate hand hygiene agent used. It is commonly accepted that cleaning hands is one successful means of reducing healthcare-transmission of contagions between patients. The U.S. Public Health Service established recommendations (Garner & Favero, 1985) for all health-care workers to wash their hands with soap and water for 1 – 2 minutes before and after patient contact. Making the decision about which antimicrobial, non-antimicrobial, and/or waterless antisepsis agents the HCW should use will be determined according to the known community health history and expected contact with each patient. In those regions where water may not be readily available for hand washing, the hearing health care professional should consider waterless antiseptic agents and wearing gloves for patient contact situations. Clearly, initiating overly cautious standards for patient contact will ensure the health of not only the community but also the health of the limited number of health care workers and hearing health care professionals available to serve in developing countries.

OTOSCOPY

A number of studies have shown that audiometric screening without benefit of otoscopic inspection will fail to detect about one-half of those with confirmed ear disease in a developed country. In developing countries, there is a much higher incidence of ear canal occlusion and/or chronic middle ear pathology found not only in children, but also in adults. Current findings show that in ears with 40% or more obstruction, thresholds can be negatively affected by 7.5 to 16.8 dBHL, depending on frequency (Roeser, Lai & Clark, 2005). The anticipated prevalence of excessive cerumen within developed countries can be expected to be approximately 10% in children and 5 – 8% in adults (Bricco, 1985; Cooper, 1985; Gleitman, Ballachand & Goldstein, 1992). It is unfortunate that the prevalence of excessive cerumen in developing countries cannot be discussed within the text of this chapter simply due to the paucity of demographic prevalence data. However, this also highlights the necessity of collaborative efforts to document such information. Another condition more prevalent in developing countries is aural cholesteatoma associated with chronic otitis media. Considered a major indiscriminant yet remediable health problem in many populations around the world, chronic otitis media appears to present widely ranging prevalence figures (WHO/CIBA, 1996). Incidence of chronic suppurative otitis media is significantly greater in developing than in developed countries. Amongst the highest prevalence figures are those found with the Inuit and Australian Aboriginals (with 12–46% and 12–25% respectively), followed by Native American, South Pacific Islander, and African populations (with 4–8%, 4–6%, and 3–6%, respectively), with the lowest prevalence values found in India,Review Saudi Arabia (2%, 1.4%), the United States and the United Kingdom (< 0.1%). Complication rates from acute infections are significantly greater in developing countries (i.e., 60 per 1000 cases) than developed countries (1 per 1000 cases) (WHO, 1998), thereby creating an even greater need to monitor, and possibly prevent and remediate early infections. Proper otoscopic inspection of the ear canal prior to diagnostic audiometric testing

Providing Diagnostic Audiology Services … 113 would identify occlusions and possible conditions that can adversely affect individual hearing status, thus affording a more effective and efficient assessment.

HEARING TEST ENVIRONMENT

In order to meet widely accepted assessment standards, testing should be performed in as quiet an environment as possible to ensure that a sound can be heard 50% of the time (i.e., the threshold of hearing). In some facilities, dependable electrical current is not readily available, and the examiner may depend upon battery-operated equipment. It is important for personnel in an assessment program to understand that calibration of some battery-operated units becomes questionable when battery reserves drop below a certain level. A simple listening check should be made prior to, and periodically during, assessment to ensure that the test results are accurate (especially when battery concerns surface). Obviously, during the listening check if it is difficult to perceive the test stimuli at a known suprathreshold level, then the environment most likely is not satisfactory, provided that the equipment is known to be in proper calibration. Much can be done to reduce the impact of noise upon the test environment. This includes where possible, selection of the building (clinic, house, school) where tests are performed. Preferably this should be away from noisy roads or other obvious sources of external noise, e.g., play areas for children. Within the building, the room selected should be as far away as possible from areas where people congregate (e.g., waiting areas in clinics, toilets, and rooms with loud telephones). If rooms have windows they may be closed to help reduce sound from outside and thick doors to rooms attenuate noise from adjacent rooms. If there is no such opportunity to limit noise exposure then choosing times to test when the building is not in use by others can be the answer. Ideally, testing would take place within a sound booth or a sound treated room. These test environments have the advantage of not only excluding or attenuating external noise but reducing the likelihood of standing waves interfering with soundfield testing of young children. The intensity level of sound in the testing room should not exceed 40 dB A (WHO, 1999) as checked using a sound level meter. A room can receive sound treatment by using materials in the room which absorb sound. Covering the floor with any available carpeting or matting is helpful. Acoustic tiles on the walls or ceiling can be used if available, otherwise more readily accessible materials such as drapes on the walls can be used. Calibration is necessary to insure that the audiometer is consistently producing a pure tone at the specified frequency and intensity, that the stimulus is present only in the earphone to which it is directed, and that the stimulus is free from unwanted noise, interference, and distortion. Needless to say, the validity of audiometric test data is only as good as the equipment used to obtain them. A more in-depth monthly biological check can be completed by assessing the thresholds of three to five individuals. If all reflect a similar threshold shift in the same frequency, this would be a good indicator of equipment falling out of calibration. If there is accessReview to a sound level meter and coupler, the monthly biological check can be replaced with an electroacoustic measurement of the audiometer output levels. The advantage of physical measurement is that if the outputs are found to be incorrect by more than 3 dB it may be possible to correct them by making correction factors notations on the audiometer by frequency and intensity. Due to expense, and weight, the highly sensitive and precise

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industrial sound level meter may at times be an unrealistic luxury in a developing country. However, a less expensive, lightweight instrument with ample precision (~+/- 2 dB at 114 dBSPL) and limited frequency range may be a much more viable option for assessing the test environment

AUDIOMETRIC MEASURES

Assessment of Hearing

Screening is a pass/fail procedure in which the test sounds are presented at one intensity level, and those failing the screening are exhibiting signs of potential hearing loss. Thus the need to proceed onto the next stage of measuring the degree of hearing impairment requires documentation of pure tone thresholds, and potentially speech performance and other diagnostic testing. As detailed in the World Health Organization’s Guidelines for hearing aids and services for developing countries (2004), the term “hearing impairment” can denote any or all levels of severity or degree of hearing difficulty. It is worth noting, however, that “disabling hearing impairment” is defined as a permanent unaided hearing threshold level for the better ear of 41 dB or greater in adults, and 31 dB or greater in children under 15 years old, for the better ear averaged for four frequencies (500, 1000, 2000 and 4000 Hz). Detection of a hearing impairment is only the first step in a process of providing effective habilitation. It is recommended (WHO/CBM, 1998) that priority be given to infants and children with mild, moderate and severe hearing loss for provision of hearing aids, without regard to the type of hearing loss (i.e., conductive, sensorineural or mixed). Depending on resources, a clinician can make the determination of unilateral or bilateral amplification for patients. More information is necessary concerning the degree of hearing impairment and the type of hearing loss before decisions can be made regarding appropriate medical treatment and/or non- hearing aid management required.

Determining Degree of Hearing Impairment When no hearing loss is present, pure tone air and bone conduction thresholds will often likely be approximately 0 dB HL at all frequencies. In a very few cases, it is possible to find thresholds below 0 dB HL, which would suggest threshold sensitivity that is significantly better than the normal ear. Although 0 dB HL is the value representing “perfect”, normal hearing sensitivity, there is a range of intensities considered to be within normal limits (0-15 dB HL for children and 0-25 dB HL for adults). Those with thresholds in this range should have minimal or little difficulty hearing normal conversational speech, unless other audiological manifestations are present. However, it should be remembered that any deviation from 0 dB represents a decrease of hearing from the norm; a 10 dB threshold is a loss of 10 dB compared to the normal reference level. The amount of hearing loss shown on the pure tone audiogram is used to classify the amount of Reviewhearing impairment. Hearing impairment is determined by results from audiometric data, and is a function of the amount of abnormal or reduced audiological function. Hearing impairment is typically described by the degree of loss, and the results from pure tone tests are used as the primary means for classifying hearing impairment. No universal schemes are available for classifying the degree of hearing loss from pure tone tests.

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For this reason, there is diversity from clinic to clinic in specifying the degree of loss. Table 1 shows a comparison of the Northern & Downs (1991) degrees of hearing loss used in developed countries with the WHO definitions of varying grades of hearing impairment corresponding to dBHL values at 500, 1000, 2000 and 4000 Hz, averaged. Stating that a loss is mild, moderate, severe, grade 1, grade 2, etc., based on pure tone data provides assistance in describing the degree to which an individual will experience difficulty in communicating. Unfortunately, these simple terms do not detail the communicative, social, and emotional effects the loss may cause. In fact, it is impossible to predict the effects hearing loss will have on communicative and social function for an individual patient from pure tone data alone.

Behavioural Tests

These can be used for testing both children and adults and are applicable for both screening and diagnostic testing. The developmental ages at which the tests can be used are shown in Table 2. Whereas pure tone audiometry will be the test of choice for children of chronological age 3 years and older as well as adults, the behavioural tests applicable at a younger age can be used with older children and adults should pure tone audiometry prove to be too difficult.

Visual Reinforcement Audiometry For this test an infant must be able to see and must be developmentally capable of turning its head. The test involves conditioning an infant or child to turn to a sound by simultaneously introducing a visual stimulus. When conditioning is achieved the sound is introduced alone via soundfield or earphones and the visual stimulus (reinforcer, reward) is presented only after a clear turning of the head has indicated that the sound has been heard. Soundfield presentation of stimuli is preferable with the two loudspeakers positioned to optimally elicit a clear head turning response from a child. Magnusson, Borjesson & Axelsson (1997) measuring real-ear sound pressure levels and actual soundfield conditions showed that mounting the loudspeakers at a distance of 50-70 cm from the child makes a generally appropriate arrangement for VRA, if loudspeakers are too close small head movements affect the test results. Warble tones are usually used as the test stimulus at 0.5, 1, 2, 4 kHz but narrow band noise can be useful where an infant is thought to be inhibiting a response to warble tones. Cultural factors should be taken into consideration when undertaking the VRA assessment protocol. For example, children throughout Asia associate warble tones with ghosts, due to their use in animated television soundtracks; such tones may induce anxiety in young children if chosen for use with VRA (McPherson, 2007). The disadvantage of the use of loudspeaker presentation is that only the threshold of the better ear is obtained although localization difficulties may indicate a significant threshold difference between the two ears. Review

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Table 1. Grades of hearing impairment with corresponding audiometric values

Degrees of Grades of Hearing Loss Hearing Impairment with (Northern & ISO values (WHO, 1997) Downs, 1991) Audiometric ISO Grade of Performance Recommendations value impairment (avg. 500, 1000, 2000, 4000 Hz) 0 – 25 dB HL 25 dB or better 0 No or very slight None None hearing problems. (better ear) Able to hear whisper 26 – 40 dB HL 26 – 40 dB 1 Able to hear words Counseling. Hearing Mild Slight spoken in normal aids may be needed (better ear) voice at 1 m 41 – 55 dB HL 41 – 60 2 Able to hear and Hearing aids usually Moderate Moderate repeat words using recommended (better ear) raised voice at 1 m 56 – 70 dB HL 61 – 80 dB 3 Able to hear some Hearing aids needed. If Moderate- Severe words when shouted no hearing aids Severe (better ear) into better ear available, lip reading or sign needed 71 – 90 dB HL 81 dB or greater 4 Unable to hear and Hearing aids may help Severe Profound understand even understanding words. 91+ dB HL (better ear) including shouted voice Additional Profound deafness rehabilitation needed From WHO (1997).

Table 2. Developmental ages at which pediatric tests can be conducted

Behavioral Tests of Hearing Age in Months Tests 0 6 12 18 24 36 Distraction

Visual Reinforcement Performance

Pure Tone

Visual reinforcers can be simply a toy in a box lit up by a bulb or, if available, DVDs or videos can Reviewbe shown. They are usually mounted above the loudspeaker. Culpepper and Thompson (1994) suggested that audiologists may increase the amount of audiometric information obtained from children in the older age range for VRA by decreasing the length of their exposure to the visual reinforcer.

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The sound stimulus may preferably be introduced through insert earphones. The latter has the advantage of enabling pure tones to be presented instead of warble tones and a masking noise can be introduced to obtain information from each ear separately. It is also possible to obtain threshold information in dB HL more easily. In young children thresholds at 1 kHz, 2 kHz, 4 kHz and 0.5 kHz are usually obtained but it may be necessary for the infant to be seen on several occasions to obtain this information on both ears. At the first test session the aim would be to obtain air conduction thresholds at 1 kHz in each ear first before proceeding to other frequencies. Bone conduction thresholds may also be obtained in VRA. Figure 2 illustrates one possible room arrangement for carrying out this test depending upon whether one or two rooms are available. A number of audiologists have reported successfully obtaining audiometric information on both ears of infants using insert earphones (Day, Bamford, Parry, Sheperd and Quigley, 2000; Widen et al., 2000). Widen et al. (2000) described a large study of 3134 infants aged 8- 12 months who underwent hearing testing using VRA and insert earphones at 1 kHz, 2 kHz and 4 kHz. In the study 95% completed 4 minimum threshold level responses. In the context of a developing country with severely restricted resources, insert earphones with disposable foam eartips may become financially and hygienically prohibitive. One possible substitute would be reusable olive-shaped immittance tips with special adapters for insert earphone use.

Distraction Testing This test is applicable for infants who can see and are able to sit unsupported as they need to turn round to locate a sound signal. Additionally, this test involves one person (the distracter) controlling the infant’s attention while another person (the tester) introduces a sound stimulus outside the infant’s sight. The test arrangement can be seen in Figure 3. The infant is sat upon the knee of an adult and supported lightly at the waist. The sound stimuli can be warble tones, which have the advantage of being frequency specific, or more familiar sounds made which have their maximum frequency energy within low or high frequency bands. A high frequency rattle may be used or voiced sounds if warble tones are not available or to supplement them. Testing commences at the screening level of 35 dBA at one meter behind the infant, at the horizontal level of the ear and at an angle of about 45 degrees to avoid being seen if the infant’s head moves. If there is no response the sound level is raised until a response is obtained, or touching the child or providing a visual clue indicates a profound hearing loss or disinterest. A profoundly deaf infant will usually respond quickly when touched or on seeing the tester whereas one who can hear but is not interested and is inhibiting a response to sound may ignore other stimuli as well. As the intensity is increased it will be necessary to move to a position nearer the child in order for the sound stimuli presented to reach the eardrum at a louder level if needed. Stimuli, such as a high frequency rattle, when presented and measured at ear level would have a greater intensity (e.g., 70 dBA) 1 meter from the ear than a signal presented 25 cm away from the ear. At this closer position frequency specificity is maintained for a higher intensity. Coming closer allows for a higher intensity of some sounds (e.g., the voiced “s”) before loss of frequencyReview specificity, and potentially would allow testing at levels as high as 55 dBA.

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Figure 2. Visual reinforcement audiometry testing arrangement shown is for use when two visual reinforcers and an observation room are available.

Tester Position Tester Position

450 Parent + infant Table

Distracter Review Figure 3. Distraction testing arrangement shown for parent and infant with tester positions.

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Those audible sound s should be measured on a sound level meter and recorded. In the absence of a sound level meter at the time of testing a tester could estimate the level of sound if they had previously had access to a sound level meter. This would have involved measuring the level of the various test stimuli for testing at specific distances and recording the measurements. The distracter, whilst endeavoring to control the infant’s attention, perhaps by manipulating a toy, must beware of being too interesting otherwise the infant may be afraid to miss something by responding to the sound signal. On the other hand too dull a distraction will encourage an infant to check what is happening behind them and so see the tester. The distracter must also take care not to stare into the infant’s eyes or to give clues by glancing towards the tester. The tester has to beware of allowing the infant to predict their position by alternating the side from which the sound stimulus is presented and taking care not to move noisily. When coming close it is essential not to give olfactory clues through wearing strong perfumes or colognes. An advantage of this test is that it involves minimal equipment and some useful information can be gauged from these techniques using only voice if no equipment is available at all. The distraction test has the disadvantage of obtaining the threshold in the better ear only, though again localization difficulties can be indicative of a poorer threshold in the other ear. A further disadvantage is that sounds cannot be presented as loudly as they can be using VRA and insert earphones. There is evidence suggesting that VRA is more likely to elicit minimal response levels than distraction testing (Gliddon, Martin, & Green, 1999).

Performance Test/Play Audiometry In order to perform this test the child must be at a developmental stage where they are able to wait whilst holding an object until a sound signal is given. A child who is unable to see can be conditioned to perform this test by appropriate selection of the activity to be performed, e.g., dropping an object in a bucket. As shown in Figure 4, the optimal testing arrangement will have the child sitting alongside the caregiver. A predetermined action has to be carried out by the child to be considered a response to a sound signal. This action may be putting a wooden ring on a stick, a peg in a board or tin, or another simple activity. It should not be an activity which requires the child to select a particular color toy or a particular size or shape as this distracts their attention from listening for a sound. The sound stimulus may be warble tones or voiced sounds (“Go” and “s”) can be used if electronically generated tones are not available. Warble tones have the advantage of being more frequency specific. Conditioning is performed from the front and involves giving an additional visual cue. This is important as it enables a profoundly deaf child to be conditioned. The frequencies tested using warble tones are 0.5, 1, 2 and 4 kHz, usually starting at 1 kHz or 0.5 kHz. When using voice, conditioning is for “Go” at first and, when this test is completed, then conditioning for “s” follows. Review

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Tester Position

Child Parent or caregiver

Table Tester in position for conditioning

Figure 4. Performance testing arrangement shown with parent or caregiver beside the child and testers positions.

Vignette 1

A vivacious 5 year old, “Baby” (as mother called her), dressed in Sunday best leopard print skirt and chartreuse blouse arrived at the end of a very long day of a philanthropic, free hearing clinic program in Chicuque, Mozambique. Mother explained that Baby has never spoken meaningful words or sentences, but denies knowledge of major medical problems or other developmental delays. Subjective observation revealed a bright and compliant youngster, who did not vocalize and maximized her visual cues. Otoscopic examination was unremarkable for both ear canals. Though very task-oriented and well natured, Baby was unable to independently carry out the behavioral task of raising her hand when she heard the signals (as intense as 105 dB HL) across frequencies during the conditioning phase. A quick improvisation of individually wrapped alcohol swabs and an empty container for Play Audiometry resulted in the same inability to independently respond to the signals during the conditioning phase. Fortunately, the audiometer was equipped with a bone conduction oscillator, and Baby was found to be quite capable of independently and correctly responding to hand-held bone conduction stimulation after completing only three conditioning trials, even to very low intensity levels at varying frequencies, and of not responding in the absence of a signal. While standing approximately 5 feet behind Baby, her mother was coached to verbalize a variety of words and sounds both in conversational and much louder vocal levels. This clinician kept Baby’s attention forward during the various noise makings, and did not note any change in affect between presence or absence of sound. In addition, when changing test positions withReview mother, there were no changes noted in Baby’s affect even in the presence of loud stomping and clapping sounds. With the assistance of bone conduction stimuli, it was possible to determine that Baby’s lack of response to an acoustic signal was not a behavioral or cognitive deficit, but instead an auditory impairment. Pure tone audiometry coupled with voice test findings confirmed an

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absence of measurable audition for Baby. While the techniques used might be considered quite antiquated in a developed region, they were found effective in yielding objective results. Baby’s mother was counseled on the severity of the hearing loss and the necessity for Baby to attend a nearby class for hearing impaired children in the province. With the mother participating in the voice test (both as observer and signal provider), she had a much better understanding of Baby’s hearing status.

When the child is adequately conditioned to carry out the prescribed activity the test starts. The tester goes behind the child, staying quite close initially to see if the child responds to sound alone or can only do so when given an additional visual or tactile cue, indicating a very severe/profound hearing impairment. Then, moving back a metre from the child, a sound signal is presented at a quiet level of 35 dBA. If there is no response from the child then the level of the sound is raised until a response is obtained and this is then measured on a sound level meter and recorded. In the absence of a sound level meter an estimate of the sound intensity is made as described previously. The sound stimuli should not be presented at regular intervals as a child may predict its onset and give an affirmative response. The performance test provides information regarding the hearing thresholds of the better ear. The ability of the child to localize sound is not assessed in the test and needs to be examined separately for an indication of difference between the thresholds of the two ears. The performance test is a useful introduction to pure tone audiometry with a young child.

Auropalpebal Reflex This reflex is present when a sound is around 80 dB above hearing threshold and involves an involuntary blink in response to a loud sound. Its presence indicates that there is some hearing. This may be normal but, on the other hand, normal hearing thresholds could be only in the lower frequency range. Seeing a reflex does not exclude a severe sensorineural hearing loss across all frequencies either because of the phenomenon of recruitment, an abnormal response to Reviewsound associated with cochlear hair cell damage. Absence of a reflex would be consistent with a severe or profound hearing loss but should only be interpreted as providing confirmation of hearing tests performed.

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Standard Behavioral Audiometry Standard behavioral audiometry typically can be easily conducted with individuals presenting a developmental ability to attend and volitionally respond to signal presentations over a 30-minute time period. Some children younger than 3 or 4 years of age may have reached such a maturity level to maintain attention, while some older children may not. A standard behavioral test would be conducted with the patient seated comfortably either with their back toward the examiner or with a barrier blocking visual cues from the control panel. The two response strategies to signal the perception of the stimuli that are most commonly used with the cooperative adult patient are a hand held switch/button and hand/finger raising. Instructing the patients to raise their hands/fingers on the side corresponding to the ear in which they perceive the test signal helps to confirm reliability of patient responses. Tapping with a stick on a board or tin can also be helpful. The tapping tends to get quieter as threshold approaches. Once the patient is conditioned to the agreed upon task (such as raising a hand or finger, etc.), a trial presentation at suprathreshold intensity levels will confirm that the patient is prepared to proceed with threshold seeking testing.

Speech Audiometry Tests Speech tests are an invaluable part of an audiological assessment, providing information which can:

9. Confirm the results of hearing tests; 10. Demonstrate to a parent that a child does/does not have a hearing problem; 11. Indicate site of lesion in the case of a retrocochlear hearing loss; 12. Indicate a non-organic hearing loss; 13. Be used to demonstrate and compare hearing aid performance.

Speech discrimination tests are used to determine the percentage of speech sounds heard correctly at different intensity levels. Tests used for assessing speech discrimination can involve whole sentences, words, spondees (words such as ‘ice-cream’ and baseball’), nonsense sounds or pictures or toy items. The redundancy is greatest when using whole sentences, which are often easy for the testee to predict after hearing only a portion. Word lists are usually employed in the audiological assessment of adults, presented through headphones for diagnostic testing, or in the soundfield for rehabilitation purposes. Avoidance of visual clues is necessary when using soundfield presentation to ensure that lip/speech reading does not invalidate the test. Whenever there is a danger of crossover to the non-test ear while using headphones there will be a need to use a speech or white noise masking signal. Picture or toy tests are used with young children but older children are tested using word lists or sentences (Hickson, 2001). Presenting speech sounds in the presence of noise is being used increasingly and gives a better indication of function in a normal environment than tests performed in a quiet clinic setting (Nilsson, Soli & Sullivan, 1994). There areReview a number of recorded tests available in the English language and some tests in other languages, too (Hong, 1984; Kishon-Rabin & Rosenhouse, 2000; Wong & Soli, 2005). It is important to remember that tests cannot be simply transferred from one language and culture to another due to spectral qualities and frequency of use within the community for the speech stimuli. It is necessary to develop a speech test which is based upon the specific

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language and culture for which it is intended. Words selected because they are common in one language and have a specific formulation (e.g., consonant-vowel-consonant) may not translate to a word with a similar configuration in another. Pictures and toys familiar to one community of children may be unknown to another. Defined as the intensity level at which the presence of a speech signal can be detected 50% of the time, the Speech Detection Threshold is useful in confirming pure tone thresholds. Usually average pure tone thresholds at 0.5 kHz, 1 kHz and 2 kHz are used or the average of the best two out of the three, depending upon the steepness of the audiometric slope. Equivalence (within 10 dB) between the results of pure tone audiometry and the threshold for speech would suggest that the hearing test was indeed accurate. The speech discrimination scores obtained as a result of word tests can be plotted against the intensity level of presentation on a graph (Figure 5). A normal curve can be obtained using a group of normal hearing individuals and this will show a maximum discrimination score at a particular intensity. A test resulting in a maximum test score but at a higher than normal intensity would be consistent with a conductive hearing loss as the patient only requires sound to be louder to hear clearly. In a sensorineural hearing loss a normal maximum score will not be obtained if the hearing loss is severe and the score may diminish with greater intensities as a result of distortion due to recruitment. Speech tests which are poorer than would be expected for the audiogram can be a useful indicator of a retrocochlear hearing loss. A number of measures are used for comparison in addition to the maximum discrimination score (e.g., the 50% discrimination score). Some individuals may, for reasons of which they may or may not be aware, present with hearing levels which are above their hearing thresholds. The results of speech tests may indicate that hearing thresholds are better than would be possible if the audiogram was correct. Speech tests can be performed in the soundfield to demonstrate how well the patient can hear sound at different intensities, the intensities being measured using a sound level meter. The speech test results can be compared with and without additional visual clues. The tests can be performed comparing one hearing aid to another but care needs to be taken in designing the way this test is carried out to avoid biasing the results.

Physiologic Measures An audiological evaluation should include pure tone and speech audiometry with the inclusion of tests of auditory function such as tympanometry, immittance and otoacoustic emissions. Prior to 1970, there were no practical means for confirming or dismissing ear disease findings during assessment other than through otoscopy. However, with the emergence of microprocessors and miniaturized electronic components, portable audiometric equipment that can provide objective tests of auditory physiology have become a feasible part of an assessment and monitoring program in developing countries. There is a greater need to include tests of function, such as tympanometry, in a developing country context because much of the literature suggests that hearing impairment is due to chronic suppurative otitis media in about 20/1000 children and this disorder is often remediable if detected (WHO/CBM,Review 1998).

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Speech discrimination

100

A B

D E 50

C Thresholdspeech of intelligibility

0 FG Speech discrimination score (%) 25 50 75 100 Decibel level (SPL)

Figure 5. Speech discrimination graph shows a normal curve “A”, a conductive loss “B” and sensorineural loss “C”. The difference between: D and E is an indication of the degree of conductive hearing loss; F and G is an indication of the degree of sensorineural hearing loss. Differences greater than 15 dB would need further investigation in case a retrocochlear hearing loss is present.

Those tests of auditory physiology, (i.e., immittance, otoacoustic emission and auditory brainstem measures) are at the forefront of those most applicable in the context of developing countries. When behavioral audiometric tests cannot be used or are unreliable, valid information on middle ear function and hearing sensitivity can be obtained with physiologic measures including: immittance measures, otoacoustic emissions and auditory brainstem response (ABR). Physiologic measures not only assess hearing sensitivity, but also provide valuable data that can be used for diagnosis and treatment of hearing loss. An advantage of physiologic measures is that they can be applied to those who cannot be assessed with behavioral measures because they do not require a volitional response such as raising the hand or repeating words. Electrophysiological evaluation, vestibular function and auditory processing assessment should also be included where available and where the initial diagnostic audiometric results would suggest the value of these tests.

Immittance Audiometry

As a means of easily diagnosing and providing on-site treatment, the concept of “visiting ‘Ear Camps’”Review was suggested during an international workshop on primary ear and hearing care (WHO, 1998). Such “Ear Camps” can easily incorporate immittance measures to validate findings and treatment decisions. From a theoretic point of view, few would argue that middle ear (immittance) measures provide invaluable replicable and objective information beyond behavioral responses to audiologists and other health professionals. In fact, over the past few

Providing Diagnostic Audiology Services … 125 decades, measuring middle ear function has become a standard of audiological care in developed countries. Because little cooperation or behavioral conditioning is required, immittance tests can be performed quickly while yielding tympanic membrane mobility and function information. With the advent of miniaturized and more rugged immittance equipment such measures have become economically feasible as well as attainable in more programs in developing countries. The primary application of middle ear measures is to identify and classify architectural and functional defects within the auditory system that include the external auditory canal, tympanic membrane, middle ear space, and/or brain stem neural pathways. When used in conjunction with other diagnostic audiological procedures, immittance measures will help: identify and monitor tympanic membrane immobility associated with otitis media; assist in the diagnosis of auditory neuropathy; provide diagnostic information regarding facial nerve lesions; diagnose perforations of the tympanic membrane; and detect the presence of otosclerosis. Because little cooperation is required from the patient, tests of middle ear function become invaluable for those patients who may not be testable with behavioral procedures. Another clear advantage in developing countries is having the ability to pair immittance findings with air conduction thresholds (or minimal response levels in children) when bone conduction thresholds may not be obtainable due to limited equipment resources or patient compliance. When combining the two basic immittance procedures (tympanometry and acoustic reflex measures) with behavioral audiometry, the diagnostic interpretation is exponentially strengthened.

Table 3. Tympanogram types and their description using the classical (A, B, and C) and absolute systems (reprint by permission; Clark & Roeser, 2007)

Classical and Absolute Description of Tympanogram Types

Tympanogram Compliance Static Peak Clinical Audiological Findings Type (ml) Admittance Pressure (daPa) Represents normal middle ear function. The peak (point of maximum compliance) occurs Type A 0.4 – 1.5 .27 – 2.8 +50 to -150 within normal static admittance limits and at pressures between +50

to -150 mm/H20. Represents abnormal stiffness in the middle ear system resulting in a

Type As 0.4 – 1.5 < .27 +50 to -150 fixation of the ossicular chain as in otosclerosis. Static admittance measures are abnormally low. Represents a flaccid tympanic Reviewmembrane resulting from scar tissue Type Ad 0.4 – 1.5 > 2.8 +50 to -150 or a possible disarticulation of the middle ear ossicles. Compliance measures are abnormally high.

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Table 3. (Continued)

Classical and Absolute Description of Tympanogram Types

Tympanogram Compliance Static Peak Clinical Audiological Findings Type (ml) Admittance Pressure (daPa) Represents some pathological condition exists in the middle ear. Type B > 1.5 < .27 no peak Static compliance (admittance) (perforation) measures are abnormally low but initial compliance values are high. Represents restricted tympanic membrane mobility and would Type B indicate that some pathological < 0.4 < .27 no peak (otitis media) condition exists in the middle ear. Static compliance measures are abnormally low. Represents significant negative pressure in the middle ear cavity (considered significant for treatment -200 or when more negative than -200 mm/ Type C 0.4 – 1.5 .27 – 2.8 worse H20). This may indicate a precursory or resolution of otitis media. Compliance measures are usually within normal limits.

B Ad A C

As Admittance (compliance) Admittance Review+ 200 0 - 200 Pressure (daPa)

Figure 6. The classical (descriptive) method of classifying tympanogram types, and is most often noted as the “A, B, C” classification method (see Table 3 for complete description of each type).

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Tympanometry Regardless of the specific tympanometry classification system chosen, it is important to choose one that is consistently used within the country and region so that interpretation of results can be easily shared by those professionals reviewing the information. Several systems have been proposed to classify tympanograms, but the most clinically prevalent are the classical method and the absolute method. Described by Jerger (1970), the classical (descriptive) method is by far the most widely used system due to its simplicity, and is most often noted as the “A, B, C” classification (Figure 6). Although the classical method for describing tympanograms is easy to apply, it is subjective and not all tympanograms fall into the A, B, and C classifications. The absolute system is a method for quantifying tympanometric shapes and classification using static admittance (Peak Y) or tympanogram height, ear canal volume (Vea) tympanometric peak pressure (TPP), and tympanometric width (TW) or tympanometric gradient (GR), based on norms for objective interpretation. Table 3 provides a summary of how the classical and absolute methods can effectively predict clinical audiological findings. For those who have little experience with the absolute system of classifying middle ear status, a brief description follows. Static admittance/compliance (Peak Y) or tympanogram height provides objective information on the height of the tympanogram by quantifying its peak relative to the tail value (obtained at +200 daPa) as well as providing data on the equivalent volume measure of the external and, possibly, middle ear. Ear canal volume or physical volume test (Vea) measures are diagnostically significant when equivalent ear canal volumes (ECV) exceed or are less than expected norms in the presence of a flat tympanogram. In such cases, the static admittance measure helps to detect eardrum perforation (in the case of large ECV), or detect an occlusion in the external ear canal (when ECV are significantly less than the expected). As mentioned earlier, there will likely be a higher incidence of perforated tympanic membrane in developing countries. Consequently, when testing an ear with a tympanic membrane perforation, the pressure may suddenly release when introducing a positive pressure into the external ear canal. This finding would indicate that the eustachian tube is functioning appropriately. TPP is a direct measure of the air pressure in the middle ear at which the peak of the tympanogram occurs. Negative TPP is indicative of the early stages of otitis media; positive TPP is found in early stages of acute otitis media. TW (or GR) describes the width (and slope) of the sides of the tympanogram surrounding the peak. TW is calculated by measuring the pressure range from the tympanogram corresponding to a percentage of reduction in static admittance from the maximum peak admittance. TW/GR measures appear to be sensitive to middle ear diseases that are not detected by other immittance measures or otoscopy (Fiellau-Nikolajsen, 1983; Nozza, Bluestone, Kardatzke & Bachman, 1994). It should be noted that when tympanograms are flat (Type B), the TW/ GR cannot be measured properly. Acoustic reflex measures: As supplied by the VIIth cranial nerve, the stapedius muscle normally contracts simultaneously in both ears when stimulated by a loud signal. The presence/absence of this reflex is an indicator of middle ear function as well as the integrity of the auditoryReview and facial nerves involved in the reflex arc. In addition to assessing the function of neuronal structures bilaterally, the acoustic reflex has a great added value in providing an indirect gross estimation of hearing sensitivity of the patient in those instances that language or other barriers may negatively impact behavioral threshold results. It is important to realize that acoustic reflex measurements do not measure middle ear muscle contraction directly, but

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rather measure the effect of middle ear muscle contraction on tympanic membrane stiffening. This has an important implication in interpreting the clinical value of acoustic reflex results, because middle ear pathology will obliterate the identification of the middle ear contraction recorded with the immittance instrument. Contralateral and ipsilateral acoustic reflexes share common generators, yet their unique pathways can yield different measurement outcomes resulting from specific pathologies. Therefore, the acoustic reflex threshold obtained for a limited number of frequencies and intensities gives physiologic but not behavioral indicators of hearing. The presence of reflexes within normal limits at all frequencies is consistent with normal middle ear function; there is also a high probability that auditory sensitivity is within normal limits. However, acoustic reflexes may occur at expected intensities at all frequencies when mild or moderate-to-severe sensorineural hearing loss is present. For this reason, acoustic reflexes cannot be used to predict hearing threshold sensitivity with absolute assurance. Absent reflexes may also indicate some form of middle ear disease, a moderate-to-severe sensorineural hearing loss without recruitment, or a paralysis of the VIIth cranial nerve in the central auditory pathways. In the cases of bilateral middle ear pathologies, as often seen in developing countries, acoustic reflexes are typically absent ipsilaterally and contralaterally. Consequently, an acoustic reflex assessment can provide valuable insight and confirmation of other audiometric findings. Elevated reflexes are those that are present at a hearing level exceeding 100 dB HL. Partially present reflex is seen in only some (not all) frequencies tested and absent at others. Partial or elevated reflexes may indicate the presence of a hearing loss at those frequencies in which they are absent. If a conductive hearing loss exists, the contralateral acoustic reflex threshold will reflect the degree of conductive hearing loss for the affected ear. As mentioned earlier, elevated reflexes may exceed 100 dB HL. However, a clinician is well advised to avoid presenting stimuli in excess of 105 dB when assessing acoustic reflex thresholds to ensure that a temporary threshold shift is not triggered to negatively affect the behavioral threshold responses.

Auditory Brainstem Response Audiometry Also termed brainstem evoked response audiometry, the auditory brainstem response (ABR) is a highly reliable and successful procedure to give objective information about the auditory system of those individuals that are unable to provide reliable behavioral audiometric responses. Fortunately, over the past few years, reduced cost and size of basic clinical instruments has improved access for many audiologists involved in providing clinical services in both developed and developing countries. Typically these commercial units are heavily dependent upon stable electrical sources without reduction or surges in electrical power. If the environment is conducive and the target population is appropriate within the context of a program within a particular developing country, any audiological data derived from an ABR will certainly provide valuable insight.

Review

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Vignette 2

In testing young children it is important to gain their confidence. This may be easy but with some children it takes time. Involving the mother in the test can make all the difference. It was an afternoon clinic in an African city. A solemn, wide-eyed little girl (‘N’) entered the room clutching her mother’s hand. Her mother sat down at the table and her daughter sat next to her but keeping as close as she could to her mother. The history was taken from the mother and indicated poor speech development as the main cause of concern. On the table were a set of colored pegs and a board but the little girl didn’t attempt to touch them and wouldn’t join in play. N was 4 years old and clearly shy. It was decided to try and condition her for a performance test rather than introduce headphones straight away for pure tone audiometry. She watched my face when I introduced a peg into her field of vision and drew her attention upwards by holding it next to my mouth. I said “GO” and then put the peg in the board. N drew back her hand rather than take hold of a peg I offered but held one when given it by her mother. She didn’t put it in the board when “GO” was signaled. Her mother was told how to help. She held her daughter’s hand and, whilst N watched my face, they put the peg in the board together in response to the signal on several occasions. After this N tentatively responded by herself, gradually becoming more confident. One headphone was then held just off the ear and a 500 Hz tone introduced at an intensity indicated by her responses to “GO” as likely to be audible. I put a peg in the board after the tone was introduced and she followed suit. After a few more signals to which she responded alone the headphone was brought near enough to touch the ear. A few more responses indicated that she was sufficiently confident for us to place the headphones on fully and perform pure tone audiometry. Three thresholds were obtained from each ear indicating that N had a moderate hearing loss. Otoscopic examination and tympanometry were straightforward as N was relaxed. They indicated that her hearing loss was sensorineural and the probable cause of the speech delay.

Clinicians may establish an ABR threshold, considered the lowest intensity level in which a brainstem response is obtained and replicated, by using both click and tone burst stimuli in rapid secession presentation. However, since click-evoked ABR assesses the auditory system more rigorously in the high frequencies (from 1000 to 4000 Hz range), it is easy to rationalize the inclusion of tone burst stimuli when this is feasible. Tone burst stimuli produce frequency specific responses from the brainstem. Since responses generated by tone burst stimuli are more prone to physiological and electrical artifact, their interpretation can be challenging for even the more seasoned clinician. It is important to remember that ABR evaluates auditory sensitivity only, but it will not suggest how an individual uses "hearing" or interprets sounds (i.e., compared to a cognitive interpretation of sound such as required in speech audiometry tasks).

OtoacousticReview Emissions Otoacoustic emissions (OAEs) are measured by coupling a small microphone to the external ear canal with a probe that is similar to the system used in immittance measures, but with a goal of assessing cochlear function. Clinical efficacy of OAE measures continues to

130 Jackie L. Clark and Valerie Newton broaden with the heightened awareness of auditory neuropathy, monitoring otoxicity in individuals, infant hearing screening programs as well as the addition of OAEs into the standard diagnostic auditory test battery. When used appropriately by trained personnel, there is a high correlation between OAE results and degree/type of hearing loss. Over the past few decades the literature has pointed to the medial olivary complex (MOC) as an important contributor for OAEs. When paired with the theory that all otoacoustic emissions arise from either reflection or distortion source mechanisms (Shera & Guinan, 1999), auditory science is recognizing that OAEs are a more complex phenomenon than initially believed. There are, in fact, two basic categories of OAEs: spontaneous otoacoustic emissions (SOAEs) and evoked (or stimulated) otoacoustic emissions (EOAEs). Implicit in name, SOAEs occur in the absence of stimulation to the ear. SOAEs are low intensity sounds that usually are inaudible to the individual and their presence is still not fully understood. EOAEs are recorded by introducing different types of stimuli to the ear. Stimulus type is the determinant for which of the three EOAEs will be recorded: transient evoked otoacoustic emissions (TEOAE), stimulus-frequency otoacoustic emissions (SFOAE), or distortion product otoacoustic emissions (DPOAE). TEOAEs are produced after delivering a brief stimulus (click) to the ear. SFOAEs appear during the presentation of a tonal stimulus and occur at the frequency of the stimulus. DPOAEs are evoked by introducing two tonal stimuli simultaneously. DPOAEs occur at frequencies that are different from the stimulus frequencies and the observed response has a mathematical relationship to the frequencies of the primary stimuli. Current literature suggests that MOC activity affects outer hair cells of the cochlea differentially depending upon stimulus used (Guinan, Backus, Lilaonitku, & Aharonson, 2003). More specifically, activity increases according to the stimulus with the order of magnitude going from smallest to largest respectively: single tone, two tones (e.g., DPOAE primaries), repetitive tone pips, repetitive clicks and broadband noise. Clearly, TEOAEs and DPOAEs provide valuable information regarding cochlear integrity, but with differing methods. TEOAE instruments currently have better noise rejection and response validation abilities than DPOAE measures. Conversely, DPOAE instruments have greater dynamic range testing especially in higher frequencies that could be particularly applicable for monitoring noise or drug effects (Lonsbury-Martin & Martin, 2007). In recognizing that OAEs will continue to grow in importance in the audiological test battery, it is difficult to predict if one form (i.e., DPOAE or TEOAE) will ultimately yield the most valuable information. Until more evidence provides adequate insight, a clinician may conservatively choose instruments that can gather both forms of OAE measure.

REDISCOVERING CLASSIC DIAGNOSTIC TESTS

Many audiologic site of lesion tests, such as the Tuning Fork, the Alternate Binaural Loudness Balancing and Short Increment Sensitivity Index, have become historical footnotes over the pastReview 20 years. This reduction in usage of many site of lesion tests are likely due to their 67–80% accuracy compared to the 90–100% accuracy in lesion identification with the more prevalent digitized radiographic imaging readily available in many urban hospitals in developed countries. In regions where an MRI, C-T or even X-ray may not be readily available, those classical tests for site of lesion can still provide valuable input. Despite their

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ability to differentiate cochlear, conductive or retrocochlear pathology from an unaffected ear, some of the skills to initiate these audiological procedures have been put aside for decades. Most current commercially available audiometers no longer come equipped with options for these specialized tests. For those professionals working in developing regions and making purchase decisions there should be serious consideration of equipment that will allow utilization of some classic diagnostic site of lesion tests where appropriate.

Table 4. Summary of three classic tuning fork tests (reprint by permission; Clark & Roeser, 2007)

Test Purpose Procedure Results

Assesses the Tuning fork base is If louder when ear closed, the presence of placed on the patient’s loss is sensorineural. conductive mastoid while the If the same when the earcanal is Bing hearing loss. earcanal is alternately open and closed, the loss is opened and closed by conductive. depressing tragus. Compares air Tuning fork is If louder when held to the ear, the conduction to alternately held to the ear loss is sensorineural (Rinne bone conduction and then the base is Positive). Rinne sensitivity. placed on the mastoid If louder when base is placed on process. the mastoid process, the loss is conductive (Rinne Negative). Used for patients Tuning fork base is If lateralizes to the ear with loss, reporting placed midline on the the loss is conductive. Weber unilateral hearing patient’s forehead. If lateralizes to the ear without loss. loss, the loss is sensorineural or mixed.

Tuning Fork Tests

Because they provide preliminary diagnostic information, require no special equipment or electricity, and are easily administered, tuning forks should find their way to accepted practice in a developing country. Three commonly used tuning fork tests are: Bing, Rinne, and Weber. Results from tuning fork tests are determined by the presence or absence of an occlusion effect and consequently are dependent on low frequency tuning forks (256 or 512 Hz). As shown in Table 4, the Bing test is used for patients who have either a bilateral conductive or sensorineural hearing loss. In this test, the tuning fork is set into vibration and the handle isReview placed on the mastoid process. With the tuning fork on the mastoid, the ear canal is alternately occluded and unoccluded by having the patient apply slight pressure on the tragus with his/her finger and report if loudness increases when the ear canal is occluded (Bing Positive) or no difference in the loudness occluded or unoccluded earcanal (Bing

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Negative). A Bing Positive result is consistent with normal hearing or sensorineural hearing loss. If a Bing Negative result occurs, it is suggestive of a conductive impairment. Wih the Rinne test, the tuning fork is set into vibration and held close to the patient's ear. The patient is then asked to report when he/she can no longer hear the sound produced by the tuning fork. Once the signal is no longer audible, the handle of the tuning fork is quickly placed against the patient's mastoid process and the patient is asked if he/she can again hear the tone. If the patient is able to hear the tone produced by the fork for a longer duration by bone conduction than by air conduction, the result is called a Rinne Negative, as is observed in patients with a conductive hearing loss. A Rinne Positive occurs when the patient hears the tone longer by air than by bone conduction, and is indicative of normal hearing or a sensorineural hearing loss. Care must be taken when interpreting results from the Rinne test, because if the non-test ear has better bone conduction sensitivity than the test ear, the signal from the mastoid could crossover to the non-test ear and provide an inaccurate diagnosis of conductive pathology. The Weber test is a test of lateralization used for patients who report unilateral hearing loss. After the tuning fork is set into vibration, the handle is placed on the forehead, and the patient is asked to report where the signal is heard. If the signal lateralizes to the ear with the hearing loss, a conductive hearing loss is indicated. If the signal lateralizes to the ear with better hearing, a sensorineural hearing loss is indicated and patients with normal hearing will report the sound in the midline position. Audiometric tuning fork tests can replace standard tuning fork by placing a bone conduction oscillator set at 35-40 dB HL on the patient’s forehead. The use of a bone conduction oscillator for the Bing or Weber tests provides greater intensity and frequency control over the stimulus, increasing the reliability and validity of findings. There is no argument that pure tone bone conduction testing is significantly more sophisticated than tuning fork tests. However, tuning fork tests can be used to provide a preliminary diagnosis or validate pure tone audiometric data. Pure tone bone conduction tests provide both quantitative and qualitative information.

CLASSIC BEHAVIOURAL DIAGNOSTIC TESTS

Differential audiological testing gained popularity when the phenomenon of recruitment was found to have an association with particular sites of lesion. Recruitment is defined as a rapid growth of loudness. Originally, recruitment was thought to be an abnormal finding, but research and clinical investigation has shown that recruitment is, in fact, a normal finding. The lack of recruitment is the abnormal finding (Sanders, 1979). A positive result on a test of recruitment is associated with cochlear pathology while an absent recruitment is associated with retrocochlear pathology. One pathophysiological hypothesis for the recruitment phenomenon suggests that a signal intensity increases above the already pathologically altered threshold while the sensory cells and neighboring neurons are maximally stimulated resulting in Reviewa subjective disproportionately rapid increase of sound sensitivity. Some of the following differential tests focus on identifying the presence and degree of recruitment for a patient.

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Alternate Binaural Loudness Balancing

Matching method procedures have been used extensively in psychoacoustics as a means of differentiating response performance between subjects. A classic matching procedure prevalently used in the past, Alternate Binaural Loudness Balancing (ABLB) has the listener compare loudness of the same frequency between the two ears, one with normal hearing and the other with hearing loss, as a means to detect abnormal loudness growth in a pathological ear (Fowler, 1936). Consequently, the ABLB became a sensitive test for loudness recruitment (i.e., a rapid growth of loudness). Loudness recruitment is observed in patients with cochlear pathology. Individuals with eighth nerve tumors may not experience loudness recruitment in the presence of hearing loss. Using the standard ABLB procedure, the intensity level is kept constant at 20 dB SL in the normal (reference) ear while intensity is adjusted in the other (variable) ear until the signal intensity is judged equivalent between ears. The listener is instructed to report whether the variable tone is “softer than”, “louder than”, or “equal” in loudness to the reference ear. After equal loudness is determined, the intensity is increased in 20 dB increments until the patient’s uncomfortable loudness level or maximum limits of the audiometer are reached. Those individuals with cochlear hearing loss will experience a narrower range of loudness than expected by those with normal hearing. Plotting loudness balance results (as shown in Figure 7) can be accomplished with either a laddergram or graph. As noted in Figure 7, no recruitment is demonstrated when the listener reported equal loudness growth (i.e., +/- 10 dB) between the impaired and unimpaired ear. Conversely, the listener will report equal loudness at equal intensities (+/- 10 dB) when complete recruitment exists.

Short Increment Sensitivity Index

Based on the supposition that recruiting ears are able to detect small changes in suprathreshold signal intensities, the short increment sensitivity index (SISI) was devised (Jerger, Shedd & Harford, 1959). A listener’s perception of a change in intensity is recognized as a change in loudness (difference limen for intensity). Instead of measuring Difference Limen for Intensity (DLI), the SISI procedure tests the ability of a patient to detect the presence of 1 dB incremental changes in the presence of a carrier signal. Clinical experience with the DLI suggested that patients with cochlear disorders can detect small intensity changes in an otherwise steady-state signal at low intensities. Those with normal hearing and patients with disorders other than in the cochlea do not have this ability. The classical SISI procedure involves presenting twenty 1 dB increments simultaneously during a carrier tone of the same frequency at 20 dB SL. A percentage score for the 1 dB increments heard by the patient is then calculated as a small increment sensitivity index. A high SISI score (70–100%) would be characteristic of cochlear (sensory) hearing impairment and a low score (< 20%) indicative of non-cochlear or neural pathology (Cooper & Owen, 1976). Clearly, a diagnosticReview audiometer with a processor that has the capability of producing small 1 dB incremental steps with a simultaneous carrier frequency is necessary to conduct the SISI testing.

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Threshold Tone Decay

Auditory adaptation is the decline of perception of a stimulus as a result of “continuous” stimulation; auditory adaptation is a normal phenomenon. However, auditory fatigue (or threshold decay) is the diminishing response that continues to accumulate under sustained stimulation using a wide frequency and intensity range of pure tones (Carhart, 1957). In those patients presenting with progressive hearing loss, auditory fatigue is associated with retrocochlear lesions. A conventional pure tone audiometer can be used to assess the phenomenon of auditory adaptation through the threshold tone decay test (TTD). Owens Threshold Tone Decay (Owens, 1964) test incorporates a 20 second rest period between each stimulus presentation with each presentation beginning at 5 dB SL. If the patient does not perceive the tone, a 20 second rest period is followed by a 5 dB increase in intensity. Incremental increases in intensity continue until the patient perceives the tone for 60 seconds or until the 20 dB SL is reached. A retrocochlear lesion will cause rapid adaptation at all frequencies; cochlear lesions result in slower adaptation at one or two frequencies. Instead of 5 dB SL starting level, the Olsen Noffsinger TTD will start at 20 dB SL. For more in-depth detail of the above-mentioned classic behavioral diagnostic tests, the reader can review a recent chapter written by Brunt (2002).

Pseudohypoacusis or Nonorganic Hearing Loss

On occasion, a patient may present unusually elevated “thresholds” in the absence of an anatomical or pathological condition. This would be described as “functional”, “non- organic”, “pseudohypoacusis” or “psychogenic” hearing loss and may be due to conscious or sub-conscious factors. Children as young as six years old may present pseudohypoacusic hearing loss, but typically it is exhibited by an adolescent or adult. Conscious factors in an adult may be a desire for financial gain when compensation is involved. Sub-conscious factors in a child include a cry for help as a result of difficulties at school or at home. The hearing loss may be unilateral or bilateral. The audiogram obtained usually indicates a sensorineural type of hearing loss and is often flat in configuration. Underlying the raised thresholds may be normal hearing or a genuine hearing loss. It is unfortunate that in addition to a lack of objective data regarding prevalence of hearing loss, there is limited published data regarding incidence of pseudohypoacusis in various populations within developing countries. Clearly motivating factors for an individual to exhibit a non-organic hearing loss may differ in a developing country than a developed country. Research has indicated that in developed countries the degree of hearing loss claimed is related to the severity of the psychological factors involved (Aplin & Rowson, 1990). Individuals living in an economically deprived developing country may choose to exhibit a non-organic hearing loss for the purposes of obtaining an additional hearing aid for any number of reasons (e.g., a hearing aid would be considered a status symbol or desirable for resale at a Reviewprofit). Detection of a non-organic hearing loss is important in order to avoid unnecessary investigations and treatment where resources are often quite limited. In addition, if emotional issues are identified as a causal factor then psychological help can be considered where needed.

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No Recruitment O O

O X X Recruitment

O X X

Figure 7. Air conduction results from ABLB testing indicating equivalent loudness growth in two ears at 1000 and 4000 Hz. Results from 1000 Hz demonstrate equal loudness report with a 40 dB SL signal in each ear; consistent with no recruitment. Results from 4000 Hz demonstrate presence of loudness recruitment with unequal loudness growth in the two ears.

Voice Test Initial suspicions may be raised during the interview and before formal testing has taken place. A sudden hearing loss with no obvious causation is unusual in childhood. A history of school or family problems, exaggerated listening behaviour, or an accurate response to conversational speech without the aid of lip-reading may all indicate the possibility of a non- organic hearing loss. One way of assessing this is to place the hand over the mouth when speaking or place the headphones from behind the patient and ask quietly if these are comfortable. The result may be an answer not possible from someone claiming a severe degree of bilateral hearing loss. Another non-technological, alternative method of assessing hearing, the three level 'voice test', has been developed, standardized and suggested for use in developing countries (Prescott, Omoding, Fermor, & Oglivy, 1999). The three levels of voicing for the ‘voice test’ included: a whispered voice equating with normal hearing; conversational voice with mild hearing loss; and a loud voice to moderate/severe hearing loss. When comparing the voice test with standard audiometry in the classrooms a specificity of 97.8% and a sensitivity of 83.3% was reported. Prior to undertaking the voice test, an individual validation using a sound levelReview meter held 1 meter from the signal’s origin in a quiet room is used, with an averaged whispered voice corresponding to 30–45 dBA; conversational voicing at 45–60 dBA; and loud voicing at 60–80 dBA. With this degree of accuracy in detecting hearing impairment and its administration simplicity, the three level voice test could be of great utility

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not only for diagnostic evaluation, but also confirmation of audiometric testing when pseudohypoacusic hearing loss is suspected.

Audiometric Tests Simple tests for non-organic hearing loss can be performed using a standard audiometer. One common hallmark seen is inconsistent thresholds and the absence of a shadow curve in the presence of a unilateral hearing loss. Another simple test for a unilateral non-organic hearing loss is placing the bone vibrator on the side of the “poor” ear. If the other ear is normally hearing, a normal bone conduction threshold should be obtained unless a non- organic hearing loss is present. The Stenger test is another useful test and can be performed quite quickly. It is based upon the principle that if two tones of the same frequency are introduced at the same time, one into each ear, then only the louder one is perceived. If a tone is introduced 10 decibels above the threshold in the “good” ear and 10 decibels below the threshold in the “poor” ear and a response is obtained this suggests that the threshold was genuine in the “poorer” ear. No response would suggest a non-organic hearing loss (i.e., a positive Stenger was obtained). Behavioural tests for a non-organic hearing loss are based upon distracting the individual from the loudness of the tone being introduced. They include counting the number of signals given whilst varying the intensity of the signals presented; the which ear test—changing the ear in which the signal is presented and the intensity level of the tone—and the Yes/ No test—say “Yes” when you hear it and “No” when you don’t (Nolan & Tucker, 1981). In tests using word lists there may be a consistent tendency to respond with part of a word. The speech discrimination curve obtained may be better than the degree of hearing loss suggested by the audiogram. Many physiologic tests (as described earlier in this chapter) can be enlisted to confirm or deny the audiological diagnosis of pseudohypoacusis hearing loss in a patient. Auditory brainstem response (ABR) testing may help with indicating whether on not there is an underlying genuine hearing impairment. Unfortunately, a normal ABR threshold does not exclude a genuine hearing loss that may be cortical in origin. Cortical evoked responses would give a definitive result but are not always easy to obtain in children. Adults need to be given a task to keep them alert during the test. Some researchers have used otoacoustic emissions to indicate whether hearing is normal or not (Saravanappa, Mepham, & Bowler, 2005). In the absence of middle ear dysfunction the presence of otoacoustic emissions would be consistent with normal hearing but the possibility of auditory neuropathy would have to be considered.

EFFECTIVE COMMUNICATION OF TEST RESULTS

Presentation of the test results is a significant event for the patient or the parents involved, and should be carried out with due care. Having a hearing impairment or a child with a hearingReview impairment could have far reaching implications, and how the information is received is dependant upon the way in which it is delivered. The information given should never be hurried and there should be an opportunity for questions. When a group of parents within the United States were asked to rate priorities of topics dealing with the initial diagnosis of their child’s hearing loss those with the highest priority

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were: causes of hearing loss; coping with the emotional aspects of hearing loss; understanding the audiogram; learning to listen and speak; and understanding the ear and hearing (Roush and Harrison, 2002). Yet, after some period of time, these parent’s priorities changed with the top two priorities being: learning to listen and speak; realistic timelines for learning to listen and speak. Professionals must be prepared to provide as much information to parents as possible, as well as direct parents to sources of information when requested. Clearly there are questionable parallels between parental concerns in a developing country and a developed country. However, it is important to keep in mind that families living in developing countries will have their own unique beliefs that may be the result of limited awareness of hearing loss as well as negative cultural values about disabilities and only vague knowledge of the options available for remediation (Stephens, Stephens, & Eisenhart-Rothe, 2000). For example, a study by Olusanya, Luxon and Wircz (2006) showed that almost 30% of mothers (in a cohort group of 101) in Nigeria, when asked, believed that hearing impaired children can still hear and speak or that babies could not be born with hearing loss. In addition, local folklore or poorly informed community leaders may suggest to the mother that her child’s hearing loss is due to some action or inaction on her part during pregnancy. Depending on the language and/or dialect expertise of the hearing health care professional, there may be a need to enlist an interpreter to provide test results and render an audiological diagnosis. This has many pitfalls. Unfortunately most “interpreters” are family members who are willing to “re-interpret meaning” and are not experienced in providing an exact translation. When seeking the help of a translator, words should be chosen carefully to avoid undue distress as well as allowing for a straightforward interpretation and translation in a particular language. Even when an interpreter is present it is important to look at, and to speak directly to the person concerned, and not the interpreter. It is essential to be truthful about what is known and what is still uncertain and the words chosen to describe the findings should be selected with sensitivity regarding their impact. A demonstration of a child’s degree of hearing loss can facilitate the counseling process and provide the family or caregivers a clearer idea of the extent of the problem. By having the parent or caregiver seated near the child when presenting signals in soundfield the first step of successful habilitation is more easily achieved. Conversely, being able to demonstrate that a non-speaking child has normal hearing may be an important step towards directing the parent’s attention to other disabilities causing the child’s lack of communication. Once the information is provided one individual may react with an expressive emotional outbreak, while another will display a quiet and stoic demeanor. It is the clinician’s skills and experience that will determine success in building rapport to address each family’s emotional and informational needs. It is an established fact that many do not fully comprehend the diagnosis information given during the initial counseling session. Information given may need to be repeated at that time and later. Where it is feasible, written information should be given, which can be taken and read at home. In addition to the degree of loss, a complete description of an individual's hearing impairment should include whether one ear (unilateral) or both ears (bilateral) are involved and the type of loss. DespiteReview limited resources, there is still an onus on the professional to ensure that careful records about hearing loss are kept with standardized methods and techniques used. Through knowledge of the nature of the test, the test equipment, the test procedures and careful execution, an accurate assessment of the patient’s hearing status can be made.

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REFERENCES

Aplin, A., & Rowson, V.R. (1990). Psychological characteristics of children with functional hearing loss. British Journal of Audiology, 24, 77-87. Archibald, L.K., & Reller, L.B. (2001). Clinical microbiology in developing countries. Emerging Infectious Diseases, 7, 302-305. Boyce, J.M., & Pittet, D. (2002). Guideline for hand hygiene in health care workers. CDC: Morbidity and Mortality Weekly Report, 51(RR16),1-44. Bricco, E. (1985). Impacted cerumen as a reason for failure in hearing conservation programs. Journal of School Health, 55, 240-241. Brunt, M. (2002). Cochlear and retrocochlear behavioral tests. In J. Katz (Ed.), Handbook of Clinical Audiology, 5th ed. (pp. 111-123). New York: Lippincott,Williams & Wilkins. Carhart, R. (1957). Clinical determination of abnormal auditory adaptation. Archives of Otolaryngology, 65, 32-39. Clark, J.L. & Roeser, R.J. (2007). Middle Ear Measures. In R.J. Roeser, M. Valente, H. Hosford-Dunn (Eds.), Audiology: Diagnosis (pp. 372-391). New York: Thieme. Cooper, S.J. (1985). Relationship of hearing protector type and prevalence of external auditory canal pathology. Paper presented at the American Speech and Hearing Association Conference. Las Vegas, NV. Cooper, J.C., & Owen, J.H. (1976). In defense of SISIs: Short Increment Sensitivity Index. Archives of Otolaryngology, 102, 396-399. Culpepper, B., & Thompson, G. (1994). Effects of reinforcer duration on the response behavior of preterm 2-year-olds in visual reinforcement audiometry. Ear and Hearing, 15, 161-167. Day, J., Bamford, J., Parry, G., Sheperd, M., & Quigley, A. (2000). Evidence on the efficacy of insert earphone and sound field VRA with young infants. British Journal of Audiology, 34, 329-334. Fiellau-Nikolajsen, M. (1983). Tympanometry and secretory otitis media: Observations on diagnosis, epidemiology, treatment, and prevention in prospective cohort studies of three- year old children. Acta Otolaryngology, (Suppl. 394), 1-73. Fowler, E.P. (1936). A method for the early detection of otosclerosis. Archives of Otolaryngology, 24, 731-741. Garner, J.S., & Favero, M.S. (1985). CDC guidelines for handwashing and hospital environmental control. Infection Control, 7, 231-243. Gleitman, R.M., Ballachand, B.B., & Goldstein, D.P. (1992). Incidence of cerumen impaction in the general adult population. Hearing Journal, 45(5), 28-32. Gliddon, M.L., Martin, A.M., & Green, R. (1999). A comparison of some clinical features of visual reinforcement audiometry and the distraction test. British Journal of Audiology, 33, 355-365. Guinan, J.J., Backus, B.C., Lilaonitku, W., & Aharonson, V. (2003). Medical olivocochlear efferentReview reflex in humans: otoacoustic emission (OAE) measurement issues and the advantages of stimulus frequency OAEs. Journal of the Association for Research in Otolaryngology, 4, 521-540.

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Hart, A.R., & Karuiku, S. (1998). Antimicrobial resistance in developing countries. British Medical Journal, 317, 647-650. Hickson, F.S. (2001) Behavioural tests of hearing. In V.E Newton, (Ed.) Paediatric Audiological Medicine (pp. 91-112). Chichester, UK: John Wiley & Sons. Hinman, A.R. (1998). Global progress in infectious disease control. Vaccine, 16, 1116-1121. Hong, Y.K. (1984). Disyllabic Malay word lists for speech audiometry. Medical Journal of Malaysia, 39, 197-204. Jerger, J., Shedd, J.L., & Harford, R. (1959). On the detection of extremely small changes in sound intensity. Archives of Otolaryngology, 69, 200-211. Jerger, J. (1962). Hearing tests in otologic diagnosis. ASHA, 4, 139-145. Jerger, J. (1970). Clinical experience with impedance audiometry. Archives of Otolaryngology, 92, 311-324. Kishon-Rabin, L., & Rosenhouse, J. (2000). Speech perception test for Arabic-speaking children. Audiology, 39, 269-277. Lonsbury-Martin, B.L., & Martin, G.K. (2007). Otoacoustic Emissions. In R.F. Burkard, M. Don, & J.J. Eggermont (Eds.), Auditory Evoked Potentials (pp. 159-179). Baltimore, MD: Lippincott Williams & Wilkins. Magnusson, L., Borjesson, E., & Axelsson, A.C. (1997). Visual reinforcement audiometry: Comparison of loudspeaker arrangements. Scandinavian Audiology, 26, 247-251. McPherson, Bradley (2007). Personal communication. Nilsson, M., Soli, S.D., & Sullivan, J.A. (1994). Development of the Hearing in Noise Test for the measurement of speech reception thresholds in quiet and in noise. Journal of the Acoustical Society of America, 95, 1085-1099. Nolan, M., & Tucker, I.G, (1981). Functional hearing loss in children. Journal of the British Association of the Deaf, 5, 2-10. Northern, J., & Downs, M. (1991). Hearing and hearing loss in children. In J. Butler (Ed.), Hearing in children (pp. 1-31). Baltimore, MD: Williams & Wilkins. Nozza, R., Bluestone, C., Kardatzke, D., & Bachman, R. (1994). Identification of middle ear effusion by aural acoustic admittance and otoscopy. Ear and Hearing, 15, 310-323. Olusanya, B.M., Luxon, L.M., & Wircz, M.L. (2006). Maternal views on infant hearing loss in a developing country. International Journal of Pediatric Otorhinolaryngology, 70, 619-623. Owens, E. (1964). Tone decay in VIIIth nerve and cochlear lesions. Journal of Speech and Hearing Disorders, 29, 14-22. Prescott, C.A., Omoding, S.S., Fermor, J., & Ogilvy, D. (1999). An evaluation of the ‘voice test’ as a method of assessing hearing in children with particular reference to the situation in developing countries. International Journal of Pediatric Otorhinolaryngology, 51, 165-170. Roeser, R.J., Lai, L., & Clark, J.L. (2005). Effect of ear canal occlusion on pure tone threshold sensitivity. Journal of the American Academy of Audiology, 16, 740-746. Roush, J., & Harrison, M. (2002). What parents want to know at diagnosis and during the first year. TheReview Hearing Journal, 53 (11), 56-60. Sanders, J.W. (1979). Recruitment. In W. Rintelman (Ed.). Hearing Assessment (pp 261– 280). Baltimore, MD: University Park Press.

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Saravanappa, N., Mepham, G.A., & Bowler, D.A. (2005). Diagnostic tools in pseudohypacusis in children. International Journal of Pediatric Otorhinolaryngology, 69,1235-1238. Shera, C.A., & Guinan, J.J. (1999). Evoked otoacoustic emissions arise by two fundamentally different mechanisms: a taxonomy for mammalian OAEs. Journal of the Acoustical Society of America, 105, 782-798. Smith, A. (2001). WHO activities for prevention of deafness and hearing impairment in children. Scandinavian Audiology (Supp 53), 30, 93-100. Stephens, D., Stephens, R., & Eisenhart-Rothe, A. (2000). Attitudes toward hearing impaired children in less developed countries: a pilot study. Audiology, 39, 184-191. World Health Organization (WHO). (1997). Report of the first informal consultation on future programme development for the prevention of deafness and hearing impairment. Geneva: World Health Organization, Prevention of Blindness and Deafness. World Health Organization (WHO). (1998). Report of the International Primary Ear and Hearing Care Working Party. Cape Town, South Africa. Geneva: World Health Organization, Prevention of Blindness and Deafness. World Health Organization (WHO). (1999). WHO ear and hearing disorders survey protocol for Population-based survey of prevalence and causes of deafness and hearing impairment and other ear diseases. Geneva: World Health Organization, Prevention of Blindness and Deafness. World Health Organization (WHO). (2004). Guidelines for hearing aids and services for developing countries. 2nd ed. Geneva: World Health Organization, Prevention of Blindness and Deafness. World Health Organization (WHO). (2006). Fact sheet: Deafness and hearing impairment. http://www.who.int/mediacentre/factsheets/fs300/en. Accessed June 27, 2006. World Health Organization/Christian Blind Mission (WHO/CBM). (1998). Hearing aids services – needs and technology assessment for developing countries. Report of a WHO/CBM workshop. Bensheim, Germany: World Health Organization, Prevention of Blindness and Deafness. World Health Organization/CIBA (WHO/CIBA). (1996). Prevention of hearing impairment from chronic otitis media: Report of a WHO/CIBA Foundation workshop. London: World Health Organization, Prevention of Blindness and Deafness. Widen, J.E., Folson, R.C., Cone-Wesson, B., Carty, L., Dunnell, J.J., Koebsell, K., et al. (2000). Identification of neonatal hearing impairment and hearing status at 8 to 12 months corrected age using a visual reinforcement audiometry protocol. Ear and Hearing, 21, 471-487. Wong, L.L.N., & Soli, S.D. (2005). Development of the Cantonese Hearing in Noise Test (CHINT).Review Ear and Hearing, 26, 276-289.

Chapter 7

REHABILITATION OF HEARING LOSS: CHALLENGES AND OPPORTUNITIES IN DEVELOPING COUNTRIES

Ron Brouillette* Directorate of Primary and Mass Education, Dhaka, Bangladesh and ‘Wings’, Consultants for International Deafness and Development, United States of America

ABSTRACT

There are approximately 186 million people with hearing loss residing in developing countries. Their access to aural rehabilitation services that can significantly reduce the effects of hearing loss and improve communication is largely non-existent or very limited. Aural rehabilitation includes identification of hearing loss, assessment, counselling, hearing aid fitting, communications interventions and follow-up. Within the 149 lower and lower middle income nations of the developing world necessity has spawned innovative aural rehabilitation alternatives to meet the growing demand for hearing health. This chapter, guided by the World Health Organization’s Guidelines for Hearing Aids and Services for Developing Countries describes the situation regarding hearing aid provision in developing nations and introduces a range of affordable and appropriate options that may potentially meet local needs. Due to the scarcity of information on audiological services in lower income nations, this chapter borrows largely from anecdotal evidence based on field reports and personal experiences. The topics covered include raising public awareness and acceptance of hearing aids and services, the hearing aid market in developing countries, barriers to successful hearing aid provision and ways to create effective services in developing regions. Review

* Correspondence: [email protected]

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BACKGROUND

Aural rehabilitation includes the counselling, device fitting, communication intervention and follow-up services that should take place after the accurate identification and assessment of hearing loss. The goal of aural rehabilitation is to facilitate adequate receptive and expressive communication in individuals with hearing impairment (American Speech-Language- Hearing Association, 1984). Aural rehabilitation is an essential component to any hearing health care process. Unfortunately, access to these services is extremely limited in many developing nations. Approximately 186 million people with hearing loss reside in developing countries (WHO, 2004a). Their access to aural rehabilitation services that can significantly reduce the effects of hearing loss and improve communication is largely non-existent or very limited. For example, the provision of hearing aids is fundamental to the rehabilitation process. Yet, of the estimated 35 million hearing aids required each year in developing countries, only one million hearing aids are distributed (Smith, 2007). The field of aural rehabilitation is vast, encompasses counselling, the provision of assistive devices such as telephone couplers, visual alarms, telecoil systems and personal FM systems, speechreading training among others. This chapter, however, will focus narrowly on the provision of hearing aids in developing countries. Without the availability and affordability of this instrument very little worthwhile aural rehabilitation can be accomplished in any community. Increasing the access to hearing aids in developing countries has been addressed by many European organisations and individuals since the late 1960s and 1970s. In particular, the Commonwealth Society for the Deaf, a charitable organization based in the United Kingdom, conducted several international seminars on aural rehabilitation needs and reducing barriers to hearing aid provision, including the first such seminar in Africa (Commonwealth Society for the Deaf, 1968). Later, a European Initiative on Hearing Impairment in Developing Countries sought to delineate the issues involved in hearing aid provision and to devise ways to improve delivery systems in non-industrialized countries (Royal National Institute for the Deaf, 1991). More recently, the World Health Organization has taken a leadership role in highlighting the needs of those with hearing disability in developing countries (Kumar, 2001). An outcome of WHO’s activities has been the recent formation of WWHearing—World Wide Hearing Care for Developing Countries. This body of international experts advocates the development of models for affordable hearing health care systems, and particularly affordable hearing aids and delivery services, in developing countries (WWHearing, 2008). These philanthropic and inter-governmental organizations have drawn attention to the financial and technical difficulties inherent in the commercialization of hearing health care in low income countries and propose alternatives to overcome these difficulties. The outgrowth of their efforts and emerging shifts in delivering hearing aid Reviewservices in developing countries are described in this chapter.

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BARRIERS TO EFFECTIVE REHABILITATION SERVICES

Affordability—The High Cost of Hearing

Those who seek amplification in developing countries are often shocked by the cost of hearing aids. Costs are prohibitively high for the vast majority of individuals in impoverished regions with hearing impaired communities (Alberti, 1999; McPherson & Holborow, 1985), where the majority of potential hearing aid users earn less than $2.00 per day (see Chapter 2 for an overview). Hearing aid sales worldwide in 2005 were estimated to be 7 million units out of a needed 52 million units. Of these, however, only 3% were sold in developing nations where around 70% of people with hearing impairment reside (Smith, 2007). Uptake of hearing aids, even under ideal conditions meets a small fraction of need. In the United States for example, only 23% of those who need hearing aids can afford or will choose to wear them (Hearing Mojo, 2007). In 2004, the average cost of a hearing aid fitting in the United States was $2,300 (Allen, 2004). The WHO has established a guideline for ‘affordability’ as no more than 3% of gross national product per hearing aid (McPherson, 2007). This has the advantage of relating hearing aid cost in each country to average income. Table 1 lists examples of how the WHO guideline determines affordability in a range of developed and developing countries, using 2006 gross national product statistics. However, in developing countries the average price of a basic hearing aid—available in mostly urban areas— is well over $US200. Hearing aids, depending on the level of technical sophistication, retail for between $250 and $1,500 in a developed Asian economy (Cheng & McPherson, 2000). In typical developing Asian nations a body-worn hearing aid prescribed by an audiologist retails between $80 and $250, while a behind-the-ear (BTE) model will cost from $100 to more than $1,000 (Brouillette, 2001). Globally, the WHO estimates that the average cost of hearing aids is between $200 and $500 in developing countries (Kumar, 2001). However, long-term affordability is often not improved when large numbers of ‘free’ hearing aids are provided by overseas charitable agencies. Anderson (2008) discusses the impact of ‘free’ hearing aids on the existing audiological service network in the Dominican Republic. Although well-intended, this kind of humanitarian activity may be counterproductive and unsustainable unless linked to the local audiology infrastructure’s resources and cultural knowledge. Additionally, field experience has demonstrated that the financial or in-kind participation of a hearing aid recipient (such as through purchase of an earmold or batteries) leads to a sense of ownership and responsibility. The cost of conventional hearing aid batteries, when they can be found, is another major constraint on affordability. A standard pack of six zinc-air hearing aid batteries, at an average cost of $4.50, will strain a family’s resources—especially in the 49 least-developed countries, where the majority of the population lives on less than $2 a day (UNCTAD, 2002). The annual cost of batteries—perhaps $36 or more —may be, after an average of four years of hearing aid use, equal to or greater than the initial cost of a hearing aid. Often, even if funds can be foundReview to cover this cost, BTE hearing aid batteries are unavailable in local markets (McPherson & Brouillette, 2004). In most of the least developed nations, an alternative to expensive zinc-air cells for hearing aids that take size 675 batteries is the LH44 battery. This costs only 10% of the price of the 675 cell but has a shorter working life (normally one week

144 Ron Brouillette to ten days). This battery fits nearly all later model 675-based hearing aids. There are anecdotal reports of users experiencing slighter greater gain in the high frequencies with this battery. For many hearing aid users this may be a welcomed distortion. While hearing aid manufacturers and most audiologists advise the use of zinc-air batteries, the substitution of LH44 cells will continue until there is affordable availability of other battery types including rechargeable batteries.

Table 1. Gross national product and affordable hearing aid costs in US dollars

Country GNP Target price Switzerland $48,230 $1,450 United States $41,400 $1,250 South Korea $13,980 $420 Thailand $2,540 $80 China $1,290 $40 Zimbabwe $825 $25 Viet Nam $550 $20 Uganda $270 $10

Hearing instruments are often classified as ‘medical appliances’ for the purposes of assigning import duties and sales tax in many nations. In developing countries, import tax regimes may be very high and be a very significant additional cost component of the retail price of medical goods (Bate, Tren & Urbach, 2006), including hearing aids. This is discussed in Chapter 2 of the present volume. There are local many factors in addition to import taxes, loss in transhipment and informal customs tariffs that contribute to the relatively high retail cost of hearing instruments. These include the commercial distribution system, the often low volumes of devices purchased by distributors from the manufacturer, the limited sales volume achieved, the expenses associated with a traditional audiology clinic, the cost of upgrade training of personnel and high profit margins established for wealthier urban clients in developing nations. In addition, the actual number of hearing aid manufacturers has dwindled significantly over the past two decades, reducing competive pricing. Seven manufacturers (often referred to as the ‘seven sisters’) now control the vast majority of the worldwide $2 billion market for hearing aids (Hearing Mojo, 2007). The major manufacturers (GN Resound, Denmark; Oticon, Denmark; Phonak, Switzerland; Siemens, Germany; Sonic Innovations, U.S.A.; Starkey Laboratories, U.S.A.; Widex, Denmark) have a combined market share of nearly 90% of sales. All have high research and development, marketing and training costs associated with creating each new generation of sophisticated, digital, hearing aid product lines. The remaining market is shared by over 30 other companies, such as Rion (Japan) and Amplifon/Miracle Ear (USA). Three developing countries that are producing hearing instruments to any scale, but mostly for local or regional consumption, are China, India and Botswana. In India the major companies includeReview Alps, Novax, Elkon and Arphi. Hearing aid provision in India is discussed in detail in Chapter 8. In China, the main producers—other than manufacturing units of the ‘seven sisters’— are LiSound, Tianle, and Goldluck. In Botswana, Godisa produces a range of hearing aids from kits (see Vignette 1). For the most part, these companies offer less sophisticated products and hence prices for their hearing aids are more affordable for those

Rehabilitation of Hearing Loss 145 living in developing countries. Basic hearing aid technology is neither complicated nor expensive. Like most transistor era hearing aids, the US$7 body worn hearing aid currently available from Tianle (2008) in China consists of a transducers (microphone and receiver— which are often the most expensive components of a system), a small integrated circuit amplifier, a wheel volume control, a tone (bass cut) switch and casing. The unit is robust and can serve 7 years or more in normal conditions. The sound quality of a device such as the Tianle hearing aid may be limited compared to a unit with sophisticated signal processing and higher quality components, but a balance between quality and affordability may need to be made when providing hearing aids in developing countries. Several Danish studies have shown that the subjective and objective benefits derived from low cost BTEs may be similar to those gained from more sophisticated products (Parving, 2003; Parving & Christensen, 2004; Parving, Christensen, Nielsen & Konradsson, 2005). The tested output values of this unit matches the manufacturers declared levels and meets basic WHO specifications (see Table 2). WHO specifications were developed to guide manufacturers in the mass production of low cost hearing aids using currently available technology (WHO, 2004a). The guidelines also include a recommended temperature operating range of 5 to 45°C and 0 to 80% humidity, to meet climatic conditions encountered in developing countries. Hearing aids, particularly in the harsh environments often found in developing countries, also often break down and require repair (Butler, 1991). Again, this is a cost burden to hearing aid provision that needs to be considered.

Table 2. WHO minimum performance requirements (WHO, 2004a)

Hearing aid parameter Minimum requirement Maximum OSPL (90) 118 dB SPL +/- 4dB OSPL (90) at 1 kHz 114 dB SPL +/- 4dB Maximum Full on acoustic gain 45- 55 dB SPL +5/-0 dB Full-on acoustic gain at 1kHz 42 dB SPL +5/-0 dB Basic frequency response 200 Hz to 4500 Hz 200 Hz to 2000 4500 Hz +/- 4dB SPL 200 Hz to 4000 Hz +/- 6dB SPL on a nominal frequency response curve Total harmonic distortion at 70 dB SPL input 500 Hz < 5% 800 Hz < 5% 1500 Hz < 2 Equivalent input noise level < 25 dB SPL Battery Current < 1 mA

Hearing instruments are systems that deliver amplified sound from the external environment to the ear canal. Well-made, custom earmolds are a necessity when using medium and high gain hearing aids (Nolan & Tucker, 1988). These require manufacture by a trained technicianReview and are another significant cost burden in developing countries. The provision of proper fitting earmolds is crucial to hearing aid acceptance and use. There are typically three approaches to delivering earmolds: 1) stock earmolds such as ear canal tips that come with many hearing aids in developing countries; 2) custom made two-stage earmolds; and 3) custom made one-stage earmolds.

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Hearing aids typically are packaged with ‘L tubes’ that connect from the earhook and a two or three sizes of ear canal tips. Most audiologists in developed nations will use these canal tips for trial purposes only and replace them with a superior sounding custom fit mold. WHO guidelines (2004a) recommend that an earmold production laboratory should be established at the start of any hearing aid service to avoid reliance on stock earmolds that often offer a poor fit and cause acoustic feedback. The WHO guidelines also call for earmold production using a two stage process—an impression is taken and a ‘positive’ earmold is produced from this negative cast. The earmolds are typically made from either soft or hard acrylic or a soft silicone and require grinding and polishing to complete. This process often takes a full week of turn-around time and usually the final product requires fine adjustments when the hearing aid user returns for a fitting. A custom earmold is useable for around two years, but with older children the earmold should be changed every year. For children less than five years, who have a developing external ear, earmolds should ideally be renewed around every six months Northern & Downs, (2002; p. 325). Earmolds are a very significant cost factor in device fitting in developing countries.

Limited Professional Support

Audiological rehabilitation procedures, equipment and devices are global commodities. Hearing health professionals whether they are practicing in high or low income nations typically adhere to similar assessment, fitting and counseling protocols. There can be vast differences, however, on the types and quality of services offered in developing nations due to the lack of resources and access to trained specialists. Hearing aid provision depends on availability of support personnel who form an assessment, fitting and follow-up team. This team may be hospital-based, community-based, school-based or managed by a voluntary agency (Chalmers, 1991). The team typically includes at least an audiologist or audiology technician and an earmold / repair technician. The team and might also include an administrator, medical doctor (family physician or otorhinolaryngologist), community health worker, teacher of the deaf and speech therapist. As noted in Chapter 2, there are serious skill shortages in most developing countries of all the personnel required for quality hearing aid delivery and follow-up service. In particular, without the availability of appropriate follow-up personnel, “the process of fitting hearing aids is quite useless” (Miles, 1991). University trained audiologists are in demand by employers in most developed countries, who can offer attractive employment conditions. Many audiologists who receive training in developing countries such as India and South Africa emigrate to developed nations in large numbers. In the Indian context, audiology instructors report that more than 60% of all nationally trained audiologists are working abroad. Many audiologists from developing countries receive their training in Australia, Europe, and North America and prefer long-term employment in these ‘lands of opportunity’ over their country of birth.

Review Awareness and Stigma

Two factors mitigate the popularity, uptake and sustained use of hearing aids: prohibitive cost and lack of an awareness of their benefit. The majority of cases of hearing impairment

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can be improved with correctly fitted hearing aids. However, many hearing impaired users in developing countries are unaware that their loss can be improved. Aural rehabilitation is founded on a personal awareness of one’s own hearing disability and an understanding of the ways it can be remediated. Personal awareness of the need for and benefits of amplification in developing countries is the result of public awareness campaigns utilizing the power of social marketing (see Vignette 2).

OVERCOMING BARRIERS TO EFFECTIVE REHABILITATION

Purchasing Hearing Devices in Quantity

Ordering large quantities of hearing aids from a manufacturer or distributor usually ensures a “quantity advantage”. Discounts can range from 5% to up to 40% or more depending on the quantities ordered. Most hearing aid distributors and retailers in lower- income nations are likely to be quantity disadvantaged due to the limited numbers of hearing aids and accessories they normally import from industrialized nations. These minimum orders reflect several realities: 1) the turn-over volume per projected sales period; 2) the fear that the imported devices will be delayed in customs, attract substantial customs duty and unfair related costs; 3) concerns regarding loss in shipment; and 4) the importer’s available capital. Limited sales of higher priced hearing aids translate also into the need for a higher profit margin to make ends meet. However, the vicious cycle of exorbitant, unaffordable prices due to low volumes leading to lower uptake can be broken. Through networking on a cooperative basis, non-governmental organizations (NGOs) in lower income nations can tap resources found within other developing nations to lower the cost of goods without greatly sacrificing the quality of hearing aids and other assistive devices. There are benefits in negotiating directly with the multinational manufacturers of hearing aids and assistive devices. There are good examples of NGOs successfully pooling resources for bulk purchasing—and a quantity price advantage—for both hearing aids and batteries. Some of these arrangements have been through cooperatives such as in the Philippines. However, these limited attempts at bulk purchasing have proven somewhat disappointing in some cases. Where quantity discounts are negotiated, manufacturers may demand unrealistically high volumes to be taken in one or two shipments. Even so, the purchase price relative to the manufacturer’s cost price may not show the anticipated reduction. In this situation, sourcing hearing aids from manufacturers based in developing countries such as China, India and Botswana may help reduce costs substantially.

Developing Hearing Aid Assembly Units

Another viable option is to develop small businesses to assemble hearing aids from kits. This has been successfully accomplished in places like India, Botswana, Viet Nam and the Philippines,Review and other assembly units are likely to start in Central America. Hearing aid kits can be sourced through manufacturers who might be convinced to participate in this arrangement if the quantities to be assembled are sufficient and the local assembly does not interfere with the manufacturers’ local and regional distribution system. Most countries have local distributors of the major brands of hearing aids. Manufacturers at times complain that it

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actually costs more to send kits because they often disassemble stock hearing aids to provide the kits. Potential customers of kits are also dissuaded by manufacturers citing quality control issues, especially when the hearing aids assembled from kits carry a manufacturer’s brand name. Manufacturers are likely to discourage local assembly using the argument that the cost difference between the kits and fully assembled devices is usually less that 5% to 10%. However, in countries with significant import duties on imported medical devices such as hearing aids, assembly in-country may be a very effective way to reduce purchase costs. Hearing aid kits can be purchased in two forms: semi knocked down (SKD) or completely knocked down (CKD). In places where import duties on hearing aids are exorbitant, importing SKD hearing aid kits is a viable option because the importation of parts is often free or costs are far less than for assembled items. SKD kits usually require only soldering the transducer(s) onto the printed circuit board and closing the unit with small screws. The savings in this process are often offset in part by the cost of the hearing aid analyzer necessary to test the finished product. CKD requires a higher degree of precision and technology. These kits provide a printed circuit board and all components and the device must be assembled under ideal conditions. In Botswana, Godisa employs highly skilled Deaf technicians who provide all the labour to assemble hearing aids and solar battery rechargers (McPherson & Brouillette, 2004). In Chapter 12, links to international manufacturers of hearing aids are given. Some of these companies allow local assembly of their products.

Developing Global Solutions through Social Enterprise

Meeting the challenge of equitable distribution of hearing aids in low income countries may not be an economic priority for large multinational manufacturers. Certainly, the massive quantities of assistive devices required for the world cannot be met by existing commercial enterprises nor can these be delivered by civil society alone though a charitable approach. A synergy of business and social conscience or social enterprise is required for this task. Social enterprise can be defined as any earned-income business or strategy undertaken by a non- profit organization to generate revenue in support of its charitable mission. "Earned income" consists of payments received in direct exchange for a product, service or privilege (Social Enterprise Alliance, 2004). Social enterprise is necessary in order to make hearing aids affordable and accessible to people with limited incomes in developing nations. Bold strategic business plans need to be crafted and dedicated specialists and resource people need to be identified to implement these plans.

Vignette 1 Godisa — Technologies for a Developing World

Background Godisa was formed from an initiative of the Camphill Communities Trust, a charitable organizationReview with a longstanding commitment to children and adults with disabilities. One Camphill Community is located in Otse, a village located 24 miles from Gaborone, the capital of Botswana, southern Africa. In 1992 the Solar Aid Workshop was formed by the Otse Community, in collaboration with the Botswana Technology Centre, to manufacture solar rechargeable hearing aids that could be used in Africa and other parts of the developing world.

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The Solar Aid body-worn hearing aid used a fixed rechargeable cell with no user access. The body-worn hearing aid and recharger package won a South African Bureau of Standards “Design for Development Award” in 1998 for its innovative qualities. The body-worn hearing aid incorporated solar panels on the instrument itself. In 2002 Solar Aid was manufactured under an NGO trust called ‘Godisa’. Godisa means ‘to do something that is helping others to grow’ in Setswana, the national language of Botswana. The name change reflected the expansion of the product line and provision of related services to persons with hearing loss. The Godisa Technologies Trust is a charitable entity whose aim is to offer technologies and/or services for the relief of hearing disability in developing countries. Godisa chose to assemble hearing aids in Otse and employs local young people with severe or profound hearing loss in the manufacturing process. Fourteen local technicians, including 10 with disabilities, have been trained and employed in hearing aid assembly, repair or quality assurance procedures. The initial Solar Aid models and its design concepts generated keen interest in Godisa. The second generation of this model additionally incorporated a low tone cut control for more flexible fitting. However, the initial prototype hearing aids had limitations. The body-worn hearing aid was found to be unacceptable in many parts of Africa, where it was first marketed, due to its weight, size and visible receiver cord. The integrated charger unit was found to be not as robust as desired. The body-worn hearing aid is currently being redesigned

Present Products and Future Plans Godisa now produces a range of behind-the-ear hearing aids, including models that may use either zinc-air or rechargeable Ni-MH batteries. Recharging is supported with a newly redesigned solar power battery recharger and the first known size 13 and low-cost size 675 rechargeable button-cell batteries. The latter can be charged up to 300 times over their two-year lifespan and sell for less than $US1.50. The hearing aids available are all BTEs and cover a wide range of hearing loss fitting requirements. Hearing aid models and their specifications can be viewed at the Godisa website (http://www.godisa.org/index.html). The electroacoustic characteristics of the hearing aids can be altered in the field by simple trim-pot adjustment. All hearing aids are produced and tropicalised at Godisa’s Otse assembly center and efforts are continually made to improve quality standards. The purchase price of the hearing aids is dependent on the model and the quantity ordered, but is in the target $35 to $99 range. Godisa is attempting to reduce costs further, in line with the WHO objectives. Field trials in a developed country, with prototype sample instruments, indicated that the Godisa low-gain hearing aid offered “substantial benefit” to persons with moderate to severe sensorineural hearing loss (Parving & Christensen, 2004). The field trial also provided valuable constructive criticism that led to improved hearing aid quality control. Improved production quality was noted in a subsequent evaluation of Godisa’s high-gain, compression hearing aid (Parving, Christensen, Nielsen & Konradsson, 2004). Feedback from users of hearing aids supplied to developing countries has been positive, although rigorous quantitative and qualitative evaluations are not yet completed. The Godisa solar battery charger has been designed to accept a variety of hearing aid cells. It is able to rapidly charge three sizes, AA, 675 or 13, of rechargeable Ni-MH battery using solar power with no operating costs. The recharger has been designed to be weather-resistant and shock-resistant.Review

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Appropriate Earmold Technology

Earmolds should complement any hearing aid, be comfortable and avoid acoustic feedback problems. Custom-made earmolds while usually creating the best fit are not necessarily required. Low cost, stock earmolds can often be used as a custom substitute for low and medium gain hearing aids (Smith, Riley, Davis, Davies & Jeffs, 2008). Perhaps as many as 60% of hearing aid users in least developed countries use “temporary” plastic eartips rather than custom-made earmolds (Brouillette, 2001). In a developing nation, locally sourced materials for earmold manufacture typically cost approximately $1.50. The technician labor cost for 35 minutes per earmold is about 50 cents. The retail price on this earmold is typically $5 to $8. These costs are based on a two-stage technique with a pressure cooker and bicycle pump method—the cheapest but most labor intensive method. A low-cost appropriate technology two-stage kit has been developed by an Australian audiologist, David Pither. The kit, which includes air compressor or bicycle pump, pressure cooker, grinder, drill and drill components, is available for around $500 from Godisa. The purchase price and benefit of a locally produced earmold compared to the price and benefit of a stock eartip for moderate to severe hearing loss sways many new hearing aid users to make do with the noncustom eartip supplied with the hearing aid. There are several cases in the author’s experience where the user preferred the ‘temporary’ ear canal tip over a poorly made or hard and heavy full earmolds that are often produced in newly established low-cost laboratories. However, in the case of severe to profound hearing loss, the stock ear canal tip is usually not an option due to the acoustical feedback that occurs when one is used. One alternative to the higher cost two-stage earmold is the one-stage “instant” earmold that is most appropriate for large “ear camps” and other community-based settings. The 2004 edition of the WHO guidelines suggests that a one-stage technique may be appropriate in these community settings, but adds the caveat that more research and development for this technique is needed. The advantages of the one-stage earmold are numerous. Okpojo (1992) suggests that the one-stage approach can reduce the usual two-stage problem of shrinkage of impression material in transit and on the benchtop, and reduce the loss of good fit that can occur in the polishing process. Newly created polymers are resulting in more versatile one- stage earmolds. Silicon compounds are injected into the ear canal as if to make an impression. The material then cures in the ear and once removed can be immediately drilled to create a sound bore and any required vents. There are typically two types of one stage material: one that pre-packages the polymer and monomer into a syringeable cartridge and one that requires hand-mixing polymer silicon or acrylic with the monomer liquid. Hard acrylic earmolds are more suitable for pocket (body worn) hearing aids that require the installation of an “O” ring for the earphone receiver. One advantage of the self-mixing method is its flexibility. With the hand mixed material the technician can make a one stage BTE earmold by mixing a slightly wetter compound than is generally called for and wrapping the chewing gum-like compound evenly around the a preformed tube with wall thickness appropriate to the client’s hearing loss. The diameter thickness of the mixture depends on the size of the ear canal that is to be fitted. MostReview of the mixture remains at the outer end of the wrap that is spread into the concha. The mixture plus tube is carefully inserted into the canal beyond the fist bend with the help of the otolight and then spread into the concha. When the mixture cures, after five to seven minutes depending on mix and climate, the complete earmold is removed for polishing and removal of unwanted tubing. The same process may be used for a hard acrylic earmold for a

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body worn hearing aid. The “O” ring passes through the outside portion of the tubing and is carefully pressed into the curing acrylic. Addresses for earmold material suppliers are found in Chapter 12 of this book.

Vignette 2 Tips on Organizing a Hearing Health Awareness Campaign

• Synchronize your campaign with one of the existing international or regional observances such as International Noise Awareness Day (3rd Wednesday in April) or Hearing Awareness Day in Asia (3 March [3 / 3]). • Consult with any national committee or organization on hearing health care and/ or national occupation health and safety agency and plan collaboratively. • Link awareness campaign to a large prevention of hearing impairment campaign. • Organize free hearing screening or examinations at popular public sites. • Encourage famous persons/celebrities who wear a hearing aid to be part of the campaign. • Offer promotions on affordable hearing aids. • Write press releases and hold news conferences. • An effective hearing health campaign should increase the uptake of hearing aids. Seek manufacturer and distributor support for your campaign.

Raising Public Acceptance of Hearing Loss and Hearing Aids

A local, regional or national hearing health awareness campaign that includes hearing assessment or “ear camps” can create a positive and receptive mind-set to hearing aids. One important requirement prior to organizing such an awareness campaign is to ensure an accessible supply of affordable hearing aids and related services in the geographical region of the campaign. An affective hearing health campaign can, in principle, increase the uptake of hearing aid. “Ear camps” may be organized in tandem with the more popular “eye camp” initiatives.

Research and Evaluation of Hearing Aid Provision

Only a small percentage of the world’s annual output of published health research relates to diseases of poverty (WHO, 2004b). Similarly, very little research has been published on the effectiveness of hearing health care services in developing nations. There is an urgent need for information that can guide audiologists, other health professionals and policy makers regarding effective intervention strategies in developing countries. Research on practical questions related to issues such as simplified earmold manufacture and the effects of humidity on hearing aid batteries need answers. Larger issues such as the economic costs of hearing aid provision underReview different health service paradigms require urgent attention. A newly established NGO, WWHearing (World Wide Hearing Care for Developing Countries) is now actively supporting hearing health care research projects in China, India and Brazil that evaluate hearing health care procedures and systems. This type of research should be encouraged globally.

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CONCLUSION

There is a growing demand among many hearing health professionals, consumers and organizations working in developing countries for access to those basic rehabilitation tools and techniques found in more developed countries. Technical and financial support from major international bodies such as the World Health Organization, Lions Club International, CBM, Rotary International and the IMPACT Foundation, among others, can assist in reaching modern but appropriate standards of technology and service. Improved social marketing initiatives, such as the not-for-profit Godisa Technologies Trust, and focused applied research may fundamentally alter the quality of life of many individuals with hearing loss in the developing world. By making affordable, appropriate amplification devices and quality fitting services widely available, the benefits of aural rehabilitation will one day become a reality for the majority of the world’s people with hearing loss.

REFERENCES

Alberti, P.W. (1999). Pediatric ear nose throat services’ demands and resources: a global perspective. International Journal of Pediatric Otorhinolaryngology, 49 (Suppl. 1), S1- S9. Allen, J. (2004). Hearing aids becoming easier & cheaper to buy. http://consumeraffairs. com/health/hearing/hearing_aids_01.html American Speech-Language-Hearing Association. (1984). Definition of and competencies for aural rehabilitation. ASHA, 26 (May), 37–41. Anderson, M. (2008). Humanitarian Audiology. Days in La Republica Dominicana? Audiology Now, 32, 55,57. Bate, R., Tren, R. & Urbach, J. (2006). Still taxed to death: An analysis of taxes and tariffs on medicines, vaccines and medical devices. Washington, DC: American Enterprise Institute-Brookings Joint Center for Regulatory Studies. Brouillette, R. (2001). Hearing aids in developing countries: Problems and promises. In Proceedings of the WHO Informal Consultation on Hearing Aids for Developing Countries, July 11-12, 2001 (Document No. PBD/PDH/01.2). Geneva: World Health Organization. Butler, J.A. (1991). The whole question of repair. In Hearing aids. Their production, delivery systems and effective use, pp. 49-51. London: Royal National Institute for the Deaf. Chalmers, P. (1991). Personnel and equipment to access hearing loss, provide earmoulds and fit hearing aids. In Hearing aids. Their production, delivery systems and effective use, pp. 29-31. London: Royal National Institute for the Deaf. Cheng, C.M., & McPherson, B. (2000). Over-the-counter hearing aids: Electroacoustic characteristics and possible target client groups. Audiology, 39,110-116. Commonwealth Society for the Deaf. (1968). Report on the first seminar on deafness to be held in ReviewAfrica, 1968. London: Commonwealth Society for the Deaf. Hearing Mojo. (2007). Spotlight: Affordable hearing aids WHO. http://www.hearingmojo. com/blog-mt/blog-mt/hearing_aids/ Kumar, S. (2001). WHO tackles hearing disabilities in developing world. Lancet, 358(9277), 219.

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McPherson, B. (2007). Challenges to current practice: Ensuring equity of access and equity of outcome. Presentation at WHO/WWHearing Fifth Workshop on the Provision of Hearing Aids and Services for Developing Countries, 8-9 November 2007, Geneva. McPherson, B. & Brouillette, R. (2004). A fair hearing for all: Providing appropriate amplification in developing countries. Communication Disorders Quarterly, 25, 219-223. McPherson, B., & Holborow, C. (1985). Parent guidance in developing countries. Journal of the British Association of Teachers of the Deaf, 9, 81-83. Miles, S. (1991). Follow-up support for hearing aid users. In Hearing aids. Their production, delivery systems and effective use, pp. 37-39. London: Royal National Institute for the Deaf. Nolan, M., & Tucker, I. (1988). The hearing impaired child and the family. London: Souvenir Press. Northern, J.L., & Downs, M.P. (2002). Hearing in children. 5th ed. Baltimore: Lippincott Williams & Wilkins. Okpojo, A. (1992). Advances in earmold technology: One-stage (direct) approach. Journal of the American Academy of Audiology, 3, 142-144. Parving, A. (2003). The hearing aid revolution: Fact or fiction? Acta Otolaryngologica, 123, 245-248. Parving, A., & Christensen, B. (2004). Clinical trial of a low-cost, solar-powered hearing aid. Acta Otolaryngologica, 124, 416-420. Parving, A., Christensen, B., Nielsen, J., & Konradsson, K. (2005). Clinical trial of a low- cost, high power compression hearing aid. Audiological Medicine, 3, 76-81. Royal National Institute for the Deaf. (1991). Hearing aids. Their production, delivery systems and effective use. London: Royal National Institute for the Deaf. Smith, A. (2007). Update on burden of hearing impairment, and progress of WHO/WWH hearing aids initiatives. Presentation at WHO/WWHearing Fifth Workshop on the Provision of Hearing Aids and Services for Developing Countries, 8-9 November 2007, Geneva. Smith, P., Riley, A., Davis, A., Davies, W. & Jeffs, E. (2008). Study finds compliant eartips can be used instead of custom earmolds. Hearing Journal, 61(2), 27-28,32,34,36. Social Enterprise Alliance (2004). http://www.se-alliance.org/ World Health Organization. (2004a). Guidelines for hearing aids and services for developing countries. 2nd edition. Geneva: World Health Organization. World Health Organization. (2004b). World Report on Knowledge for Better Health. Strengthening Health Systems. Summary. Geneva: World Health Organization. Tianle. (2008). http://www.tianle.com United Nations Conference on Trade and Development. (2002). The Least Developed Countries. Report 2002. New York: United Nations. WWHearing. (2008). http://www.wwhearing.org Review

Chapter 8

HEARING AID PROVISION IN DEVELOPING COUNTRIES: AN INDIAN CASE STUDY

Vijayalakshmi Basavaraj* All India Institute of Speech and Hearing, Mysore, India

ABSTRACT

Since the 1960s, India has worked against the forces of its massive and diverse population and low per capita income to distribute hearing aids to those in need. Developments in the area of hearing aid provision have been tremendous both in terms of manufacture of indigenous hearing aids as well as in the availability of international brands in the open market. However, the cost of hearing aids in the market is exorbitant for most Indians. Attempts have been made to develop cost effective indigenous hearing aids. The Government of India has introduced schemes for distribution of free or subsidized hearing aids to individuals with low incomes. However, the aids distributed are, by and large, of body level type. There is an acute shortage of hearing health care personnel such as audiologists, earmold technicians, and hearing aid repair technicians to serve those who require care. With the National Program for Prevention and Control of Deafness (NPPCD) being implemented throughout the country in 2008, it is expected that access to services for persons with hearing impairment will improve considerably. The country also intends to develop high quality, low cost hearing aids to serve the needy.

INTRODUCTION

India, with a population of over one billion, covers an area of 3.288 million km². It is a ‘potpourri’ of all possible terrains spread across the 35 states and union territories—having snow clad mountains,Review deserts, coastlines, valleys and hill stations.

* Correspondence: [email protected]

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Services to diagnose hearing impairment and fit hearing aids have been available since the 1960s in a few cities in the country. However, there were no national estimates about the number of persons with hearing impairments until India participated in the observance of the International Year of the Disabled in 1980. The 1980 Indian census collected information on persons with disabilities, albeit insufficiently. A national sample survey of persons with disabilities was also instituted and implemented. Since then, prevalence data have been made available every ten years. Thus, India now has some estimates regarding persons with hearing impairment. The National Sample Survey Organization (NSSO) reported in 2002 that there are over 3 million persons with hearing impairment in the country, with the majority in rural areas. There were 300,000 children below 6 years age with hearing impairment in the year 2000. This is considered as a very rough estimate as the personnel involved in the survey did not have the skills or tools to identify hearing loss of less than moderate degree in one or both ears. In addition, it is estimated that one in every 750 live births will have severe to profound bilateral hearing loss and hence about 21,000 such children are born every year given the national birth rate of 22.69 per 1000 population. Government and non governmental organizations (NGOs) have attempted to estimate the number of persons with hearing impairment in the country through various small scale surveys. In 1996, a World Health Organization (WHO) project entitled “Prevention of Deafness and Communication Disorders” was undertaken by the All India Institute of Speech and Hearing (AIISH). It has now become an ongoing research project. The extrapolated estimates from the project data (1996 till 2007) put the incidence of hearing impairment in infants in the range of 3.29% to 7.67%, and in school children in the range of 9.07% to 38.1%. Periodic studies of neonatal hearing screening programs are also underway. One such program undertaken by Ali Yavar Jung National Institute for the Hearing Handicapped (AYJNIHH) in collaboration with King Edward Memorial Hospital, Mumbai, reports that the incidence of hearing impairment in high risk neonates is 3.97% (Basavaraj & Nandurkar, 2005).

AVAILABLE INFRASTRUCTURE FOR SERVICE PROVISION

There are about 20 government organizations which have ‘the state of art’ facilities for early identification, diagnosis and intervention of persons with hearing impairment. AIISH and AYJNIHH are among the leading service providers at the tertiary level. In addition to this, it is estimated that there are about 150 government organizations, 350 NGOs and about 500 private clinics providing services. The Indian Ministry of Social Justice & Empowerment set up about 130 District Disability Rehabilitation Centers (DDRC’s) covering all zones in the country in 2001. There are five Composite Rehabilitation Centers (CRCs) providing services to persons with all types of disabilities. It is envisaged that DDRCs will be established in more than 600Review districts in India in the next 5 years. There are about 270 medical colleges in the country providing services at the tertiary level. The Medical Council of India (MCI) has made it mandatory for the medical colleges to have facilities for audiometry, hearing aid evaluation and dispensing.

Hearing Aid Provision in Developing Countries 157

MANPOWER AVAILABLE FOR SERVICE PROVISION

There has been a slow but steady attempt to develop manpower to serve persons with hearing impairment. Undergraduate and postgraduate programs began in 1967, albeit in only a few institutes. As of today, there are 30 training centers accredited by the Rehabilitation Council of India (RCI) offering 4-year undergraduate programs or 2-year postgraduate programs in Audiology and Speech Language Pathology. Several institutions are recognized to run PhD programs as well. About 2000 qualified Speech Language Pathologists and Audiologists have been trained in the country. However, over 50% of them have migrated to other countries with brighter job prospects. More postgraduates and PhDs are working as master trainers rather than as direct service providers. Since 1994, the Diploma in Hearing, Language & Speech Disorders (DHLS), which is recognized by RCI, has been offered. The entry level for enrollment is 12 years education in the science stream. The course is of 10 months duration. There are about 400 diploma holders in India. This program is now offered at 12 training centers across the country, awarding the diploma to about 180 persons every year. AIISH launched the DHLS program through distance mode in 2007. The institute has study centers in 4 major medical institutions in the country: Maulana Azad Medical College, New Delhi; Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry; All India Institute of Physical Medicine and Rehabilitation, Mumbai; and Regional Institute of Medical Sciences, Imphal. The classes conducted in Mysore are received by the study centers through video conferencing with real time audio-video interaction. Clinical training is imparted at the respective study centers. AIISH plans to expand the program by setting up more study centers across the country. Diploma (of 2 years duration), graduate and postgraduate programs (of one year duration each) in special education are also available in the country. It is estimated that there are about 20,000 trained special educators. The other potential manpower providers who can be included for hearing screening and assisting service delivery are the primary health care workers such as the anganwadi workers & multipurpose health workers. Anganwadi workers and helpers are those who work for the state-operated Integrated Child Development Services. These services focus on the health and preschool education needs of 0-6 year old children as also the health and nutrition needs of pregnant women, nursing mothers and adolescent girls. There are over 1 million anganwadi workers who are available in the ratio of one per 1000 population.

THE STATUS OF HEARING AID PROVISION IN INDIA

WHO (2005) estimates that at least 278 million persons in the world have disabling hearing impairment. Out of these, well over 30 million are in India (NSSO, 2002). The global production of hearing aids is reported to be very inadequate, meeting the needs of only 10% of the number of persons with hearing impairment. A very small portion of this number of amplificationReview devices, estimated to be about 100,000 to 125,000, is manufactured in India. In addition to this, about 50-60,000 hearing aids are imported from other countries. Thus, there is a huge gap between the estimated need and production/import of hearing aids in India.

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The Past to the Present Scenario

Even though several opticians imported and dispensed hearing aids prior to the 1960s, Arphi hearing aids, manufactured in Bombay in 1962, were the first indigenous aids (Peston Jamas, 2003). Under an Indo-Danish project ‘Danaid’, hearing aids were available for distribution from the 1960s to the 1980s in a few central government institutes. Several other Indian makes came into the Indian market in the next decade or two. Each of them had several models of their own. Some of the manufacturers survived even though the market was small, but others closed down. The Indian Standards Institute (ISI, now known as Bureau of Indian Standards) standards for hearing aids were published in 1967 (IS: 4406 & 4482 – 1967). With the availability of standards, researchers in the area of aural rehabilitation carried out studies to determine the quality of hearing aids available in the market. The results documented the quality of Indian hearing aids as rather poor (Kacker, Deka, Sharma, & Basavaraj, 1989; Kumar, Mahendru, Ojha, & Raturi, 1995; Pandaley & Murthy, 1972; Ravishankar, & Sashidhar, 1989; Sharma, Basavaraj, & Kacker, 1989). The process of venturing into design and production of newer and better indigenous makes and models continued. Under an Indo-US collaborative project dealing with selective amplification, Basavaraj et al. (1995) tested a wearable binaural digital amplification device developed in New Mexico, USA. The Indian Institute of Technology (IIT), Bangalore, produced research prototypes of FM hearing aids (Sneha, 1995), ITI, New Delhi, designed a body level hearing aid with a digital amplifier (Anand, 1994). Artificial Limbs Manufacturing Corporation of India (ALIMCO) has designed and manufactured body level hearing aids since 2001 and has procured BIS approval since 2002. Contralateral routing of signals (CROS) hearing aid research prototypes were developed by AYJNIHH (Sinha, 2002). The Center for Design of Advanced Computing (CDAC), of the Indian Ministry of Information and Technology, in collaboration with AIISH, has developed prototypes of low cost digital body level hearing aids, field trials of which are in progress. The leading manufacturers, such as Alps, Arphi, Elkon and Novax assemble behind-the- ear (BTE), in-the-ear (ITE) and in-the-canal (ITC) aids and are marketing them under their own brand names. Further, with the liberalization of Indian import policies, the whole world market has been opened to Indian consumers. As a result, in the last five to ten years, several international brand hearing aids, including those offering digital completely-in-canal (CIC) hearing aids, have become available. Today, over 20 brands of hearing aids with their several hundred models are in the market. However, it is worth noting that they are available only to the urban elite and not for the majority of the population living in villages in the country.

Cost of Hearing Aids

The manufacturer’s recommended price for body level hearing aids vary anywhere between Rs. 500 to 10,000 (US$ 10 to 250) and that for BTEs and other styles range from Rs. 2,500 to 80,000Review (US$ 50 - 1600) for digital aids. It is estimated that the manufacturer’s recommended price of a hearing aid is never less than 10 times its manufacturing cost. The additional costs associated with the distribution network are alarmingly high, making the product cost exorbitant for many Indians.

Hearing Aid Provision in Developing Countries 159

AYJNIHH and AIISH are dispensing hearing aids of all makes and models at a reduced cost. This has enabled the beneficiaries to obtain good quality hearing aids with a discount of 25% to 50% on the manufacturer’s recommended price. It is estimated that more than 1000 hearing aids are dispensed in this manner every year.

Hearing Aid Recommendations and Procurement

Persons with hearing impairment or their caregivers have various options to procure hearing aids. Some of them are as follows:

1. Consult a general physician for the problem who in turn refers the patient to an otolaryngologist, audiologist or hearing aid dealer; 2. Consult an otolaryngologist who may a) assess and dispense the hearing aid himself, b) assess and refer to a hearing aid dealer, or c) refer the patient to an audiologist; 3. Consult a government or non-governmental specialist institution, a hospital or special school (in case of children), where the assessment is done by qualified or semi- qualified professionals. The aid is dispensed or the client is referred to a hearing aid dealer after assessment; 4. Consult an audiologist who assesses and dispenses the hearing aid; or, 5. Go directly to a hearing aid dealer to procure a hearing aid.

It is estimated that the leading hearing aid manufacturers have a network of about 300 dealers each, spread across the country. However, the network in the northeastern states is reported to be very poor. Since the country does not have any registering or licensing policy for hearing aid dealers, ear, nose and throat specialists and pediatricians, audiologists and speech language pathologists, special educators (hearing impairment), opticians, pharmacists, and even grocers dispense hearing aids in various parts of the country. It is worth noting that hearing aid dealers play an important role in client procurement of hearing aids.

Prescription of the Hearing Aids

The procedure followed in prescribing a hearing aid depends on who prescribes the aid and in what type of organization they work. There are several training institutions where functional-gain and insertion-gain measurements are performed using standard equipment and procedures. Many dealers of digital hearing aids have the facility to prescribe and program digital hearing aids. However, by and large, the procedure followed for prescribing hearing aids is not satisfactory. It is very common to find clients who are prescribed hearing aids without even an audiological assessment.

Review Hearing Aid Testing Facilities

Some of the major referral centers include AIISH and AYJNIHH (Mumbai and its regional centers). Secunderabad, Delhi, and Kolkata have world-class facilities for testing

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hearing aids. The aids selected for distribution under the Assistance to Disabled Persons (ADIP) Scheme are subjected to electroacoustic characteristics assessment as well as physical checks to ensure distribution of good quality hearing aids.

The Assistance to Disabled Persons Scheme

In 1981, the Indian Ministry of Social Justice and Empowerment introduced the ADIP scheme for distributing free hearing aids or hearing aids at 50% of cost. Those whose family monthly income is less than Rs. 6500 (US$ 130) are eligible for free hearing aids and those whose monthly income is between Rs. 6501 to 10,000 (US$ 130 - 200) are eligible for a 50% concession. In the ADIP scheme, hearing aids and their accessories are selected under a bulk contract. Presently only body worn hearing aids are distributed through the scheme and their cost varies from Rs. 440 to 1,500 (US$ 10 - 35). There were 38 models from four to five manufacturers approved in the bulk contract in 2006. Along with the hearing aids, AA solar battery chargers (including two chargeable batteries) are also provided. The solar battery recharger costs about Rs. 214 (US$ 4.5). Provision to provide aids and appliances costing up to Rs. 8000 (US$ 160) for each ear is made under the ADIP scheme. Children studying up to 10th grade are given binaural hearing aids. They are eligible for new hearing aids every two years. It is estimated that about 90,000 hearing aids manufactured in India are distributed through the ADIP scheme by about 200 implementing agencies (both government and non-governmental organizations) spread across the country.

Other Facilities under the ADIP Scheme

The ADIP scheme also makes provision for the following:

1. Free earmolds (by reimbursing the cost of the earmold to the implementing agencies); 2. Traveling expenses for visiting the facility (under specified rules); 3. Daily allowance for stay while attending the facility (under specified rules).

ADIP Scheme Implementing Agencies

The Ministry of Social Justice and Empowerment has opened the ADIP scheme for implementation by any agency which satisfies certain criteria. This was done to broaden the network of implementing agencies in the country to reach the unreached. About 200 implementing agencies (governmental and non-governmental organizations combined) are presently servingReview individuals with hearing impairment. A project to study the feasibility of providing binaural BTEs under the ADIP scheme is underway. The project is expected to throw light on the cost effectiveness of providing binaural BTE hearing aids and the issues involved in their maintenance.

Hearing Aid Provision in Developing Countries 161

The other sources of funds for the purchase of hearing aids are the Central Government Health Scheme (CGHS), which provides up to Rs. 60,000 (US$ 1200) for digital hearing aids, various Employees Scheme of Insurance (ESI) and charitable organizations.

FACILITIES FOR PROMOTING USE AND MAINTENANCE OF HEARING AIDS

Earmolds

Custom made earmolds ensure the optimal use of the output of the hearing aid by securely coupling it to the ear. This is an essential component for satisfactory use of the hearing aid. Hard acrylic molds are commonly used in India. The cost of this type of mold is about only Rs. 67 (US $1.35). The facilities for making custom made earmolds need to be expanded. They are available only in major cities and big towns. It is estimated that not more than 500 centers have facilities for earmold making. These include about 150 government organizations (mentioned earlier), about 200 non-government organizations and about 150 hearing aid dealers. Due to a lack of facilities that manufacture custom made earmolds, hearing aids are often used either with stock earmolds or eartips. Some of the major institutions in the country have tried cost effective methods of plaster casting the ear impression in diagnostic camps so that they can be brought to their laboratories for processing. The prepared molds are later mailed to the clients. Even though this strategy for service delivery is excellent, it cannot be sustained for long due to the costs involved. Renewing this strategy with better and more widely distributed facilities for impression taking, plaster casting and mailing would enable more people to have earmolds. Soft earmold facilities have been available since the 1990s. The estimated cost of a soft mold is about Rs. 350 (US $ 7). However they are sold with about 100 to 150% profit in the private sector and hence unaffordable by the majority of clients. The earmolds are not always made by trained personnel. Earmold modification to suit individual needs is rarely heard of. Given that very few earmold labs are available in the country and the lengthy processing time of conventional procedures, there is undue delay in fitting hearing aids to clients, even after the hearing assessment is completed. This presents a hurdle in utilizing the critical period of learning in young children with hearing impairment who are identified early. Only several dozen centers in the country have ultraviolet light curing facilities that enable faster preparation of molds.

Batteries for Hearing Aids

An estimated 70% of Indian hearing aid users use body level hearing aids with 1.5V AA batteries. These batteries are now available even in rural areas and cost Rs. 7 (US $ 0.20) onwards perReview piece. These batteries have a life of about 100 hours. Most of the BTE hearing aids take 675 size zinc-air batteries costing Rs. 25 to 30 (US$ 0.75) or rechargeable AAA batteries costing Rs. 45.50 (US$ 1.10), both with a battery life of about 180 - 200 hours. Both types are becoming widely available throughout the country.

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Spare Parts for Hearing Aids

The spare parts required for hearing aids include cords, body cases, microphones, receivers, and switches. Except for the microphones and receivers, the leading local manufacturers are making these spare parts and hence they are available at a modest cost. Microphones, receivers and ear hooks (for BTE devices) are imported and hence are expensive. The quality of locally produced parts is likely to improve further if local manufacturers develop an international market. Defects in the spare parts mentioned above frequently contribute to the malfunctioning of hearing aids (Kacker et al., 1989). The availability of spare parts is, however, restricted to urban regions.

Training of Personnel for Earmold Making and Hearing Aid Repairs

Continued efforts are being made to train more earmold technicians and hearing aid repair technicians. Practical training in this area is given at the diploma, graduate and post graduate levels in audiology and speech language pathology courses, as well as in special education programs. Thus, the graduating students of these courses have the required skills to prepare earmolds and undertake hearing aid repair. AIISH is offering a one-year diploma program in earmold making and hearing aid repair which is recognized by the Rehabilitation Council of India. AIISH, AYJNIHH and its regional centers, and a few other major centers, conduct regular short-term training programs in these two areas for special educators, other staff of special schools, and ADIP implementing agencies. Attempts to train the adult deaf as ear mold technicians have also been made. In spite of these efforts, more earmold technicians and hearing aid repair technicians are needed in the country.

OTHER FACILITIES AVAILABLE

Assistive Listening Devices

Assistive listening devices, such as alerting devices, induction loop systems, TV and telephone listening devices, are used more as exhibition items than as regularly prescribed devices for the hearing impaired. Since the present demand is low, the availability is also poor and the costs are high. Induction loop systems have been installed in railway booking counters, auditoria, reception areas in offices, and other locations to illustrate their use in promoting barrier-free environments for persons with hearing impairment. They cost about Rs. 8000 (US $160) and should be installed more widely.

Correspondence/Review Online Assistance regarding Hearing Aids

AYJNIHH and a few other major institutions have facilities to reach out to the people through correspondence, e-mail and online assistance. These initiatives provide token

Hearing Aid Provision in Developing Countries 163 assistance to those who cannot physically visit the centers and promote public awareness regarding hearing impairment.

RECENT DEVELOPMENTS

The Ministry of Health and Family Welfare has drafted a proposal to launch the ‘National Program of Prevention & Control of Deafness (NPPCD)’ in India’s 11th Five-Year Plan (with effect from April 2007). The pilot phase of the program was initiated in August 2006, implementing the planned strategy in 25 districts belonging to ten states and one union territory across the country. The overall objective of the program is to prevent hearing loss due to disease or injury, provide early diagnosis, treatment, and medical rehabilitation, strengthen linkages, create databases, and facilitate needs-based research. The long-term objective is to reduce the total disease burden from 6.3% to less than 3% prevalence of hearing loss in the designated areas by 2012. The planned strategies are:

1. To strengthen service delivery including rehabilitation; 2. To develop human resources for ear care; 3. To promote outreach activities and public awareness through innovative and effective information, education and communication strategies with special emphasis on the prevention of deafness; 4. To develop institutional capacity.

In the preparatory phase of the program, it is envisaged to plan activities to train health workers; sensitize the state health community and State Medical College staff regarding the national program; fund the state health and district health communities for the procurement of equipment, aids and appliances. In the second phase, active manpower training and capacity building will be undertaken. Hearing screening at schools and camps will be conducted followed by rehabilitation of the identified population. The third phase would focus on monitoring and evaluation of manpower training, capacity building, service provision and information, education and communication activities. BTE hearing aids under bulk contract will be distributed free of cost. The project’s Hearing Aid Provision Scheme has incorporated the provision of hearing aid repair and maintenance services under the bulk contract.

CONCLUSION: OUR NEEDS AND FUTURE PLANS

1. Research and development in the area of hearing aids and earmolds: a. Action is required to further improve the quality of spare parts and components. This would improve the mechanical and electroacoustic quality of the devices. b. Dust and humidity resistant components need to be explored so that better Reviewquality, durable hearing aids are manufactured and assembled in India. c. The central and state governments may consider minimizing or exempting import duty, sales tax and local taxes on the components of the hearing aids and assistive listening devices, so that hearing aids become more affordable.

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d. Cost effective assistive listening devices need to be designed and manufactured. More attention must be given to television and telephone listening aids as the geriatric population is on a steady increase and more and more elderly persons are living independently.

2. The referral route has to be strengthened and followed up for better service delivery.

3. Attempts must be made to empower and widen the existing hearing aid recommendation and procurement system. Some effective steps may be: a. Licensing of hearing aid dealerships. b. Training hearing aid dealers to dispense hearing aids professionally and equip them with: basic and user friendly literature about hearing aid use, care and maintenance; hearing aid repair and earmold facilities lists of referral centers. c. The network of governmental and non-governmental organizations needs to be further expanded. d. Strengthening of public awareness programs regarding the need for hearing assessment, hearing aid trial and custom made earmolds before purchasing hearing aids, utilizing primary and secondary level workers. e. Disseminate information in user-friendly mode regarding the facilities offered by the Government of India, so that the ‘Persons with Disability’ Act of 1995 can be implemented with full vigor. f. WHO guidelines (2001) which state that ‘Behind-the-ear hearing aids should be the preferred option but body-worn aids will still be required in some situations’ (WHO, PBD report, 2001) be considered for the ADIP Scheme.

4. Ear mold manufacture needs to be improved and made more affordable. Centralized earmold laboratories need to be set up by governmental and non- governmental organizations across the country in all the states so that mailed ear impressions are processed and returned to the beneficiaries. Associated costs should be borne under the ADIP Scheme. The Government of India should be approached to waive the mailing cost of aids and appliances used by the disabled population. Suitable earmold material for one stage processing should be explored, developed and tested so that custom made molds are provided at lower cost within a short period of time. Adult deaf persons may be trained as earmold technicians at the special schools for the deaf. This would serve the dual purpose of expanding the earmold facilities and of providing employment to individuals who are deaf.

5. RadioReview mechanics, who are available in large numbers across the country, should be trained to repair hearing aids so that hearing aids are utilized adequately over their optimal working life.

Hearing Aid Provision in Developing Countries 165

6. Solar battery chargers for 675 type batteries (used with BTE aids) should be developed to reduce considerably the maintenance cost of BTEs.

REFERENCES

Anand S. (1994). Personal communication. Basavaraj, V., Kacker, S.K., & Kaur, M. (1995). Digital master hearing aid (DMHA) and CUDLS – our experience. Journal of the Indian Speech and Hearing Association, 14, 41– 50. Basavaraj, V., & Nandurkar, A. (2005). Implications of hearing impairment in a child and neonatal hearing screening programs. Paper presented at the 7th course of Neuro-otology and Audiology. Hinduja Hopsital, Mumbai, October 2005. Indian Standard: 10775 – 1984 (Superceding IS: 4406 – 1967 and IS: 4482 – 1967). Specification for body level hearing aids. Indian Standard: 10776 (part 1) – 1984. Methods of measurement of the electroacoustical characteristics of hearing aids, part 1. General measurements for air conduction hearing aids. Indian Standard: 10776 (part 2) – 1984. Methods of measurement of the electroacoustical characteristics of hearing aids, part 2. Additional measurements for hearing aids with induction pick-up coil input. Indian Standard: 10776 (part 3) – 1984. Methods of measurement of the electroacoustical characteristics of hearing aids, Part 3. Additional measurements for hearing aids with automatic gain control circuits. Indian Standard: 10776 (part 4) – 1984. Methods of measurement of the electroacoustical Ccharacteristics of hearing aids, part 4. Hearing aids with bone vibrator. Indian Standard: 10781 – 1984. Specification for reference coupler for the measurement of hearing aids using earphones coupled to the ear by means of ear inserts. Kacker, S.K., Deka, R.C., Sharma, R., & Basavaraj, V. (1989). Common defects in hearing aids. Indian Journal of Otolaryngology, 41(1), 34-36. Kumar, S., Mahendru, A., Ojha, S., & Raturi, S. (1995). A study of the status of the use of hearing aids in school going children. Journal of the Indian Speech and Hearing Association,14, 78-83. National Sample Survey Organization (NSSO). (1991). National sample survey. New Delhi: Department of Statistics, Government of India. National Sample Survey Organization (NSSO). (2002). Disabled persons in India. Report No.485: 58th Round. New Delhi: Department of Statistics, Government of India. Pandaley, S.P.C., & Murthy, S.S. (1972). Performance characteristics of Indian hearing aids. Journal of the All India Institute of Speech and Hearing, 3, 108-113. Peston Jamas, P.A. (2003) Personal communication. Rangasayee, R. (1991). Photovoltaic battery charger for use with body level hearing aids. UnpublishedReview manuscript submitted to S & T Mission Mode of Ministry of Social Justice and Empowerment, Government of India. Ravishankar, K.C., & Shashidhar (1989). Electroacoustical performance of hearing aids. Journal of the Indian Speech and Hearing Association, 5-6, 26-33.

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Rehabilitation Council of India (RCI). (1996). Report on manpower development. New Delhi: Ministry of Social Justice and Empowerment, Government of India. Sharma, R., Basavaraj, V., & Kacker, S.K. (1989). Physical and electroacoustical characteristics of hearing aids. In K.B.Sahay & R.K. Saxema (Eds.), Biomechanics (pp. 20-205). New Delhi: Wiley Eastern Ltd. Sinha, A.K. (2002). Personal communication Sneha, V.B. (1995). Comparative study of subjects performance with FM system and their personal body level hearing aids. Journal of the Indian Speech and Hearing Association, 14, 35-40. World Health Organization (WHO). (1995). Prevention of hearing impairment. Resolution of the 48th World Health Assembly, 12, May, 1995. WHA 48.9. Geneva: WHO. World Health Organization (WHO). (2001). Press release WHO/34. 11 July, 2001. Geneva: WHO. World Health Organization (WHO). (2001). Guidelines for provision of hearing aids and services for developing countries. WHO report No.PBD/PDH/01.1 July, 2001. Geneva: WHO. World Health Organization (WHO). (2005). World-wide Hearing Care for developing countries. WW Hearing Strategic Plan version 5.3. October 2007. Geneva: WHO.

Review

Chapter 9

EDUCATIONAL AUDIOLOGY IN DEVELOPING COUNTRIES

Susie Miles* and Wendy McCracken University of Manchester, United Kingdom

ABSTRACT

School-based audiological services can deliver considerable benefits to deaf children and their families, especially in developing countries where audiology clinics may not yet have been established, or where they are only based in capital cities. In this chapter we explore the origins of ‘educational audiology’ and consider the advantages of locating hearing health care and hearing assessment services in schools for deaf children. In order to understand the challenges faced in setting up and maintaining such services, we identified a range of practitioners in developing countries and asked them a series of questions by email about their practice, their training needs and the challenges they faced. We used a purposive sample of practitioners identified through the Enabling Education Network and audiology graduates from the University of Manchester. We also wrote to audiologists based in the United Kingdom who have advised practitioners in various developing countries on the development of audiology services and who have provided audiological training to some of those practitioners. This chapter reviews the findings from this small survey, presents a set of case examples and considers the implications for the further development of educational and school-based audiology services in the most cost-effective and sustainable way.

Review

* Correspondence: [email protected]

168 Susie Miles and Wendy McCracken

INTRODUCTION

This chapter looks in detail at some of the challenges in providing audiological support to deaf children in developing countries. We begin with a brief history of the development of educational audiology. We then go on to identify some of the advantages of locating audiological services in school settings, while appreciating the fact that most schools do not see themselves as centres of audiological expertise. We use real world examples from Africa, Asia and South America, provided by audiology graduates from the University of Manchester, Deaf Child Worldwide (formerly known as the International Deaf Children’s Society)1) and the Enabling Education Network2 (EENET), to explore the potential for developing more widely available community based services for deaf children.

WHAT IS EDUCATIONAL AUDIOLOGY?

The concept of educational audiology became a commonly used term during the 1970s. It is firmly rooted in Western countries as well as in China and Russia. Although medically- based, clinical audiology services have much to offer, the importance of developing audiology skills in teachers of deaf children is also recognised. Teachers of deaf children are able to provide the following audiological services alongside their teaching commitments:

1. Responsibility for the day-to-day management of personal hearing aids and other audiological equipment; 2. Advice on acoustics in classrooms and the promotion of good listening environments; 3. Audiological advice to children and families, since teachers are more likely to have regular contact with families than medical practitioners; 4. Interpretation of hearing assessments for non-specialist teachers to help ensure the most appropriate teaching approaches are used; 5. Monitoring of developmental progress in the use of aids, allowing appropriate adjustments to be made to equipment.

Over the past 30 years there have been major changes in audiology. This has included the development of post-aural (behind the ear) hearing aids; the introduction of FM radio systems (initially as body-worn aids but now as plug-ins to post aural aids); of classroom amplification; of paediatric cochlear implantation; and in some areas digital rather than analogue amplification. Methods of assessment have moved from using behavioural measures to implementing newborn hearing screening programmes; the use of a battery of objective tests; paediatric hearing aid fitting protocols; and real ear measurements for the verification of hearing aid fittings. Whilst basic audiological training has been part of the specialist qualification to teach deaf children, new knowledge and understanding of audiological issues Review 1 Deaf Child Worldwide is the international development wing of the UK’s National Deaf Children’s Society (NDCS), which is a parents’ organisation. It was set up in 2002 with the aim of supporting initiatives with deaf children and their families in developing countries. 2 The Enabling Education Network supports and promotes the inclusion of marginalised groups of children in education worldwide by providing useful and relevant information. It is based in the University of Manchester.

Educational Audiology in Developing Countries 169

make additional training important to ensure that deaf children and their families benefit from these developments. In the income-rich, industrialised ‘developed’ countries, responsibility for the education of deaf children tends to lie with specialist support services or special schools. These schools and services ensure that the children receive appropriate support, usually from a specially trained teacher of deaf children, in a variety of educational settings. In the United Kingdom, educational audiologists have traditionally come to the profession as trained and experienced teachers of deaf children. This is different in the United States, where educational audiologists typically have training in speech and hearing sciences. This ‘second tier’ approach to training was designed to be suitable to individuals who were already specialists in education, deaf education or communication difficulties. These professionals have an understanding of child development, developing communication skills, educational programmes and basic audiology. This knowledge provides an ideal foundation for a more specialised range of audiological knowledge and skills, typically including: anatomy and physiology of deafness; epidemiology and screening; assessment of hearing status; sensory aids, earmoulds, impression taking, manufacture and adjustment; fitting, verification and ongoing monitoring of amplification; measurement and management of room acoustics; acoustic phonetics and speech intelligibility testing; calibration and care of equipment.

ADVANTAGES OF SCHOOL-BASED EDUCATIONAL AUDIOLOGY

Schools for deaf children offer a real opportunity for the development of educational audiology services in southern countries, both to the deaf children within the school and also to those in both the immediate area and the wider region. Special schools have a potential wealth of experience and resources and so could become a base for a range of audiological services. They have the potential to:

1. Test hearing and dispense hearing aids; 2. Train mainstream teachers, families, community members in deaf awareness and deaf friendly schools, potentially improving the acoustic environment for all learners; 3. Make earmoulds, supply batteries and repair hearing aids; 4. Develop and deliver outreach services; 5. Provide a venue for ‘earcamp’3 and other screening services offered by outside agencies.

Schools offer some very real advantages over hospitals in providing audiology services and educational advice to families. Hospitals are commonly associated with sickness and disease, tend to be situated in major urban centres, and are often prohibitively expensive. Although many schools are also based in urban centres, schools can offer an alternative, less

3 Review Ear camps typically involve medical audiologists, audiologists and ENT staff who undertake short, focused assessments of audiological and otological needs, although the high rate of discharging ears makes this a difficult task. Advice is provided regarding aural hygiene and some minor surgery is conducted, such as mastoidectomies and myringoplasties. Professional time is donated, with the cost of equipment, travel and disposable items frequently met by charities, including the Red Cross and Red Crescent. Ear camps provide a service to the community serving all ages.

170 Susie Miles and Wendy McCracken threatening setting, within a community. Services for deaf children were developed in a similar way in industrialised countries many years ago. Some of the most famous schools for deaf children were set up by philanthropists, for example Gallaudet University in the United States and Taralye in Australia. Many have gone on to become highly specialised centres that provide specialist training and outreach services as well as educational provision for specialised populations of deaf children. Many schools for deaf children do not see themselves as providing a wider service and limit the service they provide to a relatively small number of children, rather than offering a more comprehensive service to the community in which they are located (Miles, 1999). If a special school actively seeks to become a local and regional resource, services can be developed to suit local and regional needs. Ideally such services would complement hospital settings to avoid duplication, and maximise the use of these complementary resources. This would also offer the possibility of faster and more efficient referral services for those children requiring urgent medical care and local treatment, as well as advice for less urgent and non- medical treatment.

EDUCATIONAL AUDIOLOGY IN DEVELOPING COUNTRIES

The highly resourced provision of educational audiology is an appropriate extension of a well developed system of health and educational services. In this context assessment, fitting and follow up services are readily available for those who face hearing health care problems. The cost of hearing aid provision and maintenance is either covered by the state or the individual. The place of such specialist resources in ‘developing’ countries is less clear, especially where primary health care services are poorly developed and education is neither free nor compulsory. Yet there is a need for accessible child and family-centred audiology services—even where hearing aids are not available. Where hearing aids are available, there is an urgent need for such services if deaf children are to have access to optimum ear care and make use of their aids and other amplification. Community based rehabilitation (CBR) programmes can play a major role, ideally in collaboration with schools for deaf children. Where specialist facilities exist in schools, they can become a major resource for CBR workers, deaf children and their families. Appropriately trained educational audiologists, based in schools for deaf children, could potentially develop a range of services for deaf children, their families, mainstream teachers and the wider community. A clear development plan is needed if such specialist services are to be developed, with itemised input from a range of agencies including national, regional and possibly international sources. Clear roles and responsibilities should be identified including achievable time lines. Developments will need to take into account local culture and beliefs and ensure that local communities understand the purpose, possible outcomes and benefits for the wider community. It is important, however, not to under-estimate the scale of the challenge of providing appropriate and affordable audiological services. Review

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THE CHALLENGE IS ENORMOUS

Statistics on school attendance and non-attendance in developing countries are notoriously difficult to collect. As the latest UNESCO Global Monitoring Report on Education for All states: “Calculating the number of children of primary school age who are not in school is not straightforward” (2007, pp. 27-28). The results—which tend to be widely quoted—thus need to be considered with caution. It is even more difficult to determine the prevalence of deafness in developing countries and of deaf children attending school. UNESCO estimates that only 10% of disabled children are in school and that one third of the 77 million children currently not in school are disabled (UNESCO, 2007). Wirz & Lichtig (1998: 189) cite Helander’s estimate (1993) that the global prevalence of moderate and severe hearing loss was between 0.5% and 0.8%. However they point out that this does not account for the higher prevalence of meningitis, measles, mumps and other preventable diseases in some developing countries. Although there is considerable variation in these published estimates, it is clear that the majority of deaf children in developing countries do not have access to education or to audiological services, so the scale of the challenge of providing appropriate services is enormous. It is not possible to generalise from published estimates since the situation varies enormously between countries. A community-based epidemiological survey of hearing impairment and deafness, conducted in Swaziland in 1986, by the Liverpool School of Tropical Medicine, revealed that almost 50% of profoundly deaf children were being educated in the only school for deaf children in the country, but little was known about the estimated 4,000-6,000 children of school going age who had mild to moderate hearing losses, largely due to neglected otitis media (White, Newell & Gell, 1987). The population of Swaziland was less than one million people at the time. By contrast neighbouring Mozambique, with its population of 20 million, had only two relatively small schools for deaf children, and so it seems likely that the proportion of deaf children being educated was significantly smaller. Although the challenge of providing services is clearly enormous in most developing countries, schools for deaf children that work in collaboration with CBR programmes could have a much greater impact by reaching more children. Schools for deaf children are rich in knowledge, skills and equipment and have the potential to provide services to the large majority of deaf children who do not have access to medical or educational services. In this chapter we provide examples of some of the efforts made to overcome considerable financial, logistical and technical barriers to the development of sustainable audiological services. We do this through a series of short case studies from Brazil, India, Jordan, Namibia, Nigeria, South Africa and Vietnam. We recognise that there is a great deal of excellent work taking place in developing countries which has not been documented and so cannot be discussed here. The importance of sharing examples of promising and helpful practice between developing countries cannot be emphasised enough. Practitioners can learn a great deal from short, simply written case studies which illustrate a range of ways of overcomingReview barriers to the provision of services in developing countries, even across diverse cultural settings (Miles and Ahuja, 2007).

172 Susie Miles and Wendy McCracken

AUDIOLOGY FOR THE DEAF BY THE DEAF IN JORDAN

An audiological service was set up many years ago at the Holy Land Institute for the Deaf in Salt, Jordan. This was a service not only for the deaf children at the school, but also for the wider community, including Palestinians living in refugee camps. However the hearing facilities were poorly managed and many of the deaf students at the school were suspicious of audiologists, fearing that they would discourage them from using sign language. In 1994, the Christian Blind Mission (CBM) supported the development of audiology services through the appointment of a British audiologist. Her first discovery was that many students’ ears were blocked with wax (Litzke, 2004). Although many of the 180 students had hearing aids, only one of them was using the aid effectively. The audiologist worked closely with a Deaf staff member and ex-pupil, who had responsibility for the earmould laboratory. This Deaf assistant became proficient in carrying out pure tone audiometry and began to better understand the importance of well-fitting ear moulds. The involvement of a Deaf person in the process of running an efficient educational audiology service had an extremely positive impact on the attitudes of the deaf students towards hearing aids. Families now realised that hearing aids were not a miracle cure, but that they could help improve communication. This short account demonstrates that the presence of audiological facilities in a school for deaf children is not in itself sufficient to ensure that services are well developed. It requires a coordinated team effort. It also demonstrates the way audiological expertise from outside can be used to nurture the development of insider expertise. In this example it was on-the-job training, not formal qualifications, that made the difference. Lichtig, Woll, Silvia Cárnio, Akiyama, & Gomes (2004) also found that the employment of deaf staff in a family centred educational audiology service for 3-6 year olds in Brazil improved the quality of service provision and parents’ confidence in those services.

DEVELOPING AUDIOLOGY SKILLS IN NAMIBIA

A British audiologist was recruited to work in 1996 at the Eluwa School for the Deaf in Northern Namibia, the second school to be established in the country (Roberts, 2001). Namibia is a very large country with a population of less than 2 million people. At that time there were only two audiologists working in government service, one in health and one in education. Both were based in the capital city, Windhoek, 650 kilometres south of Eluwa. Prior to the appointment of the British audiologist, the audiologist for the Ministry of Education visited the school three to four times a year to provide much needed educational audiology services – but this was clearly not a satisfactory arrangement. An ex-Eluwa student was sent for training in Botswana as an ear mould technician. On her return she was employed by a private company in the capital city, which provided an excellent service to Eluwa School. Over a period of three years, four Namibian teachers who had no specialist qualification in teaching deaf children were trained by the British audiologist to run the school-basedReview service. A report of a brief visit to Namibia by a Deaf Child Worldwide staff member (Wilson, 2005) reveals that the Ministry of Health and a national NGO provide hearing aids free of charge, but parents have to pay the equivalent of $US10 per ear mould. However, audiology posts in the two main government hospitals are currently vacant. This further reinforces the

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importance of the development of audiological expertise in schools for deaf children and other community based centres, such as health clinics. Nurses have been trained by a British- based organisation, Soundseekers (no date), in various countries, including Ghana, Guyana, India, Lesotho, Namibia, Sierra Leone, South Africa and Swaziland. The nurses identify and treat middle ear disease, and in some countries a mobile service is offered through the use of a specially designed and equipped vehicle, or Hearing Assessment Centre, known as a ‘HARK’ (EENET, 2002).

MOBILE EAR CARE SERVICES IN NIGERIA

The development of appropriate forms of training for community based educational audiologists is a more complicated challenge. It could be argued that educational audiology training in developed countries is inadequate for the particular challenges of developing such services ‘from scratch’ in the context of extreme poverty and poorly developed welfare services. The difference between the services available to urban populations and those available to rural areas is also stark, with rural areas being most neglected. Whether families are based in rural or urban areas, audiological services are likely to be unaffordable. The Mobile Ear Care Service (MECS) in Akwaibo State in rural Nigeria was started by a Nigerian Catholic sister at St Louise’s Special School (Ali, 2007). The Sister was trained as a teacher of the deaf in Manchester in 2000 and spent a further year receiving informal training in audiology in London. She is now the headteacher of the school, which caters for 200 deaf children and sixty additional children who have learning difficulties. As the only staff member with training in audiology, she spends three days per week during school time, and five days per week during school holidays, travelling around the local community with the MECS. An ear mould laboratory is run by one of the teachers after school hours and an ex- pupil has been trained to make ear moulds. In-service training sessions are run over a nine month period for those who work with the MECS, but this has not yet been affiliated to a university. The trainees are able to give advice, but cannot provide any equipment. Children with hearing impairment are supported by the MECS in local schools through a cycle of three monthly visits. The service is funded by a combination of school fees and donations from CBM and the Daughters of Charity of St Vincent de Paul. The MECS faces some obvious challenges, such as the extreme heat and dust, poor roads and limited equipment. Unfortunately this low-cost provision of audiological services is seen as a threat by some private audiologists, many of whom have been trained in industrialised countries and who have returned to Nigeria to ‘sell’ their audiology services. Audiological investment in existing schools for deaf children in developing countries would go some way towards providing more comprehensive and equitable services. Investment should not be interpreted as being purely equipment based. Investment must include training of the staff who need to use the equipment and to cascade skills to others. This would help to promote greater awareness and knowledge about deafness, meet the audiologicalReview needs of deaf children within their local communities, and potentially enable greater numbers of deaf children to access educational opportunities. Ideally schools should be encouraged to work collaboratively with local and regional health services to meet the audiological needs of deaf children. In their article about the use of non-specialists in providing services for children with hearing impairments, Wirz and Lichtig (1998) discuss the

174 Susie Miles and Wendy McCracken challenge of promoting collaborative working arrangements in developing countries between highly trained specialists who can dispense hearing aids and community workers who can mobilise communities and counsel deaf children and their families. We argue in this chapter that schools for deaf children have the potential to play a key role in promoting such collaboration.

COMMUNITY BASED TRAINING IN INDIA

The Irakgada Centre in Karnataka provided a four day training course and a one day field visit to three deaf children in their homes, following an analysis of the training needs of a small NGO, ‘Samuha Samarthya’ (Wilson, Miles, & Kaplan, 2008). The training included:

1. Anatomy of the ear, causes of deafness and amplification; 2. Communication, language and teaching methods—with role play; 3. Making teaching aids; 4. Working with children and parents; 5. Evaluation of the training.

During the training parents learned to make sense of audiograms and came to understand the value of wearing hearing aids. The CBR trainers felt confident that some participants would be able to become trainers themselves one day, initially working with the CBR team. This account demonstrates that well-planned and well-delivered basic training is often highly valued by non-specialists. Educational audiologists and teachers of deaf children are well placed to offer such training. Schools for deaf children have the potential to jointly develop training packages that could be delivered across a region or country. Support from NGOs and other civil society organisations in such an enterprise could help to ensure materials were catalogued and used in other settings.

THE IMPORTANCE OF COORDINATING SERVICES

Nhloso was seven when his teachers noticed he had difficulty in hearing (Wilson et al., 2008). It is not unusual for deaf children to be identified late in childhood in developing countries. Visiting a hospital for a hearing assessment in South Africa involved a long and expensive journey and an overnight stay for the family. A hearing test was carried out, but no results were received as the person who did the test left their job at the hospital. Nhloso’s mother recounted the details of the assessment to school staff who requested support from a special school. A whole year later a new speech therapist was contacted and Nhloso’s hospital records were found. Nhloso had a severe to profound hearing loss, possibly associated with meningitis when he was quite young. He was referred to a specialist hospital and eventually, after a numberReview of visits, earmoulds were made and hearing aids fitted, although initially the earmoulds did not fit well, causing a further delay in amplification. The special education services provided the school with a video with information about deafness, but there was no video player at the school so staff were unable to watch it.

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Finally it was agreed that a school for the deaf would offer the best opportunities for Nhloso. A further delay arose when Nhloso’s family were unable to find his birth certificate because it had been eaten by termites. This prevented him from being enrolled at school. When a duplicate certificate was obtained, Nhloso was almost nine years old. He started attending a school for the deaf almost two years after the initial suspicion that he might be deaf. This vivid account provides some insight into the enormous challenges parents face in identifying appropriate audiological support. It also highlights the urgent need to ensure that children are identified as early as possible and that sensitive and efficient support services are made available. Specialist educational services are not always sufficient in themselves in making the most appropriate interventions. Services are more likely to work more efficiently when linked to CBR programmes, although CBR programmes do not always cater to the needs of deaf children (Miles, 1995). The publication, ‘Family Friendly’ (Wilson et al., 2008) provides innovative examples of CBR programmes which have made a difference to the quality of family support, sign language teaching and audiological services.

TRADITIONAL UNDERSTANDING OF DEAFNESS

In many countries misunderstandings about the nature and causes of deafness persist. Clinical experience in Swaziland revealed a range of traditional beliefs and responses to deafness (Miles, 1991). The sudden onset of deafness, for example, was sometimes interpreted as a sign that the person had been given special powers and should be encouraged to train as a traditional healer. Parents sometimes asked the ear, nose and throat (ENT) specialist to cut the child’s tongue as they thought the lack of speech meant the child was ‘tongue-tied’. It was very common to hear of children and adults who had received traditional treatment involving a concoction of herbs poured into the ears, often causing sickness and dizziness, especially where the ear drum and the bones of the middle ear had been destroyed by neglected middle ear disease. Some were instructed to run up to the top of a termite mound and shout into it, in the belief that this would cure the deafness. Parents were left surprised and confused when these treatments were ineffective. Traditional healers command enormous respect in some cultures and are usually more numerous, more easily accessible and better trusted than hospital based services (de Andrade and Ross, 2005). In establishing the Swaziland Speech and Hearing Clinic Services in the mid-1980s (Miles, 1990), nurses, teachers and traditional healers were invited to engage in dialogue on the issue of hearing impairment, its causes and possible treatment. It made no sense to condemn traditional practices, since most of the people using the Speech and Hearing Clinic Services also consulted traditional healers. The only positive and productive way forward in order to develop greater understanding at community level about hearing loss was to work with traditional healers, rather than against them. In Vietnam some parents were convinced that the process of audiological assessment caused theirReview child to be deaf (Maarse, Phouc, McCracken, & Nga, 2001). Any attempt to explain that children had a hearing loss prior to assessment was quickly dismissed. It was only through a community-based health care approach, which discussed the causes of deafness in the local context, that this belief could be addressed in a way that was acceptable to the parents. At the time of this review the ENT community in Vietnam did not have a

176 Susie Miles and Wendy McCracken recognised position for an audiologist. Demands on ENT services were high and there was little expertise in paediatric audiology. In such a setting teachers of the deaf were trained to provide audiological management, including assessment and fitting of hearing aids. This training was funded by a non-governmental organization.

HEARING SCREENING: THE ROLE OF EDUCATIONAL AUDIOLOGY SERVICES

The identification of hearing loss in a child is a major trauma for families. This situation is exacerbated by lack of referral for treatment and a lack of services. The fact that the hearing screen reveals a major difficulty and a need for audiological support which cannot be met is of little relevance to the immediate experience of families dealing with the shock of having a deaf child. Hearing screening initiatives may be useful in convincing governments that services are needed. However it would be unethical to screen for hearing impairment and deafness if follow up services are not readily available, as McPherson and Olusanya point out in their chapter on screening in the present volume. The type, extent and quality of service available vary considerably across the developing and developed world. Small projects and piecemeal development of services, often established by NGOs and individual professionals, tend to be the only audiology services that exist, yet they offer considerable benefits to individual deaf children and their families. In order to effect lasting change, however, it is important to plan not only for immediate need, but also for medium and long term needs. Planning is most effective when placed within the context of national primary health care and educational services. Financial constraints can mean that clinical audiology services are unlikely to be developed, or if they do exist, that families cannot afford to use them. Wirz and Lichtig (1998) argue that the cost of specialised services in urban centres can be prohibitive; of 94 children diagnosed as deaf (free of charge) in an audiology clinic in Sao Paulo, Brazil, only one child was able to purchase a hearing aid. In Burma (Myanmar) there is only one audiologist and two schools for deaf children serving a population of 48 million people (Vaughan, 2000). The planning and implementation of a national framework for ear care and audiology services is understandably not on the national health agenda. Given that many countries lack developed audiological services, educational audiologists have a role to play at a local and regional level in identifying deaf children through screening programmes, where they exist. This type of undertaking has major training and human resource implications. Educational audiologists could play a role in training personnel in screening so that they could then provide a regional service. Any referrals from the hearing screen would require onward referral to audiological services. There would also be the need to recognise that identification of hearing loss is a recursive process rather than a single assessment point. Furthermore such a screen would ideally require pre-school services and early childhoodReview education opportunities to be made available to families. In a recent study Swanepoel, Louw and Hugo (2007) describe a model of infant hearing screening for developing countries, based on their work in South Africa. Since a significant number of births do not occur in hospitals (Olusanya, Luxon, & Wirz, 2004; Swanepoel,

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Hugo, & Louw, 2006), this study suggests an integrated approach to immunisation and hearing screening. In the proposed model immunisation programmes act as a “platform” allowing hearing screening to be carried out at the same time. Follow up audiological assessments are also linked to multi-dose immunisation visits, usually occurring at 10 and 14 weeks. This is a pragmatic approach that uses the system in place to add in a further screen without any further appointments or time demands on parents or professionals. For a country like South Africa that has a well-established immunisation programme the potential is clear. In other countries where such programmes are less well established it is more problematic.

CONCLUSION

The provision of hearing aids and other clinical audiology services, without adequate follow-up services, is highly unethical. It is unlikely that hearing aids will be used effectively or maintained, even in schools for deaf children, unless a sustainable and affordable educational audiology service has been established. Ideally this service would be based in a school, rather than in a hospital setting, and would work in close collaboration with health and rehabilitation services. Schools for deaf children are centres of expertise, which are rarely used for the benefit of the wider community. Yet if teachers of deaf children can be provided with basic audiological training, they would be able to provide a more comprehensive service to the children they serve, their families and community members who may have hearing problems. Where deaf school leavers have been trained to repair hearing aids and make ear moulds, they fulfil a dual role: the provision of audiological services and positive role models for deaf young people. Schools for deaf children could develop links with parent groups, associations of deaf people, and work closely with non-governmental organizations, in order to develop outreach audiological services. It is important that audiology practitioners and families have realistic expectations about the benefit of hearing aids. Families need opportunities to discuss the type and degree of hearing loss in a non-threatening environment. They need time to explore the implications of deafness and the possibilities of amplification and/or access to sign language teaching. The environment in which hearing screening and audiological assessment takes place can be critical to families’ further use of services. A medical environment, where there are heavy demands on staff time and on space, constraints in resources, together with a lack of experience and training in the needs of deaf children among hospital-based staff, may result in a very medical model of deafness being stressed. The provision of such audiology services, in isolation from educational and other community based interventions is, in any case, highly questionable. Screening and audiological service provision within educational settings, where staff have training and experience of deaf and hearing impaired children on the other hand, could offer a more child-centred approach. Hearing screening may initially focus on school entry, or on children already attending school, but could be extended to pre-school screening, if strong links are built with local communities.Review Community workers and teachers of deaf children could be trained to carry out hearing screening at a local level under the guidance of the regional school for the deaf. The introduction of hearing screening programmes, ear camps and community based rehabilitation programmes have the potential to help provide wider coverage and easier access to services for families of deaf children. Underpinning all developments in this area is the need for public

178 Susie Miles and Wendy McCracken

awareness campaigns that are locally developed and delivered. Parents of deaf children could be actively involved in such campaigns as they have relevant experience and expertise.

REFERENCES

Ali, M.E. (2007). Personal communication. de Andrade V., & Ross E. (2005). Beliefs and practices of Black South African traditional healers regarding hearing impairment. International Journal of Audiology, 44, 489-99. Enabling Education Network (2002, June). What does the South really want from the North? A report of a seminar co-organised by the Deaf Africa Fund and the Enabling Education Network (EENET). Birmingham, Manchester: EENET. Retrieved July 24, 2007, from http://www.eenet.org.uk/key_issues/deaf/deafness_report_2002.doc. Helander, E. (1993). Prejudice and Dignity: An introduction to Community-Based Rehabilitation. New York: United Nations Development Programme. Lichtig, I., Woll, B., Silvia Cárnio, M., Akiyama R., & Gomes, M. (2004). Deaf staff members’ participation in a Brazilian intervention programme for deaf children and their families: impacts and consequences. Deaf Worlds, 20, 281-297. Litzke, C. (2004). Audiology for the Deaf by the Deaf. London: International Deaf Children’s Society. Retrieved July 24, 2007, from http://www.idcs.info/docs/Audiology_ for_the_Deaf_by_the_Deaf.pdf. Maarse A, Phouc N.T.M., McCracken W., & Nga, T.T.T. (2001). External Review: Project to support the development of Early Intervention for Hearing Impaired Children. Unpublished report, Netherlands: Committee Twee. Miles, S. (1990). Follow up Support for Hearing Aid Users. Paper presented to a ‘Conference on Hearing Aids in Developing Countries’. London: Royal National Institute for the Deaf. Miles, S. (1991), Unpublished case studies. Manchester: Enabling Education Network. Miles, S. (1995). The Deaf Dilemma. CBR News, 20. London: Appropriate Health Resources Technology Action Group. Retrieved July 24, 2007, from http://www.eenet.org.uk/ key_issues/deaf/deafdilm.shtml. Miles, S. (1999). Experience of working with the Deaf Community in Africa. Retrieved August 7, 2007, from http://www.idcs.info/resource_library/experience_of.html. Miles, S., & Ahuja, A. (2007). Learning from difference: sharing international experiences of developments in inclusive education. In L. Florian (Ed.), The Sage Handbook of Special Education (pp. 131-145). London: Sage. Olusanya, B.O., Luxon, L.M., & Wirz, S.L. (2004). Benefits and challenges of infant hearing screening for developing countries. International Journal Pediatric Otorhinolaryngology, 68, 287-305. Roberts, N. (2001). Working with deaf children in Northern Namibia. In A. Callaway (Ed.), Deafness and Development. Learning from projects with deaf children and deaf adults in developingReview countries (pp 44-48). Bristol: Centre for Deaf Studies. Sound Seekers – The Commonwealth Society for the Deaf (no date). Projects. London: Sound Seekers. Retrieved July 24, 2007, from http://www.sound-seekers.org. uk/projects.html.

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Swanepoel, D., Hugo, R., & Louw, B. (2006). Infant hearing screening at immunization clinics in South Africa. International Journal of Pediatric Otorhinolaryngology, 70, 1241-1249. Swanepoel, D., Louw, B., & Hugo, S. R. (2007). A novel service delivery model for infant hearing screening in developing countries. International Journal of Audiology, 46, 321- 327. UNESCO (2007). EFA Global Monitoring Report. Strong Foundations: Early Childhood Care and Education. Paris: UNESCO. Vaughan, G. (2000). The hearing impaired children of Burma. British Society of Audiology News 31, 33-35. White, E., Newell, K., & Gell, F. (1987). The national sample study of the prevalence of hearing impairment in children in Swaziland. Unpublished report. Liverpool: Hearing Impairment Research Project, Liverpool School of Tropical Medicine. Wilson, K. (2005). A summary of provision for deaf children in Namibia. London: International Deaf Children’s Society. Retrieved July 24, 2007, from http://www.idcs.i nfo/docs/Summary_of_provision_for_deaf_children_in_Namibia.pdf. Wilson, K., Miles, S., & Kaplan, I, (2008). Family Friendly: Working with deaf children and their families around the world. London: Deaf Child Worldwide. Wirz, S., & Lichtig, I. (1998). The use of non-specialist personnel in providing a service for children disabled by hearing impairment. Disability and Rehabilitation, 20, 189-194.

Review

Chapter 10

AUDIOLOGICAL COUNSELING IN A DEVELOPING COUNTRY: A JOURNEY THROUGH GUATEMALA

Patricia Castellanos de Muñoz* and Sandra E. Sosa Centro de Audición y Adiestramiento Fonético, Guatemala City, Guatemala

ABSTRACT

As in most developing countries, Guatemala faces many challenges. After considering the actual status of health and education services for the overall population, a starker reality arises when analyzing the situation for people with hearing loss. This chapter includes a description of the progress made in the audiological field and the efforts placed in providing quality client-family counseling to those in need, within a context affected by the constraints of socio-economic instability. Despite potential obstacles, proactive measures and preventive education have shown some success; realistic goal-setting for children and adults with hearing impairment has been accomplished, and changes have been implemented in order to address the needs observed among those seeking assistance There is much to be overcome. Services that provide culturally sensitive client- family counseling are lacking as acknowledgement of cultural diversity and identity remain at an early stage of development. An authentic Guatemalan social conscience is still pending. In regards to community-based counseling, there is no significant evidence of growth. Although crucial, given the social, economic and cultural aspects of the country, few professionals willingly engage this field. Funding is also lacking. Despite many challenges, it is important to recognize the pioneering work that has taken place in both the audiological and counseling fields. Therefore, this chapter offers the reader a picture ofReview the challenges Guatemala faces and the steps taken towards improved hearing health care.

* Correspondence: [email protected]

182 Patricia Castellanos de Muñoz and Sandra E. Sosa

INTRODUCTION

The development of specific skills in client or family-centered counseling is crucial, when it comes to achieving a breakthrough in audiology. In Guatemala, with a population of approximately thirteen million, three out of every one thousand births result in severe to profound hearing loss. In developing countries such as Guatemala there are certain issues of importance that have to be addressed. These include the constraints of poverty, cultural sensitivities, need for realistic goal-setting for children and adults with hearing impairment, and community-based counseling that includes village health providers and others.

BACKGROUND RGARDING AUDIOLOGICAL AND EDUCATIONAL SERVICES FOR THE HEARING IMPAIRED IN GUATEMALA

Before the 90s, audiology in Guatemala was far from reaching its position today. When in 1988 I (Patricia Castellanos) returned after completing my Masters in Education for the Deaf at Gallaudet University, audiology was hardly developed in the country. Some ear, nose and throat (ENT) doctors performed pure tone audiometry, a very few performed tympanometry, and three or four neurologists along with an otoneurologist and a psychologist conducted auditory brainstem evoked response audiometry. This added up to 5 or 6 city-based service centers for the whole country. In 1990, I, with the support of three ENTs, decided to establish Centro de Audición y Adiestramiento Fonético (CEDAF) as a private audiological and educational institution. This fusion may be unusual in other developing and first world countries, and is what makes our work unique. My personal educational background and, that of the staff that has accompanied me throughout the years, provide the rationale for this combination of services. We started with the best brands and technology available. It was my personal goal to introduce everything that we learned at conferences such as the American Academy of Audiology, International Hearing Society, the Instituto Mexicano de la Audición y el Lenguaje, and courses we enrolled in as part of a self-committed and self-funded process. On a personal level, that is what led me to pursue studies at McGill University, Canada, in pediatric audiology during 1990 and, fifteen years later, my audiology doctorate (Au.D.), at the University of Florida under the supervision of my mentor, and now colleague and friend, Fred Rahe, Au.D. I also worked part time at the Hospital of the National Committee for the Deaf and Blind, the only ear and eye hospital in Guatemala. Throughout this time, my specific interest remained in finding equivalent opportunities for the rest of my staff. Over the years CEDAF has grown and made much progress in providing hearing services. After 1996, as a result of constant effort, body worn and used hearing aids were no longer prescribed. By the year 2000, CEDAF was able to provide diagnosis at birth; dispense analog and digital hearing aids; offer speech and language therapy; open a full cochlear implant program;Review and participate in a variety of consultations. In 2007, we initiated a neonatal screening program, systematic training for parents and professionals, hearing health and conservation services, and frequency modulated personal listening systems. We are very pleased to offer our patients high end technology in hearing aids, available only through

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CEDAF and one other audiological clinic in our country. Other clinics provide hearing aids locally without professional or technical support; therefore they are more accessible in terms of pricing. It is fair to say that even though services are scarce—because there are very few professionals with the adequate training—some accomplishments have been made. We still are in need of trained audiologists not only to attend to the needs of those with hearing impairment, but also to allow the general public and our health care colleagues to gain familiarity with the audiological profession. CEDAF has been able to accomplish results in both the fields of audiology and education for the hearing impaired. Educationally, deaf and blind school children in Guatemala have been separated and specific programs for each population have been created; the educational system available for children with hearing impairment was evaluated and restructured; and educational programs for professionals and ongoing training by international speakers were instituted. In audiology, we acquired highly sensitive and specific modern equipment for diagnosis; began fitting new hearing aids as opposed to used ones; instituted preferential use of behind-the-ear hearing aids; and started the first neonatal hearing screening program.

DEALING WITH THE CONSTRAINTS OF POVERTY

When faced with such high levels of poverty and the constraints that come from such a limited way of living, health and educational services inevitably are discarded as priorities. Families face many significant challenges, without considering a child with special needs. Because of this, it is very difficult for parents and families, not only to detect initial signs of hearing loss, but also to be totally committed towards meeting the responsibilities that come along with a diagnosis of hearing impairment. Children in Guatemala were usually, until recent changes, diagnosed between the ages of three to six years. Consequently, early intervention is not always a feasible option. Due to the lack of knowledge and options, parents and families occasionally do not make informed decisions. Much valuable time is frequently wasted, not only during the ongoing grieving process, and this delays full engagement in the audiological and rehabilitation process. When parents and families finally come to terms with the hearing impairment, they are faced with many financial obstacles. At times, they hardly are able to gather the resources needed for the proper diagnosis, let alone purchase and maintain services involving hearing aid fitting or cochlear implantation. Partial aid is available through a very limited number of institutions. A significant few are able to gain access to the educational services available for preschool, grade school and junior high school students, even though these are in need of many improvements. At present the National Committee for the Deaf and Blind remains the only institution that offers all services regarding diagnosis, audiological management and education for the hearing impaired. Taking this context into perspective, CEDAF since its beginnings has striven to establish client-family counseling as part of the habilitation or rehabilitation process, addressing it through a varietyReview of alternatives. First of all, our course of action is generally program-based, in order to cover a greater amount of the population at a much lower cost when compared to the traditional clinical approach. Thanks to the generous response from our personal contacts and fellow colleagues throughout the world, all screening or diagnostic events organized locally or by organizations from abroad, as well as all hearing aid donations, are accompanied

184 Patricia Castellanos de Muñoz and Sandra E. Sosa by training courses for parents and for professionals (including doctors, regular and special education teachers, language therapists, and psychologists). These courses are also offered free of charge so that clients and families can learn the basics through practical instruction. All programs involve a multidisciplinary approach, in order to provide the proper counseling from accredited professionals in the areas of need. Second, all efforts are focused on short- term as well as longer-term goals that are set according to each situation. That way people perceive prompt results, and are therefore more willing to get involved to a greater degree in the counselling and rehabilitation process. Finally, all attempts are directed towards prevention and proper intervention, so positive changes can gradually be achieved thanks to a greater awareness.

DEALING WITH CULTURAL SENSITIVITIES

Since Guatemala is a country of many cultures and languages, additional effort must be placed in developing courses of action related to hearing impairment. Forty percent of Guatemalans speak one of 22 Amerindian languages as their mother tongue and Guatemala is the least urbanized country in Latin America. These factors often adversely affect the outcome initially pursued because services are city-based, provided in Spanish, and very few interpreters are available or willing to provide ongoing support. Illiteracy rates are also high, making it harder to reach many Guatemalan families. Guatemalan society can be generally considered very conservative and patriarchal, leading to misconceptions and myths about disabilities and special needs. As a cultural trait, appearances should be maintained. This, added to the lack of proper education and knowledge, evolves into a significant resistance towards the acceptance of hearing impairment, the use of rehabilitation devices and the need to make necessary life adjustments. Another issue is the pressure to conform to cultural norms and the low standard of expectations present among many people, especially when it comes to women. This way of thinking predisposes people to discard the use of hearing aids or cochlear implants as meaningful resources to improve quality of life and provide better opportunities for them and/or their children. Finally, even when services are provided at a low cost or free of charge, people tend to not be fully aware of the value these represent and the responsibility implied in accepting services. For instance, it is common for people to sell donated hearing aids for personal short-term financial gain due to poverty. Thus some take advantage of free services creating conflict with, or skepticism among, those willing to offer services. In terms of the above, CEDAF has developed certain strategies that have been effective when it comes to audiological and educational services. Background checks are made among the population in order to determine where help will be more useful and where resources will be most wisely invested. The people that are sought out are clients and families that are committed to acknowledging what has been provided to them, and who are willing to attend follow-up services and to assume the responsibilities that come with the habilitation or rehabilitationReview process. Finally, CEDAF seeks out beforehand a local support system or network to become a valuable liaison between the people and those providing audiological and educational services.

Audiological Counseling in a Developing Country 185

REALISTIC GOAL-SETTING FOR CHILDREN AND ADULTS WITH HEARING IMPAIRMENT

One of the decisive factors involved in determining the amount of success obtained in client-family counseling, during the habilitation or rehabilitation process, is the goal-setting that takes place among all parties. During every step of the way, expectations should be grounded in reality and not from ideal or presupposed conditions. This transparency allows people to be more receptive and open to change, even though this is somewhat difficult for the average Guatemalan, due to their upbringing and culture. Professionals in this sense should be fully aware of how to manage each situation accordingly and the need to model by example the ethical standpoints that are involved. Unfortunately, it is not uncommon for people to be victims of deceit or scams, due to uninformed professionals and/or wrongful intentions. Therefore, building a trustworthy relationship is vital. Our experience when it comes to this aspect has shown us the need to follow certain guidelines. We started by building a sense of trust and credibility among patients, so they could rest assured that they are being treated by highly trained professionals and that the services and technology offered to them met the up-to-date standards set in developed countries. We have found it very useful to demonstrate that clients will receive the same type of benefits from our local services as those offered abroad. Something that we also consider important is assisting those who come to us over a period of time. No matter what service is involved, information is not provided on a one consultation basis. Sessions are programmed according to need and are addressed in terms of each patient’s life story, setting, needs and wants. We set ourselves at the same level as patients, so they can perceive with full clarity the benefits and goals that can be accomplished for each case and under what terms or conditions. A signed agreement form is used when needed. Finally, we also provide clients and their families with reliable contact people who are part of a greater support system, during the post-diagnosis grieving process, in making decisions, and throughout the habilitation or rehabilitation process. Expectations are discussed with the immediate family in order to make the necessary adjustments and also to assure a positive outcome.

COUNSELING PROVIDED AT CEDAF

Those who seek counseling in Guatemala face significant barriers. In general, counseling services are available only through private specialized institutions, making them unaffordable for the majority. Very few institutions offer services free of charge or at an accessible price, but even so, none of them are specialized in treating the needs of the hearing impaired. Another challenge is that counseling services are city-based and therefore in Spanish, leaving out those who live elsewhere or speak Amerindian languages. At this Reviewpoint, keep in mind that we are not professional counselors. Our background is in educational psychology and audiology. Therefore, the counseling we offer is very focused. In terms of audiology, we try to set realistic expectations, starting by offering orientation to the evaluations needed to obtain the proper diagnosis, and to the required monitoring and follow-

186 Patricia Castellanos de Muñoz and Sandra E. Sosa up. The same principles apply when it comes to making decisions on hearing aids or cochlear implants. Expectations are set according to each patient, their family, and their setting. Families are also trained in the use of the device of choice, as well as in the proper care and maintenance involved. In the field of education, we explain the limited options that are available regarding schools for the deaf and regular schools willing to enroll hearing impaired children. As addressed above, there are few choices in Guatemala when in comes to educational services for the hearing impaired. Consequently, we try to facilitate an adequate transition into certain schools. We also offer consultation services to regular schools that accept our patients. We train teachers and advise them on measures such as placement within the classroom and learning strategies. At an emotional level, we center our effort in assisting parents through the grieving process that follows diagnosis, while promoting in them the ability to make informed decisions, to manage discipline and behavior adequately, not only with their deaf child but with hearing siblings. We have also worked with a reliable group of psychotherapists, to whom we refer patients due to their experience with individuals with disabilities in general.

COMMUNITY-BASED COUNSELING

Another strategy we have found useful is working with village health providers, educators and others as an interdisciplinary team. This has allowed us to provide greater coverage and continuity of follow-up services, especially for people that live outside of Guatemala City. Gradually, we have been able to develop community-based programs that are under the care of people who have been adequately trained and are constantly supervised. Also, this has been a way to initiate networking among trustworthy professionals and institutions. Additional advantages that evolve from the team approach include: People are attended to locally; goals are set according to everyday living situations; costs are lowered for families; and points of referral are established. In a broader sense, this allows us to coordinate our efforts in an even more efficient manner and allows an ongoing assessment of needs in different areas of the country. Hence resources are administered in a way that allows us to keep growing in matters of coverage and outreach.

CONCLUSION

Although we have accomplished much in terms of our audiological journey through Guatemala, we have not performed tasks single-handed. We have had the help of many and the privilege of receiving many donations. Hearing aids have been made available on a regular basis, through the Ronald McDonald Foundation Guatemala and the Starkey Foundation.Review Others, like Healing the Children and Fred Rahe, Au.D., professor at University of Florida, have supported us with the acquisition of equipment, training and ongoing assistance. Training and technical support has been provided through all distributors and other highly respected colleagues we have met along the way. Therefore, it is fair to say, that the

Audiological Counseling in a Developing Country 187 secret of our success has rested in authentic teamwork, perseverance and a true sense of commitment towards our country and the population we serve.

Review

Chapter 11

OCCUPATIONAL HEARING LOSS IN DEVELOPING COUNTRIES

Geoffrey K. Amedofu1,* and Adrian Fuente2 1Kwame Nkrumah University of Science and Technology, Kumasi, Ghana 2 Universidad de Chile, Santiago, Chile

ABSTRACT

Modern industry brings many benefits to society. However, for workers, especially those in developing countries, industrialization does not only bring benefits. Many hazardous agents exist in work place environments. Noise has long been known to cause hearing loss. Noise is the commonest preventable cause of sensorineural hearing loss and is a great problem in developed as in developing countries. As industrialization spreads to developing countries, workers are often exposed to hazardous noise without taking measures to prevent auditory damage. Studies have shown that exposure to chemicals, such as organic solvents and pesticides, in the workplace is also related to increased risk of hearing loss. In industrial settings, exposure to organic solvents such as toluene, xylene, styrene and n-hexane is commonly accompanied by exposure to noise. In cases of combined exposures, the risk of hearing loss is substantially higher than in noise only and solvents only exposed populations. Agriculture in developing nations now makes greatly increased use of pesticides, herbicides, insecticides, fertilizers and specially treated seeds. This has brought chemical hazards into a sphere of work that is poorly equipped to deal with them. There are reports that pesticides, insecticides in particular, have an effect on the nervous and auditory systems. About 80% of chemicals produced are used in industrialized countries and the remaining 20% in developing countries. Thus, exposure to noise and chemicals has become a routine part of human life, sustaining human activities and increasing industry and agriculture in developing countries but with attendantReview health problems. In many developing countries, occupational health and safety standards are not enforced rigorously. However, audiologists have a professional responsibility to monitor

* Correspondence: [email protected]

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industries, educate employers and help prevent hearing handicap. The intent of this chapter is to discuss noise-induced hearing loss in developing countries by examining historical perspectives of noise-induced hearing loss, the impact of noise on hearing and sources of noise in developing countries, especially in both the formal and informal sectors. Secondly, the chapter surveys the use of solvents and pesticides in developing countries and their adverse impact on the auditory system. The chapter also discusses prevention of noise-induced hearing loss, opportunities for hearing conservation programs and protective programs for chemical safety at the workplace in developing countries.

NOISE AND IS EFFECTS

Noise is any undesired sound and, by extension, any unwanted disturbance within a useful frequency band. Noise has physical, physiological and psychological connotations. Physically, it is a complex sound having little or no periodicity. However, it can be measured and its characteristics analysed. Physiologically, acoustically and electronically, noise is defined as a signal that bears no information and whose intensity varies randomly with time. Psychologically, noise is any sound irrespective of its waveform, which is unpleasant and unwanted. Like any sound, noise is defined in terms of its duration, frequency spectrum measured in Hertz (Hz) and often measured in terms of sound pressure level (SPL) expressed in decibels (dB). Noise may be continuous, intermittent, impulsive or explosive. An important classification of noise is impulse and impact noise. Impact noise is the acoustic phenomena produced by two hard objects ‘banging’ together. Impact noise is often described by its amplitude and duration. The amplitude of an impact noise is measured at the maximum amplitude peak and the duration is the time it takes for the wave to decay 20 dB from its peak level. Impulse noise, on the other hand, is the acoustic phenomenon associated with explosions. The wave-form of impulse noise is described by the amplitude of the initial overpressure and the duration of time required for decay of the peak pressure to ambient pressure level. Hearing loss due to noise probably dates from the Bronze Age. Man’s discovery of the use of metals, created first from bronze and later iron, came with the attendant noise of beating, hammering and forging these metals to fashion weapons and implements. Perhaps the use of metals was the first occasion in which human hearing was at risk for industrial noise exposure. This was followed by the use of gunpowder, which appeared about 1300AD in China. From before the start of the industrial revolution, to the development of railways and the internal combustion engine, power driven ships and aircraft to the highly technological world of today, man has recognised the hazards of noise pollution. The site and nature of the lesion in the ear produced by noise was first described through light microscopic observations as early as the turn of the 20th century. The organ of Corti, the sensory and supporting cells are the primary susceptible parts of the inner ear. Fowler (1939) first observed dips in the hearing thresholds of noise-exposed workers at 4 kHz, after the advent of pure-tone audiometry.Review Longitudinal audiometric data depicting classical high-frequency hearing loss acquired through exposure to hazardous noise was first described by Bunch (1937).

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EFFECTS OF NOISE ON HEARING

A noise is considered hazardous when employee noise exposures equal or exceed an 8- hour time weighted average sound level (TWA) of 85 dBA measured on the slow response scale of a sound level meter. However, without noise measuring equipment the following rule of thumb can be adopted: If it is necessary to shout over noise, the level of sound is damaging. If ringing in the ears occurs after exposure or if a sense of fullness in the ears and loss of hearing is experienced after exposure, the level of the noise is damaging (May, 2000). The effects of noise on hearing may be grouped generally into three categories: Temporary threshold shift (TTS); permanent threshold shift (PTS) and acoustic trauma (AT) (Miller, 1971). Temporary threshold shift refers to an elevation in the threshold of hearing which recovers gradually following the noise exposure. Since the noise produces a transient shift in the threshold, it has become known as TTS. This shift can vary hearing sensitivity from a few dB in a narrow frequency range to changes that render the ear temporarily deaf. After the cessation of the noise, hearing sensitivity can return to pre-exposure levels. Structural changes associated with TTS have not been fully established, but may include subtle intracellular changes in the sensory hair cells and swelling of the auditory nerve endings. Other potentially reversible effects include vascular changes, chemical changes in the hair cells and a decrease in the stiffness of the stereocilia, which may recover (NIH, 1990). Hearing conservation programs designed to provide evidence of the existence of permanent hearing loss must be wary of the possibility of a contaminating temporary component. This is especially true when obtaining valid pre-employment audiograms. Permanent threshold shift is found primarily among industrial workers who have been exposed repeatedly to high intensity noise for a relatively long period of employment. In this type of injury, cochlear blood flow may be impaired. Although most structures in the inner ear can be harmed by excessive sound exposure, the sensory hair cells are the most vulnerable. Gallo and Glorig (1964) reported that the magnitude of the PTS showed that the maximum loss was in the range between 4000 Hz to 6000 Hz with smaller losses occurring at the frequencies above and below this range. The symptoms of noise-induced hearing loss (NIHL) are subtle in the early stages. Hearing loss tends to occur first for high-pitched sounds only. Consequently, the volume of sound heard may be unchanged but its quality lessens. Speech may be heard but not completely understood. The presence of background noise can make speech hard to understand. Acoustic trauma refers to the effects of single exposures or relatively few exposures to a very high-level of sound (e.g., an explosion or gun fire). This may result in an immediate, severe and permanent hearing loss. In this case, virtually all of the structures of the ear can be damaged; in particular, the organ of Corti may be torn apart. AT may also result in ruptured eardrums and damaged ossicles (Hamernick, Turrentine & Roberto, 1986). Hearing loss from acoustic trauma is to a large degree permanent. The precipitating event is dramatic and pronounced in the memory of the person experiencing it. Noise can also cause tinnitus (ringing in the ears), which may occur in the presence or absence of hearing loss. Tinnitus can often be more annoying than the hearing loss itself. AlthoughReview not as well documented as the auditory effects, studies in industrial settings and with laboratory animals have shown that exposure to noise may result in higher prevalence of heart disease, high blood pressure and high blood cholesterol levels. Other non-auditory

192 Geoffrey K. Amedofu and Adrian Fuente

effects may include interference with sleep, decrease of work performance, headache, mood changes and anxiety (Stansfeld & Matheson, 2003).

NOISE-INDUCED HEARING LOSS IN DEVELOPING COUNTRIES

Exposure to excessive noise is the major avoidable cause of permanent hearing impairment worldwide. In developed countries, it is at least partially the cause of hearing loss in more than one-third of cases and in many countries NIHL is the biggest compensable occupational hazard. Though noise-induced hearing loss is an established occupational health problem in industrialized countries, it must not be thought that developing countries are exempt. In 2004, the World Health Organization reported the fraction of adult-onset hearing loss attributable to occupational noise exposure. Also, the percentage of total disability adjusted life years (DALYs1) attributable to occupational noise were calculated for different world regions. The global analysis indicates that 16% of deafness is due to occupational noise, with a higher proportion in males (22%) than in females (11%) owing to differences in occupational categories, economic sectors of employment and working lifetime. Approximately 89% of the total burden is in the 15-59 years age group, with the remaining 11% in people over 60 years of age. Overall, more than four million DALYs were lost to NIHL. Developing Asian countries accounted for more than half of the years of healthy life lost, as they have large populations with a relatively large proportion working in high- exposure occupations. Figure 1 shows a world map with the distribution of DALYs around the world. Over 3.8 million DALYs come from developing countries, and only about 0.3 million from developed countries (Nelson, Nelson, Concha-Barrientos & Fingerhut, 2005). Fifty percent of world-wide calculated DALYs came from Asian developing countries.

INFORMAL INDUSTRIAL SECTOR

Exposure to noise causing noise-induced hearing loss in developing countries occurs in both the formal and informal work environments. The informal sector typically operates with a low level of organized activities (Kelly, 2003). The definition of small enterprises may vary from country to country and depends on the size of the economy and level of development of a particular country. However, enterprises in the informal sector typically have five or fewer people per firm or business concern. Common types of occupations in the informal sector and among small enterprises in developing countries where workers are exposed to high levels of noise include building construction, textiles, brick making, carpentry, metal artisans, motor vehicle repairs, corn-mills and shoe making. Workers in developing countries are also exposed to noise in farm jobs where noisy equipment such as tractors (with and without cabs), chainsaws and grain crushers are used. Table 1 summarizes the main industries, formal and informal, in developing countries where workers are exposed to high levels of noise. Review 1 The causes of the global burden of disease are assessed according to the percentage of total disability adjusted life years (DALYs) in the world attributable to each cause. DALYs are a measure of the years of healthy life lost (YLL) due to premature mortality, and the years lived with disability (YLD). The utility of using DALYs as an indicator of disease burden is that it allows the health burden to be compared for different geographical areas and with the health burden from other risk factors (Ezzati, 2004).

Occupational Hearing Loss in Developing Countries 193

An example of the informal sector is the textile industry in Botswana, where the textile industry is widely dispersed and activities are commonly carried out in private households. Due to a lack of adequate work space, machines are usually placed in garages or living rooms which function as production areas. Workers in these areas are exposed to hazardous noise and also there is risk of fire, because the materials used are easily ignitable (Regoeng, 2003). Another common informal industrial activity is grain milling. A study conducted by Boateng and Amedofu (2004) among corn-mill operators in Ghana revealed that noise levels in corn-mills exceeded 90 dBA. The locally made corn-mills produced more noise than imported equipment. The study showed that 23% of the 193 corn mill operators had the evidence of NIHL. Table 2 depicts noise levels in sawmills, corn mills and printing presses as reported by Boateng and Amedofu (2004). Yisa (2005) reported that noise levels at an operator’s ears in corn-mills in Nigeria also exceeded the recommended value of 85 dBA. The highest recorded noise level was 110.3 dBA. In some of the corn-mills studied, communication was so hampered by the noise level that sign language became the mode of communication between the operator and the clients. Mbuligwe (2004) investigated levels of, and influencing factors on, noise pollution from small-scale industries in Dar es Salaam, Tanzania. Two sites for wood and metalwork industries were investigated. Both sites exhibited equivalent noise levels higher than 90 dBA, the permissible Tanzanian exposure level limit for occupational noise. Measures taken at the small-scale woodworks found that noise levels correlated well with machine use, wood feed and wood cut depth.

Figure 1. DALYS attributable to occupational noise for different world regions (data from WHO, 1997b). Review

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Table 1. Main industries in developing countries where workers are exposed to high levels of noise

Informal sector Formal sector Motor vehicle repairers Textile factories Carpenters Cocoa-processing factories Metal artisans Mining and quarrying industries Sugar-cane crushers Construction workers Corn mills Petroleum and gas plants Brick making Pharmaceutical and printing industries Shoe making workers Military, police and aviation workers Farm jobs Textile industry

Table 2. Noise Levels Measures on Corn-Mills at Six different Locations

Factory I II III IV V VI Total average dBA Type of machine

imported 90-1-3 95-99 96-100 94-105 85-98 89-98 97 corn-mill

locally made 100-104 98-103 98-109 103-107 94-106 89-102 101 corn-mill

From: Boateng & Amedofu, African Journal of Health Sciences, 11, 55-60, 2004.

FORMAL INDUSTRIAL SECTOR

Over the past 50 years many developing countries embarked on industrial projects to process primary products for export and also to produce finished goods for both local consumption and export. Among the manufacturing industries in developing countries that may cause exposure to high levels of noise are textile factories in China, Ghana, Kenya, Nigeria, South Africa, India, Pakistan and many other countries; petroleum and gas plants, cocoa processing companies in Ghana, Nigeria and Brazil; pharmaceutical and printing industries in many developing countries; and mining and quarrying industries, as can be found in Ghana, South Africa, Swaziland, Zimbabwe and other countries. Every developing country hasReview construction and other industry workers who are exposed to hazardous noise, as well as military, police, fire fighters and aviation workers. Many studies have focused on noise-induced hearing loss in developing countries. Kahema, Moynyo and Svedberg (1981) investigated textile mills in Tanzania and observed that machines in the weaving and spinning sections of the factories emitted high noise levels.

Occupational Hearing Loss in Developing Countries 195

The risk of permanent injury to hearing increased with the length of exposure. Foo and Saarinen (1985) conducted a study of Asian workers exposed to hazardous noise and found that approximately 38 percent (Singapore), 42 percent (Hong Kong), 83 percent (Korea) and 92 percent (Philippines) of workers were exposed to noise levels above 85 dBA in their work places. The study further revealed that 40 percent (Singapore), 15 percent (Hong Kong), 12 percent (Korea) and 74 percent (Philippines) of workers exposed to hazardous noise had hearing loss above 30 dB HL. Many reports have shown similar results, including: a study of wood working industries in Ethiopia (Mulugeta, 1992); a survey of 173,300 workers who registered with Sindh Social Security in Karachi, Pakistan of which 12 percent out of the total had noise-induced hearing loss (Hassan and Beg, 1994); a report on 200 workers in an auto- assembly plant in Nigeria (Oleru, Ijaduola & Sowho, 1993); studies of mine workers in Ghana (Amedofu, Brobby & Ocansey, 1998; Amedofu, 2002); and a study of 78 factories producing food, chemical, plastics, metals and paper mills (Alidrisi, Jamil, Jiffry, Jefri & Erturk, 1990). Further evidence that hearing loss is often produced by hazardous noise in developing countries has been provided in studies by: Kamal, Eldamati and Faris (1989) of road traffic policemen in Cairo, Egypt; Moselhi, El-Sadik and El-Dakhakhny (1979) of workers at a textile factory in Egypt; Evans and Ming (1982) of five industries, weaving, bottling, metal working, spinning and aviation in Hong Kong; Bhattacharya, Saiyed, Roy & Chatterjee (1981) of textile weavers in India; Raja and Ganguly (1983) in the weaving and engineering industry in India; Oleru (1980) of textile workers in five factories in Lagos, Nigeria; Shaikh (1996) of a polyester fibre plant in Pakistan; Tay (1996) in shipping, metal, manufacturing and quarrying industries in Singapore; Hessel and Sluis-Cremer (1987) of mining in Johannesburg, South Africa; Khogali (1970) of cotton ginning in Sudan; and Obiako (1979) in the copper mining industry in Zambia. As a typical example, noise levels in some common industrial plants in Pakistan are shown in Table 3. As can be seen, moulding machines and power tools produce the highest level of noise.

EFFECTS OF SOLVENTS ON HEARING

In recent years increasing attention has been given to a holistic approach to studying health in the workplace. A combination of physical, chemical, biological and organisational factors impact negatively on workers health and welfare. A holistic approach supports initiatives that investigate the combined effects of occupational exposure to noise and other factors on hearing. In particular, the potential interaction between noise and chemicals poses a new challenge to investigators and hearing conservationists. Many chemicals have been shown to be ototoxic, and, in the case of solvents, some will have synergistic effects when present in conjunction with noise. Currently, many industries, especially in developing countries, are involved in the use of solvents. Millions of workers are potentially exposed to these chemicals in developing countries. Table 4 summarizes the main industries where specific organicReview solvents are used.

196 Geoffrey K. Amedofu and Adrian Fuente

Table 3. Noise levels in some common industrial plants in Pakistan

Source Noise Levels dBA Power tools (pneumatic) 90 – 115 Moulding machines 107-160 Air blow-down devices (painting/cleaning) 90 – 105 Blowers (forced, induced, fan) 80 – 100 Air compressors 95 – 100 Combustion (furnaces) 85 – 97 Turbo generators (steam) 80 – 90 Industrial trucks 80 Transformers 80 From: Wahab and Zaidi (1997).

Definition of a Solvent

A solvent is a liquid used to dissolve other substances, but the most toxic solvents are extracted or manufactured for chemical use. Most solvents are colourless liquids at room temperature that volatize easily and have strong odours. These compounds may be referred to as volatile organic compounds in reference to their physiochemical properties. Solvents are most commonly inhaled in their volatized form and absorbed through the respiratory tract.

Table 4. Main industrial uses of specific organic solvents

Organic solvent Industrial uses Adhesive manufacture, electroplating, laboratory chemicals, Toluene machinery manufacture and repair, metal degreasing, paint manufacture, paint stripping, paper coating, pharmaceuticals manufacture, pesticide manufacture, printing, rubber manufacture, wood stains and varnishes, and footwear manufacture. Styrene Pulp and paper manufacture and in plastics, resins, coatings, and paints manufacture. Xylene Electroplating, laboratory chemicals, machinery manufacture and repair, paint manufacture, paint stripping, paper coating, pesticide manufacture, pharmaceuticals manufacture, printing, rubber manufacture, and in wood and varnishes. Trichloroethylene Electroplating, integrated iron and steel manufacture, machinery manufacture and repair, metal degreasing, pulp and paper manufacture, and semiconductor manufacture. Carbon disulphideReview Manufacture of regenerated cellulose rayon and cellophane. Protection of fresh fruit from insects and fungus during shipping. Vulcanization and manufacture of rubber and rubber accessories.

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Table 5. Site of lesions induced by solvent exposure within the auditory system

Solvent Site of lesion Carbon disulphide Auditory cortex Toluene Cochlea – auditory cortex Styrene Cochlea – auditory cortex Xylene Cochlea – auditory cortex n-hexane Auditory nerve

Significant doses of solvents may occur through skin exposure and absorption. Most solvents dissolve in lipids but some are water soluble. A review of individual solvents yielded a list of both proven human neurotoxicants and probable neurotoxicants. Included in the list are five common solvents that have been shown to affect the auditory system, namely toluene, styrene, xylene, trichloroethylene and carbon disulphide (Morata, Dunn & Sieber, 1994). Solvents have been shown to have an effect on the auditory system of both animals and humans (see Table 5). Their effect can be observed independently to that caused by exposure to noise (Morata, Dunn, Kretschmer, Lemasters & Keith, 1993; Franks & Morata, 1996; Hirata, Ogawa, Okayama & Goto, 1992; Johnson & Nylén, 1995; Morata & Lemasters, 1995). In animal studies there is strong evidence that solvent exposure produces cochlear lesions similar to that caused by noise exposure (Morata & Lemasters, 1995). A brief discussion of the previously mentioned solvents follows.

Toluene

Toluene (C6H5CH3) is a systemic toxicant that affects the liver, kidney and central nervous system (ATSDR, 2001), the latter being the main targeted organ (Byrne, Kirby, Zibin & Ensminger 1991). Data on toluene effects on hearing originate from animal studies and case reports of toluene abusers. The first report of possible ototoxic effects of toluene in rats was published in 1983 (Pryor, Dickson, Howd & Rebert, 1983). Subsequent studies showed a frequency-specific loss of auditory sensitivity after toluene exposure (Pryor, Dickinson, Feeney & Rebert, 1984; Rebert, Sovenson, Howd & Pryor, 1983), and that factors such as concentration, exposure time and duration of exposure influence the loss of auditory sensitivity in rats. Evidence suggests that toluene exposure causes permanent damage to the outer hair cells of the rat cochlea. The adverse effect of toluene exposure on the auditory system of workers has also been demonstrated by researchers in a study of effects of toluene on balance function of rotogravure printers. Hearing loss was observed in 11 of the 15 workers who had vestibular impairment (Coscia et al., 1983). There is a paucity of research data on the effect of toluene on the auditory system of workers in developing countries even though many workers in the printing, petroleum and furniture industries are exposed to this solvent. Morata, Fiorini et al. (1997) explored the effects of occupational exposure to toluene on the hearingReview of rotogravure printing workers from São Paulo, Brazil. In this study, occupational exposure to toluene was shown to increase the probability of hearing loss. Mendoza-Cantú et al. (2006) performed a cross-sectional study with print industry workers in Mexico City. The study population consisted of 103 unrelated male print workers employed as flat or rotary printing press operators (24%), operator assistants (33%), ink handlers (22%),

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machine maintenance personnel (13%) and supervisors (8%). Workers in the industry were exposed to high concentrations of toluene. The geometric mean toluene concentration in the air was 52.80 ppm (see Table 6 for details of the permissible exposure level for toluene and other organic solvents) and 54% of the workers were exposed to toluene concentrations that exceeded the maximum permissible level. Hearing level was however not determined for the exposed workers.

Table 6. Permissible exposure limits (PEL) to different organic solvents for the U.S.A., the U.K. and Brazil. Values are calculated for an exposure average (TWA) of 8 hours a day.

Toluene Styrene Xylene Carbon Trichloroethylene disulphide Country/agency NIOSH 100 ppm 50 ppm 100 ppm 1 ppm 25 ppm ACGIH 50 ppm 20 ppm 100 ppm 10 ppm 50 ppm OSHA 200 ppm 100 ppm 100 ppm 20 ppm 100 ppm COSHH 100 ppm 100 ppm 100 ppm 10 ppm 100 ppm BRAZIL 78 ppm 78 ppm 78 ppm 16 ppm 78 ppm PPM: parts per million. OSHA: Occupational Safety and Health Administration (U.S.A). NIOSH: National Institute for Occupational Safety and Health (U.S.A). ACGIH: American Conference of Industrial Hygienists (U.S.A). COSHH: Control of Substances Hazardous to Health (U.K). BRAZIL:Ministerio do Trabalho e Emprego.

Styrene

Styrene (C8 H8 or C6H5 CH=CH2) is a member of the alkyl-benzene family of aromatic hydrocarbons that consist of a single-benzene ring containing one or more aliphatic side- chains. It is a colourless to yellow, oily liquid, with a sweet sharp odour. It is volatile with a low vapour pressure. A consequence of the volatility of styrene is that a major route of exposure is through the respiratory system. Once vapour enters the lungs, it diffuses across respiratory membranes and enters the blood stream (Engström, Astrand & Wigaeus, 1978). Liquid styrene is also rapidly absorbed through the skin (Limasset, Simon, Poirot, Subra & Grzebyk, 1999). Studies indicate that styrene exposure causes permanent and progressive damage to the auditory system of rats (Campo, Lataye, Loquet & Bonnet, 2001). Styrene induced hearing loss is species specific. While rats are sensitive to styrene, guinea pigs seem to resist adverse effects. Unfortunately, in humans styrene metabolism is closer to that of the rat. Another point to note is that mid-frequency hearing loss in the rat is most often observed. The outer hairReview cells are more susceptible to damage than the inner hair cells. The intoxication process may continue even after exposure is discontinued. These effects have been observed in short-term exposures to high concentrations and/or long-term exposures to lower concentrations. Workers exposed to low levels of styrene did not appear to have increased age-dependent hearing loss at high frequencies. However, a comparison within a group of

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exposed workers between the least exposed and the most exposed revealed a statistically significant deterioration in hearing thresholds at high frequencies in the most exposed subgroup (Muijser, Hoogendijk & Hooisma, 1988; Sass-Kortsak, Corey & Robertson, 1995). The effect of styrene on hearing has been observed among workers in the fibre and plastic industries in developed countries. Since many developing countries also have such factories, it is to be expected that workers in these industries would definitely be at risk for styrene induced hearing loss.

Xylene

Xylene (C6H4CH3)2) is structurally closely related to toluene, and some exposures to mixed xylene compounds have caused pronounced hearing deficit in rats (Crofton, Lassiter & Rebert, 1994). Xylene has even been suggested to be more ototoxic in rats than toluene (Pryor, Rebert & Howd, 1987). Data on the effect of xylene alone in humans is sparse. However, it is known that the interaction of xylene and other solvents and noise has adverse effects on the hearing of workers in the yacht, ship, plastic, shoe, paint and lacquer industries (Sliwinska-Kowalska et al., 2000). Many workers in developing countries may be exposed to xylene in the industries mentioned.

Carbon Disulphide

Apart from being a general neurotoxicant, carbon disulphide (CS2) has been associated with hearing loss. In animal studies, effects on the latencies and amplitudes of ABR have been demonstrated (Rebert, Sorenson & Pryor, 1986). In a study carried out in a viscose rayon factory in Japan, workers exposed to CS2 were divided in three groups according to the length of exposure and compared with unexposed controls selected from workers in a nylon filament factory. Brain stem auditory evoked responses records suggested that chronic exposure to CS2 in humans has an effect on the auditory pathways in the brain stem (Hirata et al., 1992). Sulkowski (1979) conducted an investigation to determine the effect of carbon disulphide on workers’ health. Workers exposed to various levels of concentration of carbon disulphide were tested. The auditory and neurologic test results showed an increased incidence of pathological vestibular symptoms and sensorineural hearing loss compared with a group of textile workers with no carbon disulphide exposure. Although research on exposure to carbon disulphide and its effect on the auditory mechanism is scarce, it is expected that workers in many developing countries would be exposed and may have associated auditory disorders.

Trychloroethylene (TCE) Review This solvent (CICH=CCI2)) is primarily used for degreasing in industry but is also used as a dry cleaning agent and paint remover. Ototoxic effects after exposure to TCE have been reported in rats (Jaspers, Muijser & Lammers, 1993; Rebert, Day, Matteuccie & Pryor, 1991).

200 Geoffrey K. Amedofu and Adrian Fuente

It appears at least 2000 ppm is needed to produce hearing loss in the mid frequencies as shown by ABR measurements or acoustic reflex response audiometry. TCE can cause hearing deficiency in humans, as has been demonstrated by audiometric measurements in workers exposed from one to 23 years. A case was reported of a 54 year old male dry cleaner with 10 years of occupational inhalation of TCE. The worker voiced many health complaints and suffered from high frequency hearing impairment (Tomasini & Sartorelli, 1971). Sulzc- Kuberska, Tronczynska & Latkowaki (1976) studied 40 workers exposed to TCE and found that 26 cases had hearing loss. The hearing loss was bilateral, sensorineural and affected the high frequencies. Workers in developing countries are often exposed to TCE in degreasing industries, dry cleaning and paint removing industries.

OTOTOXIC EFFECTS OF SOLVENTS IN COMBINATION

Occupational health research is generally characterised by the study of single agents as if they occurred alone in the environment. A wealth of information has been generated by this single-agent approach and as a result, many risks have been identified and are now controlled. However, the limitations of this approach are revealed by recent investigations of mixed exposures. Advances in research and statistical methods have facilitated an increase in the number of scientific studies on such combined or simultaneous exposures (Morata, 2003). Several non-additive interactions have been reported after combined exposures to solvents in animal and human studies. There is a controversy regarding the methods used to evaluate and describe interactions after combined exposures to solvents. Some investigators (Calabrese, 1991; Nylén & Hagman, 1994) proposed that the term antagonism should refer to the observation that the effect of the combined exposure is less than predicted by the individual effects. In addition, the term synergism is used to refer to the observation that the effects of the combined exposure are greater than predicted by the individual effects. A long- term exposure study by Nylén, and colleagues (Nylén, Hagman & Johnson, 1994, 1995) in which rats were exposed to n-hexane, toluene or toluene with n-hexane revealed a synergistic enhancement of the loss of auditory sensitivity in the mixed exposure group. The researchers suggested that the demonstrated non-additive enhancement was caused by an interaction within the cochlea between toluene and n-hexane. Similar observations were made by other researchers who conducted animal experiments on the effect of combined exposure to solvents on the auditory system. There are few controlled studies of hearing impairment in humans exposed to solvents. Morata et al. (1993) and Sliwinska-Kowalska et al. (2001) demonstrated an increased risk of hearing loss in lacquer and paint industry workers exposed to a mixture of organic solvents comprising mainly toluene and xylene or xylene respectively. An increased risk of hearing loss was also demonstrated in employees of oil refineries who were exposed to a mixture of toluene, xylene, ethylbenzene and cyclohexane at relatively low concentrations below the currently admissible exposure limits (Morata, Engel et al., 1997). Similar findings were reported byReview Jacobsen, Hein, Suadicani, Parving and Gyntelberg (1993) in a study on 3,284 subjects with a history of occupational exposure to different organic solvents. Data on the effect of a mixture of organic solvents on the hearing capabilities of workers in developing countries are scarce. In several developing countries, organic solvents are frequent atmospheric contaminants in paint and lacquer factories and dockyards, as well as in plants

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manufacturing furniture, plastic, fibres, rubber tires, oil refineries, kerosene and many other products. Solvents such as paints, lacquers and kerosene are also used other than in occupational procedures, especially in households in many developing countries. It is expected that those who are exposed to solvent mixtures in developing countries would be as at risk for hearing loss as those exposed in developed countries.

Ototoxic Effect after Combined Exposure to Solvents and Noise

Hearing loss is often caused by several factors including age, heredity and exposure to ototoxic substances. Noise exposure, the most common external cause of hearing loss, damages the inner ear in both animals and humans. In the work setting where solvent exposure occurs, a high level of noise is also common. There is evidence which suggests that noise interacts synergistically with various drugs and chemicals (Boettcher, Henderson, Gratton, Danielson & Bryne, 1987). Additive or synergistic effects for solvents and noise have been demonstrated in animal studies (Johnson & Nylén, 1995; Lataye & Campo, 1997). In industrial settings, exposure to chemicals often coexists with an increased level of noise, the intensity of which is related to the specific technological processes involved. Barregard and Axelsson (1984), in a case study of four workers, were the first to describe hearing loss in individuals with a history of occupational exposure to a mixture of organic solvents and noise. Hearing loss as a result of combined exposure was more profound than after exposure to noise alone. In a 20-year longitudinal study of hearing sensitivity of 319 employees in a paper mill, it was observed that 23% of the workers from a chemical division showed pronounced hearing loss through exposure to lower noise levels (80-90dBA) as compared to workers solely exposed to higher noise levels (95-100 dBA) (Bergstrom & Nystrom, 1986). At a frequency of 4 kHz, hearing loss was more common in persons exposed to noise and solvents (32%) than in those who were exposed to only noise (22-23%). Chang, Chen, Lien and Sung (2006) conducted a study on workers exposed to toluene and noise in an adhesive materials manufacturing factory. Pure-tone audiometry (.5 to 6 kHz) was conducted in three groups of workers: noise and toluene exposed (n=58), noise exposed only (n=58) and non- exposed to either (n=58). Results showed that the prevalence of hearing loss (hearing thresholds equal or worse than 25 dB HL at the frequencies tested) was much higher in the toluene and noise group (86.2%) in comparison to the noise only (44.8%), and control (5%) groups. The estimated risk for hearing loss among workers exposed to toluene and noise was 10.9 times greater than the group of workers exposed only to noise. The researchers concluded that toluene exacerbates hearing loss in noisy environments, the lower frequencies being the most affected. Morata et al. (1993) and Morata, Engel et al. (1997) drew similar conclusions. In their first report, Morata et al. (1993) indicated that occupational exposure was associated with 4, 5 and 11 fold increases in the risk of hearing loss in the case of noise-only, solvents-only, and noise and toluene among printing and manufacturing workers respectively. In the second report, Morata,Review Engel et al. (1997) found that sole exposure in petroleum refinery workers to a mixture of solvents (toluene, xylene, ethylbenzene and cyclohexane) was associated with a relatively low risk of hearing loss while in the solvents and noise group, this value was higher. Many subsequent studies have corroborated these results, including a large survey of yacht and plastic factory workers exposed to a mixture of noise and organic solvents having

202 Geoffrey K. Amedofu and Adrian Fuente

styrene as its main compound (Sliwinska-Kowalska et al., 2003). The reference group in this latter study included white collar workers exposed to neither solvents nor noise and metal factory workers exposed exclusively to noise. This study provided epidemiological evidence that occupational exposure to styrene is related to increased risk of hearing loss. Combined exposure to noise and styrene seemed to be more ototoxic than exposure to noise alone. The analysis of the worker audiograms showed the dominant effect of noise to be mainly at frequencies from 3 kHz to 6 kHz with an additional hearing loss at 8 kHz in the case of combined exposures to noise and styrene. The synergistic effect of combined exposures to noise and styrene on severity of hearing loss is supported by currently available experimental data in animals, as reported earlier. The damage caused by noise and styrene seems to result from two parallel mechanisms (chemical and mechanical). Noise-induced hearing loss is related to the mechanical injury of hair cell stereocilia whereas styrene induced hearing loss is related to the toxic damage to the hair cells. A synergistic effect on hearing was also reported by Sliwinska-Kowalska et al. (2004) among dockyard workers exposed to noise and a mixture of organic solvents. Contrary to these findings, Sass-Kortsak et al. (1995) reported that the relationship between noise exposure and hearing loss was significant, but there was no relationship between hearing loss and styrene exposure among workers in the fibre– reinforced plastic manufacturing industry. The findings of this review have serious implications for developing countries. Many workers in developing countries are exposed to noise and/or solvents and it is expected that such exposure has serious effects on the hearing capabilities of the workers. In these countries, studies on combined exposure to noise and solvents are scarce. In most of these countries, occupational hearing loss has been recognised as a direct health effect of overexposure to noise, but exposure to solvents as a contributor to the development of hearing-impairment has not generally been considered.

AGRICULTURAL USE OF PESTICIDES

Available records indicate that over 60 percent of the economically active population in developing countries depend on agriculture (WHO/UNEP, 1989). The use of high chemical inputs in agriculture has become an important factor in these countries. Amongst the inputs encouraged by this form of intensified agriculture are potentially hazardous chemicals used widely to combat pests and to boost production but which also carry significant risks to human health and the environment. In addition, pesticides are used for public health purposes to control vector-born diseases, common in many developing countries, and for livestock and poultry rearing to control ectoparasites. According to a WHO/UNEP working group, developing countries consume between 20 and 25 percent of the world’s pesticide production. The fastest growing markets are located in Africa, South and Central America, Asia and the eastern Mediterranean region. Large scale farms are the greatest consumers, but small scale farmers also have increasing access to agrochemicalReview compounds, often through the development of projects (Murray, 1994), because the use of pesticides is a frequent requirement for bank credit even for small producers of crops grown for export. These crops, including cotton, bananas, coffee, rice, melons, flowers, decorative plants and vegetables, have a high pesticide consumption per hectare of cultivated land and hence consume large amounts of toxic compounds. A review of the literature

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revealed that banana production in Costa Rica consumes 40-50 kg of active chemical compounds per hectare per year (Castillo, 1995). Pesticide application is also high in the cultivation of cotton and non-traditional crops in Central America while the production of snow peas for export in Guatemala required even more pesticides than banana and cotton (Murray, 1994). In Ecuador, potato farmers are perceived to overuse pesticides both in quality and quantity, with mixtures of chemicals, locally known as ‘cocktails’, being a favoured form of application (Crissman, Cole & Carpio, 1994). In Southern Africa, the use of pesticides is very common in the cultivation of new cash crops such as flowers and vegetables, in addition to traditional exports such as coffee, cotton, tea, and cashew nuts (Ngowi & London, 2006). The same is true for cocoa and vegetable production in the West African states of Ghana, Cote d’Ivoire and Nigeria.

Toxicity of Pesticides

The pattern and types of pesticides in use varies in countries over time. In some developing countries, trends follow those of the industrial world, where an increasing proportion of herbicides and fungicides are being consumed. Herbicides and fungicides are generally less acutely toxic. However, they pose greater carcinogenic and terratogenic risk (WHO/UNEP, 1989). Pesticides currently in use involve a wide variety of chemicals. Insecticides, which can be neurotoxic to humans, present the greatest proportion of pesticides used in developing countries because of their cheaper cost (Araki, Yokoyama & Murata, 1997). A paper presented by many researchers from Asia, Africa, South America and the Middle East at a symposium in Ottawa on the ‘Impact of Pesticide Use on Health in Developing Countries’ listed commonly used hazardous chemicals (Table 7). A survey of three East African countries (Kenya, Uganda and Tanzania) reported frequent use of organochlorine compounds such as DDT, dieldrin, aldrin, lindane and camphechlor on food crops and livestock (Mbakaya et al., 1994) applications that are banned worldwide. In East Africa, externally funded projects such as the East African Pesticide Network Project (EAPNP) have been initiated to raise awareness of the health hazards posed by pesticides. This project revealed that in Tanzania pesticides were a health hazard in coffee and cotton producing areas (Ngowi, Meada, Partanen, Sanga & Mbise, 2001). Similar observations were made in Mexico (Albertson & Cross, 1993) and Kenya (Ohayo-Mikoto, 1997). Ngowi (2003) reported that about 96 active ingredients of pesticides in more than 124 permutations were found at flower farms in Northern Tanzania. There is no doubt the use of pesticides poses a health hazard to farmers in developing countries. Toxicological and epidemiological data on the pesticides are available from animal and human studies. There is evidence that farm families experience elevated levels of pesticide residues in their blood and urine. An investigation from an agricultural health study (Shealy, Barr, Ashley, Patterson, Camann & Bond, 1997) reported that USA agricultural families couldReview receive an absorbed dose of pesticides after application by a member of the family. Additional preliminary results from the study revealed that elevated blood serum pesticide levels were detected in some families. The very potent pesticide dieldrin, which was banned in the USA in 1987, was found at significantly elevated levels in the blood of all members of one of the six farm families sampled. Additionally, exposures to

204 Geoffrey K. Amedofu and Adrian Fuente organophosphate pesticide drift might result in quantifiable cholinesterase inhibition in residents living nearby application fields (Perry & May, 2005).

AUDITORY EFFECTS OF EXPOSURE TO PESTICIDES

There is evidence that low-level and long-term exposure to pesticides can cause diverse health effects (WHO/UNEP, 1990). The WHO/UNEP Working Group on the Public Health Impact of Pesticides Used in Agriculture estimated that 35,000 neuro-behavioural sequelae might occur each year worldwide. Studies on the auditory effects of exposure to pesticides are rare. However, some reports are available. It is known that organophosphates, and other organic compounds that are derived from phosphoric acid inhibit cholinesterase, producing an accumulation of acetylcholine, which affects the peripheral nervous system (Hawkes, Cavanagh & Fox, 1989) as well as the cognitive and sensory systems (Fornazzari, Wilkinson, Kapur & Carlen, 1983). An Indian study of two groups exposed to organophosphates with different levels of pseudocolinesterase activity reported peripheral neuropathies in the group with low values of pseudocolinesterase. Both groups had sensorineural hearing loss, ranging in severity from mild to moderate (Ernest, Thomas, Paulose, Rupa & Gnanamuthu, 1995). Profound bilateral sensorineural hearing loss associated with residual peripheral neuropathy in the extremities was reported for patients with acute poisoning from sprays containing a mixture of two organophosphates, 75% malathion and 15% metamidophos (Harell, Shea & Emmett, 1978). Peripheral auditory disorders were also observed in a group of 98 Brazilian farm workers free from noise exposure (with ages ranging from 15 to 59 years old). The hearing losses were found to be associated with combined exposure to organophosphates and pyrethroid insecticides. Audiometric screening revealed that 57.1% of those exposed had high frequency sensorineural hearing loss (Teixeira & Brandao, 1998). Beckett et al. (2000) performed a source apportionment analysis for hearing loss in a large, multiphasic health survey, the New York Farm Family Health and Hazard Survey. This survey of 185 workers found that hearing loss was associated with a history of spraying crops with insecticides including organophosphates and pyrethroid compounds. Other factors associated with hearing loss were age, gender, lack of high school education, firearms use, and a history of grain dryer operation. Teixeira Augusto, and Morata (2002) studied Brazilian pesticide applicators exposed to organophosphates and pyrethroids and non-exposed workers. Data on work history, medical history, current diseases, occupational and non-occupational exposure to noise or chemicals and lifestyle factors were obtained through interviews. Central auditory system functions were assessed through pitch pattern sequence and duration pattern sequence testing. Fifty six percent of the exposed workers had central hearing dysfunction and the relative risk for this was 7.58 for the group with exposure to insecticides (95% CI 2.9 – 19.8) when compared to the non-exposed group. The group exposed to insecticides and noise had a relative risk for central disorders of 6.5 (95% CI 2.2 – 20.0) when compared to the non- exposed groupReview and 9.8 (95% CI 1.4 – 64.5) when compared to the group exposed solely to noise. The authors surmised that exposure to organophosphates and pyrethroid products can induce damage to the central auditory system. Kimura et al. (2005) studied the effects of pesticides on the peripheral and central nervous system in tobacco farmers in Malaysia using nerve conduction velocity ABR and computerised posturography. After a careful

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investigation, they concluded that nerve conduction velocities and postural sway seen to be sensitive indicators of the effects of pesticides on the central and peripheral system. In Brazil, Ferraz (1988) associated occupational exposure to maneb (manganese bisdithiocarbanate), a fungicide widely used in Latin America, with chronic neurological disease. Chinese investigators found disturbances in the peripheral nervous system among cotton workers exposed to various pyrethroid insecticides, but these changes were not persistent and full recovery took place within two days in all cases (Jeyaratnam, 1990) In summary, the deleterious effects of occupational noise on hearing have been well documented for many years. However, it was only recently that attention has shifted to the individual and synergistic ototraumatic effects of solvents and noise exposure combined. Evidence in this review supports the notion that solvents can injure the sensory cells and peripheral nerve endings of the cochlea. There is also the suggestion that because of the known solvent-related effects in the cortex retrocochlear disorders may also be expected (Fuente & McPherson, 2006). Organic solvents enhance the damaging effects of noise. A few recent studies have alluded to the ototraumatic effects of pesticides. The impact of solvents, solvents and noise combined, and pesticides pose a challenge to industrial workers, agriculture workers, occupational health workers and hearing conservationists in developing countries.

Table 7. Most frequently used Pesticides in selected Asian Countries and their WHO Hazard Classification

Pesticide Hazard Classification Carbaryl 11 Malathion III Methyl Paratheon Ia Dazinon II Monocrotophos Ib Endolsutan II Carbofuran Ia Oxydemeton-methyl Ib 24D II BPMC II From: Wesseling et al., 1997. Ia = Extremely hazardous. Ib = Highly hazardous II = Moderately hazardous III = Slightly hazardous

Review

206 Geoffrey K. Amedofu and Adrian Fuente

PREVENTION OF NOISE-INDUCED HEARING LOSS IN DEVELOPING COUNTIRES

Excessive noise causes permanent hearing loss. Virtually all such hearing loss is preventable. The primary motive for industrial noise control and related programs is that of protecting the health of the employees and reducing the legal liability of employers who may be held accountable for the impairments or disabilities incurred through employment. The major social value underlying protection from work place noise is that an employee should not have to risk material injury to earn a living. In specific employment settings such as the military or public safety, an additional motive may be that of avoiding deterioration of job performance because of reduced sensory ability. Here, the underlying social value is worker efficiency and effectiveness. A good hearing loss prevention program is good business in that it promotes positive labour relations. Employees enrolled in such a program know that management is concerned for their welfare and this awareness may translate into improved productivity. Studies of companies that have implemented hearing loss prevention programs often show reductions in accident rates, worker illnesses and lost time (Franks, Stephenson & Merry, 1996). Additionally, hearing loss prevention programs bestow enormous benefits on employees throughout life since the ability to communicate is critical in all of our interpersonal relationships. When good hearing is a prerequisite for a job, an effective hearing loss prevention program will enable employees to sustain their hearing ability and this continues to qualify them for jobs (including higher level positions) that have such requirements. Finally, these programs are used to identify “tender ears” (ears which already exhibit permanent threshold shift) or ears that exhibit a hearing disease that may be progressive. It is important for the employer to identify the latter group of hearing disorders, because potentially, the employer could become liable for hearing loss caused by disease that subsequently could not be differentiated from that caused by noise. It is therefore logical and reasonable for all companies to adopt a practical long-term approach to noise-induced hearing loss prevention. Figure 2 shows a pyramid of different levels of prevention that may be initiated in occupational hearing loss programs.

Primary prevention Eliminate/reduce agents hazardous to hearing

Secondary prevention Early detection of occupational hearing loss and action to avoid further loss.

Tertiary prevention Minimize adverse effects of occupational hearing loss. Appropriate treatment and Reviewcounseling for those with occupational hearing loss.

Figure 2. Levels of prevention applied to occupational hearing loss.

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Vignette 1 A case report of an effective Hearing Conservation Program in Ghana

In 1999 a large gold mining company in Ghana embarked on a hearing conservation program (HCP). Activities included in the HCP involved the following: noise measurements; pure tone audiometry; poster displays and warning signals in specific areas in the company to alert workers; and worker education in the use of ear protectors. In order to judge the effectiveness of the HCP, the audiometric data compiled by the company were examined retrospectively. Data for the analysis consisted of audiograms of 200 workers from various departments in the company, namely pit, processing, geology, survey mining, and safety and health environments. At the start of the HCP in 1999, individual work histories were collected and noise levels in the different working conditions were measured. Those who were exposed to recreational or military noise were excluded. In all, 200 base-line audiograms obtained in 1999 were compared with 200 audiograms obtained from the same workers in 2003 (OSHA, 1983). Shifts of 10 dB or greater at 2, 3 and/or 4 kHz were classified as STS (standard threshold shift). In order to determine the effectiveness of the HCP, only the percentage of employees exceeding the STS criterion in a positive direction was used; less than 6 – 8% of workers should show additional hearing loss in an effective program (Royster & Royster, 1982). Only hearing level decrement was considered and age correction factors were not employed in the calculation of these shifts. Out of the two hundred audiograms which were examined, 11 (5.5%) showed an increase in thresholds of more than 10 dB in one or both ears. That is, hearing loss became worse in only 5.5% of cases. The HCP was considered effective, since less than 6% of workers had additional hearing loss over the four year period of the HCP. The management of this company has to be commended for protecting their workers. The occupational physician at the company was actively involved in all aspects of the HCP.

Regulatory Action and Traditional Hearing Conservation Programs in Developing Countries

In developed countries, there are increasing efforts to regulate noise and to administer hearing conservation programs. In these countries the awareness and acceptance of the reality of noise as an occupational hazard has increased. Indeed, there are laws in such countries that require employers in manufacturing and mining companies to protect employees against hazardous noise. In the United States of America for instance, the military established regulations to manage noise exposure as early as 1956 (USA Air Force, 1956) but noise limits for non-military occupational exposure were not suggested until 1969 by the modification of the Walsh–Healey Public Contracts Act (Office of the Federal Register, 1969). Later, the Occupational Safety and Health Administration (OSHA) was established in 1970 and charged with the responsibility for promulgating and enforcing regulations established to protect the safety and Reviewhealth of American workers. In 1972, the National Institute for Occupational Safety and Health (NIOSH) published the first criteria for a recommended standard on occupational exposure to noise. The exposure limit recommended by NIOSH was an 8-hour time weighted average (TWA) of 85 dBA. In Europe, statutory controls in industry were in

208 Geoffrey K. Amedofu and Adrian Fuente place since the 1970s and in Japan guidelines for the prevention of hearing loss were issued in 1992. There are also laws in some developing countries which protect workers who are exposed to hazardous noise. In Ghana, the liability for hazardous noise exposure and noise-induced hearing loss is that imposed by the Workman’s Compensation Acts, both the Workman’s Compensation Act 174 of 1963 and the Factories, Offices and Shops Act of 1970. This is under review. Under these laws, noise levels of 85 dBA or more for an 8-hour exposure is considered potentially damaging. There were no laws protecting workers in mining companies against hazardous noise, although the potential danger of NIHL in this work setting has been recognised and an exposure level of more than 85 dBA for 8 hours is considered hazardous. In Pakistan, legislation was enacted against noise induced hearing loss in 1965 and 1969, but at present any impairment that is less than 100% of hearing loss is not compensated (WHO, 1997a). In Swaziland, the Factories, Machinery and Construction Works Regulations came into effect in 1974. To strengthen the enforcement of these legal instruments, Legal Notices were devised. For example, Legal Notice No. 11 of 1980 stipulated the allowable level of noise in factories and other premises under the scope of existing legislation. It also defined the steps to be undertaken to reduce noise levels or to protect workers from excessive noise. Legal Notice No.91 of 1985 empowered the Inspector of Factories to issue notices in order to regulate working conditions and protect workers against hazardous noise (Shilla, 1994). Similar laws exist in other developing countries, some of which require employers to offer hearing protection to employees exposed to hazardous noise (Morata et al., 2001) including Brazil, Saudi Arabia (Ahmed et al., 2001), Kenya and India. Additionally, there are hearing conservation programs (HCPs) in some developing countries but not all of them incorporate all the interrelated program elements as advocated and practiced in developed countries. These interrelated elements (see Figure 3 for a summary of strategies) include monitoring noise exposure to characterise the hazard accurately and to identify at risk employees, implementing engineering and administrative control whenever possible to reduce the noise or removal of the worker from the noise, providing for periodic audiometric evaluation of noise exposed workers, using hearing protection devices when engineering controls are inadequate, educating and motivating both workers and management to champion hearing loss prevention, maintaining accurate records and establishing a consistent, ongoing approach for evaluating success of all aspects of a hearing conservation program (Franks et al., 1996). In Brazil, for example, employers are required to offer hearing protection devices (HPDs) and appropriate training for noise-exposed workers (Ministerio do Trabalho, 1997). In Ghana, Anglo-Gold Ashanti (a large underground mining company) has a hearing conservation program and workers are compensated for hearing loss attributable to excessive noise. A study conducted in one of the subsidiary companies of Anglo-Gold Ashanti, a surface gold mining company, indicated that the hearing conservation program was effective (Amedofu, in press). However, in general, hearing conservation laws in developing countries are rarely enforced. While there are laws in many developing countries to protect workers fromReview hazardous noise, inconsistent compliance, spotty enforcement of governmental regulation and lack of HCPs in most industries are the cause of NIHL. It is true that some companies provide HPDs for their workers but often workers do not use them due to comfort issues, especially in hot and humid countries in Africa and Asia. In these countries, there is a general lack of a functioning occupational health system, at times combined with severe

Occupational Hearing Loss in Developing Countries 209

repression of trade unions that would act to encourage the growth of HCPs. Additionally, employers in developing countries are reluctant to develop HCPs in their industries because it involves an extra cost to the company. Many of these companies may not operate at full capacity and are economically marginal. Again, due to high levels of unemployment, employees are reluctant to assert their rights for fear of being laid off.

Engineering control

Aim: to diminish noise levels in the source. Strategies: replacement of old machinery, isolation, maintenance.

If noise > 80 dBA TWA Administrative actions

Aim: to diminish time that workers are exposed to noise. Strategies: use of shifts, change workers’ function.

If noise >80 dBA TWA

Aim: To protect the inner ear when noise levels are still higher than 80 dBA. Strategy: HPD according to noise characteristics.

Review Figure 3. Strategies to reduce worker noise exposure.

210 Geoffrey K. Amedofu and Adrian Fuente

Another problem for implementing HCPs in developing countries is that the majority of workers in these countries work in the informal sector. It is estimated that over the past decade the informal sector created over 90 percent of all new jobs in Africa (Gërxhani, 2004). In Mali, Nepal and Pakistan the informal sector represents 70 percent of total employment. It is very difficult to provide hearing loss prevention programs to informal sector employees for various reasons: they work alone or in small groups; they are often employed temporarily; they may be itinerant; they may have more than one employer per year; and they may not be exposed to traditional manufacturing noise hazards. In addition, because informal sector workers tend to be unorganised, it is difficult to reach them through traditional routes such as trade unions, craft organisations or corporate structures. Such workers may come to accept noise exposure and hearing loss as part of the job. These types of workers are considered to be underserved (Franks et al., 1996) in developing countries.

LOW COST METHODS OF NOISE REDUCTION IN DEVELOPING COUNTRIES

Given the conditions within both the informal and formal sectors in developing countries, consideration should be given to adopting other, low cost methods of noise control to supplement/replace the use of hearing protection devices. Kahkonen and Muchiri (1989) gave some practical suggestions that are economical to carry out in noisy environments, some of which can be utilized by industries in developing countries to supplement other efforts. The following low cost methods of noise control can be used in developing countries to protect workers from hazardous noise exposure.

Location of Equipment

The most important part of noise control planning is the layout both inside a plant and outside. An appropriate layout involves the use of distance to reduce noise level. Noise level falls rapidly as one moves away from the noise source. Outdoors in the acoustically free field, the sound pressure level can be reduced by as much as 6 dB for every doubling of distance. However, indoors the effect of reverberation may limit the degree of reduction. Also, noisy work operations can be grouped together in one area. This reduces the area requiring noise control measures and provides automatic control to the other employees by virtue of distance. Quiet areas like storerooms and holding areas can be used as buffer zones between noisy and quieter areas.

Selection of Quieter Machines and Quiet Processes

CarefulReview selection of equipment may also be of help in reducing noise. It has gradually becoming easier to obtain noise data on machines and processes from vendors. Where the distributor cannot provide information, a visit to see the machinery in operation is informative

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in regard to noise and other factors. The sound power data can be used as a starting point to predict the general noise level of the planned work area.

Installation of Absorption Materials

Reductions from 3 to 7 dB SPL can be achieved by installing acoustic absorption materials. Hard, smooth, impervious surfaces which reflect sound should be changed into soft, rough, porous surfaces which absorb sound. In hot, humid countries such as in Africa, open windows and doors can also be sometimes used to effectively absorb noise.

Maintenance of Machines

Increased noise or vibration of a machine is often an indication of the poor condition of the machine. It is important for employers to perform proper maintenance of their machines. The service department has an important role to play in keeping equipment in good low noise condition.

Rotation of Jobs

In some cases job rotation of employees can be used to reduce the effect of noise on workers. Transfer of those who work in noisy areas to quieter areas can ensure that workers intermittently perform noisy and quiet tasks. However, due to different labour skills and wages as well as worker resistance, this form of noise control may at times be difficult to implement. In the world today, democracy and globalisation bring about opportunities for developing countries to enhance work conditions, including reduced noise levels. This may be possible through the commitment from employers to pursue and enforce local legislations on noise exposure at the work place. Company sponsored programs should stress the importance of good hearing conservation practices on and off the job and inform employees about factors (e.g., diseases and recreational noise exposure) that may affect their hearing. Employers must bear in mind that even though special training sessions may be devoted specifically to the prevention of hearing loss, the hearing conservation program must be recognised as an essential element in the overall health and safety climate of the work place. High visibility media campaigns to develop public awareness of the effects of noise on hearing and means of self-protection should be promoted in developing countries. Self-education materials for adults should be readily available and need to be developed. The prevention of NIHL should be part of the health curricula in pre-university institutions in developing countries. There should be improved access to programs for training more audiologists, audiology technicians and otolaryngologistsReview in developing countries to provide a professional base for preventive audiology.

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Vignette 2 A study on the effectiveness of a hearing conservation program among noise-and solvent-exposed workers in a petrochemical plant in Colombia

In the Ecopetrol petrochemical plant in Barrancabermeja, Colombia, a hearing conservation program has been conducted since 1972. In 1997, to evaluate the effectiveness of this program as well as to assess the risk of solvent-induced hearing loss among workers of the complex, a study on the prevalence of hearing loss (Londoño et al., 1997) was carried out. The company, in conjunction with experienced researchers from the National Public Health Faculty of the University of Antioquia, Colombia, carried out the study. A sample of 745 workers was selected (out of 2775 workers at the plant). Four different groups of workers were studied: those exposed to industrial noise only, those exposed to industrial solvents only, those exposed to both agents, and those exposed to neither. The aim of the study was to obtain the total number of workers with hearing loss in each subgroup and ultimately suggest preventive actions in order to avoid occupational hearing loss in workers. According to the hearing conservation program that operates in the complex, noise- exposed workers must have a yearly audiometric test and non-exposed workers are assessed every five years. Periodic noise levels were obtained in the plant as well as measures of environmental solvent concentrations. Workers exposed to 85 dB(A) or greater levels of noise were required to wear hearing protectors. Workers from workstations where organic solvents were used wore respiratory masks. Files of each selected worker were analysed. Data regarding pure-tone thresholds, noise levels and environmental concentration of organic solvents were taken into consideration for the analysis. The prevalence of hearing loss (hearing thresholds equal or worse than 25 dBHL) varied between 8% and 13.5% among the four studied groups of workers. No significant differences were found among the groups. However, when hearing thresholds at 4 kHz were considered to be abnormal only at a level of 30 dBHL or higher, the overall prevalence of hearing loss diminished to 4%. This prevalence was much lower than the rate noted in two previous studies carried out in the same plant. The study revealed that low environmental solvent concentrations and the use of hearing protectors were key issues to successfully maintain a low prevalence of hearing loss among workers. Researchers concluded that controlling the sound emissions from the source as well as in the environment, periodic pure-tone audiometric controls, and the use of hearing protectors and respiratory protection for solvent exposure promoted the good hearing health conditions observed among the workers studied. The study showed that the hearing conservation program carried out in this petrochemical plant was successful. From this Colombian experience, it can be appreciated that unifying efforts between the private and public sectors, and/or between industry and research, can lead to positive results. Also, monitoring environmental solvent concentrations and supplying workers with the pertinent protective devices help to protect workers’ hearing health. Review

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OPPORTUNITIES FOR PREVENTING CHEMICAL INDUCED HEARING LOSS

There is sufficient evidence to clearly show that exposure to chemicals such as solvents and pesticides can cause permanent damage to the auditory system. In industrial settings, solvents such as toluene, styrene, xylene, trichloroethylene and carbon disulphide have been shown to be ototoxic. Large worker populations in developing countries, in the desire to increase agriculture production and to control pests, are exposed to increasing amounts of pesticides which are also ototoxic. These chemicals are often actively produced in or introduced to developing countries so as to avoid the restrictions caused by often stringent legislation in industrialized countries, and to find new markets for the products outside the saturated industrialized economies. In industrialized countries, stringent legislation and control have slowed down the growth rate of chemical pollution, which has led to a decline in the incidence of occupationally determined acute and chronic intoxications such as peripheral nervous system injuries (Rantanen, 1993). In developing countries, however, poor agricultural practices by vulnerable farmers contribute to occupational health problems including hearing loss, a problem exacerbated by an ignorance of the dangers inherent in pesticides, illiteracy, inadequate legislation, lack of enforcement, lack of technical and laboratory capacity, inadequate pest control policies and under resourced research facilities. The easy availability of hazardous pesticides coupled with the close proximity of the living environment to the work place (London, 1998) leads to farm workers and their families being overexposed. Work is often performed in hot, humid climates that discourage the use of protective gear (Ngowi, Meada, Wesseling et al., 2001). Some farmers store pesticides inside their homes, sometimes with food or animal feed and within the reach of unauthorised persons like children (London, 1998; Naidoo, White, London, Viera & Janulewicz, 2005). Thus, unlike those in developed countries, agricultural policies in third world countries have more markedly emphasized short-term economic gains at the expense of environmental sustainability and health. Seychelles is one of the few developing countries where, under stringent provisions, all pesticide handlers are medically examined annually and their food tested every six months, even before symptoms occur, in order to detect early chronic intoxication by pesticides (Adam, 1993). The Work and Health in South Africa (WAHSA) project on pesticides was an initiative by the Swedish International Development Cooperation Agency (SIDA) that focuses on developing skills and resources to manage the health and environmental impact of pesticides in the region (Ngowi & London, 2006). The East Africa Pesticide Network (EAPN) project was also established to assess the health hazards posed by pesticides (Ngowi, 2003).

Key Strategies for Chemical Safety in Developing Countries Review In order to recognise the hazards of ototoxic chemicals and to focus on preventive measures, risk assessment of chemicals and their registration is vital. Indeed, registration of solvents and pesticides is at the core of regulation issues because it determines whether a chemical (e.g., solvent or pesticide) can be used in a country. So far, it appears registration

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has usually failed as a strategy for risk management of pesticide use in many developing countries (Mbakaya et al., 1994). This is an important issue, which developing countries must address. The passage of a comprehensive Chemical Act to control usage in all sectors of the economy is required in many developing countries. In addition, there should be legislation on chemicals such as solvents and pesticides used in industry and agriculture which have been shown to be ototoxic, with associated regulatory bodies making pesticide management decisions in these countries. These bodies should best be set up at national and regional and community levels to make them more effective. The Food and Agricultural Organisation Code of Conduct advocates support to governments of developing countries in setting up regulatory bodies, but in most countries authorities in charge encounter overwhelming problems because of insufficient technical knowledge (FAO, 1990). There should be adequate technical and laboratory capacity capable of conducting analysis for solvents and pesticides and their residues at standards that meet good laboratory practice. It is vital to train more experts in the field of toxicology, health and control technology to implement policies and legislation. The main channels through which solvents and pesticides are absorbed are through the respiratory tract and through the skin. Therefore it is necessary to educate workers on self-protection by promoting use of more climate-friendly protective clothing and masks to prevent contact with these chemicals.

CONCLUSION

The hazardous effects of noise on hearing have been extensively recognised by clinicians, researchers and workers for many decades. However, occupational hearing loss is not due to noise exposure alone, but also due to compounds such as solvents and other chemicals. Certain chemicals, due to either oto- or neuro-toxicity or both, may induce auditory damage. Solvents in conjunction with noise have also been demonstrated to have an adverse synergistic effect on hearing. These findings present a new challenge for hearing health-care professionals, especially in the developing world where the level of awareness of occupational health and safety issues is low. It is the responsibility of audiologists, otolaryngologists, and occupational health and safety specialists to prevent hearing loss that is caused by occupational hazards. In many developing countries, the work place is still a hazardous environment with excessive risk levels.

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Pryor, G.T., Dickinson, J., Howd, R.A., & Rebert, C.S. (1983). Transient cognitive deficits and high-frequency hearing loss in weanling rats exposed to toluene. Neurobehavioral Toxicology and Teratology, 5, 53-57. Pryor, G.T., Rebert, C.S., & Howd, R.A. (1987). Hearing loss in rats caused by inhalation of mixed xylenes and styrene. Journal of Applied Toxicology, 7, 55-61. Raja, S., & Ganguly, T. (1983). Impact of exposure of noise on the hearing acuity of employees in a heavy engineering industry. Indian Journal of Medical Research, 78, 100- 113. Rantanen, J. (1993). Chemical safety – a key issue in occupational health. African Newsletter on Occupational Health and Safety, 3, 34-36. Rebert, C.S., Day, V.L., Matteucci, M.J., & Pryor, G.T. (1991). Sensory-evoked potentials in rats chronically exposed to trichloroethylene: Predominant auditory dysfunction. Neurotoxicology and Teratology, 13, 83-90. Rebert, C.S., Sorenson, S.S., Howd, R.A., & Pryor, G.T. (1983). Toluene-induced hearing loss in rats evidenced by brain stem auditory-evoked response. Neurobehavioral Toxicology and Teratology, 5, 59-62. Rebert, C.S., Sorenson, S.S., & Pryor G.T. (1986). Effects of intraperitoneal carbon disulfide on sensory-evoked potentials of Fischer-344 rats. Neurobehavioral Toxicology and Teratology, 8, 543-549. Regoeng, K.G. (2003). Safety and health in the informal sector and small-scale industries: the experience of Botswana. African Newsletter on Occupational Health and Safety, 13(1), 10-12. Royster, L.H., & Royster, J.D. (1982). Methods of evaluating hearing conservation program audiometric data bases. In P.W. Alberti (Ed.), Personal hearing protection in industry, pp. 511-540. New York: Raven Press. Sass-Kortsak, A.M., Corey, P.N., & Robertson, J.M. (1995). An investigation of the association between exposure to styrene and hearing loss. Annals of Epidemiology, 5, 15- 24. Shaikh, G.H. (1996). Noise problem in a polyester fibre plant in Pakistan. Indian Health, 34, 427-431. Shealy, D.B., Barr, J.R. Ashley, D.L., Patterson, D.G.Jr., Camann, D.E., & Bond, A.E. (1997). Correlation of environmental carbaryl measurements with serum and urinary 1- naphthol measurements in a farmer applicator and his family. Environmental Health Perspectives, 105, 510-513. Shilla, C.P.N. (1994). Improving work conditions in Swaziland. African Newsletter on Occupational Health and Safety, 4, 60-62. Sliwinska-Kowalska, M., Zamyslowska-Szmytke, E., Szymczak, W., Kotylo, P., Fiszer, M. et al. (2001). Occupational solvent exposure at moderate concentration increases the risk of hearing loss. Scandinavian Journal of Work, Environment and Health, 27, 335-342. Sliwinska-Kowalska, M., Zamyslowska-Szmytke, E., Szymczak, W., Kotylo, P., Fiszer, M. et al. (2003). Ototoxic effects of occupational exposure to styrene and co-exposure to styrene Reviewand noise. Journal of Occupational and Environmental Medicine, 45, 15-24. Sliwinska-Kowalska, M., Zamyslowska-Szmytke, E., Szymczak, W., Kotylo, P., Fiszer, M. et al. (2004). Effects of coexposure to noise and mixture of organic solvents on hearing in dockyard workers. Journal of Occupational and Environmental Medicine, 46, 30-38.

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Sliwinska-Kowalska, M.,Zamyslowska-Szmytke, E., Szymczak, W., Kotylo, P., Wesolowski, W., Dudarewicz, A. et al. (2000). Assessment of hearing impairment in workers exposed to mixtures of organic solvents in the paint and lacquer industry. Medycyna pracy, 51, 1- 10. Stansfeld, S.A., & Matheson, M.P. (2003). Noise pollution: non-auditory effects on health. British Medical Bulletin, 68, 243-257. Sulkowski, W.J. (1979). Badania and prxdatnoscia kliniczna audiometeri elektronystamografii w. diagnostyce przwleklych zatruc dwusiarcz wegla. Medycyna Pracy, 30, 135-145. Szulc-Kuberska, J., Tronczynska, J., & Latkowaki, B. (1976). Oto-neurological investigations of chronic trichloroethylene poisoning. Minerva Otorinolaringologica, 26, 108-112. Tay, P. (1996). Severe noise-induced deafness – A 10-year review of cases. Singapore Medical Journal, 37, 362-364. Teixeira, C.F., & Brandao, M.F.A. (1998). Effects of agro-chemicals on the auditory system in rural workers. Caderno informativo de Prevencao de Acidentes, 19, 218. Teixeira C.F, Augusto L.G, Morata T.C. (2002). Occupational exposure to insecticides and their effects on the auditory system. Noise & Health, 4, 31-39. Tomasini, M., & Sartorelli, E. (1971). Intossicazione cronica da infalazione di trieleina commercial com compromissione dell’ vii palo de nervi cranici. Clinica del Lavoro, 62, 277-280. U.S. Airforce (1956). Hazardous noise exposure. AF Regulation 160-3.Washington, D.C.: Office of the Surgeon-General. Wahib, U. & Zaidi, S.H. (1997). Noise induced hearing loss in Pakistan. Pakistan Journal of Otolaryngology – Head and Neck Surgery, 13, 75-78. World Health Organisation (WHO). (1997a). Prevention of noise-induced hearing loss. Report of an informal consultation. Geneva: WHO/Prevention of Blindness and Deafness. World Health Organisation (WHO). (1997b). Occupational noise: assessing the burden of disease from work-related hearing impairment at national and local levels. Geneva: WHO. World Health Organization/United Nations Environmental Programme (WHO/UNEP). (1989). Public health impact of pesticides used in agriculture. Geneva: WHO/UNEP. Wesseling, C., McConnell, R., Partanen, T., & Hogstedt, C. (1997). Agricultural pesticide use in developing countries: health effects and research needs. International Journal of Health Services, 27, 273-308. Yisa, M.G. (2005) Ergonomics in small-scale grain mills in Nigeria. African Newsletter on Occupational Health and Safety,15(1), 7-10.

Review

Chapter 12

RESOURCES FOR AUDIOLOGISTS IN DEVELOPING COUNTRIES

Bradley McPherson1 and Ron Brouillette2,* 1University of Hong Kong, Hong Kong, China 2Inclusive Education Consultant, Directorate of Primary and Mass Education, Dhaka, Bangladesh and "Affordable Hearing" and "Wings", Consultants for International Deafness and Development, United States of America

ABSTRACT

This chapter is designed to give the reader an overview of the wealth of information now available for audiologists and other hearing health workers with an interest in developing country issues. The information is categorized into four sections, based on whether it relates to health/education policy, organizations involved in funding and appropriate technology, hearing health care information or private hearing health care companies. Most of the organizations listed in this section provide useful material that can be downloaded free-of-charge from their websites. Internet access in many developing countries is becoming more available as telecommunications costs decrease and networks expand.

RESOURCES

Health/education policy www.asha.org The American Speech-Language-Hearing Association (ASHA) has numerous documents that are of relevanceReview to audiologists, including Guidelines for the Audiologic Assessment of Children, which are worth considering prior to implementing clinical procedures in developing countries.

* Correspondence: [email protected]

224 Bradley McPherson and Ron Brouillette

www.audiology.org The American Academy of Audiology also has an informative series of position statements that advise on screening and diagnostic protocols, such as Preventing Noise-Induced Occupational Hearing Loss. www.ifhoh.org The International Federation of Hard of Hearing People (IFHOH) represents the interests of hard of hearing people and their national organizations. IFHOH publishes a regular journal. www.infanthearing.org National Center for Hearing Assessment and Management (NCHAM) is located at Utah State University. The Center’s aim is to ensure that all infants and toddlers with hearing loss are identified as early as possible and provided with timely and appropriate audiological, educational, and medical intervention. The NCHAM website has a a great deal of information on newborn hearing screening programs and intervention services for children with hearing impairment. www.isa-audiology.org The International Society of Audiology has developed important guidelines regarding a model audiology training curriculum and hosts a message board open to all. The society website gives links to documents and other websites useful for those working in developing countries. www.nhsp.info The National Health Service Neonatal Hearing Screening Programme provides information in English and other languages on the practical application of newborn hearing screening. www.unohrlls.org The United Nations Office of the High Representative for Least Developed Countries, Landlocked Developing Countries and Small Island Developing States provides up-to- date lists of least-developed nations and statistics related to LDCs. www.who.int The World Health Organization publishes a huge range of resources for international health policy. In particular, the Prevention of and Blindness and Deafness section of WHO [www.who.int/pbd] maintains an essential library of documents that all audiologists working in less developed regions should access, including Guidelines for hearing aids and services for developing countries. www.worldbank.org The World ReviewBank produces an extensive range of health care policy documents. A recent publication, Disease Control Priorities in Developing Countries, includes discussion of cost-effective prevention and treatment options. The World Bank also provides annual reports on the state of the world’s people in the Human Development Report, an important source of information on the status of people in developing countries.

Resources for Audiologists in Developing Countries 225

Funding and appropriate technology www.audmed.org.uk The AUD-M-ED Trust is a British charity that focuses on providing resources to aid the prevention, detection and management of hearing impairment and deafness in developing countries. The Trust supports projects and sends trainers, equipment, training materials and scientific literature to developing countries.The Trust provides grants to professionals working in developing countries. www.cbmi.org The Christian Blind Mission (CBM) is a large, international organization, headquartered in Germany, which provides support to health care and education projects for children and adults with vision impairment and/or hearing loss throughout the developing world. www.comcareinternational.org A series of innovative body-worn solar powered hearing aids have been developed by ComCare International for use with children and adults in developing countries. ComCare provides hearing aids at reduced cost to many clinics, particularly in Latin America. www.deafchildworldwide.info Deaf Children Worldwide is the international development agency of the National Deaf Children's Society, a British based charitable organisation dedicated to enabling deaf children to overcome poverty and isolation. Deaf Child Worldwide works with partners in the countries where need is greatest throughout the world The agency at times offers small grant project funding and supports locally registered organisations working with deaf children in developing and transitional countries.

www.earsinc.org EARS Inc. is an Australian charitable organization dedicated to the training and equipping of health workers in developing countries to provide rehabilitation services for individuals with hearing loss.

www.godisa.org Godisa is a not-for-profit trust based in Otse, Botswana. Godisa assembles and distributes affordable hearing aids designed to be appropriate for use in developing countries. Godisa also distributes hearing health care equipment, such as ear mold manufacturing kits and audiometers for use in developing countries.

www.impact.org.uk The IMPACT Foundation is a United Kingdom-based charity that sponsors many programs that benefit people with handicaps in developing countries. IMPACT’s activities include the developmentReview of a solar powered hearing aid battery charger and low cost hearing aids.

226 Bradley McPherson and Ron Brouillette

www.oticon.org The Oticon Foundation has a long-established mission to assist those working to alleviate hearing handicap. The organization regularly provides substantial funding to many charitable groups in developing countries.

www.sotheworldmayhear.org The Starkey Foundation provides more than 20,000 hearing aids annually through more than 100 hearing missions a year, mainly in developing nations The Foundation also promotes hearing health awareness while supporting research and education.

www.sound-seekers.org.uk Soundseekers (the Commonwealth Society for the Deaf) is a British charity working to improve the lives of deaf children and children suffering from ear disease and hearing loss in the developing countries of the British Commonwealth. Soundseekers provide specialist equipment, training and support throughout the developing Commonwealth.

www.wwhearing.org WWHearing (World-Wide Hearing Care for Developing Countries) is a recent initiative that seeks to promote better hearing by the provision of appropriate and affordable hearing aids and services. WWHearing at present sponsors pilot projects in various developing nations. The outcomes of these projects will inform the future introduction of large scale hearing aid assessment and fitting programs.

Hearing health care information www.agbell.org The Alexander Graham Bell Association for the Deaf and Hard of Hearing helps families, health care providers and education professionals understand childhood hearing loss and the importance of early diagnosis and intervention. The website gives access to a rich store of information regarding hearing loss.

www.allearscambodia.org All Ears Cambodia is a good example of an enterprising non-governmental organization helping to improve hearing health care in a developing country and providing an informative website to support its mission.

Audiology journals on CD-ROM A wealth of professional research literature is available on CD-ROMs compiled by the Veterans’ Administration Auditory Research Laboratory. The complete set of disks includes back issues of the Journal of Speech and Hearing Research, Journal of the American Academy of Audiology, Journal of Audiological Medicine, British Journal of Audiology and many other titles. The disks are available, for the cost of shipping only, from: Review Dr Richard H. Wilson Senior Research Career Scientist Audiology – 126 VA Medical Center

Resources for Audiologists in Developing Countries 227

Mountain Home TN 37684 USA e-mail: [email protected]

Audiology basic training manual Shah, S & Rupani, H. (2006). Practical audiology. Nairobi: IMPACT Foundation. This textbook can be obtained at low-cost from [email protected]

www.healthinternetwork.net To allow health care research findings to reach those working in developing countries the WHO and the international biomedical publishing community established the Health InterNetwork: Access to Research Initiative (HINARI). Not-for-profit institutions that provide educational or clinical services in many developing countries are eligible to register with HINARI for free or very low-cost access to the world’s health research literature.

www.healthlink.org.uk Healthlink Worldwide produces an informative newsletter, Disability Dialogue, which discusses community-based approaches to rehabilitation in developing nations. This newsletter at times features the needs of those with communication disorders

www.hearf.org The Hearing Rehabilitation Foundation is a non-profit organization formed in 1996 to provide and promote speech communication training for children and adults with hearing loss. The Foundation offers a wide range of material suitable for use in aural rehabilitation programs with severely and profoundly deaf children and adults.

www.hearinginternational.org Hearing International is a not-for-profit society that actively seeks to improve hearing health in developing regions throughout the world. HI publishes a regular and informative newsletter.

www.hearingreview.com The Hearing Review is a high-circulation hearing health care trade journal published in the United States. The journal website features major articles from the journal and is a good source of up-to-date information about hearing devices.

The Holy Land Institute for the Deaf, in Salt, Jordan, was produced a useful guide to planning hearing health care services in developing countries—Things to think about before starting hearing aid services in a developing country. This guide is available from [email protected] Review www.icthesworldcare.com ICTHES World Care publishes Community Ear and Hearing Health, which is a very valuable source of information for understanding hearing health care issues in developing countries.

228 Bradley McPherson and Ron Brouillette www.ifhohyp.org The Federation of Hard of Hearing Young People is an international non-governmental federation for national and regional youth organizations that are dedicated to hard of hearing young people throughout the world. IFHOHYP is comprised of organizations from mostly European countries. The major aim of IFHOHYP is to improve the quality of life of young persons with hearing impaired worldwide and promote equal rights for hard of hearing young people at all levels of society. The website lists a valuable range of hearing health care resources. www.jtc.org The John Tracey Clinic is a private, non-profit education center founded in 1942. Its mission is to offer “hope, guidance and encouragement to families of infants and preschool children with hearing losses” by providing parent-centered services worldwide. The John Tracey Clinic is especially well-known for its free parent distance education / correspondence courses for families of young deaf children ages birth to 5 years. A special course is available for parents of preschool deaf-blind children. www.lhh.org/index.html The League for the Hard of Hearing, New York was founded in 1910 and provides hearing rehabilitation and human services support for infants, children and adults who are hard of hearing, deaf and deaf-blind, and their families. The website gives access to a useful range of information, particular on hearing conservation. www.nad.org The National Association for the Deaf is a United States organization that offers extensive information on assistive listening devices, sign language, vocations for persons with hearing impairment, etc. www.pinpointmedical.com/ent_news/ent_home.html ENT News is a monthly publication that covers otolaryngology, audiology and related professions. ENT News often has information that is highly relevant to those working in developing countries. The July/August 2007 issue gives a list of 50 internet sites that may be useful to hearing health care workers. www.who.int/pdb In addition to policy documents, the World Health Organization has produced a collection of training manuals for primary health care workers—Primary Ear and Hearing Care Training Resource. These are important references for anyone considering a hearing health care training program in a developing region.

Private hearing health care companies www.hearing.orgReview The Hearing Aid Industries Association has a very convenient webpage that offers links to most major commercial hearing aid manufacturers’ websites. European.

Resources for Audiologists in Developing Countries 229 www.audex.com Audex Assistive Listening Systems manufactures and markets infrared and magnetic induction wireless assistive listening devices, and hardwired assistive listening devices for hearing impaired people. USA. www.audiocontrole.com Audio Controle, Inc focuses on research, development, design, production, repair and distribution of hearing aid instruments and related products. Canada. www.audimed.com Audio Medical Devices Ltd manufactures a full range of digital and analog hearing systems, active noise protectors and tinnitus devices. UK. www.beltone.com Beltone Electronics Corp. is a large manufacturer of hearing instruments. USA. www.hansaton.de Hansaton Hearing Systems produces hearing aids, digital hearing systems, hearing instrument care and cleaning products, along with health information and research findings. Germany. www.instamold.com Insta-Mold Inc. is a company specializing in the development of ear impression silicones for the hearing health industry. The company focuses on one-stage impression/mold materials. USA. www.knowleselectronics.com Knowles Electronics, LLC is a leading manufacturer of miniature audio transducers, microphones, receivers, wax protection systems, acoustic dampers, and accessories for the hearing health industry. USA. www.earmolds.com Microsonic, Inc produces earmold materials, custom swim plugs, hearing protection molds, precision impression materials, and hearing health care accessories. USA. www.oticon.com Oticon Inc is a large manufacturer of digital hearing aid instruments and assistive listening devices. Denmark. www.phonak.com Phonak Hearing Systems specializes in the design, development, production and worldwide distributionReview of hearing instruments. A large scale manufacturer of hearing aids for children and adults, and assistive listening devices. Switzerland.

230 Bradley McPherson and Ron Brouillette www.precisionweb.com Precision Laboratories, Inc is a manufacturer of custom earmolds, hearing protection, monitor earphones and communications. USA. www.siemens-hearing.com Siemens Hearing Instruments, Inc offers audiological software and a wide variety of equipment for hearing care professionals, as well as a range of hearing aids and assistive listening devices such as amplified telephones. www.tdi-online.org Telecommunications for the Deaf promotes the further distribution of telecommunications devices in the deaf community and publish an annual directory of TTY numbers. It is an active advocacy organization focusing on equal access issues in telecommunications and media for people who are deaf, hard-of-hearing, late-deafened, or deaf-blind. USA. www.unitedhearing.com United Hearing Systems is a manufacturer of digital hearing aid amplifiers, digital hearing aids, tinnitus maskers and bone conduction hearing aids. USA. www.warnertechcare.com Warner Tech-Care supplies impression materials, assistive listening devices, and hearing health care accessories. The company catalog is available on-line. USA. www.widex.com Widex International is a leading manufacturer of digital hearing aids. Denmark. www.williamssound.com Williams Sound Corp provides a wide range of assistive listening devices. Products include infrared listening systems, personal amplifiers and TV listening systems. USA.

Review

CONTRIBUTING AUTHORS

Geoffrey K. Amedofu PhD. Associate Professor. Kwame Nkrumah University of Science and Technology. Kumasi, Ghana. [email protected]. Chapter 11. Vijayalakshmi Basavaraj PhD. Director. All India Institute of Speech and Hearing. Mysore, India. [email protected]. Chapter 8. Ron Brouillette PhD. Inclusive Education Consultant, Directorate of Primary and Mass Education, Bangladesh. and "Affordable Hearing" and "Wings", Consultants for International Deafness and [email protected]. Chapters 1,7 and 12. Patricia Castellanos de Muñoz AuD. Centro de Audición y Adiestramiento Fonético (CEDAF). Guatemala City. Guatemala. [email protected]. Chapter 10. Jackie L. Clark PhD. Clinical Assistant Professor. University of Texas at Dallas. Dallas, United States of America. [email protected]. Chapter 6. Adrian Fuente PhD. Centre for Communication Disorders. University of Hong Kong. Hong Kong, China. [email protected]. Chapter 11. Helen Goulios PhD. Lecturer in Audiology. University of Western Australia. Perth, Australia. [email protected]. Chapter 4. Wendy McCracken MEd. Senior Lecturer in the Education of the Deaf. University of Manchester. Manchester, United Kingdom. [email protected]. Chapter 19. Bradley McPherson PhD. Associate Professor. Centre for Communication Disorders. University of Hong Kong. Hong Kong, China. [email protected]. Chapters 1, 2, 5 and 12. Susie Miles BA, Cert Deaf Ed.. Lecturer in the Education of the Deaf . University of Manchester. Manchester, United Kingdom. [email protected]. Chapter 9. Valerie Newton MD. Emeritus Professor in Audiological Medicine. University of Manchester. Manchester, United Kingdom. [email protected]. Chapter 6. Bolajoko O. Olusanya MBBS, FMCPaed, FRCPCH. Institute of Child Health. University College London. London, United Kingdom, and . Institute of Child Health and Primary Care. UniversityReview of Lagos. Lagos, Nigeria. [email protected]. Chapter 5. Robert Patuzzi PhD. Director of Audiology. University of Western Australia. Perth, Australia. [email protected]. Chapter 3. Andrew W. Smith MBBS, MSc, FRCP . Medical Officer, Prevention of Blindness and Deafness,World Health Organization, Geneva, Switzerland, [email protected]. Chapter 2

232 Contributing Authors

Sandra E. Sosa. Centro de Audición y Adiestramiento Fonético (CEDAF). Guatemala City. Guatemala. [email protected]. Chapter 10.

Review

INDEX

Afghanistan, 10, 41, 42 A Africa, 6, 7, 12, 13, 55, 64, 68, 104, 142, 148, 152, 168, 177, 178, 194, 202, 203, 208, 210, 211, 213, abnormalities, 87 218, 219 aboriginal, 68, 101 Afrikaans, 12 absorption, 197, 211, 217 afternoon, 129 academic, 2, 51, 52, 71, 78, 80, 98, 108 age, 12, 13, 22, 26, 27, 28, 29, 30, 32, 36, 48, 75, 79, academic performance, 98 81, 84, 94, 95, 96, 97, 100, 101, 102, 103, 115, access, 1, 5, 10, 17, 18, 25, 60, 68, 84, 85, 93, 96, 116, 122, 140, 156, 171, 192, 198, 201, 204, 207 111, 113, 119, 128, 141, 142, 146, 148, 152, 153, ageing, 51, 52, 72, 216 155, 170, 171, 173, 177, 183, 202, 211, 223, 224, ageing population, 51, 52, 72 226, 227, 228, 230 agent, 112, 199, 200 accidents, 37 agents, 112, 189, 200, 212, 215 accommodation, 24 agricultural, 11, 203, 213 accuracy, 76, 87, 92, 93, 98, 130, 135 agriculture, 7, 11, 14, 189, 202, 205, 213, 214, 217, acetylcholine, 204 219, 221 achievement, 75, 100 aid, 1, 7, 11, 15, 16, 18, 39, 47, 48, 52, 53, 61, 62, acid, 204 63, 66, 74, 90, 96, 103, 114, 122, 123, 134, 135, acoustic, 24, 26, 87, 90, 120, 125, 127, 128, 139, 141, 142, 143, 144, 145, 146, 147, 148, 150, 151, 145, 146, 150, 169, 190, 191, 200, 211, 217, 229 153, 155, 156, 158, 159, 161, 162, 163, 164, 165, acoustic emission, 24, 26 168, 170, 172, 176, 183, 225, 226, 227, 228, 229, acoustical, 150 230 acute, 112, 127, 155, 204, 213 AIDS, 13, 17, 20, 96 acute infection, 112 air, 114, 117, 125, 127, 131, 132, 143, 148, 150, 161, adaptability, 70 165, 198 adaptation, 134, 138 aircraft, 190 adipose, 216 Albania, 40, 43 adipose tissue, 216 alcohol, 49, 120 adjustment, 148, 169 alcohol consumption, 49 administration, 12, 87, 135 aldrin, 203 administrative, 76, 208 Algeria, 40, 43 adult, 8, 11, 21, 27, 28, 29, 31, 33, 36, 37, 38, 41, 48, Alps, 144, 158 50, 66, 88, 96, 117, 122, 134, 138, 162, 192 alternative, 71, 91, 108, 135, 143, 150, 170 adult literacy, 8, 11 alternatives, 141, 142, 183 adult population, 50, 138 ambient pressure, 190 adults, 1, 7, 17,Review 18, 22, 29, 47, 49, 66, 75, 76, 79, 88, American Academy of Pediatrics, 88, 97 96, 99, 112, 114, 115, 122, 148, 175, 178, 181, American Psychological Association, 19, 99 182, 211, 225, 227, 228, 229 amplitude, 190 advocacy, 88, 230 analog, 182, 229 aetiology, 48

234 Index anatomy, 169 awareness, 21, 23, 26, 34, 52, 61, 70, 71, 77, 93, 102, Angola, 10, 18, 30, 40, 42, 46 107, 108, 130, 137, 146, 151, 169, 173, 178, 184, animal studies, 197, 199, 201 203, 206, 207, 214, 226 animals, 191, 197, 201, 202 Azerbaijan, 40, 42 anoxia, 17 antagonism, 200 antimicrobial, 111, 112 B anxiety, 109, 115, 192 babies, 17, 81, 82, 83, 84, 85, 137 application, 77, 87, 125, 203, 224 background noise, 39, 90, 91, 191 applied research, 152 bacterial, 111 appropriate technology, 150, 223, 225 Bahrain, 40, 43 Argentina, 9, 14, 40, 43, 57, 58, 59, 60, 61, 64, 72 bananas, 202 argument, 132, 148 Bangladesh, 1, 10, 41, 42, 55, 56, 60, 64, 73, 83, 91, Armenia, 40, 42 98, 99, 105, 141, 223, 231 aromatic, 198 Barbados, 40, 43 aromatic hydrocarbons, 198 barrier, 5, 122, 162 artificial, 82 barrier-free, 162 Asia, 6, 7, 13, 42, 44, 50, 55, 60, 64, 101, 115, 151, barriers, 2, 5, 15, 127, 141, 142, 171, 185 168, 202, 203, 208 batteries, 143, 147, 148, 151, 160, 161, 165, 169 Asian, 46, 59, 60, 61, 143, 192, 195, 205 battery, 92, 113, 130, 143, 148, 160, 161, 165, 168, Asian countries, 46, 59, 60, 61, 192 225 asphyxia, 17, 83 BCG immunization, 84 assessment, 1, 6, 15, 16, 21, 28, 36, 38, 39, 53, 61, beating, 190 63, 66, 67, 86, 96, 97, 104, 107, 108, 109, 113, behavior, 99, 103, 138, 186 115, 122, 123, 124, 128, 137, 140, 141, 142, 146, behavior of children, 99 151, 159, 160, 161, 164, 167, 168, 169, 170, 174, Belarus, 40, 43 175, 176, 177, 186, 226 Belgium, 40, 44, 55, 57, 61 assessment techniques, 1 beliefs, 137, 170, 175 associations, 51, 52, 177 benchmark, 8 asymptomatic, 76, 77, 78 benefits, 1, 26, 34, 145, 147, 152, 167, 170, 176, atlas, 218 185, 189, 206 atrophy, 96 benzene, 198, 219 attention, 1, 13, 94, 107, 108, 111, 117, 119, 120, Bhutan, 10, 41, 42 122, 129, 137, 142, 151, 164, 195, 205 bilateral, 30, 31, 32, 52, 80, 93, 96, 103, 114, 128, attitudes, 108, 172 131, 134, 135, 137, 156, 200, 204 atypical, 216 bilingual, 12 audio, 157, 229 biological, 113, 195 audiology, vii, 1, 2, 6, 7, 14, 15, 16, 51, 52, 53, 54, biomedical, 227 55, 58, 60, 61, 62, 63, 64, 66, 67, 68, 71, 72, 73, birth, 6, 8, 14, 17, 30, 79, 80, 82, 83, 84, 96, 146, 95, 109, 143, 144, 146, 162, 167, 168, 169, 170, 156, 175, 182, 228 172, 173, 176, 177, 182, 183, 185, 211, 216, 224, birth rate, 6, 82, 156 227, 228 birth rates, 6, 82 audition, 87, 120 births, 6, 12, 13, 14, 17, 75, 80, 83, 96, 156, 176, 182 auditory cortex, 197 blindness, 36 auditory evoked potential, 217 blog, 152 auditory nerve, 191 blood, 191, 198, 203 auditory stimuli, 81 blood flow, 191 Australia, vii, viii, 10, 20, 23, 31, 41, 44, 46, 51, 52, blood stream, 198 53, 57, 64, Review66, 68, 71, 86, 95, 97, 146, 170, 231 Bolivia, 40, 43 Austria, 40, 44, 57, 61, 62 bone, 30, 114, 120, 125, 131, 132, 136, 165, 230 availability, 62, 71, 96, 110, 142, 144, 146, 155, 158, Bosnia, 40, 43 162, 213 Boston, 20 aviation, 194, 195

Index 235

Botswana, 11, 40, 43, 57, 64, 104, 144, 147, 148, CDC, 138 172, 193, 217, 220, 225 cell, 121, 143, 148, 202 boys, 13 Central America, 147, 202 brain, 24, 79, 125, 199, 217, 220 Central Asia, 42, 44 brain stem, 125, 199, 217, 220 central nervous system, 79, 197, 204, 217 brainstem, 81, 82, 100, 124, 128, 129, 136, 182 certificate, 175 Brazil, vii, 26, 31, 40, 43, 46, 52, 53, 56, 58, 59, 60, Chad, 10, 40, 42 63, 151, 171, 172, 176, 194, 197, 198, 205, 208, Chagas disease, 13 218 channels, 214 Brazilian, 93, 99, 178, 204 charitable, 142, 143, 148, 161, 225, 226 breakdown, 54 charitable organizations, 161 breast, 82 charities, 169 brick, 192 chemical, 96, 189, 190, 191, 195, 196, 201, 202, 203, British, 19, 47, 49, 86, 101, 102, 103, 138, 139, 153, 213, 216, 219 172, 173, 179, 221, 225, 226 chemicals, 22, 189, 195, 196, 201, 202, 203, 204, broadband, 130 213, 214, 221 buffer, 210 chewing, 150 Bulgaria, 40, 43 child development, 169, 218 Burkina Faso, 10, 40, 42 child mortality, 10, 17, 41 Burma, 176, 179 childhood, 15, 17, 29, 30, 38, 47, 48, 50, 75, 76, 79, Burundi, 8, 10, 40, 42 80, 83, 92, 93, 94, 98, 99, 100, 101, 102, 103, business, 148, 192, 206 105, 135, 174, 176, 226 buttons, 111 children, 1, 6, 7, 12, 13, 15, 17, 18, 19, 20, 22, 23, 27, 29, 30, 39, 47, 48, 49, 62, 75, 76, 77, 78, 80, 81, 85, 86, 87, 88, 89, 90, 92, 93, 94, 95, 96, 97, C 98, 99, 100, 101, 102, 103, 104, 105, 112, 113, 114, 115, 116, 117, 120, 122, 123, 125, 129, 136, calibration, 15, 26, 107, 113, 169 137, 138, 139, 140, 146, 148, 153, 156, 157, 159, Cambodia, 9, 10, 14, 16, 17, 20, 41, 42, 56, 62, 64, 161, 165, 167, 168, 169, 170, 171, 172, 173, 174, 226 175, 176, 177, 178, 179, 181, 182, 183, 184, 186, Cambodians, 16 213, 224, 225, 226, 227, 228, 229 Cameroon, 40, 42 Children’s Fund, 80, 104 campaigns, 147, 178, 211 Chile, viii, 40, 43, 56, 59, 61, 189 Canada, viii, 40, 44, 52, 53, 57, 68, 182, 229 China, vii, 1, 5, 6, 9, 14, 18, 20, 26, 32, 41, 43, 44, canals, 120 45, 46, 48, 56, 61, 63, 64, 70, 75, 144, 147, 151, candidates, 90 168, 190, 194, 223, 231 capacity, 85, 88, 163, 213, 214 Chinese, 54, 205 capacity building, 85, 163 cholinesterase, 204 Cape Town, 140 chronic, 23, 36, 37, 68, 71, 74, 88, 90, 108, 112, 123, capital, 7, 12, 14, 16, 147, 148, 167, 172 140, 199, 205, 213, 215, 221 carbon, 196, 197, 198, 199, 213, 217, 220 Cincinnati, 216, 219 carcinogenic, 203 circulation, 227 caregiver, 110, 119, 120, 137 citizens, 11, 13, 96 caregivers, 83, 137, 159 civil society, 148, 174 Caribbean, 13, 35 civil war, 96 carrier, 133 civilian, 14 case study, 201, 217 classes, 63, 93, 157 cash crops, 203 classical, 125, 126, 127, 130, 133, 190 cast, 146 Reviewclassification, 11, 21, 41, 45, 126, 127, 190 casting, 161 classified, 7, 55, 92, 144, 207 categorization, 22 classroom, 88, 92, 93, 101, 168, 186 Catholic, 173 classroom teacher, 92, 101 causation, 135 classroom teachers, 92 Cayman Islands, 44

236 Index classrooms, 89, 91, 92, 135, 168 community-based, 68, 70, 83, 146, 150, 171, 175, cleaning, 112, 196, 199, 229 181, 182, 186, 227 clients, 71, 96, 144, 159, 161, 184, 185, 193 compensation, 84, 88, 134 clinical, vii, 1, 2, 15, 26, 52, 53, 61, 63, 65, 66, 67, competence, 19, 99 69, 71, 72, 82, 90, 109, 127, 128, 132, 138, 168, complement, 150, 170 176, 177, 183, 223, 227 complementary, 170 clinical approach, 183 complexity, 66, 71 clinician, 108, 111, 114, 120, 128, 129, 130 compliance, 78, 125, 126, 127, 208 clinicians, 214 complications, 29, 77 clinics, 15, 18, 54, 62, 83, 84, 103, 104, 113, 156, components, 123, 145, 148, 150, 163 167, 179, 183, 225 composition, 11 closure, 15 compounds, 53, 150, 196, 199, 202, 204, 214, 216 cluster sampling, 24 compression, 148, 153 clusters, 24, 58, 62 computer, 26 CNS, 216 concentration, 89, 197, 199, 212, 216, 220 coatings, 196 conceptual model, 51, 53, 71, 72 cochlea, 81, 95, 130, 133, 197, 200, 205 conditioning, 115, 119, 120, 125 cochlear implant, 36, 168, 182, 183, 184, 186 conduction, 114, 117, 120, 125, 131, 132, 135, 136, cocoa, 194, 203 165, 205, 217, 230 codes, 22 conductive, 22, 30, 81, 83, 88, 95, 96, 114, 123, 124, coding, 24, 25 128, 131, 132 coffee, 202, 203, 219 conductive hearing loss, 81, 83, 88, 95, 96, 123, 124, cognitive, 23, 79, 80, 92, 98, 120, 129, 204, 220 128, 131, 132 cognitive deficit, 120, 220 confidence, 111, 129, 172 cognitive deficits, 220 configuration, 123, 134 cognitive development, 79, 80 conflict, 12, 110, 184 cohort, 15, 137, 138 confusion, 111 coil, 165 consciousness, 94 collaboration, 18, 148, 156, 158, 170, 171, 174, 177 consensus, 90, 218 colleges, 156 conservation, 18, 87, 97, 138, 182, 190, 191, 207, Colombia, 40, 43, 56, 60, 64, 212 208, 211, 212, 215, 219, 220, 228 colonial, 12 constraints, 84, 85, 176, 177, 181, 182, 183 Columbia, 6, 86 construction, 15, 21, 192, 194 combat, 17, 202 consumers, 152, 158, 202 combined effect, 195 consumption, 144, 194, 202 commercial, 128, 144, 148, 221, 228 contaminants, 200 commercialization, 142 continuity, 186 commodities, 7, 146 contracts, 127 communication, 12, 19, 23, 48, 60, 63, 68, 71, 88, control, 17, 24, 25, 35, 111, 119, 122, 132, 139, 144, 90, 91, 92, 93, 101, 103, 108, 137, 139, 141, 142, 145, 148, 165, 201, 202, 206, 208, 210, 211, 213, 163, 165, 166, 169, 172, 178, 193, 227 214, 217, 219 communication skills, 169 control group, 219 communication strategies, 163 controlled, 39, 200 communication technologies, 71 controlled studies, 200 communities, vii, 16, 23, 68, 82, 83, 84, 85, 143, conversion, 8 163, 170, 173, 177 Cook Islands, 41 community, 1, 5, 6, 10, 13, 26, 37, 47, 49, 52, 68, 70, coordination, 18 71, 77, 78, 79, 83, 84, 90, 91, 92, 93, 95, 98, 108, Copenhagen, 31, 217 112, 122, 137,Review 142, 146, 150, 163, 168, 169, 170, copper, 195 171, 172, 173, 174, 175, 177, 181, 182, 186, 214, corn, 192, 193, 194, 215 227, 230 correction factors, 113, 207 community relations, 26 correlation, 93, 130 corruption, 10

Index 237 cortex, 197, 205 171, 173, 174, 175, 176, 177, 178, 192, 215, 216, cortical, 79, 136, 216 221, 225 cost effectiveness, 18, 34, 36, 160 death, 13, 18, 36, 111, 152 Costa Rica, 40, 43, 56, 59, 60, 86, 101, 203 deaths, 6, 29 cost-effective, 17, 24, 34, 35, 36, 39, 51, 52, 53, 66, debt, 17 71, 72, 167, 224 decay, 134, 139, 190 costs, 5, 6, 15, 19, 21, 23, 24, 34, 36, 39, 51, 66, 71, deceit, 185 85, 93, 95, 102, 103, 104, 143, 144, 147, 148, decentralized, 70 150, 151, 158, 160, 161, 162, 164, 186, 223 decibel, 22 cotton, 95, 101, 195, 202, 203, 205, 219 decision makers, 34, 35 counsel, 174 decision making, 93 counseling, 87, 137, 146, 181, 182, 183, 185 decisions, 79, 110, 114, 124, 131, 183, 185, 186, 214 coupling, 129, 161 defects, 125, 165 coverage, 17, 37, 82, 96, 177, 186 defense, 138 covering, 156 deficiency, 13, 200 cranial nerve, 81, 127, 128 deficit, 199, 216 credibility, 185 deficits, 21 credit, 202 definition, 9, 22, 29, 60, 76, 86, 90, 192 critical period, 161 degree, 52, 61, 62, 63, 67, 80, 81, 87, 110, 114, 124, criticism, 148 128, 130, 132, 134, 135, 136, 137, 148, 156, 177, Croatia, 40, 43, 57, 58, 61, 64 184, 191, 210 crops, 202, 203, 204 delays, 80, 183 cross-sectional, 49, 197, 217 delivery, ix, 5, 16, 18, 68, 72, 76, 78, 85, 97, 142, cross-sectional study, 197, 217 146, 152, 153, 157, 161, 163, 164, 179 Cuba, 8, 40, 43, 86 demand, 51, 52, 53, 70, 96, 141, 146, 147, 152, 162 cues, 120, 122 democracy, 211 cultivation, 203 demographic, viii, 6, 7, 12, 112 cultural, 68, 78, 110, 137, 143, 171, 181, 182, 184 demographic change, 6 cultural norms, 184 demographic data, viii cultural values, 137 demographics, viii, 24 culture, 107, 108, 122, 170, 185 Denmark, 3, 31, 40, 44, 57, 61, 144, 229, 230 curing, 151, 161 dependant, 136 currency, 7, 54 depression, 37 curriculum, vii, 52, 67, 224 depressive disorder, 38 customers, 148 deprivation, 104 cyclohexane, 200, 201 derivatives, 219 Cyprus, 40, 44 designers, 68 cytochrome, 218 desire, 134, 213 cytomegalovirus, 83 detection, 3, 17, 18, 27, 75, 76, 77, 80, 81, 82, 84, Czech Republic, 8, 40 85, 86, 87, 95, 99, 100, 103, 105, 138, 139, 225 developed countries, 6, 7, 11, 15, 36, 51, 52, 53, 66, 68, 71, 72, 80, 81, 82, 83, 84, 85, 89, 92, 108, D 112, 115, 125, 130, 134, 140, 143, 146, 150, 152, 173, 185, 192, 199, 201, 207, 208, 213, 216 Dallas, 107, 231 developed nations, 6, 7, 9, 14, 143, 146, 224 danger, 122, 208 development assistance, 17 data base, 220 developmental delay, 120 data gathering, 38 deviation, 114 DDT, 203 Reviewdiabetes, 47 de novo, 71 diagnostic, 1, 5, 14, 15, 16, 66, 76, 78, 81, 89, 92, 96, deafness, 15, 17, 18, 19, 20, 22, 27, 29, 31, 34, 35, 107, 108, 109, 111, 112, 114, 115, 122, 124, 125, 36, 38, 46, 47, 48, 49, 51, 52, 53, 55, 61, 74, 99, 130, 131, 133, 134, 136, 161, 183, 224 100, 102, 104, 105, 108, 116, 140, 152, 163, 169, direct measure, 127

238 Index disability, 21, 23, 29, 36, 37, 38, 47, 87, 88, 92, 94, ectoparasites, 202 99, 105, 108, 142, 147, 148, 192 Ecuador, 40, 43, 203 disabled, 164, 171, 179 education, 1, 2, 6, 8, 11, 13, 16, 17, 18, 19, 20, 51, discipline, 186 52, 53, 54, 55, 61, 62, 63, 64, 66, 68, 69, 70, 71, discounts, 147 72, 73, 76, 78, 86, 87, 93, 100, 141, 157, 163, discrimination, 122, 123, 124 167, 168, 169, 170, 171, 172, 176, 178, 181, 182, diseases, 13, 17, 19, 24, 76, 78, 83, 95, 98, 100, 102, 183, 184, 186, 204, 207, 211, 223, 225, 226, 228, 103, 111, 127, 151, 171, 211 231 disorder, 77, 78, 79, 81, 87, 89, 90, 93, 95, 96, 109, Education for All, 171 123, 217 educational background, 61, 182 distance education, 228 educational institutions, 68, 70, 72 distraction, 119, 138 educational programs, 13, 183 distress, 137 educational psychology, 185 distribution, 3, 10, 28, 36, 54, 144, 147, 148, 155, educational services, 170, 171, 175, 176, 183, 184, 158, 160, 192, 216, 229, 230 186 disulfide, 217, 220 educational settings, 62, 169, 177 diversity, 11, 12, 51, 52, 53, 115, 181 educational system, 183 division, 14, 201 educators, 157, 159, 162, 186 dizziness, 111, 175 efficacy, 81, 98, 129, 138 doctor, 96, 146 effusion, 77, 86, 90, 96, 101, 103, 104, 139 doctors, 17, 182, 184 Egypt, 40, 43, 56, 61, 64, 195 Dominican Republic, 9, 14, 18, 40, 43, 64, 143 Egyptian, 102 donations, 173, 183, 186 El Salvador, 40, 43 donor, 83 elderly, 17, 27, 48, 96, 98, 102, 164 doors, 113, 211 elderly population, 98 download, 73 electrical, 81, 113, 128, 129 dream, vii, 101 electrical power, 128 drowsiness, 111 electricity, 107, 131 drug resistance, 111 electrodes, 81 drug therapy, vii electronic, 123 drugs, 22, 201 electrophysiologic, 81 dry, 199 electroplating, 196 duplication, 170 elementary school, 86, 102 duration, 36, 63, 79, 132, 138, 157, 190, 197, 204 email, 167 dust, 173 emerging economies, 2 duties, 25, 82, 144, 148 emission, 92, 101, 124, 138 emotional, 80, 115, 134, 137, 186 employees, 200, 201, 206, 207, 208, 210, 211, 220 E employers, 146, 190, 206, 207, 208, 211 employment, 23, 53, 62, 69, 72, 100, 146, 164, 172, ears, 32, 39, 110, 112, 115, 117, 121, 127, 133, 135, 191, 192, 206, 217 137, 156, 169, 172, 175, 191, 193, 206, 207 empowered, 208 East Asia, 37, 38, 42, 44, 50 encouragement, 228 Eastern Europe, 7, 42, 44, 60, 73 energy, 117 economic, vii, 1, 6, 7, 8, 10, 11, 14, 15, 21, 23, 24, engagement, 183 34, 36, 39, 67, 68, 77, 79, 80, 103, 108, 148, 151, engineering, 52, 195, 208, 220 181, 192, 213 English, 12, 54, 55, 59, 60, 86, 122, 224 economic development, 23 enrollment, 157 economic disadvantage, 77 Reviewenterprise, 148, 174 economic status, 108 environment, 62, 69, 90, 91, 95, 101, 107, 113, 114, economically disadvantaged, 68 122, 128, 169, 177, 200, 202, 212, 214 economics, 67, 108 environmental, 10, 92, 138, 212, 213, 215, 220 economies, 1, 6, 7, 11, 12, 14, 55, 69, 213 environmental control, 138 economy, 3, 5, 7, 11, 14, 69, 70, 143, 192, 214

Index 239 environmental factors, 215 extreme poverty, 16, 173 environmental impact, 213 eye, 151, 182 Environmental Protection Agency, 218 eyes, 119 environmental sustainability, 213 epidemic, 20 epidemiological, 28, 32, 35, 36, 37, 46, 47, 107, 171, F 202, 203, 217 facial nerve, 111, 125, 127 epidemiology, 38, 50, 103, 138, 169, 217 failure, 85, 89, 90, 138 equality, 9 false, 22, 82, 91 equating, 135 false positive, 91 Equatorial Guinea, 8, 10, 11, 40, 43 family, 10, 24, 79, 80, 94, 110, 135, 137, 146, 153, equipment, 1, 5, 8, 15, 24, 25, 26, 69, 71, 72, 79, 91, 160, 170, 172, 174, 175, 181, 182, 183, 185, 186, 95, 107, 108, 113, 119, 123, 125, 131, 137, 146, 198, 203, 220 152, 159, 163, 168, 169, 171, 173, 183, 186, 191, family history, 24 192, 193, 210, 211, 225, 226, 230 family life, 10 equity, 153 family members, 137 Eritrea, 10, 40, 42 family physician, 146 estimating, 37, 39 family support, 175 Estonia, 40, 43, 74 FAO, 214, 216 ethanol, 219 farm, 192, 203, 204, 213, 216, 219 ethical, 26, 75, 82, 84, 96, 97, 185 farmers, 202, 203, 204, 213, 215, 217 ethical issues, 26 farms, 202, 203, 219 ethical standards, 75, 96 fatality rates, 36 ethics, 77 fatigue, 134 Ethiopia, 9, 10, 14, 40, 42, 195 fear, 147, 209 Ethiopian, 218 Federal Register, 207, 219 ethnic diversity, 12 Federal Republic of Yugoslavia, 45 ethylbenzene, 200, 201 feedback, 26, 70, 146, 150 etiology, 15 feeding, 69, 82 Europe, 15, 42, 44, 64, 73, 146, 207 fees, 16, 71, 173 European, vii, 8, 12, 37, 52, 58, 59, 60, 61, 67, 73, feet, 120 86, 142, 228 females, 13, 192 European Union, 8, 12 fertility, 12 eustachian tube, 127 fertility rate, 12 evidence, 29, 36, 72, 119, 130, 141, 181, 191, 193, fertilizers, 189 195, 197, 201, 202, 203, 204, 213 fetus, 79 evoked potential, 217, 220 fever, 111 examinations, 76, 86, 151 field trials, 158 exchange transfusion, 83 fighters, 194 execution, 137 Fiji, 41, 43 exercise, 45 filament, 199 expert, 24, 88 financial resources, 10, 75, 89 expertise, viii, 7, 24, 51, 81, 82, 95, 137, 168, 172, financial support, 83, 152 173, 176, 177, 178 Finland, 31, 40, 44, 101 experts, 142, 214 fire, 191, 193, 194 explosions, 190 firearms, 204 explosive, 190 first language, 93 exports, 11, 203 fixation, 125 exposure, 17, Review110, 113, 116, 189, 190, 191, 192, 193, flexibility, 150 194, 195, 197, 198, 199, 200, 201, 202, 204, 205, flora, 111 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, focusing, 230 217, 218, 219, 220, 221 folklore, 137 external environment, 145 food, 11, 195, 203, 213

240 Index footwear, 196 government, 15, 16, 18, 25, 34, 36, 51, 52, 58, 61, foreign exchange, 8 62, 64, 70, 72, 85, 97, 156, 158, 159, 160, 161, formal sector, 210 163, 172, 176, 214 France, 40, 44, 45, 57, 59, 61, 64 grades, 86, 115 freedom, 2, 10 grain, 192, 193, 204, 221 full capacity, 209 grants, 2, 225 funding, 2, 5, 11, 16, 18, 61, 64, 68, 72, 223, 225, graph, 123, 124, 133 226 Great Britain, 47 funds, vii, 143, 161 Greece, 40, 44 fungicide, 205, 216 Greenland, 44 fungicides, 203 Grenada, 40, 43 fungus, 196 gross domestic product, 7, 24 furnaces, 196 gross national product, 23, 143 furniture, 197, 201 grouping, 8 fusion, 182 groups, 8, 42, 44, 61, 63, 64, 67, 68, 75, 86, 95, 109, 152, 168, 177, 199, 201, 204, 210, 212, 226 growth, vii, 1, 6, 70, 132, 133, 135, 181, 209, 213 G growth rate, 213 Guam, 44 Gabon, 40, 43 Guatemala, viii, 40, 43, 55, 56, 62, 64, 93, 181, 182, gas, 194 183, 184, 185, 186, 203, 231, 232 gauge, 92 guidance, 101, 153, 177, 228 Gaza, 43 guidelines, 17, 18, 85, 88, 90, 100, 107, 111, 138, GDP, 7 145, 146, 150, 164, 185, 208, 224 GDP per capita, 8 Guinea, 10, 40, 42 gender, 10, 28, 204 Guyana, 40, 43, 173 gender equality, 10 general practitioner, 98 general practitioners, 98 H generation, 144 generators, 128, 196 hair cells, 81, 130, 191, 197, 198, 202 genetic, 18, 76, 84, 105, 108 Haiti, 10, 40, 42 genetic counselling, 18 handling, 219 genetic factors, 76, 84, 108 hands, 112, 122 Geneva, 3, 19, 20, 46, 47, 48, 49, 50, 74, 98, 100, harmful, 17 105, 140, 152, 153, 166, 216, 221, 231 hazards, 75, 189, 190, 203, 210, 213, 214 geography, 10 head, 110, 115, 117 geology, 207 head injury, 110 Georgia, 40, 42 headache, 192 geriatric, 164 health care, vii, ix, 2, 5, 6, 8, 10, 11, 13, 14, 15, 16, Germany, 40, 44, 57, 61, 64, 140, 144, 225, 229 17, 18, 51, 52, 53, 54, 55, 58, 59, 60, 61, 62, 64, gestation, 79 66, 67, 68, 69, 70, 72, 75, 77, 79, 86, 89, 96, 98, girls, 13, 157 108, 109, 111, 112, 137, 138, 142, 151, 155, 157, global trends, 35 167, 170, 175, 176, 181, 183, 223, 224, 225, 226, globalization, 51, 53, 72, 102 227, 228, 229, 230 gloves, 112 health care professionals, 15, 51, 59, 60, 112 GNP, 144 health care system, 13, 58, 66, 67, 68, 70, 79, 142 goals, 8, 17, 18, 87, 184, 185, 186 health care workers, 2, 51, 52, 108, 112, 138, 157, goal-setting, 181,Review 182, 185 228 God, 148 health clinics, 32, 173 gold, 26, 207, 208, 215, 217 health education, 18 gold standard, 26 health effects, 204, 219, 221 goods and services, 8 health expenditure, 85 health information, 111, 229

Index 241 health insurance, 58 health problems, 53, 76, 108, 189, 217 I health services, viii, 34, 86, 173 ice, 122 health status, 13, 36 identification, 49, 75, 77, 78, 81, 86, 87, 88, 90, 92, healthcare, 76, 82, 85, 97 93, 95, 97, 98, 99, 100, 101, 102, 103, 104, 105, heart, 48, 191 108, 109, 128, 130, 141, 142, 156, 176 heart disease, 191 identity, 181 heat, 173 illiteracy, 213 height, 127 ILO, 93, 100 herbicides, 189, 203 imaging, 130 herbs, 175 immunization, 17, 76, 83, 84, 96, 103, 104, 179 heredity, 201 impairments, 30, 49, 81, 156, 206 herpes, 83 implementation, 24, 35, 67, 108, 160, 176 hexane, 189, 197, 200, 219 impulsive, 190 high blood cholesterol, 191 in situ, 75 high blood pressure, 191 in transition, 12 high risk, 76, 88, 156 incidence, vii, 12, 27, 28, 32, 36, 80, 112, 127, 134, high school, 204 156, 199, 213 higher quality, 145 inclusion, 38, 107, 123, 129, 168 high-frequency, 190, 218, 220 income, 5, 7, 8, 9, 11, 13, 15, 16, 21, 42, 43, 44, 55, highlands, 30 56, 61, 63, 85, 141, 142, 143, 146, 147, 148, 160, high-level, 191 169 Hispanic, 30, 31, 47, 48 income distribution, 9 HIV, 13, 17, 19, 37, 96, 98, 101 income inequality, 5 HIV infection, 13, 19 incomes, 148, 155 HIV/AIDS, 13, 17, 37, 96 independence, 54 holistic, 78, 100, 195 India, viii, 6, 8, 9, 12, 14, 15, 18, 19, 26, 31, 41, 42, holistic approach, 195 53, 56, 61, 63, 64, 83, 91, 100, 103, 112, 144, Holland, 219 146, 147, 151, 155, 156, 157, 158, 160, 161, 162, homes, 83, 174, 213 163, 164, 165, 166, 171, 173, 174, 194, 195, 208, homogeneity, 46, 73 231 homogenous, 5, 68 Indian, 12, 47, 49, 97, 100, 146, 155, 156, 158, 160, Honduras, 40, 43 161, 165, 166, 204, 215, 216, 220 Hong Kong, 1, 2, 5, 44, 45, 57, 61, 75, 195, 216, Indians, 155, 158 223, 231 indication, 8, 88, 110, 121, 122, 124, 211 hospital, ix, 15, 16, 37, 75, 78, 82, 83, 84, 96, 102, indicators, 11, 36, 128, 205 138, 146, 159, 170, 174, 175, 177, 182 indices, 7, 10, 29 hospitals, 78, 80, 82, 83, 130, 169, 172, 176 indigenous, 12, 68, 93, 95, 155, 158 households, 26, 193, 201 Indonesia, 9, 14, 26, 32, 41, 42, 55, 56, 60, 64, 74 housing, 11 induction, 162, 165, 229 human, 9, 11, 13, 55, 67, 79, 89, 163, 176, 189, 190, industrial, 7, 75, 88, 114, 189, 190, 191, 193, 194, 197, 200, 202, 203, 216, 218, 228 195, 196, 201, 203, 205, 206, 212, 213, 216, 217 human development, 9 industrial revolution, 190 Human Development Index (HDI), 8, 9, 13 industrialization, 7, 11, 189 Human Development Report, 10, 224 industrialized countries, 6, 13, 53, 86, 142, 189, 192, human immunodeficiency virus, 13 213 human resources, 55, 163 industrialized societies, 5, 11, 77 humanitarian, 1, 143 industry, 6, 72, 189, 193, 194, 195, 197, 199, 200, humans, 138, Review197, 198, 199, 200, 201, 203 202, 207, 212, 214, 215, 219, 220, 221, 229 humidity, 145, 151, 163 ineffectiveness, 89 Hungary, 40, 43, 73 inequality, 9, 11 hygiene, 112, 138, 169 infancy, 80 hypothesis, 132 infant mortality, 8, 13, 16, 17

242 Index infant mortality rate, 13, 16 intervention, 34, 75, 80, 81, 83, 84, 85, 86, 89, 97, infants, 3, 17, 26, 79, 81, 82, 84, 96, 100, 103, 104, 100, 102, 103, 105, 108, 142, 151, 156, 178, 183, 114, 117, 138, 156, 224, 228 184, 224, 226 infection, 49, 104, 111 intervention strategies, 151 infections, 15, 37, 39, 83, 96, 108, 110, 112 interview, 37, 135 infectious, 27, 37, 39, 111, 139 interviews, 204 infectious disease, 37, 111, 139 intoxication, 198, 213, 216 infectious diseases, 37, 111 intracranial, 111 informal sector, 190, 192, 193, 210, 216, 220 intraperitoneal, 220 Information System, 74 investment, 173 informed consent, 26 ions, 152 infrared, 229, 230 ipsilateral, 128 infrastructure, 14, 15, 34, 70, 71, 72, 74, 89, 108, 109 Iran, vii, 40, 43 inhalation, 200, 220 Iraq, 40, 43 inherited, 110 Ireland, 9, 14, 40, 44, 57, 61, 64 inhibition, 204 iron, 190, 196 initiation, 72 ischaemic heart disease, 37 injuries, 213 Islam, 105 injury, 163, 191, 195, 202, 206 Islamic, 40, 43 inner ear, 95, 190, 191, 201 island, 95 insecticide, 216 ISO, 22, 116 insecticides, 189, 204, 205, 221 isolation, 23, 71, 177, 225 insects, 196 Israel, 40, 44, 57 insertion, 38, 159 Italy, 6, 9, 31, 40, 44, 49, 57, 61, 64 insight, 128, 130, 175 ITC, 158 inspection, 86, 88, 112 instability, 11, 12, 181 institutions, 5, 51, 52, 55, 71, 97, 157, 159, 161, 162, J 183, 185, 186, 211, 227 JAMA, 46, 48 instruction, 184 Jamaica, 40, 43, 86, 91, 99, 101 instructors, 146 Japan, 6, 9, 12, 14, 41, 44, 57, 61, 63, 144, 199, 208 instruments, 36, 39, 61, 81, 82, 90, 91, 128, 130, job performance, 206 144, 145, 148, 208, 229 jobs, 192, 194, 206, 210 integrity, 81, 127, 130 Jordan, 40, 43, 56, 171, 172, 227 intensity, 81, 88, 89, 90, 91, 95, 113, 114, 117, 120, judge, 207 121, 122, 123, 129, 130, 132, 133, 134, 136, 139, junior high school, 183 190, 191, 201 intentions, 185 interaction, 66, 157, 195, 199, 200, 215 K interactions, 51, 53, 72, 200, 215 interdisciplinary, 186 Kazakhstan, 40, 43 interference, 113, 192 Kenya, viii, 17, 30, 40, 42, 47, 86, 101, 194, 203, internal combustion, 190 208 international, viii, 1, 2, 7, 13, 17, 18, 51, 52, 53, 57, kerosene, 201 61, 62, 71, 72, 73, 124, 142, 148, 151, 152, 155, kidney, 197 158, 162, 168, 170, 178, 183, 224, 225, 227, 228 kindergarten, 101 International Classification of Diseases, 22 kindergarten children, 101 internet, 223, 228 Kiribati, 10, 11, 41, 43 interpersonal Reviewcommunication, 23 Korea, 32, 41, 42, 43, 195 interpersonal relations, 206 Korean, 47 interpersonal relationships, 206 Kuwait, 40, 44 interpretation, 81, 125, 127, 129, 137 Kyrgyzstan, 40

Index 243

liquids, 196 L listening, 8, 79, 113, 119, 135, 162, 163, 164, 168, 182, 228, 229, 230 labour, 148, 150, 206, 211 literacy, 8, 13, 16, 80 lactation, 83 literacy rates, 13 land, 202 literature, 87, 123, 130, 164, 202, 216, 225, 226, 227 language, 12, 17, 18, 19, 23, 58, 60, 63, 66, 67, 68, Lithuania, 40, 43, 57, 58, 64 71, 75, 78, 79, 80, 92, 93, 99, 102, 103, 107, 108, liver, 197 122, 127, 137, 148, 159, 162, 172, 174, 175, 177, livestock, 202, 203 182, 184, 193, 228 living environment, 213 language acquisition, 17, 78, 103 living standards, 68 language barrier, 71 local community, 173 language development, 75, 79, 80, 102 local government, 15 language skills, 79 localization, 115, 119 Laos, 55, 56, 60, 64 London, ix, 3, 19, 21, 47, 86, 100, 105, 140, 152, Lassa fever, 78 153, 173, 178, 179, 203, 213, 217, 218, 219, 231 late-onset, 79 long period, 15, 191 later life, 79 longitudinal study, 201 Latin America, 6, 7, 19, 35, 55, 60, 73, 101, 184, long-term, 6, 7, 12, 16, 52, 67, 77, 78, 79, 96, 143, 205, 218, 225 146, 163, 198, 200, 204, 206, 215, 219 Latin American countries, 55 loss of consciousness, 111 Latvia, 9, 14, 40, 43 losses, 96, 191, 204 laws, 86, 207, 208 low cost, 91, 150 lead, 12, 17, 66, 70, 77, 95, 212 low risk, 201 leadership, 142 lower-income, 147 learners, 169 low-income, 8 learning, 18, 66, 137, 161, 173, 186 low-level, 204 learning difficulties, 173 lung disease, 37 Least Developed Countries (LDCs), 10, 11, 12, 153, lungs, 198 224 Luxembourg, 40, 44 Lebanon, 40, 43 lymphatic, 13 legislation, 17, 208, 213, 214 lymphocytes, 218 leisure, 110 leprosy, 13 lesions, 125, 134, 139, 197 M liberalization, 158 Liberia, 10, 40, 42 Macao, 44, 45 Libya, 43, 56, 64 Macedonia, 40, 43, 45 licensing, 159 machinery, 196, 210 life expectancy, 8, 10, 13, 14, 16, 36 machines, 193, 194, 195, 196, 210, 211 lifespan, 148 magnetic, 229 lifestyle, 204 mainstream, 80, 169, 170 life-threatening, 82 maintenance, 160, 161, 163, 164, 165, 170, 186, 198, lifetime, 6, 12, 192 211 likelihood, 22, 113 major cities, 161 limitation, 84, 107 malaria, 13, 17, 37, 108 limitations, 75, 148, 200 Malathion, 205 lindane, 203 Malaysia, 41, 43, 56, 61, 64, 99, 102, 139, 204, 217 linear, 29 Reviewmales, 13, 31, 192 lingual, 29 malnutrition, 53, 111 linguistic, 11 Malta, 40, 43 linguistically, 5 management, 17, 35, 52, 66, 107, 108, 110, 111, 114, links, 53, 148, 177, 224, 228 168, 169, 176, 183, 206, 207, 208, 214, 218, 225 lipids, 197 manganese, 205, 216

244 Index manpower, 157, 163, 166 middle class, 70, 72 manufacturer, 144, 147, 151, 229, 230 Middle East, 7, 42, 44, 64, 203 manufacturing, 11, 144, 148, 158, 194, 195, 201, middle income, 21, 27, 55, 64, 141 207, 210, 225 midwives, 17 mapping, 26 migration, 69, 72 Mariana Islands, 44 military, 14, 62, 194, 206, 207 market, 141, 144, 155, 158, 162 military occupation, 207 market share, 144 milk, 82 marketing, 144, 147, 152, 158 Millennium Development Goals, 16, 20 markets, 70, 72, 143, 202, 213, 229 mining, 194, 195, 207, 208, 215, 219 Marshall Islands, 41, 43 Ministry of Education, 172 Martinique, 45 minority, 12, 68 masking, 98, 117, 122 minority groups, 12, 68 Massachusetts, 98, 104 misconceptions, 184 mastoid, 131, 132 misleading, 7 mastoiditis, 77, 111 missions, 226 maternal, 17 mixing, 150 mathematical, 130 mobility, 125, 126 maturation, 66, 79 models, 5, 18, 52, 53, 68, 70, 72, 142, 148, 158, 159, Mauritania, 10, 40, 42 160, 177 Mauritius, 40, 43, 99 mold, 146, 161, 162, 164, 225, 229 MCI, 156 Moldova, 40, 42 measles, 17, 39, 76, 108, 110, 171 momentum, 6 measurement, 24, 36, 37, 87, 113, 128, 138, 139, money, 66, 69 165, 169, 217 Mongolia, 41, 42 measures, 7, 8, 18, 25, 87, 95, 101, 107, 108, 111, monomer, 150 123, 124, 125, 126, 127, 129, 130, 168, 181, 186, Montenegro, 45 189, 210, 212, 213 mood, 192 mechanical, 163, 202 mood change, 192 mechanics, 164 Morocco, 40, 43 media, 22, 74, 77, 90, 112, 127, 211, 230 morphological, 216 median, 81 mortality, 13, 14, 29, 36, 38, 41, 46, 48, 192 medical care, 52, 77, 79, 170 mortality rate, 13, 41 medical services, 86 mother tongue, 184 medication, 96 mothers, 76, 82, 83, 137, 157 medications, 83 moulding, 195 medicine, 52 mountains, 155 Mediterranean, 202 mouth, 129, 135 Medline, 35 movement, 72 melons, 202 Mozambique, 10, 18, 40, 42, 120, 171 membership, vii MRI, 130 membranes, 198 mRNA, 218 memory, ix, 191 multidisciplinary, 24, 184 men, 14, 29, 217 multilateral, 97 meningitis, 15, 17, 37, 83, 108, 110, 171, 174 mumps, 17, 20, 39, 76, 110, 171 mentor, ix, 182 muscle, 127 metabolism, 198 muscle contraction, 127 metals, 190, 195 music, 17 Mexican, 30 ReviewMyanmar, 10, 26, 32, 41, 42, 55, 56, 64, 176 Mexico, vii, 9, 14, 40, 43, 56, 58, 60, 64, 197, 203 Mexico City, 197 Micronesia, 41, 43 N microprocessors, 123 Namibia, 40, 43, 55, 56, 64, 171, 172, 178, 179

Index 245 nation, 2, 8, 10, 11, 12, 14, 150 noise, 17, 22, 27, 29, 82, 88, 90, 94, 95, 96, 98, 100, national, 7, 11, 12, 17, 24, 26, 31, 54, 55, 60, 71, 84, 103, 105, 110, 113, 115, 117, 120, 122, 130, 139, 108, 143, 144, 148, 151, 156, 163, 170, 172, 176, 145, 189, 190, 191, 192, 193, 194, 195, 197, 199, 179, 214, 221, 224, 228 201, 202, 204, 205, 206, 207, 208, 209, 210, 211, National Health Interview Survey, 46 212, 214, 215, 216, 217, 218, 219, 220, 221, 229 National Health Service, 224 non-governmental organization(s) (NGOs), 17, 55, national income, 7, 11, 12 64, 69, 147, 148, 151, 156, 172, 174, 176 National Institute for Occupational Safety and non-infectious, 27 Health, 198, 207, 216, 219 non-invasive, 81, 82 national product, 143, 144 non-profit, 148, 227, 228 Native American, 68, 112 non-random, 25 Native Americans, 68 normal, 26, 80, 82, 93, 94, 95, 114, 116, 121, 122, natural, 11, 77, 78 123, 124, 125, 126, 128, 132, 133, 134, 135, 136, natural disasters, 11 137, 145 Nauru, 41 normal conditions, 145 nausea, 111 normal curve, 123, 124 neck, 111 normal development, 93 negotiating, 147 norms, 127 neonatal, 80, 86, 94, 96, 97, 99, 100, 104, 108, 140, North Africa, 42, 44 156, 165, 182, 183 North America, 12, 86, 87, 104, 146 neonatal intensive care unit, 104 Norway, 40, 44, 57, 59, 61, 64 neonate, 79 not-for-profit, 152, 225, 227 neonates, 17, 156 nucleation, 70 Nepal, 10, 20, 32, 41, 42, 48, 210 nurse, 96 nerve, 133, 139, 197, 204 nurses, 15, 17, 52, 82, 95, 173, 175 nerve conduction velocity, 204 nursing, 19, 87, 157 nervous system, 79, 96 nutrition, 11, 157 Netherlands, 40, 44, 57, 59, 61, 178, 215 nuts, 203 network, 2, 143, 158, 159, 160, 164, 184 nylon, 199 networking, 147, 186 neurological disease, 205 neurons, 132 O neuropathy, 81, 82, 125, 130, 136 objective tests, 123, 168 neuroscience, 100 obligation, 82 neurotoxic, 203 observations, 25, 190, 200, 203 New England, 100 obstruction, 112 New Jersey, 97 occlusion, 95, 101, 112, 127, 131, 139 New Mexico, 158 occupational, 29, 62, 189, 192, 193, 195, 197, 200, New York, 20, 73, 100, 103, 104, 105, 138, 153, 201, 202, 204, 205, 206, 207, 208, 212, 213, 214, 178, 204, 216, 220, 228 215, 218, 219, 220 New Zealand, 41, 44, 52, 57, 59, 99 occupational health, 62, 189, 192, 205, 208, 213, Newton, viii, 2, 17, 19, 49, 93, 94, 100, 102, 104, 214, 220 139, 231 OECD, 44 Ni, 148 oil, 8, 200 Nicaragua, 40, 42, 56, 64, 86 oil refineries, 200 Nielsen, 145, 148, 153 old age, 95 Niger, 10, 40, 42 older adults, 47, 48 Nigeria, viii, 10, 26, 32, 40, 42, 48, 55, 56, 64, 73, olfactory, 119 75, 84, 96, Review102, 137, 171, 173, 193, 194, 195, olive, 117 203, 221, 231 Oman, 26, 31, 40, 43, 47 NIH, 191, 218 online, 162, 230 Niue, 41 on-the-job training, 63, 172 operator, 91, 193, 197

246 Index oral, 108 pass/fail, 78, 90, 114 organ, 190, 191, 197, 204, 216 pathogenesis, 78 organic, 122, 134, 135, 136, 189, 195, 196, 198, 200, pathogens, 111 201, 204, 212, 218, 220, 221 pathologists, 52, 61, 85, 157, 159 organic compounds, 196, 204 pathology, 18, 19, 48, 52, 55, 60, 67, 87, 112, 128, organic solvent, 189, 195, 196, 198, 200, 201, 212, 131, 132, 133, 138, 162 218, 220, 221 pathophysiological, 132 organic solvents, 189, 195, 196, 198, 200, 201, 212, pathophysiology, 95 218, 220, 221 pathways, 125, 128, 199 organism, 216 patients, 52, 77, 78, 79, 96, 102, 111, 112, 114, 122, organization, 16, 142, 148, 151, 159, 176, 225, 226, 125, 131, 132, 133, 134, 182, 185, 186, 204 227, 228, 230 pediatric, 20, 90, 91, 92, 116, 182 organizations, 1, 18, 52, 54, 62, 72, 97, 142, 147, peers, 13, 80, 93 152, 156, 160, 161, 164, 177, 183, 223, 224, 228 people living with HIV/AIDS, 96 organochlorine compounds, 203 per capita, 7, 8, 9, 11, 54, 55, 58, 59, 64, 155 organophosphates, 204 per capita income, 8, 155 orientation, 185 percentile, 84 oscillator, 120, 132 perception, 122, 133, 134, 139 ossicles, 125, 191 perforation, 126, 127 otitis media, 17, 27, 29, 46, 68, 74, 86, 88, 90, 96, performance, 22, 25, 26, 98, 107, 114, 121, 122, 129, 101, 102, 103, 108, 112, 123, 125, 126, 127, 138, 133, 145, 165, 166, 192 140, 171 perinatal, 17, 22, 37, 39, 84 otoacoustic emissions, 81, 82, 98, 99, 100, 102, 123, periodic, 208, 212 124, 130, 136, 140 periodicity, 190 otolaryngologist, 55, 66, 159 peripheral nerve, 205, 217, 219 otosclerosis, 125, 138 peripheral nervous system, 204, 205, 213 ototoxic drugs, 17, 27, 76 peripheral neuropathy, 204 ototoxicity, 108, 216 perseverance, 187 Ottawa, 203 personal, 6, 141, 142, 147, 166, 168, 182, 183, 184, out-of-pocket, 85 230 outreach programs, 16 persons with disabilities, 156 overpopulation, 111 Perth, 51, 231 ownership, 143 Peru, 40, 43 pest control, 213 pesticide, 196, 202, 203, 204, 213, 217, 218, 221 P pesticides, 189, 190, 202, 203, 204, 205, 213, 216, 217, 218, 219, 221 Pacific, 7, 13, 37, 38, 42, 44, 46, 60, 64, 101 pests, 202, 213 paints, 196, 201 petrochemical, 212 Pakistan, 13, 41, 42, 55, 56, 64, 96, 99, 194, 195, petroleum, 194, 197, 201, 218 196, 208, 210, 216, 220, 221 pharmaceutical, 194 Pakistani, 13 pharmaceuticals, 196 Panama, 40, 43, 56, 58, 59, 60, 86 pharmacists, 159 pandemic, 13 Philadelphia, 100, 101 paper, 19, 48, 71, 138, 165, 178, 195, 196, 201, 203, philanthropic, 120, 142 217 philanthropy, 69 Papua New Guinea, 41, 43 Philippines, vii, 6, 18, 41, 43, 53, 56, 61, 64, 147, Paraguay, 40, 43 195 paralysis, 128 Reviewphilosophy, 90 parameter, 145 phosphate, 204 parents, 77, 81, 82, 83, 84, 87, 93, 136, 139, 172, physicians, 57, 60, 61 174, 175, 177, 182, 183, 184, 186, 228 physiological, 129, 190 Paris, 179 physiology, 52, 123, 124, 169 partnerships, 18, 97

Index 247 pigs, 198 preschool, 75, 93, 94, 95, 97, 99, 103, 104, 157, 183, pilot studies, 84 228 pilot study, 25, 46, 140, 218 preschool children, 93, 94, 95, 103, 228 pitch, 204 press freedom, 20 planning, 21, 34, 62, 108, 176, 210, 227 pressure, 51, 52, 70, 115, 126, 127, 131, 150, 184, plants, 194, 195, 196, 200, 202, 214 190, 198, 210 plastic, 150, 199, 201 prevention, vii, 6, 17, 18, 20, 26, 34, 35, 70, 74, 76, plasticity, 79 78, 86, 97, 108, 138, 140, 151, 163, 184, 190, plastics, 195, 196 206, 208, 210, 211, 217, 224, 225 platforms, 83 preventive, 14, 15, 75, 83, 86, 181, 211, 212, 213 play, 89, 113, 129, 159, 170, 174, 176, 211 preventive approach, 15 plug-in, 168 preventive programs, 14, 75 poisoning, 204, 216, 217, 221 prices, 144, 147 Poland, 9, 14, 40, 43, 57, 58, 61 primaries, 130 police, 194 primary products, 194 policy makers, 151 primary school, 13, 78, 86, 87, 88, 93, 95, 105, 171 policymakers, 2 printing, 193, 194, 196, 197, 201, 215, 218 polio, 84 priorities, 6, 20, 27, 53, 61, 72, 97, 98, 99, 136, 183 political, 6, 10, 12, 16, 35, 77, 79 private, 2, 5, 16, 54, 62, 68, 69, 70, 72, 83, 85, 97, political instability, 16 156, 161, 172, 173, 182, 185, 193, 212, 223, 228 political stability, 10 private sector, 68, 70, 85, 161 politics, 69 proactive, 181 pollution, 190, 193, 213, 215, 218, 221 probability, 76, 128, 197 polyester, 195, 220 probable cause, 129 polymer, 150 probe, 81, 95, 129 polymerization, 216 procedures, 1, 18, 26, 76, 78, 86, 88, 89, 97, 104, polymers, 150 125, 131, 133, 146, 148, 151, 159, 161, 201, 223 Polynesia, 44 producers, 144, 202 poor, 8, 13, 14, 34, 61, 62, 68, 78, 129, 136, 146, production, ix, 11, 14, 53, 70, 85, 145, 146, 148, 152, 158, 159, 162, 173, 211, 213 153, 157, 158, 193, 202, 213, 216, 229 poor health, 13 productivity, 6, 24, 206 population, 6, 7, 10, 11, 12, 15, 16, 18, 21, 24, 25, profession, vii, 51, 52, 53, 55, 61, 67, 71, 86, 169, 27, 29, 30, 31, 32, 34, 35, 37, 39, 41, 46, 47, 48, 183 49, 51, 53, 54, 55, 61, 64, 71, 76, 77, 78, 86, 95, professions, 52, 67, 68, 86, 87, 228 96, 99, 108, 111, 143, 155, 156, 157, 158, 163, profit, 53, 134, 144, 147, 161, 227 164, 171, 172, 176, 181, 182, 183, 184, 187, 197, profit margin, 53, 144, 147 202, 218 profitability, 71 population group, 18, 76 profits, 70 population growth, 6 program, viii, 53, 67, 68, 70, 73, 75, 77, 78, 79, 80, porous, 211 83, 85, 87, 88, 89, 90, 91, 92, 96, 97, 98, 100, Portugal, 40, 44, 57, 61 101, 104, 105, 108, 109, 111, 113, 120, 123, 128, potato, 203, 216 156, 157, 159, 162, 163, 182, 183, 206, 207, 208, poultry, 202 211, 212, 215, 219, 220, 228 poverty, 11, 12, 21, 151, 182, 183, 184, 225 progressive, 79, 84, 134, 198, 206 power, 8, 14, 147, 148, 153, 190, 195, 211 proliferation, 73 powers, 175 promote, 163, 173, 226, 227, 228 pragmatic, 177 propriety, 85 preference, 79 protection, 18, 67, 206, 208, 210, 211, 212, 214, 220, pregnancy, 110,Review 137 229, 230 pregnant women, 157 protective clothing, 214 preparation,, 48, 89, 161 protocol, 24, 25, 26, 34, 35, 46, 82, 90, 95, 115, 140 presbycusis, 32, 47 protocols, 77, 87, 88, 96, 104, 146, 168, 224 prototype, 148

248 Index proxy, 83 ratings, 92 psychogenic, 134 rats, 197, 198, 199, 200, 216, 217, 219, 220 psychological, 134, 190 reading, 116, 122, 135 psychologist, 182 real time, 157 psychologists, 184 reality, 93, 152, 181, 185, 207 psychology, 52 reception, 139, 162 psychosocial, 99 recognition, vii, 51, 70, 71, 88, 98 psycho-social, 80 recovery, 205 public, 18, 34, 35, 61, 68, 69, 70, 71, 72, 76, 77, 83, recreational, 207, 211 97, 102, 108, 141, 147, 151, 163, 164, 178, 183, recruiting, 133 202, 206, 211, 212 Red Cross, 169 public awareness, 61, 70, 71, 141, 147, 163, 164, reduction, 17, 82, 127, 128, 130, 147, 210, 217 178, 211 redundancy, 122 public health, 35, 70, 76, 77, 83, 102, 108, 202 refineries, 201 Public Health Service, 112 reflection, 7, 130 public safety, 206 reflexes, 128 public sector, 212 refugee camps, 172 public service, 70 regenerated cellulose, 196 Puerto Rico, 43 regional, 21, 24, 26, 29, 35, 37, 55, 144, 147, 151, pulp, 196 159, 162, 170, 173, 176, 177, 214, 216, 228 pupil, 93, 172, 173 regular, 26, 62, 75, 83, 86, 93, 96, 121, 162, 168, pupils, 15, 88, 92, 98, 102 184, 186, 224, 227 purchasing power, 8 regulation, 208, 213 purchasing power parity (PPP), 8, 9, 54, 55, 56, 57, regulations, 17, 207 59 regulatory bodies, 214 pure tone audiogram, 114 rehabilitate, 6 pus, 111 rehabilitation, 1, 6, 16, 18, 23, 49, 53, 61, 67, 70, 80, pyrethroids, 204 87, 92, 96, 102, 116, 122, 141, 142, 146, 147, 152, 158, 163, 170, 177, 183, 184, 185, 225, 227, 228 Q Rehabilitation Center, 156 Rehabilitation Council of India (RCI), 157, 166 Qatar, 40, 44 rehabilitation program, 6, 18, 61, 177, 227 qualifications, 61, 63, 67, 172 reimbursement, 84 quality assurance, 148 reinforcement, 118, 138, 139, 140 quality control, 25, 39, 148 reinforcers, 116, 118 quality of life, 7, 8, 10, 18, 152, 184, 228 rejection, 130 quality of service, 146, 172, 176 relationship, 9, 29, 130, 185, 202 questionnaire, 24, 54, 91, 92, 93, 94, 99, 102 relevance, 176, 223 questionnaires, 54, 92, 93, 94 reliability, 54, 122, 132 religious groups, 12 R remediation, 108, 109, 137 remission, 36 radio, 168 repair, 15, 107, 145, 146, 148, 152, 155, 162, 163, rainforest, 91, 98 164, 169, 177, 196, 229 random, 24, 25, 37, 39 repression, 209 random errors, 25 Republic of the Congo, 10 range, 2, 7, 8, 13, 16, 30, 31, 32, 34, 53, 60, 61, 63, resale, 134 66, 68, 81, Review82, 88, 89, 93, 95, 114, 116, 121, 127, research, 54, 92, 94, 97, 132, 144, 150, 151, 156, 129, 130, 133, 134, 141, 143, 144, 147, 148, 156, 158, 163, 197, 199, 200, 212, 213, 221, 226, 227, 158, 167, 169, 170, 171, 175, 191, 224, 227, 228, 229 229, 230 research and development, 144, 150 rat, 197, 198 researchers, 136, 158, 197, 200, 201, 203, 212, 214

Index 249 reserves, 113 Saudi Arabia, 30, 40, 43, 50, 57, 112, 208, 214 residues, 203, 214 savannah, 12 resins, 196 savings, 148 resistance, 68, 139, 184, 211 scalp, 81 resolution, vii, 17, 18, 126 scams, 185 resource allocation, 34 scar tissue, 125 resources, 5, 7, 11, 12, 13, 15, 17, 19, 21, 24, 25, 35, scarce resources, 93 39, 51, 53, 55, 60, 62, 71, 72, 73, 85, 92, 93, 97, scarcity, 15, 34, 55, 60, 141 98, 101, 107, 108, 111, 114, 117, 125, 134, 137, school, 6, 8, 13, 15, 16, 19, 23, 25, 30, 36, 47, 62, 75, 143, 146, 147, 152, 169, 170, 177, 183, 184, 186, 77, 78, 79, 80, 86, 87, 88, 89, 90, 91, 92, 93, 95, 213, 224, 225, 228 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 113, respiratory, 37, 196, 198, 212, 214 134, 135, 146, 156, 159, 162, 163, 164, 165, 167, responsibilities, 170, 183, 184 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, retail, 143, 144, 150 183, 186 returns, 54, 146 schooling, 13 revenue, 148 science, 130, 157 rice, 202 scientific, 15, 35, 67, 200, 225 risk, 49, 75, 84, 96, 105, 189, 190, 192, 193, 195, scientists, 61 199, 200, 201, 203, 204, 206, 208, 212, 213, 214, scores, 88 216, 217, 218, 220 screening programs, 1, 14, 75, 76, 77, 78, 79, 80, 82, risk assessment, 213 83, 86, 87, 88, 89, 90, 91, 92, 96, 99, 130, 156, risk factors, 49, 84, 192, 216 165, 224 risk management, 214 search, ix, 35, 100 risks, 36, 200, 202, 216 second generation, 148 Romania, 40, 43, 56, 59, 62 secondary school students, 96, 97 Rome, 216 secret, 187 room temperature, 196 Secretary General, viii routing, 158 security, 10, 70 rubber, 196, 201 sedation, 81 rubella, 17, 39, 76, 83 seeding, 69 rural, 5, 11, 13, 15, 16, 30, 31, 47, 49, 78, 90, 91, 93, seeds, ix, 189 96, 98, 99, 101, 102, 103, 156, 161, 173, 221 seizure, 92 rural areas, 11, 13, 156, 161, 173 selecting, 34, 77 rural population, 5, 49 self, 102, 211, 217 Russia, 56, 59, 61, 168 self-report, 37 Russian, 9, 14, 40, 43, 54 semiconductor, 196 Rwanda, 10, 40, 42 Senegal, 10, 40, 42 sensitivity, 25, 48, 78, 79, 81, 82, 93, 95, 107, 110, 114, 124, 127, 128, 129, 131, 132, 133, 135, 137, S 139, 191, 197, 200, 201 sensorineural hearing loss, 30, 83, 93, 96, 98, 101, sacrifice, 71 121, 123, 124, 128, 131, 132, 148, 189, 199, 204 safety, 84, 151, 189, 207, 211, 214, 220 sensory systems, 204 salaries, 15 sentences, 120, 122 salary, 71 sequelae, 39, 88, 204 sales, 143, 144, 147, 163 Serbia, 45 Samoa, 10, 41, 43, 96 series, 167, 171, 224, 225 sample, 10, 24, 25, 26, 29, 37, 39, 104, 148, 156, serum, 203, 220 165, 167, 179, 212 Reviewservice provider, 69, 156, 157 sample survey, 24, 37, 156, 165 services, vii, viii, 3, 5, 7, 10, 14, 16, 18, 19, 20, 23, sampling, 15, 25, 39 26, 51, 52, 53, 54, 55, 64, 67, 68, 69, 70, 72, 73, sampling error, 25 74, 78, 82, 83, 85, 96, 97, 101, 104, 105, 108, Sao Paulo, 176, 218 109, 114, 128, 140, 141, 142, 148, 151, 152, 153, satisfaction, 18

250 Index

155, 156, 157, 163, 166, 167, 168, 169, 170, 171, solvent, 196, 197, 199, 201, 205, 212, 213, 215, 217, 172, 173, 174, 175, 176, 177, 181, 182, 183, 184, 220 185, 186, 224, 225, 226, 227, 228 solvents, 189, 190, 195, 196, 197, 199, 200, 201, severity, 22, 23, 28, 36, 79, 110, 114, 120, 134, 202, 202, 205, 212, 213, 214, 215, 216, 217 204 Somali, 42 sex, 28, 31, 32, 33, 36, 110 Somalia, 10, 40 Seychelles, 40, 43, 213, 214 sounds, 79, 81, 92, 94, 114, 117, 119, 120, 122, 129, shape, 119 130, 191 sharing, 72, 171, 178 South Africa, 6, 9, 12, 14, 20, 30, 40, 42, 43, 44, 49, shipping, 195, 196, 226 52, 53, 56, 58, 60, 61, 63, 64, 68, 74, 84, 91, 92, shock, 148, 176 98, 99, 102, 104, 107, 140, 146, 148, 171, 173, short period, 164 174, 176, 178, 179, 194, 195, 213, 217 shortage, 15, 28, 35, 61, 66, 72, 155 South America, 52, 59, 60, 63, 168, 203 short-term, 96, 162, 184, 198, 213 South Asia, 42, 44, 83 shy, 129 South Korea, 9, 14, 144 siblings, 186 South Pacific, 112 Siemens, 144, 230 Southeast Asia, 49 Sierra Leone, 10, 30, 40, 42, 49, 173 sovereignty, 45 sign, 25, 108, 116, 172, 175, 177, 193, 228 Soviet Union, 7 signals, 81, 120, 129, 136, 137, 158, 207 Spain, 9, 14, 40, 44, 57 signs, 111, 114, 183, 216 special education, 6, 23, 157, 162, 174, 184 silicon, 150 specialisation, 60, 61, 63 Singapore, 41, 44, 57, 61, 64, 195, 221 specialists, 85, 98, 99, 146, 148, 159, 169, 173, 174, sites, 132, 151, 193, 228 214 skill shortages, 146 specialization, 58 skills, 2, 23, 80, 85, 87, 91, 131, 137, 156, 162, 168, species, 198 169, 171, 173, 182, 211, 213 specificity, 25, 78, 79, 81, 82, 93, 95, 117, 135 skin, 111, 197, 198, 214 spectrum, 64, 190 sleep, 81, 192 speech, 19, 22, 23, 52, 55, 58, 60, 61, 63, 66, 67, 75, sleeping sickness, 13 79, 80, 85, 88, 90, 92, 94, 98, 104, 110, 114, 122, Slovakia, 40 123, 129, 135, 136, 139, 146, 159, 162, 169, 174, Slovenia, 40, 44, 57, 61 175, 182, 191, 227 smoking, 46 speech discrimination, 122, 123, 136 social, vii, 1, 6, 7, 8, 9, 12, 13, 16, 23, 68, 77, 78, 80, speech discrimination score, 123 98, 108, 115, 147, 148, 152, 181, 206 speech perception, 104 social costs, 6, 13 speech sounds, 79, 122 social development, 98 speed, 76, 79 social factors, 8 Sri Lanka, 9, 26, 31, 41, 43, 50 social impairment, 13 stages, 61, 127, 191 social problems, 23 standard of living, 8 Social Security, 55, 195 standards, vii, 8, 10, 12, 15, 55, 76, 88, 112, 113, social structure, 7 148, 152, 158, 185, 189, 214 social welfare, 16 statistics, 7, 143, 224 socially, 82 statutory, 207 society, 11, 12, 16, 24, 34, 80, 184, 189, 224, 227, steel, 196 228 stiffness, 94, 111, 125, 191 socioeconomic, 93, 98 stigmatization, 23 socioeconomic status, 98 stimuli, 117 software, 35, Review36, 230 stimulus, 81, 95, 113, 115, 117, 119, 130, 132, 134, solar, 85, 103, 148, 153, 160, 225 138 solar panels, 148 stock, 145, 146, 148, 150, 161 Solomon Islands, 10, 41, 42 strain, 143 solutions, 2, 20, 51, 53, 71 strains, 13

Index 251 strategic, 148 taxes, 15, 18, 144, 152, 163 strategies, 18, 19, 24, 27, 34, 68, 70, 71, 72, 75, 88, taxonomy, 140 122, 163, 184, 186, 208 tea, 203 stress, 211 teachers, 52, 61, 77, 87, 92, 93, 100, 168, 169, 170, strokes, 37 172, 173, 174, 175, 176, 177, 184, 186 structural adjustment, 100 teaching, 52, 69, 71, 72, 168, 172, 174, 175, 177 students, 52, 61, 63, 66, 71, 72, 93, 162, 172, 183 team members, 25, 26 styrene, 189, 197, 198, 202, 213, 216, 217, 218, 220 technician, 109, 145, 146, 150, 172 subjective, 47, 127, 132, 145 technicians, 2, 52, 60, 61, 66, 148, 155, 162, 164, sub-Saharan Africa, 11, 12, 13, 19, 37, 42, 44, 48 211 subsistence, 24 technological, 107, 135, 190, 201 substances, 196, 201 technology, 7, 17, 18, 55, 67, 72, 87, 140, 145, 148, substitution, 144 152, 153, 182, 185, 214 Sudan, 10, 40, 42, 195 Technology Assessment, 19, 99, 102 suffering, 226 technology transfer, 17 supervision, 71, 72, 182 telecommunications, 223, 230 supervisors, 26, 198 telephone, 142, 162, 164 suppliers, 151 television, 115, 164 supply, 53, 72, 151, 169 temperature, 145 support services, 169, 175 termites, 175 surgeons, 55, 57, 60, 61, 66 territory, 163 surgery, 49, 103, 169, 216, 221 test data, 113 surgical, 1, 36, 66, 77 test procedure, 78, 137 surgical intervention, 36 Texas, 107, 218, 231 surveillance, 75 textbooks, 108 survival, 11, 27, 49 textile, 193, 194, 195, 199, 215, 217, 219 surviving, 112 textile industry, 193 susceptibility, 95 textiles, 192 sustainability, 16, 67, 70 Thai, 98 Sweden, vii, 40, 44, 57, 61, 64 Thailand, 9, 14, 17, 30, 32, 41, 43, 49, 56, 61, 64, 98, swelling, 111, 191 144 Switzerland, 9, 14, 40, 44, 50, 57, 61, 64, 144, 229, The Economist, 2, 3, 10, 19 231 theoretical, viii symptoms, 111, 191, 199, 213, 216 theory, 108, 130 syndrome, 13, 83 therapists, 61, 68, 184 synergistic, 195, 200, 201, 202, 205, 214 therapy, 68, 182 synergistic effect, 195, 201, 202, 214 thinking, 35, 184 syphilis, 83, 108 threat, 173 systematic, 35, 97, 182 threatening, 170, 177 systems, vii, ix, 53, 55, 58, 69, 71, 72, 76, 78, 125, threshold, 22, 29, 81, 90, 97, 98, 113, 114, 115, 117, 127, 142, 145, 151, 152, 153, 162, 168, 182, 189, 119, 121, 122, 123, 127, 128, 129, 132, 134, 136, 229, 230 139, 191, 206, 207, 216, 217 threshold level, 22, 97, 114, 117 thresholds, 29, 77, 112, 113, 114, 117, 121, 123, 125, T 128, 129, 134, 136, 139, 190, 199, 201, 207, 212, 218, 219 Taiwan, 44, 56, 101 throat, 55, 98, 152, 159, 175, 182 Tajikistan, 40, 42 time, vii, 2, 12, 15, 17, 24, 25, 26, 27, 35, 58, 63, 66, Tanzania, 9, 10, 14, 30, 40, 42, 46, 93, 102, 193, Review70, 71, 72, 85, 88, 89, 90, 92, 94, 97, 98, 108, 194, 203, 219 110, 113, 119, 122, 123, 129, 136, 137, 146, 161, target population, 25, 96, 128 164, 169, 170, 171, 172, 173, 175, 177, 182, 183, target populations, 96 185, 190, 191, 197, 203, 206, 207 targets, 27, 88 time consuming, 25 tariffs, 15, 18, 144, 152

252 Index timing, 25, 84 Tunisia, 40, 43 tin, 119, 122 Turkey, 40, 43, 99 tinnitus, 52, 110, 191, 229, 230 Turkmenistan, 40, 42 title, 59, 61 Tuvalu, 10, 11, 41 tobacco, 204, 217 tympanic membrane, 95, 125, 126, 127, 128 toddlers, 17, 224 tympanometry, 88, 91, 95, 109, 123, 125, 127, 129, Togo, 10, 40, 42 182 Tokyo, 18, 20, 73, 74 toluene, 189, 197, 199, 200, 201, 213, 215, 216, 217, 218, 219, 220 U Tonga, 41, 43, 55, 56, 62, 64 U.S. economy, 23 total employment, 210 Uganda, 9, 10, 14, 40, 42, 91, 144, 203 tourism, 14 UK, viii, 30, 31, 64, 139, 229 toxic, 196, 202, 203 Ukraine, 9, 14, 40, 42 toxicity, 214 ultraviolet, 161 toxicology, 214 ultraviolet light, 161 toxoplasmosis, 83 UN, 11, 41 toys, 123 underemployment, 11 tracking, 84 undergraduate, 52, 67, 157 trade, 209, 210, 227 unemployment, 11, 209 trade union, 209, 210 UNEP, 202, 203, 204, 221 traditional healers, 99, 175, 178 UNESCO, 171, 179 traditional practices, 175 UNICEF, 80, 82, 83, 84, 96, 104 traffic, 195, 217 unilateral, 30, 31, 80, 98, 100, 114, 131, 132, 134, trainees, 173 136, 137 training, vii, 2, 6, 16, 19, 24, 25, 26, 51, 52, 53, 55, United Arab Emirates, 40, 44 58, 60, 61, 63, 64, 66, 67, 69, 73, 79, 82, 85, 87, United Kingdom, 15, 21, 40, 44, 52, 53, 57, 59, 60, 91, 93, 95, 100, 104, 107, 108, 142, 144, 146, 64, 107, 112, 142, 167, 169, 225, 231 157, 159, 162, 163, 167, 168, 169, 170, 172, 173, United Nations, 8, 11, 14, 16, 80, 104, 153, 178, 221, 174, 176, 177, 182, 183, 184, 186, 208, 211, 224, 224 225, 226, 227, 228 United Nations Development Programme (UNDP), training programs, 6, 16, 55, 162 8, 10, 178 transducer, 81, 148 United Nations Environmental Programme, 221 transfer, 112 United States, 1, 6, 8, 9, 11, 14, 19, 23, 40, 44, 53, transistor, 145 63, 67, 68, 86, 92, 102, 107, 112, 136, 141, 143, transition, 186 144, 169, 170, 207, 223, 227, 228, 231 transitional countries, 225 universities, 54, 62 translation, 71, 137 urban, 11, 13, 16, 31, 46, 47, 93, 102, 130, 143, 144, transmission, 112 158, 162, 169, 173, 176 transparency, 20, 185 urban areas, 16, 93, 143, 173 transportation, 84 urban centres, 169, 176 trauma, 17, 37, 96, 176, 191 urban population, 173 travel, 169 urbanized, 184 trend, 6, 12, 81, 86 urinary, 220 trial, 103, 122, 146, 148, 153, 164 urine, 203 tribal, 12, 110 Uruguay, 40, 43 trichloroethylene, 197, 213, 217, 220, 221 US dollar, 7, 144 Trinidad and Tobago, 43 users, 24, 143, 144, 147, 148, 150, 153, 161 trucks, 196 Review Utah, 224 trust, 148, 185, 225 Uzbekistan, 40, 42 trypanosomiasis, 13 tuberculosis, 37 tumors, 133

Index 253

weakness, 11, 94 V wealth, 2, 8, 169, 200, 223, 226 weapons, 190 vaccination, 84 wear, 143, 151, 212 vaccinations, 84 web, 35, 45 vaccine, 84 websites, 223, 224, 228 vaccines, 18, 105, 152 welfare, 83, 173, 195, 206 validation, 130, 135 well-being, 9, 10, 108 validity, 103, 113, 132 West Africa, 12, 14, 15, 19, 42, 44, 100, 203 values, 25, 112, 115, 116, 126, 145, 204 West Bank, 43 Vanuatu, 10, 11, 41, 43 Western countries, 168 variability, 52, 90, 91, 101 windows, 113, 211 variable, 133 wireless, 229 variables, 10 Wisconsin, 31, 47 variance, 85 women, 13, 14, 184 variation, 25, 51, 52, 58, 62, 66, 67, 84, 171 wood, 193, 195, 196, 218 vascular, 191 work environment, 17, 62, 192, 214 vector, 202 workers, 11, 15, 16, 18, 66, 70, 75, 82, 90, 91, 92, vegetables, 202 93, 95, 105, 111, 112, 157, 163, 164, 170, 174, vehicles, 24, 91 177, 189, 190, 191, 192, 194, 195, 197, 199, 200, Venezuela, 40, 43 201, 202, 204, 205, 207, 208, 210, 211, 212, 213, ventilation, 83 214, 215, 216, 217, 218, 219, 220, 221, 223, 225 venue, 75, 169 workforce, 11, 19, 62 vertigo, 111 working conditions, 207, 208 vibration, 131, 132, 211 workload, 82 victims, 185 workplace, 189, 190, 195 video, 116, 157, 174 World Bank, 8, 10, 11, 12, 13, 16, 20, 27, 42, 46, 54, Vietnam, 26, 32, 42, 47, 171, 175 74, 78, 105, 224 village, 12, 18, 90, 91, 148, 182, 186 World Development Report, 20, 105 virus infection, 96 World Health Organisation (WHO), vii, viii, 1, 3, 5, viscose, 199 6, 13, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, visible, 148 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, vision, ix, 46, 92, 129, 225 46, 47, 48, 49, 50, 52, 53, 54, 64, 68, 72, 74, 76, visual, 87, 88, 115, 116, 117, 118, 119, 120, 121, 78, 83, 85, 88, 89, 90, 91, 92, 93, 97, 99, 104, 122, 123, 138, 140, 142, 219 105, 107, 108, 111, 112, 113, 114, 115, 116, 123, visual stimulus, 115 124, 140, 141, 142, 143, 145, 146, 148, 150, 151, visual system, 219 152, 153, 156, 157, 164, 166, 192, 193, 202, 203, vocational, 62, 63, 66 204, 205, 208, 216, 221, 224, 227, 228, 231 vocational training, 62, 66 World War, 5 voice, 23, 79, 94, 116, 119, 120, 135, 139 voicing, 135 volatility, 198 X vomiting, 111 VRA, 115, 116, 117, 119, 138 X-ray, 130 vulnerability, 11 xylene, 189, 197, 199, 200, 201, 213 xylenes, 220 W Y wages, 211 Review walking, 94 Yemen, 9, 10, 12, 14, 40, 42 war, 62 yes/no, 93 Washington, 18, 19, 46, 99, 152, 218, 219, 221 yield, 128, 130 water, 82, 112, 197 young adults, 12, 219

254 Index younger children, 89 Yugoslavia, 40, 43 Z Zimbabwe, 9, 14, 30, 40, 42, 98, 105, 144, 194 zinc, 143, 148, 161

Review