The Use of Aerodynamic Analysis in the Diagnosis of Adults with Paradoxical Vocal Cord Dysfunction

THE USE OF AERODYNAMIC ANALYSIS IN THE DIAGNOSIS OF ADULTS WITH PARADOXICAL VOCAL CORD DYSFUNCTION

DISSERTATION

Presented in Partial Fulfillment of the Requirements for

the Degree Doctor of Philosophy in the Graduate

School of The Ohio State University

Kathleen Mary Treole, M.A.

The Ohio State University 1996

Dissertation Committee: Approved by Professor Michael D. Trudeau, Adviser \jL nA Professor Janet M. Weisenberger Adviser Department of Professor Jessica R. Harris Speech and Hearing Science UMI Number: 9639361

This microform edition is protected against unauthorized copying under Title 17, United States Code.

UMI 300 North Zeeb Road Ann Arbor, MI 48103 ABSTRACT

50 adults with paradoxical vocal cord dysfunction (PVCD) and 50 adult, laryngeally normal adults control subjects were evaluated to determine which of 26 aerodynamic measurements in a clinical protocol differentiated the groups.

Videolaryngostroboscopy (VLS) was performed on persons suspected of having PVCD to confirm the presence of abnormal vocal fold adduction and to determine if laryngeal lesion or abnormality (other than PVCD) contributed to the presentation of symptoms. Control subjects were examined via VLS to ensure structural and functional integrity of the larynx. The aerodynamic protocol included the following measures: vital capacity, phonatory volumes, mean flow of sustained phonemes (/a, s, z ,/), mean durations of sustained phonemes, rapid syllable repetitions (/a, ha/), spikes of flow during connected speech (reading, counting), cessations of flow during sustained phoneme tasks, and ratios of tasks (s/z, ha/a). The following measurements demonstrated a group effect in which control subjects demonstrated higher mean values than did subjects with

PVCD: volumes, durations, and mean peak flow of /a/ and /ha/ repetitions. The following measurements demonstrated a group effect in which persons with PVCD demonstrated greater means than did control subjects: number of /a/ and /ha I repetitions, number of spikes of airflow >700 ml during connected speech tasks, and the number of cessations of airflow during sustained phonation tasks. The following measurements demonstrated a significant gender effect in which males demonstrated greater means than did females: volumes, durations of sustained tasks, mean flow of connected speech tasks, mean peak flow of /a/ and /ha/ repetitions, s/z ratio (flow), spikes of flow during connected speech tasks, and cessations of flow during sustained /s/. The following measurements demonstrated gender effects in which females demonstrated greater means than did males: cessations of flow during vital capacity, sustained /a/, and sustained /z/, and s/z ratios (phonatory volume and duration). These gender effects provide evidence that indicate males and females should be considered separately in the diagnosis of laryngeal disorders such as PVCD. Several main effects and interactions of main effects were also observed including volumes tasks, durations tasks, repetitions tasks, s/z ratios, and connected speech tasks.

iii Post-hoc testing indicated that levels of these dependent variables different significantly. This may indicate that tasks which appear to be similar during production (e.g., sustained /s/ and /z/) cannot be interchanged during a diagnostic evaluation.

The results of the present study are summarized to provide a typical aerodynamic profile of adult females with PVCD and adult males with PVCD.

IV For my mother and father.. words alone cannot express my thanks, love, and appreciation for all you have done for me, always. ACKNOWLEDGMENTS

I wish to thank Michael D. Trudeau, my adviser, for his unending support and guidance throughout my life at Ohio State. His great sense of humor, and direction, provided me with the strength to persevere.

I am forever grateful to Jan Weisenberger, not only for her assistance with my dissertation, but for her friendship, support, foresight, hindsight, and instinct.

I thank Jessica Harris for her thoughtful insight during this project, and for providing a model to strive to for as a new professor.

I thank JoAnn Donohue for being president of my one-woman fan club who always lifted my spirits and provided me with inspiration to finish.

Without the comic relief provided by Karen Hodge, I most assuredly would not have completed this unending task. I pass on to her the strength given to me by our friends and faculty as she begins her doctoral endeavor.

1 am ever grateful to L. Arick Forrest for the opportunity to grow as a professional in an environment with high expectations. I appreciate not only his guidance, but his friendship.

I respectfully acknowledge the Department of Otolaryngology and the Department of Speech and Hearing Science. These departments provided me with the opportunity to succeed.

Finally, without the love of my sisters, I would be nothing.

vi VITA

August 7, 1969 ...... Bom - Passaic, New Jersey

1991 ...... B.S., Teacher of the Speech and Hearing Handicapped, Ithaca College

1993 ...... M.A., Speech and Hearing Science, The Ohio State University

1991-1994 ...... Graduate Teaching Associate Department of Speech and Hearing Science The Ohio State University

1995-1996 ...... Provost’s Teaching Fellow The Ohio State University

1994-present ...... Speech-Language Pathologist The Ohio State University Voice Center The Department of Otolaryngology

FIELDS OF STUDY

Major Field: Speech and Hearing Science

Minor Fields: Speech-language pathology Voice and voice disorders

VII TABLE OF CONTENTS

Page

Abstract...... ii

Dedication ...... v

Acknowledgments ...... vi

Vita...... vii

List of Tables ...... xii

List of Figures ...... xviii

Chapters:

1. Introduction ...... 1 Statement of the problem ...... 4 Purpose of this study ...... 5 Research questions ...... 6 Volumes ...... 6 Mean flow of sustained phonation tasks ...... 6 S/Z ratio obtained from sustained /s/ and /z/ tasks. ...6 Mean peak flow ...... 6 Mean peak flow in connected speech tasks ...... 6 Frequency of spikes of flow during connected speech tasks...... 7 Frequency of cessations of flow during sustained phonation/expiration tasks ...... 7 Procedures ...... 8 Analyses of the data ...... 8 Definitions of terms ...... 9 Organization of the study ...... 10

viii 2. Review of the literature...... 11 Introduction ...... 11 Incidence/Prevalence ...... 13 Nomenclature ...... 15 Patient characteristics...... 16 The paradoxical motion ...... 18 Wheezing/stridor...... 20 Description of treatments ...... 22 Physical treatments...... 22 Speech therapy...... 24 Psychiatric/psychologic treatments ...... 28 Normal respiration ...... 28 Normal laryngeal behavior...... 30 Possible etiologies of PVCD ...... 39 Psychogenic ...... 41 Learned behavior/compensatory strategy ...... 49 Neurological differences ...... 52 Differential diagnosis ...... 56 Pulmonary function testing ...... 62 Speech pathology/otolaryngology testing ...... 66 Aerodynamic Analysis ...... 68 Proposed model of PVCD ...... 71 Urgency of developing diagnostic methods ...... 72

3. Methodology ...... 75 Subjects...... 75 PVCD group ...... 75 Control group ...... 80 Procedures ...... 85 Informed consent ...... 85 Case history...... 85 Videolaryngostroboscopy ...... 87 Aerodynamic Analysis ...... 93 Measurements ...... 93 Vital capacity...... 98 Sustained /a/ ...... 99 Reading ...... 100 Counting ...... 100 S/Z...... 101 /a/ and /ha/ repetitions ...... 103 ix Summary...... 104 Statistical analysis ...... 106 Statistical analyses ...... 108 Rationale for each dependent variable...... 109 Vital capacity...... 109 Phonatory volume ...... I ll Maximum phonation duration ...... 114 Mean airflow rate in sustained tasks ...... 118 Mean rate of airflow during connected speech tasks ...... 120 S/Z ratio ...... 121 Spikes of airflow > 700 ml/sec ...... 123 Cessations of airflow ...... 125 Rapid vocal fold adductions ...... 126

4. Results and Discussion ...... 129 Explanation of analyses used ...... 129 Volumes measures ...... 131 Mean flows of sustained tasks ...... 145 Durations of sustained phonation tasks ...... 148 Mean flow of connected speech tasks ...... 154 Repetitions of /a/ and /ha/ ...... 159 Repetitions ...... 159 Mean peak flow of /a/ and /ha/ repetitions ...... 161 /ha:a/ ratio...... 167 S/Z ratio ...... 169 Frequency of spikes during connected speech ...... 173 Frequency of cessations during sustained phonation and vital capacity tasks...... 178 Correlation of spikes and flow ...... 184 Summary of Typical Adult Female with PVCD ...... 196 Summary of Typical Adult Male with PVCD...... 198

5. Discussion ...... 218 Limitations of the present study ...... 218 Directions for future research ...... 221

B ibl iography ...... 225 A ppendices ...... 233 Appendix A: Informed Consent Form ...... 233 Appendix B: Procedures Script ...... 236 Appendix C: Control Subject Case History ...... 238 Appendix D: PVCD Subject Case History Form ...... 240 Appendix E: The Rainbow Passage ...... 242 Appendix F: Airflow Analysis Data Collection Worksheet .244 Appendix G: Human Subjects Committee Approval Form..246

XI LIST OF TABLES

Table Page

2.1 Demographic data describing the population of persons with

PVCD reported in the literature from 1973-1995 ...... 14

2.2 Age and gender breakdowns for adults and children with PVCD

described in the literature during 1973-1995 ...... 15

2.3 Attack resolution strategies trained during a laryngeal control

program for PVCD ...... 26 2.4 Number of patients with PVCD receiving different treatments...48

2.5 Differential diagnosis of wheezing/stridor...... 58 3.1 Age and gender for persons in PVCD and control groups ...... 78

3.2 Asthma and smoking data for PVCD and control groups ...... 79 3.3 Methods of employment for PVCD and control groups ...... 82

3.4 Ethnic breakdown of all subjects in the present study ...... 83

3.5 Perceptual voice ratings of persons in PVCD an control

groups ...... 84 3.6 Levels of measurement for dependent variables ...... 106 3.7 Percentages of VC that constitute PV...... 113

3.8 MPD published data reported in the literature ...... 117

3.9 Mean airflow published data in the literature ...... 120 4.1 Mean volume data for all volume tasks and groups ...... 131 4.2 MANOVA table for dependent variable volumes ...... 132

4.3 Means and standard deviations for interaction group X gender for the dependent variable volumes ...... 132

4.4 Mean volume data for group ...... 133

4.5 Mean volume data for gender...... 133 4.6 Repeated measures ANOVA table for volumes ...... 135

4.7 Mean volume data for volumes effect ...... 137 4.8 Mean volume data for significant effect volumes X group ...... 137

4.9 Difference between means which exceed critical value

as determined by Scheffe test for volumes effect ...... 138

4.10 Percentage of vital capacity made up by the phonation volume across tasks for all subjects ...... 139

4.11 Mean significant difference for volumes X group ...... 140 4.12 MANOVA table for dependent variable volumes with asthma

independent variable ...... 142 4.13 Data for token and groups based on presence of asthma ...... 143

4.14 Mean and SD data for sustained phonation tas ...... 146 4.15 MANOVA table for dependent variable mean flow ...... 146

xiii 4.16 Duration (in seconds) data for sustained phonation tasks ...... 148

4.17 MANOVA table for dependent variable mean flow ...... 149

4.18 Mean duration and standard deviations in seconds

across groups ...... 149 4.19 Mean duration and standard deviation in seconds

across gender...... 150 4.20 Repeated measures ANOVA table for durations ...... 151

4.21 Mean duration and standard deviations in seconds across

tasks and gender...... 152 4.22 Critical differences for durations X gender interaction ...... 153 4.23 Mean duration and standard deviations in seconds across

tasks...... 153

4.24 Mean airflow (ml/sec) and standard deviations across group, gender, and task for the significant effect of

task X group X gender...... 154

4.25 MANOVA table for dependent variable connected speech tasks...... 155

4.26 Mean airflow in ml/sec across gender for the significant effect of gender during connected speech tasks ...... 155

4.27 Repeated measures ANOVA table for connected speech tasks...... 156

xiv 4.28 Significant critical differences which account for the effect for connected speech tasks X group X gender...... 157

4.29 Data for /a/ and /ha/ repetitions across groups, genders and tasks ...... 159

4.30 MANOVA table for frequency of repetitions /a/ and /ha/ ...... 160 4.31 Mean frequency count and standard deviations for the main

effect of repetitions ...... 160 4.32 Mean peak flow (ml/sec) and standard deviations for task, group,

and gender for mean peak flow during /a/ and /ha/ repetition.. 161

4.33 MANOVA table for mean peak flow (ml/sec) for repetitions /a/ and /ha/...... 162 4.34 Mean peak flow in milliliters across groups for the main effect of group ...... 162

4.35 Mean peak flows (ml/sec) and standard deviations across

gender for the main effect of gender...... 163 4.36 Repeated measures ANOVA table for repetitions peak flow ...... 164

4.37 Mean peak flow (ml/sec) across tasks for the main effect of repetitions peak flow ...... 165

4.38 Mean peak flow across group and task for interaction effect repetitions peak flow X group ...... 166

4.39 ANOVA table for ha/a ratio ...... 167

XV 4.40 Group and gender data for /ha:a/ ratio ...... 168

4.41 MANOVA table for three s/z ratios ...... 169 4.42 Data for three s/z ratios for group and gender...... 170 4.43 Mean s/z ratio (duration, PV, and flow) for the main effect

of gender...... 170

4.44 ANOVA table for s/z ratios ...... 171 4.45 Mean s/z ratio data for the main effect of ratios ...... 172 4.46 Mean data for the interaction ratios X gender...... 172

4.47 Critical differences for the ratios X gender interaction ...... 173 4.48 Means and standard deviations of spikes of flow during

reading and counting for group and gender...... 174 4.49 Chi square, frequency, expected subjects producing spikes

during counting (1-50) ...... 175 4.50 Chi square, frequency, expected subjects producing spikes

during reading of the Rainbow Passage ...... 177 4.51 Chi square, observed, and expected frequency of cessations

during all tasks (VC, /a/, Is/, IzI)...... 179 4.52 Chi square, observed, and expected frequency of cessations

during VC ...... 180 4.53 Chi square, observed, and expected frequency of cessations

during sustained /a/ ...... 181

xvi 4.54 Chi square, observed, and expected frequency of cessations

during sustained /s/ ...... 182 4.55 Chi square, observed, and expected frequency of cessations during sustained /z/ ...... 183

4.56 Spearman rank order correlation table for all subjects for

comparison of spikes and mean flow during connected speech tasks...... 184

4.57 Spearman rank order correlation table for PVCD subjects ...... 185

4.58 Spearman rank order correlation table for control subjects ...... 186 4.59 Spearman rank order correlation table for control males ...... 187

4.60 Spearman rank order correlation table for female controls ...... 188 4.61 Spearman rank order correlation table for males with PVCD.. 189

4.62 Spearman rank order correlation table for females

with PVCD...... 190 4.63 Significant effects and interactions for all measurements in the present study ...... 194

xvii LIST OF FIGURES

Figure Page 2.1 Normal larynx during inspiration (top) and larynx

demonstrating paradoxical vocal fold motion during inspiration (bottom) ...... 74

4.1 Mean volume data for the significant effect of group X gender...... 200

4.2 Mean volume data for the significant effect of group ...... 201 4.3 Mean volume values for the significant effect of gender, ...... 202

4.4 Mean volume data for volumes effect ...... 203 4.5 Mean volume data for the significant effect volumes

X group ...... 204 4.6 Mean duration (sec) for three sustained phonation tasks

for each group ...... 205 4.7 Mean duration (sec) for three sustained phonation tasks

for gender...... 206 4.8 Mean duration (sec) across task and gender for the

significant interaction duration X gender...... 207

XVlll 4.9 Mean duration (sec) across tasks for the significant

interaction of duration ...... 208 4.10 Mean airflow (ml/sec) for the main effect of gender...... 209 4.11 Mean airflow (ml/sec) across group, gender, and task

for the significant effect of task X group X gender...... 210 4.12 Number of repetitions across groups for /a/ and /ha/ repetitions ...... 211 4.13 Mean peak flow (ml) across groups for the significant

effect of group ...... 212 4.14 Mean peak flow (ml/sec) across gender for the main

effect of gender...... 213 4.15 Mean peak flow (ml/sec) across task for the main

effect of repetitions peak flow ...... 214 4.16 Mean peak flow (ml/sec) across tasks for the main effect of repetitions peak flow ...... 215

4.17 Comparison of s/z ratios for group and gender...... 216

4.18 Interaction of s/z ratios X gender...... 217

xix CHAPTER 1

INTRODUCTION

Paradoxical vocal cord dysfunction (PVCD) is a recently recognized disorder. Christopher, Wood, Eckert, Blager, Raney and Souhrada (1983) provided one of the earliest and most descriptive explanations of this disorder and advocated interdisciplinary management (including speech- language pathology) for its treatment. Prior to Christopher, et al., (1983) research pertaining to PVCD was limited to case study methods. For example, Patterson, Schatz and Horton (1974) described a case of a female aged 33 years with a history of hospital admissions for acute dyspnea. She demonstrated a rapid breathing rate and high pitched stridor during inspiration that did not resonate into the lungs. According to Patterson, et al., (1974) this indicated an upper airway obstruction at the level of the larynx. Further, asthma testing and other respiratory disease testing were negative. The authors diagnosed this patient with non-organic, factitious or

1 hysterical respiratory disease. Psychiatric treatment was recommended. Since this first case study, descriptive research predominates the literature with reports including small samples. Persons with PVCD usually present with an acute wheezing episode that researchers believe has a psychogenic basis (Barnes, Grob, Lachman, March, and Loughlin, 1986; Brown, Merritt, and Evans, 1988; Caraon & O’Toole, 1991). The disorder has been presented in the literature under many names and most reflect a psychiatric etiology: Munchausen’s stridor (Patterson, et al, 1974), factitious asthma (Downing, Braman, Fox, & Carrao, 1982), psychogenic upper airway obstruction (Barnes, et al, 1986), and emotional laryngeal wheezing (Rodenstein, Francis, & Stanescu, 1983). Paradoxical vocal cord dysfunction (Kellman & Leopold, 1982; Christopher, et al., 1983) has also been used as a diagnostic label; however, this label does not indicate suspected etiologies. Goldman and Muers (1991) provide an extensive review of paradoxical vocal cord dysfunction (PVCD). They describe three variants of vocal cord dysfunction: inspiratory, expiratory or both. The variants indicate the portion of the respiratory cycle in which the person experiences the most difficulty. Inspiratory wheezing, or stridor, is the most common characteristic of this disorder (Goldman & Muers, 1991). These authors note that PVCD patients often have an increased respiratory rate. This is the opposite effect expected of other respiratory disorders, such as asthma. Additionally, blood gas concentrations tend to be normal.

2 In persons with respiratory disorders such as asthma, blood gas values are abnormal due to failure to absorb oxygen correctly. The stridor is caused by strong adductions of the true vocal folds during inspiration. Usually, respiration is via a small posterior glottal chink (Goldman & Muers, 1991). This tight adduction can be relaxed through sedation, anesthesia, coughing or panting (Goldman & Muers, 1991). Extensive pulmonary testing is usually performed on patients with PVCD when they present to an emergency room (the typical recourse in a severe dyspnic episode). Testing and patterns of performance performed frequently includes: (1) flow-volume loops, characterized by a flat inspiratory loop with an increased ratio of forced expiratory/inspiratory flow; (2) airway resistance, which tests as normal; (3) blood gases, which test as normal; and (4) spirometric testing which tests as abnormal. Pulmonary function tests may reveal abnormality during an attack, but are otherwise normal. At times, patients are sedated to end an attack. At extremes, patients are given tracheotomies to provide an airway. A large group of the patients have asthma; however, these patients do not tend to respond to asthma medications as well as would be expected. After series of tests, physicians often discontinue asthma medications and a referral for vocal cord dysfunction is made to a speech-language pathologist for testing and treatment. There are no published reports of diagnosis or assessment from a speech pathology point of view to date. Several of the reports from the

3 pulmonology literature indicate that treatment was a combination of psychiatric counseling and speech therapy, although the exact nature of the

speech therapy is not defined (Barnes, et al., 1986; Christopher, et al., 1994; Corren & Newman, 1992). Therefore, before appropriate treatment of this dysfunction, an assessment protocol would be useful for baseline purposes for gauging therapy progress, as well as for determining actually who does fall into the category of “vocal cord dysfunction.” These measures may also be valuable in development of a severity index. Speech pathologists should develop these criteria in conjunction with otolaryngologists and pulmonologists, so that cases of severe or refractory asthma are not erroneously referred for treatment as PVCD. An assessment protocol is needed for baselining prior to therapy, for defining the population, and to develop a severity index. STATEMENT OF THE PROBLEM

There is an identified need for research regarding the diagnosis and treatment of PVCD. This research should involve several methods of study of the larynx and its functions, including aerodynamic assessment. Aerodynamic measures are necessary because they allow the investigator to sample longer periods of time than other evaluations, such as videolaryngostroboscopy (VLS). Also, because VLS can be considered an invasive procedure, some speech-language pathologists are reluctant to perform the exam. Aerodynamic analysis is not an invasive procedure and can be used for diagnosis and throughout treatment. Preliminary research should focus on positive diagnostic signs. Aerodynamic assessment may reflect positive diagnostic measures. Persons with PVCD may demonstrate differences from control subjects on aerodynamic measures because the disorder is considered a respiratory disorder. Preliminary research should also include control groups for comparison to unaffected populations. It is the goal of this investigation to determine which aerodynamic measures differentiate persons with PVCD from individuals without PVCD. PURPOSE OF THIS STUDY

The purpose of this study is to differentiate individuals with PVCD from persons without PVCD using aerodynamic measurements. Measures that are useful in differentiating individuals with PVCD from individuals without PVCD may be developed into an assessment protocol. An assessment tool for PVCD would help to decrease instances of misdiagnosis. Aerodynamic measures from the comprehensive diagnostic evaluation will be administered to individuals with PVCD and controls. The measures will be compared and contrasted across both groups. If these subjects can be differentiated, a typical case profile will be developed for potential use by speech-language pathologists, otolaryngologists and pulmonologists.

5 RESEARCH QUESTIONS Which aerodynamic measurements differentiate individuals with PVCD from controls? VOLUMES

Vital Capacity (VC) Phonatory volume of sustained /a/ (PV /a/) Phonatory volume of sustained /s/ (PV /s f) Phonatory volume of sustained /z/ (PV /z/) MEAN FLOW of SUSTAINED PHONATION TASKS (ml/sec) Sustained /a/ (/a/) Sustained /s/ (/s/) Sustained /z/ (/z/) s/z RATIO OBTAINED FROM SUSTAINED /S/ AND !7J TASKS

(1) ratio based on phonatory volume (PV) (2) ratio based on duration (DUR)

(3) ratio based on mean flow (FLOW) MEAN PEAK FLOW (ml) syllable repetitions of /a/ and /ha/ Mean peak flow of /a/ and /ha/ ratio of flow /ha:a/ MEAN FLOW IN CONNECTED SPEECH TASKS

Reading of the Rainbow Passage (RBP) Counting 1-50 (Counting)

6 FREQUENCY OF SPIKES OF FLOW DURING CONNECTED SPEECH TASKS Number of spikes of flow > 700 ml/sec during reading of the Rainbow Passage and Counting FREQUENCY OF CESSATIONS OF FLOW DURING SUSTAINED PHONATION/EXPIRATION TASKS Number of cessations of flow during vital capacity, and sustained /a/, /s/, and /z/ These measurements have been chosen based on clinical impressions of data accumulated from persons with PVCD during diagnosis and treatment at The Ohio State University Voice Center in the Department of Otolaryngology. It is suspected that some of the aerodynamic measures will differentiate persons with PVCD from controls as well as from persons with other types of voice disorders (i.e., nodules, polyps, contact ulcers, paralysis, etc.). This may be true because persons with PVCD typically do not demonstrate a voice disorder (dysphonia) . More often, a person with PVCD will complain of shortness of breath or breathing difficulty episodes rather than hoarseness or vocal fatigue. It is not the purpose of the present study, however, to compare the results of persons with PVCD to persons with traditional voice disorders. Chapter 3 will provide a rationale for the inclusion of each dependent variable.

7 PROCEDURES

Subjects consisted of two groups: persons with PVCD and a control group of laryngeally normal subjects with no evidence of either a traditional voice disorder or PVCD. Persons with PVCD consisted of patients who were referred to The Voice Center for evaluation of probable PVCD and subsequently diagnosed with the disorder based on VLS examination. Evaluation for this disorder consisted of a case history interview, VLS and transglottal airflow analysis. Persons referred to the clinic for PVCD evaluation received all three sections of the protocol as recommended by their physician. Control subjects received all three sections of the evaluation with the condition of terminating participation in the study at any time. ANALYSES OF THE DATA

Demographic data for both groups is reported including age range, gender, and occupation. Descriptive statistics are presented for each dependent variable. Multivariate analysis of variance (MANOVA) was used to analyze the data while controlling for presence or absence of PVCD and gender. Repeated measures ANOVA were used to analyze the data... Chi square analyses were used to determine if occurrence of spikes and cessations of flow during connected speech tasks differed from expected values based on the performance of the control subjects. Correlations....

8 DEFINITIONS OF TERMS

1. Paradoxical Vocal Cord Dysfunction (PVCD): A group of respiratory symptoms with the most prominent as an acute wheezing episode. The patients complain of shortness of breath due to airway constriction/obstruction. Examination reveals the constriction/obstruction to be associated with abnormal (paradoxical) laryngeal valving. 2. Asthma: a condition of the lungs in which there is widespread narrowing of the airways. It varies over short periods of time either spontaneously or as a result of treatment, due in varying degrees to contraction or spasm of smooth muscle, edema of the mucosa, and mucus in the lumen of the bronchi. It is caused by a local release of spasmogens and vasoactive substances in the course of an allergic process (Randolph, 1993). 3. Gastroesophageal Reflux Disease (GERD): Incompetence of the lower esophageal sphincter and the pharyngeal-esophageal segment resulting in a reflux of gastric juices in the esophagus to the posterior larynx. Irritation from the gastric juices in the larynx are manifested in many symptoms, including excessive throat clearing, excessive mucous production, hoarseness of the voice, chronic halitosis, acidic or metallic taste in the mouth and indigestion/heartburn (Olson, 1991). Physical changes include edema of the arytenoid cartilages, post-cricoid region and edema, erythema and pachyderma of the posterior-arytenoid space.

9 4. Anterior-posterior Dimension: The plane of the larynx from anterior (epiglottis) to posterior (arytenoid cartilages). 5. Ventricular Folds: Muscular folds directly superior to the ventricle and the true vocal folds that have the ability to medialize and lateralize superior to the true vocal folds (Stemple, Glaze & Gerdeman, 1995).

6. Arytenoid Cartilages: A set of paired laryngeal cartilages that compromise the posterior aspect of the anterior-posterior dimension. The

arytenoids provide structural support for the larynx and vocal folds and are direct attachments for the vocal folds. They provide the true vocal folds with the ability to adduct and abduct (Stemple, Glaze & Gerdeman, 1995).

7. Laryngeal Endoscopy: A procedure in which the larynx is viewed indirectly via an endoscope passed through the oral cavity (rigid rod, oral endoscopy) or nasal cavity (transnasal fiberoptic endoscopy, flexible fiberoptic laryngoscopy) (Stemple, Glaze & Gerdeman, 1995). 8. Transglottal Airflow Analysis: An aerodynamic measurement examination that provides a reflection of the valving capabilities of the larynx (Stemple, Glaze & Gerdeman, 1995). ORGANIZATION OF THE STUDY

Chapter 1 provides a statement of the problem and the purpose of the study. Chapter 2 contains a literature review. Chapter 3 describes methodology for the study. Chapter 4 presents results and discussion. Chapter 5 describes questions for future research.

10 CHAPTER 2

REVIEW OF THE LITERATURE

Introduction As described briefly in Chapter 1, the typical acute episode of PVCD is described as paroxysms of wheezing and dyspnea persisting despite aggressive asthma therapy. While the patient is symptomatic, inspiratory and/or expiratory noises are audible on auscultation of the neck; auscultation of the chest does not detect audible noises (Christopher, Wood, Eckert, Blager, Raney, & Sourhrada, 1983; Corren & Newman, 1992).

Often, the patients demonstrate a high anxiety level and believe they will die because inhalation is seemingly impossible. At first glance, it appears to be a functional disorder of the larynx mimicking bronchial asthma, and has been considered a conversion disorder (Christopher, et al., 1983).

PVCD does not respond to standard asthma regimens; these patients have been described as having refractory asthma (Chawla, Upadhyay &

11 Macdonnell, 1984). Between attacks, the patient is often symptom free, without any signs of airway obstruction (Fields, et al., 1992). These, and other characteristics, will be discussed in the following chapter. This review will begin with a discussion of incidence and prevalence. The nomenclature typically assigned to this disorder will be reviewed along with the common patient characteristics. The paradoxical motion of the structures of the larynx will be described specifically with explanations of the wheezing and stridor which usually accompany the paradoxical motion. Also, description of the most common treatments will be provided. Normal respiration and normal laryngeal behavior will be reviewed to provide background for discussion of the abnormal paradigm present in PVCD and to begin discussion of the possible etiological mechanisms for PVCD. Describing the process of differential diagnosis will begin a section outlining the typical diagnostic tests used to assess persons in which PVCD is suspected. Pulmonological tests, otolaryngological tests, and speech- language pathology procedures will be reviewed. The use of aerodynamic analysis will be described briefly in this chapter. A more detailed discussion of the rationale for use of aerodynamic analysis, descriptions of how measures are collected, and the possible relationship of how these measures are related to PVCD and what they might tell us about the disorder will be provided in Chapter 3 - Methodology.

12 Incidence/Prevalence

The true incidence of PVCD is unknown; research into the disorder has only just begun. Craig, Sitz, Squire, Smith, and Carpenter (1992) reported approximately 30 cases that had been identified in the literature since the 1970s. A recent review of the literature determined that 66 cases have been reported in the literature. The earliest report of PVCD was published in 1973 and the landmark report by Christopher, et al., followed in 1983. However, Freud discussed a case of “Dora” who demonstrated a “hysteria.” She presented with chronic dyspnea with exacerbations in which the symptom was aggravated (Cormier, Camus & Desmeules, 1980). Fields, Roy and Ossorio (1992) noted that the disorder is reported with greater frequency in the adult population than children. Further, the literature reports that PVCD is more common in women, and in patients who work in or have close exposure to the medical professions (Fields, et al., 1992; Craig, et al., 1992). However, because these data have been accrued from reports which are predominantly case study descriptions, it is difficult to say if these reports are representative of the disorder. Tables 2.1 and 2.2 illustrate the demographic make-up of the first 66 patients with PVCD reported in the literature between 1973 and 1995. Table 2.1 provides a brief gender breakdown along with notation of the presence of an asthma diagnosis, the suspected etiology before the patient was diagnosed with PVCD and whether or not the patient had a significant history for some type of

13 psychiatric intervention, diagnosis, counseling, or therapy. Table 2.2 provides a more specific breakdown of age and gender information with adults and children calculated separately.

Demographics Asthma Diagnosis

N = 66 Yes n=14 Males n=14 No n=43 Females n=52 Not specified n=6 Ratio F:M 3.71:1 Not sure n=3

Suspected Etiology History of Psychiatric Tx

Psychiatric n=42 Yes n=38 Unsure n=ll No n=13 Not specified n=13 Not specified n=15

Table 2.1: Demographic data describing the population of persons with

PVCD reported in the literature from 1973 - 1995.

14 Males Females Group Ages 18+

n 2 41 43 Mean age 21.5 30.17 29.76 Range 21-22 18-68 18-68

Ages <18

n 12 11 23 Mean age 13.08 13.27 13.17 Range 9-16 10-16 9-16

Table 2.2: Age and gender breakdowns for adults and children with

PVCD described in the literature during 1973-1995.

Nomenclature

The names used to describe this condition vary; the following names were all used in published articles to describe the same disorder: emotional laryngeal wheezing, factitious asthma, Munchausen’s stridor (Fields, et al., 1992; Christopher, et al., 1983; Caraon & O’Toole, 1991); psychogenic wheeze (Goldman & Muers, 1991; Alpert, Dearborn, & Kercsmar, 1991); laryngeal asthma (Chawla, et al., 1984); psychogenic stridor (Skinner & Bradley, 1989); paradoxical vocal fold motion, episodic laryngeal dyskinesia, vocal cord dysfunction (Corren & Newman, 1992; Sokol,

1993); false croup, hysteric croup, laryngismus stridulus (Skinner &

15 Bradley, 1989); hysterical laryngeal spasm (Appleblatt & Baker, 1981). One reason for the different labels may be that the disorder can present in many different ways and no two patients are alike. Different clinical findings will result in different labels. Patient characteristics

The literature has attempted to classify the type of patient who may present with this disorder. It is important to remember that not every subject identified in the literature complains of or demonstrates every sign, symptom, or characteristic. Patients diagnosed with PVCD have been described as having a history of previous factitious disease, a history of other psychiatric illness, and as malingering when evaluated with pulmonary function tests (Downing, et al., 1982). These assumptions about the patient reveal that the suspected etiology may be psychogenic. As there is no study describing psychological or psychiatric testing of persons with PVCD, it may be premature to accept the etiology of psychogenesis when the disorder has such obvious physical manifestations. These patients typically present with acute respiratory distress with stridor and complain of an inability to draw air into the lungs. It is a dramatic episode of wheezing refractory to conventional asthma treatments. Symptoms may be triggered by stress, cold air, exercise or inhalation of irritants (Craig, et al„ 1992). These patients have a history of repeated emergency room visits, and sometimes only have audible breathing trouble when attention is focused on them. Again, this may be an

1 6 indication of psychogenic etiology in some patients (Fields, et al., 1992). These patients have reported being attended to by multiple physicians (Craig, et al.,1992). Besides the stridorous inspirations, these patients sometimes present with a weak or absent voice and an inability to cough (Kellman & Leopold, 1982). Other times, a cough will produce maximal abduction of the vocal folds and will begin to ease the attack. Often, patients cannot voluntarily mimic the constricted glottis or the stridorous sounds. Christopher, et al. (1983) reported that when subjects were asked to imitate the stridor, the subjects were unable to reproduce the abnormal laryngeal motion continuously and the sound produced was different than that produced during the acute attack. Further, any paradoxical vocal fold action could not be sustained. Respiratory rate may be increased (Goldman & Muers, 1991). This is the opposite of persons with normal respiratory function. Persons who have no chronic respiratory disorder will demonstrate a decreased respiratory rate in the presence of an added inspiratory load such as an obstructed airway or respiratory disease (Cormier, et al., 1980). Christopher et al. (1983) did not indicate if testing was performed, but stated that their 4 subjects demonstrated normal to above normal IQ with no evidence of memory impairment. Kattan and Ben-Zvi (1985) also reported that their patients with PVCD demonstrated normal or above normal intelligence. Further, the results of psychiatric testing among their PVCD patients did not differ from results among confirmed asthmatic

17 patients; however, the specifics of the testing were not provided. Although some patients do link URI (upper respiratory infection), cold weather, or allergens to the onset of an attack, many patients cannot link a precipitating event with the onset of the acute episode. Kellman and Leopold (1982) reported that two of three cases in their study correlated the onset of the breathing episodes with an upper respiratory infection. Craig et al., (1992) noted that PVCD may be or may appear to be precipitated by exercise, viral URI, or stress. It has been the experience of the investigators of the present study that attacks may be precipitated by physical events such as cold weather or illness; but patients also report attacks being triggered when the environment had not changed, such as when watching television or sleeping. Interestingly, patients do not report trouble falling asleep. The Paradoxical Motion The hallmark physical finding is vocal fold adduction creating a posterior glottic chink; this chink serves as the airway during an attack (Fields, et al., 1992; Collett, Brancatisano, & Engel, 1983). Martin, Blager, Gay, and Wood (1987) and Corren and Newman (1992) describe the classic presentation as adduction of the anterior two-thirds of the true vocal folds with a characteristic diamond shaped chink at the posterior of the vocal folds. In some patients, the arytenoid cartilages maintain a lateral position with failure to adduct despite the vocal fold adduction (Christopher, et al. 1983). The chink is a significant finding because many

18 lung diseases demonstrate vocal fold adduction during expiration; however, in these instances, the vocal folds tend to come together uniformly and a posterior chink is not evident. Figure 2.1 illustrates a normal larynx during inspiration and a larynx demonstrating the hallmark glottic vocal fold adduction. The adduction of the true vocal folds can occur on expiration as well as inspiration (Kellman & Leopold, 1982; Fields, et al., 1992; Liistro, Stanescu, Dejonckere, Rodenstein & Veriter, 1990). Liistro, et al. (1990) summarized three “functional” glottis narrowing syndromes: (1) paradoxical inspiratory adduction of the true vocal folds, (2) narrowing of the glottis during expiration accompanied by breathing near residual volume with tidal flows reaching the maximal flow volume envelope, and (3) consistent narrowing of the glottic orifice during all cycles of respiration. Kattan and Ben-Zvi (1985) noted that the different phases of respiration in which the paradoxical motion occurs may account for different ascultatory findings; hence, different clinical diagnoses and terminologies describing these cases.

Physical findings at the time of an attack vary from complete glottal constriction to normal (Fields, et al., 1992). Nagai, Yamaguchi, Sakamoto and Takahashi (1992) describe a 15 y/o male with inspiratory stridor due to pharyngeal constriction associated with an abnormally shaped epiglottis that trembled during inspiration. Although this is not paradoxical vocal fold motion, the case study description and patient characteristics are similar to

19 a patient with PVCD; it is possible that there is a variety of paradoxical movements possible in the larynx that can contribute to stridor and shortness of breath.

The common use of sedatives to calm patients during an acute breathing episode may account for the normal findings during

laryngoscopic examination. Several reports have noted that an acute episode can be resolved through administration of sedatives such as midazolam hydrochloride (Versed) (Fields, et al., 1992). Persistent stranding of mucous between the vocal folds has been observed; it is suggested that the excessive secretions are a compensatory effect of the larynx secondary to constant vocal fold trauma during the paradoxical adductions. Wheezing/Stridor

Paradoxical vocal fold closure during the respiratory cycle frequently causes an inspiratory wheeze (Goldman & Muers, 1991). This inspiration noise has also been called stridor (Fields, et al., 1992). It has been described as a high-pitched noise audible in the chest but greatest over the larynx (Craig, et al., 1992).

Baughman and Loudon (1989) describe the acoustic signal of stridor. They reported that the acoustic signal associated with stridor post- extubation was similar to the stridor frequency of asthma; however, the asthma stridor was stronger over the chest and the asthma stridor was strongest during expiration, whereas the PVCD stridor was predominant

20 during inspiration. Further, these authors noted that stridor is a physical finding associated with a specific etiology: upper airway obstruction. Collett, et al. (1983) stated that inspiratory stridor in adults is usually due to obstruction of the upper airway by organic lesions such as tumors, aspirated foreign bodies, bilateral vocal fold paralysis, or edema of the epiglottis/larynx. Stridor can also result from dynamic inspiratory narrowing of the glottis, resulting in an increase in the inspiratory resistance. This is the case in PVCD. Reports documenting PVCD often do not discriminate between the terms wheezing and stridor. Wheezing has been called a high-pitched noise emanating from the lungs. Stridor often refers to a substantial narrowing or obstruction of either the larynx or trachea (Kattan & Ben-Zvi, 1985). Downing, et al. (1982) reported that wheezing is produced when the airways are narrowed such that opposite walls oscillate between the closed and barely open positions; the pitch of the sound is determined by mass and elastic properties of the oscillating structures. Goldman and Muers (1991) describe wheezing as the result of reversible and irreversible airflow limitation. Further, these authors state that the acoustic signals of asthmatic wheeze and stridor are similar in frequency and can be separated only by their timing in the respiratory cycle.

Rodenstein, Francis and Stanescu (1983) suggest that the wheezing- like sound is produced by high flows of air passing through a narrow glottal orifice. As air velocity increases when passing through a stenosis.

21 a fall in lateral pressure occurs (Bernoulli effect). The Bernoulli effect encourages further narrowing or closure. When complete closure is achieved, the tube reopens and the phenomenon cycles again. They suggest that the rapid succession of cycles produces rapid oscillations of the tube wall and results in wheezing. These authors suggest that under positive pressure, maximal flows cannot be achieved and glottal aperture is increased due to the higher lung volume. The glottis becomes narrow during lower lung volumes. They report a triad of respiratory signs that might suggest functional airway obstruction: (1) expiratory dyspnea, (2) wheezing with normal lung function, (3) distinctive pattern of breathing: forced low volume breathing revealed by flow volume curves. Description of treatments Physical treatments During an acute, severe episode, the patient’s only concern is getting air into the lungs. As medical personnel are concerned, too, about maintaining an airway, tracheotomy is often a last resort. Therefore, other methods of moving air through the constricted glottis to the trachea have been investigated. One method is inhalation of Heliox. Heliox is a mixture of 80% helium and 20% oxygen. Corren and Newman (1992) reported using a mixture of 70% helium and 30% oxygen. Heliox is less dense in concentration than air, and therefore, more easily inhaled. Wheezing and dyspnea have been relieved via inhalation of this mixture

22 (Christopher, et al. 1983). The inspiratory-expiratory resistance difference can be abolished in asthmatics by breathing Heliox (Cohen, 1980). The low density passes easily the obstructed vocal folds; therefore, the dyspnea is alleviated and the attack is interrupted or subsides gradually. Goldman and Muers (1991) described the beneficial effects of Heliox as the increase of laminar flow through the large airways and reduces the wheeze to relieve symptoms. Helium is less dense than air and can easily transverse areas of high turbulence, i.e., the narrowed glottis (Martin, et al., 1987). Endotracheal intubation and tracheotomy have also been used to provide a patent airway in extreme cases (Christopher, et al., 1983; Caraon & O’Toole, 1991; Corren & Newman (1992). These are severe measures that should only be used in extreme cases. It should be the goal of the medical professionals involved to maintain the airway through these means for as brief a time as possible. Dependency on a tracheotomy for an otherwise healthy individual should be avoided.

The use of some pharmacological agents has been helpful in reducing the severity of an acute attack. Glottic constriction can be reversed through sedation or anesthesia (Goldman & Muers, 1991). Amitriptyline has been beneficial because it is both an antidepressant and a bronchodilator (Barnes, et al., 1986). Other medical interventions which have proven to be less than successful in stopping an acute attack or preventing an attack include bronchodilator syrups, inhaled sodium cromoglycate, medications such as Ventolin and Becotide, oral steroids, and nebulized Ventolin and

23 Atrovent (Caraon & O’Toole, 1991). Medical personnel and families of patients report that the stridor ceases during sleep; therefore, sedation and general anesthesia have been used to interrupt a severe attack. Patients have complained of “night chokes”,sudden choking episodes that wake them from sleep. It is possible that these chokes are laryngospasm-Iike behaviors of the larynx secondary to chronic GERD. Speech Therapy

A speech therapy program for persons with PVCD was first developed at the National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado. The treatment program outlined by Christopher, et al. (1983) has been cited extensively. This program teaches the patient to focus attention away from the larynx and the inspiratory phase of breathing. The patient learns to concentrate on active respiration by using the ventral abdominal muscles and to relax the oropharyngeal muscle group. One of the main goals of speech therapy is to decrease laryngeal muscle tone through low abdominal breathing and throat relaxation activities (Corren & Newman, 1992). One principal exercise recommended during an acute attack is to lay the tongue on the floor of the mouth and to exhale gently through closed lips making a soft /s/ sound (Corren & Newman, 1992).

24 The investigators in the present study have developed a therapeutic program designed to reduce the frequency and severity of attacks. The term “laryngeal control” program is used to describe the treatment. This program includes respiratory retraining, phonatory retraining, relaxation training and vocal abuse identification/elimination as well as other individual or patient-specific topics such as management of gastroesophageal reflux or asthma care. Therapy also includes education about PVCD. Table 2.3 shows the strategies patients learn to use to prevent an attack, reduce its severity (duration or completeness of constriction), or stop the attack.

25 Breathing Facilitation Strategies

1. Try to inhale through your nose. This helps your vocal cords to open as wide as possible. 2. Try to breathe slowly. 3. Try to extend your exhalation. Make it twice as long as your inhalation. 4. Use one or several of the “positive pressure” strategies to help maintain lung pressure: a. Inhale through your nose. Exhale through an /s/ sound. b. Inhale through your nose. Exhale through pursed lips. c. Inhale through pursed lips. Exhale through pursed lips. d. Inhale through an /s/ sound. Exhale through an /s/ sound. 5. As your breathing slows down, try to take deeper inhalations. Remember to use low abdominal breathing. Place your hands on your head to promote low abdominal breathing.

Table 2.3: Attack resolution strategies trained during a laryngeal control program for PVCD

2 6 Other respiratory based exercises have been designed to alleviate the dyspnea of PVCD. Teaching the patient to cough or pant during an attack has been described (Goldman & Muers, 1991). This presumably causes the adducted vocal folds to relax, facilitating more normal respiration. Coughing and panting have been shown to decrease glottic constriction.

Stanescu, Pattijn, Clement, and van de Woestijne (1972) studied glottis opening and airway resistance in five healthy volunteers. The noted that a

significant positive correlation was found between glottis opening and lung volume as well as glottis opening and flow rate. During their procedures, they compared glottis opening during tidal breathing and panting. They found that the glottis was wider during panting, and the differences in glottic width during inspiration and expiration during panting was smaller. These authors concluded panting is a suitable method for minimizing the influence of the glottis. Their intention was to find a suitable method for measuring resistance; however, their findings can be adapted to breathing exercises to help the patient with PVCD. Other exercises that provide continuous positive airway pressure may relieve wheezing. Continuous positive pressure slows the expiratory flow rate, which encourages the glottis to widen. This allows residual volume to increase (Goldman & Muers, 1991). The exercises in Table 2.3 were designed to produce this glottis-widening positive pressure.

27 The frequency and severity of acute attacks were reduced after therapy in all patients studied in the National Jewish Center for Immunology and Respiratory Medicine speech therapy program. All of these patients received a short course of psychotherapy, as well (Christopher, et al., 1983). Follow-up of these patients occurred for 3-21 months; the patients were asymptomatic and did not take steroids or other medications for asthma. Psvchiatric/Psvchologic Treatments Many reports in the literature indicate that psychotherapy is a crucial part of the treatment of PVCD (Corren & Newman, 1992; Christopher, et al., 1983). Speech therapy is useful to relax the patient, while psychotherapy removes the need for the breathing attacks (Goldman & Muers, 1991). The exact nature of the psychological treatments has not been described in the literature. The success of these treatments has been reported anecdotally at the conclusion of the case study descriptions. As patients have been described as being co-dependent, unable to cope with anxiety or stress, and depressed, it is probable that psychotherapy is extremely individualized based on the patient’s needs and psychological/psychiatric examination. Normal Respiration A discussion of normal respiration will provide background for understanding the discussions of asthma, pulmonary function testing, and other respiratory topics that follow.

2 8 Respiration is defined as the process of gas exchange between an organism and its environment (Murray, 1985). Human respiration is divided into four components: (1) ventilation: the active motion of gas from the environment into the lungs and its distribution to sites of gas exchange, (2) blood flow: active movement of mixed venous blood into the lungs and distribution to sites of gas exchange, (3) diffusion: passive movement of molecules of oxygen (O 2 ) and carbon dioxide (CO 2 ) between inspired gas and incoming blood at sites of gas exchange, and (4) control of breathing: the regulation of ventilation to satisfy metabolic requirements and to meet voluntary needs (Murray, 1985). The most common respiratory disorders are disorders of ventilation, various forms of airflow obstruction. The discussion will be focused on measurements of the regulation phase of ventilation. The process of breathing is a cycle; however, for purposes of illustration, the beginning will be at the level of the glottis. The glottis moves to a closed position as the diaphragm moves down and the ribcage expands. The expansion of the ribcage occurs because of contraction of the external intercostal muscles. The ribcage moves outward and upward due to this contraction (Titze, 1994). Lung volume increases when the diaphragm and external intercostal muscles begin this motion. This causes pressure to reduce in the lungs. When the glottis opens (inhalation), air travels into the lungs until pressure is equalized between the lungs and the

29 atmosphere. In reality, the glottis may not close entirely before the air travels into the lungs; negative pressure is regulated in the lungs, encouraging the flow of air into the lungs due to Boyle’s law. The glottis acts as a valve in that it regulates airflow during this process, but it does not typically turn it on and off (Titze, 1994). For expiration, the opposite occurs. Lung volume is decreased by contraction of the internal intercostal muscles and the abdominal muscles.

Elastic recoil of the lungs, the abdominal viscera, and the expanded ribs also contributes to decreased lung volume. The glottis continues to regulate airflow during expiration by altering resistance to the flow (Titze, 1994). Normal Laryngeal Behavior Normal laryngeal behavior must be discussed to enable understanding of abnormal laryngeal behaviors and to discern possible physiologic etiologies. The movements of the vocal folds are under complex voluntary and visceral control. The larynx is capable of several functions that aid communication and sustain life. The larynx is primarily a valve which can take several shapes. Breathing, blowing, sucking, yawning, voiceless consonant production, and musical instrument playing are performed with the larynx as an open flow valve (Scherer, 1994). Coughing and throat clearing are produced as the larynx takes on the shape of a transient closed valve. Swallowing, and behaviors which require effort such as lifting and defecation are performed with the larynx as a

30 constant closed valve (Scherer, 1994). Therefore, the primary functions of the larynx include valving for respiration and swallowing. Phonation is a secondary, non-life sustaining function of the larynx. Laryngospasm is a prolonged laryngeal closure which serves as a protective mechanism when the sensors of the larynx detect aspiration of foreign matter.

The vagus nerve (Cranial Nerve X) is the primary innervation of the larynx. Overall, it is primarily a sensory nerve (90%) and secondarily a motor nerve (10%). The vagus controls the muscles used for phonation and swallowing; it also controls cardiac muscles, smooth muscles of the esophagus, stomach and intestine, and the muscles of the pharynx, larynx, epiglottis, thorax, and abdomen. Taste sensations from the pharynx and epiglottis are also mediated via this nerve (Bhatnagar & Andy, 1995). The vagal nuclear complex is located in the floor of the ventricles of the medulla oblongata. This complex consists of the dorsal motor nucleus, the nucleus ambiguus, and the nucleus solitarius. Sensorimotor branches to the periphery arise after exiting the brainstem from the lateral medulla between the inferior olivary nucleus and the inferior cerebellar peduncle (Bhatnagar & Andy, 1995). The general visceral afferent (GVA) component relays cutaneous sensation from the muscles of the pharynx, larynx, thorax, abdomen, heart, bronchi, and esophagus. The cell bodies of these sensory fibers are housed in the inferior ganglion in the jugular foramen. This ganglion projects to the tractus and the nucleus solitarius. Afferent fibers from the n. solitarius

31 ascend the medial lemniscus to the ventral posterior medial (VPM) nucleus of the thalamus. These fibers then ascend to the sensory cortex in the parietal lobe. General visceral efferent fibers in the autonomic nervous system parasympathetically innervate the cardiac muscles and smooth muscles of the trachea, bronchi, esophagus, stomach, and intestines. The dorsal motor nucleus is located on the floor of the fourth ventricle and sends projections to different distal ganglia. These projections extend to ganglia located along the walls of the trachea, bronchi, heart, esophagus, stomach, and intestines. These fibers regulate function of these structures (Bhatnagar & Andy, 1995). Special visceral efferent fibers from the vagus nerve innervate muscles of the larynx, pharynx, and upper part of the esophagus. These motor fibers originate from the posterior two thirds of the nucleus ambiguus. These efferent fibers control the muscles of the pharynx, soft palate (except for tensor palatini), the intrinsic muscles of the larynx, and upper portion of the esophagus. The pharyngeal branch of the vagus nerve supplies three constrictor muscles (superior, middle, and inferior) of the pharynx and the soft palate (Bhatnagar & Andy, 1995).

The cricothyroid muscle, an intrinsic laryngeal muscle, is controlled by the external branch of the superior laryngeal nerve. The recurrent laryngeal branch of the vagus follows a different path on both sides of the larynx. It innervates the intrinsic muscles of the larynx and and the

32 epiglottis. It is the primary controller of phonation. The nucleus

ambiguus receives afferent projections from tractus solitarius (fibers from the glossopharyngeal and vagus nerves). These projections, both afferent and efferent, form the circuit that produces reflexes such as coughing, vomiting, and gagging.

It is this branch of the vagus nerve that is contributing to the motor responses of PVCD. Injury to the recurrent laryngeal nerve can lead to paralysis or paresis of the vocal folds. Unilateral lower motor neuron paralysis causes a breathy voice quality, hoarseness, and possibly diplophonia due to the unequal masses and tension of the vocal folds following atrophy of the paralyzed fold . Choking and aspiration may be present due to inefficient laryngeal valving during swallows. Bilateral injury to this recurrent branch can result in vocal folds constantly in the adducted or abducted position. As stated earlier, patients with bilateral adduction paralysis typically do not demonstrate inspiratory stridor. Upper motor neuron damage will result in a spastic paralysis of the muscles of the larynx; this will produce a harsh, spastic voice quality. The larynx will not be the only organ to demonstrate deficits or changes due to vagal damage. The autonomic functions and visceral reflexes such as coronary circulation, heart rate, and relaxation and contraction of tracheal and bronchi muscles may be altered. If PVCD is due to a neurological deficit, it may be possible that the changes in autonomic and visceral functions just described account for the complicated

33 list of symptoms patient may describe. In particular, abnormalities of the contraction and relaxation of the tracheal and bronchial muscles may contribute to PVCD masquerading as asthma. However, the vagus nerve rarely is damaged in isolation. Often, the glossopharyngeal and spinal accessory cranial nerves sustain damage in conjunction with the vagus.

Patients with PVCD do not demonstrate signs of glossopharyngeal or spinal accessory damage: paralysis of the soft palate, weakening of the neck muscles (sternocleidomastoid, trapezius), altered taste sensation from the posterior third of the tongue, altered swallowing function, altered sensation of the soft palate, and altered sensation of the posterior one-third of the tongue. Appleblatt and Baker (1981) state that the pathway of “suggestion” is probably mediated by the larynx. By suggestion, these authors are referring to the ability of verbal statements to affect the response of inhaled or ingested substances by asthmatics. For example, they report that acute attacks of asthma can be induced by suggesting that inhaled material is a bronchospastic agent, when in reality, it is physiologic saline solution. Also, they report that the effect of a bronchodilator such as Isuprel can be negated by its administration under the guise that it is a bronchospastic agent. Appleblatt and Baker (1981) believed that the three cases they presented were of psychogenic etiology; therefore, they suggest that hysterical conversion reactions may alter laryngeal reflexes and lower the threshold stimulus needed to produce vocal fold spasm.

34 Respiration is controlled by reticular centers in the medulla and pons. The medullary center contributes to respiration through response to carbon dioxide in the blood and stretch receptors in the lungs. The pontine pneumotaxic center determines respiration frequency. Neurons in the medullary respiration center project to spinal intercostal or diaphragm muscle motor neurons that regulate inhalation and exhalation (Bhatnagar & Andy, 1995).

The muscles of the larynx form two groups: extrinsic and intrinsic. The intrinsic muscles interconnect the cartilages of the larynx; the extrinsic muscles connect the larynx to surrounding structures such as the hyoid bone or sternum (Titze, 1994). It is the intrinsic muscles that control the abduction and adduction capabilities of the vocal folds; therefore, discussion of their normal behavior is required.

The intrinsic muscles of the larynx are both paired and unpaired. The thyroarytenoid muscle (paired) connects the thyroid cartilage below the thyroid notch to the arytenoid cartilage. This constitutes the bulk of the vocal fold. This muscle is often divided into two sections: the vocalis and thyromuscularis. The thyromuscularis is used for quick shortening of the vocal folds and the vocalis is used for fine-tuning tension the the medial fibers of the folds. When working together, these sections contract and the arytenoid cartilages are drawn forward; this shortens and thickens the vocal folds and the vocal folds become stiff. Study of this muscle in the diagnosis of PVCD may be important. Some patients with PVCD have

35 demonstrated a severe, anterior rocking motion of the arytenoids during inspiration; this forward movement of the arytenoids is excessive when compared to normal phonation and inhalation. This forward movement contributes to the glottic chink posture (Morrison & Rammage, 1994). The cricothyroid muscle is also a paired muscle that consists of two parts. Both of these sections originate from the anterior arch of the cricoid cartilage. A vertical part of this muscle (pars recta) travels upward to attach to the lower border of the thyroid lamina. An oblique part of this muscle (pars obliqua) courses upward and backward to insert on the inferior comu of the thyroid cartilage. This muscle is the primary controller of pitch during phonation. It elevates the cricoid arch and depresses the thyroid lamina; this shortens the cricothyroid space and lengthens the vocal folds (Titze, 1994).

The lateral cricoarytenoid muscle is also a paired intrinsic muscle of the larynx. Its origin is the superior borders of the cricoid arch and the inserts on to the muscular process of the corresponding arytenoid cartilage. It adducts the vocal folds by drawing the arytenoid cartilages forward and medially. It brings the vocal processes together by rotation and forward rocking of the arytenoid cartilages on the cricoarytenoid joint (Titze, 1994). This forward motion may be exaggerated in the paradoxical motion of the PVCD attack.

36 The interarytenoid muscle connects the arytenoid cartilages. This muscle also has two sections. The transverse is an unpaired portion; it covers the posterior surface of the arytenoids. Its origin is on the lateral border of one arytenoid cartilage, and inserts on the lateral border of the other arytenoid. The oblique section of this muscle is paired and originates on the muscular process of one arytenoid cartilage. It then travels diagonally to insert onto the apex of the other arytenoid cartilage. The interarytenoid muscle is an adductor of the vocal folds. It works in conjunction with the lateral cricoarytenoid muscle to close the glottis, although it functions more to close off the posterior glottis rather than the anterior glottis.

The posterior cricoarytenoid muscle is a paired muscle that originates on the posterior surface of the cricoid cartilage. It travels upwards and laterally and inserts on the muscular process of the arytenoid cartilage. This muscle is the abductor. Contraction of this muscle rocks the arytenoids backward and rotates the vocal processes away from midline. This motion is opposite to the action of the lateral cricoarytenoid muscle. The size of the glottis typically increases during inspiration and decreases during expiration; the glottic aperture is at its maximum at total lung capacity and at its minimum at residual volume. Maximum expiratory flow rates and low lung volumes occur when the glottis is at its narrowest (Goldman & Muers, 1991).

37 Glottic narrowing during expiration is seen during quiet breathing of normal individuals. This may serve to slow expiration. Expiratory narrowing has been observed following induced bronchoconstriction. These findings support the view that the glottis is capable of reflex adjustments in parallel with changes in the airway integrity (Higenbottam, 1980). Higenbottam (1980) found that a greater inflation of lungs reduced the glottic opening. Higenbottam (1980) also reported that expiratory narrowing of the glottis was more pronounced in patients with reduced FEV j (forced expiratory volume in one second). This glottic narrowing could account for the observed increased extrathoracic resistance to airflow reported in patients with chronic obstructive bronchitis and asthma. Further, increased resistance to expiratory airflow at the level of the larynx could slow airflow in a manner similar to pursed lips breathing. This pursed lips posture has been suggested to asthmatics as a mechanism to increase respiratory capabilities during breathing attacks. Expiratory slowing may limit airway collapse and improve ventilation. Higenbottam (1980) suggested that this complex control of the width of the glottis and its anatomical location within the larynx offers a unique role of regulation of the airflow into and out of the lungs.

McFadden (1987) provides a lengthy essay describing the functions of the larynx and the possible role of glottic narrowing during respiration in chronic airway obstruction. He reports that at first glance, glottic narrowing appears to be paradoxical because one would expect the patient’s

38 symptoms to increase and add to the overall resistive work of breathing. However, the narrowing may act as a respiratory retardant which stabilizes the airways and chest wall. He describes this as cost-effective because the narrowing of the glottic aperture involves activation of a small muscle mass which may reduce the work of the larger abdominal and thoracic muscles of respiration, thus decreasing the metabolic cost of breathing as well as the tendency to respiratory muscle fatigue. This benefit may be seen predominantly during expiration. O’Halloren (1990) labels glottic narrowing during expiration “laryngeal PEEP”: positive end expiratory pressure. He describes the glottic narrowing as a maneuver similar to pursed lip breathing, which has been suggested to asthmatics to slow expiration to limit airway collapse. This maneuver provides evidence that the glottis is capable of reflex adjustments in parallel with changes in airway caliber. It is during inspiration that glottic narrowing may truly be paradoxical and dysfunctional. The integrated function of the vocal folds is lost during this paradoxical movement, which may be under psychological or physiologic control. Possible Etiologies of PVCD

Multiple etiologies may be responsible for the laryngeal behavior of paradoxical vocal fold motion. The literature illustrates two large groups: subjects with asthma where psychogenic causes are suspected or not, and subjects without asthma in which psychogenic causes are highly probable.

39 Craig, et al. (1992) reported that in the “pure syndrome” of PVCD in which psychogenic causes are highly probable, there will be no evidence of bronchial hyperreactivity. Such hyperreactivity can be demonstrated via a challenge test. During a challenge test, the patient inhales a substance, such as the chemical methacholine. A reaction to the test, dyspnea, typically indicates the presence of asthma. If there is no reaction, then the lower airway is considered to be intact. Therefore, a positive challenge test should indicate that a physiological respiratory disorder is present. Paradoxical motion may be present as a result of neurological deficit; the complicated neural inputs to the larynx could sustain injury at several levels resulting in paradoxical motion. This seems unlikely, at first glance, because patients with paradoxical motion do not complain of neurological deficits. Finally, paradoxical motion may be present as a learned behavior. There is evidence that the vocal folds will adduct in some respiratory illnesses to increase pleural pressure in order to decrease tracheal compression. It is possible that the patient with PVCD has developed paradoxical motion as a compensatory maneuver to counteract the effects of respiratory disorders such as asthma or the respiratory complications of gastroesophageal reflux.

40 Psychogenic involvement

Many of the reports in the literature characterize the patient with PVCD psychologically. The following excerpts indicate the broad range of descriptions used to characterize this disorder from a psychogenic perspective: “...have a dependent and childlike relationship with families and difficulty expressing emotions” (Goldman & Muers, 1991, page 403). “...have a difficulty directly expressing emotions...have psychological problems with difficulties in coping with stress.” (Kattan & Ben-Zvi, 1985, page 159). “All patients had difficulty in directly expressing anger, sadness, or fear. All had various degrees of secondary gain from respiratory symptoms.” (Christopher, et al., 1983, page 1568). “...difficulty in expressing anger, sadness, or pleasure directly...difficulty emancipating themselves from childlike relationships in their families.”

(Martin, et al., 1987, page 333). “Strong dependency needs and fears of separation were prominent in the setting of symptom development as well as the hospital course.” (Starkman & Appleblatt, 1984, page 328)

It is recognized that psychogenic and emotional factors can trigger an asthma attack (Kissoon, Kronick & Frewen., 1988; Fields, et al., 1992); the role of these factors in upper airway obstruction (i.e., PVCD) is less clear. Most reports of PVCD have not been able to establish a relationship

41 between the onset of symptoms and exacerbation of psychological stressors (Freedman, Rosenberg, & Schmalling, 1991); therefore, the suspicion that symptoms are emotionally based weakens. It has been the experience of the investigators of the present study that catastrophic stressors (e.g., parent dying, sexual abuse) may not always be present. Less intense stressors (e.g., argument with an athletic coach, jealousy between siblings, anger towards employer) may contribute to the onset and perpetuation of symptoms. PVCD has been called a conversion disorder (Kellman & Leopold, 1982). Conversion reactions provide a psychological defense mechanism for blocking out anxiety-provoking or painful, unpleasant memories from the conscious mind. The reaction provides a substitution for the unpleasant thoughts: an unconscious hysterical symptom (Craig, et al., 1992). In the case of PVCD, the larynx is the target organ of the conversion. Malingering is often suspected as a perpetuating factor. A patient

who is malingering may be purposefully perpetuating or mimicking symptoms for the secondary gain of medical attention or family attention.

Patients are typically unable to reproduce voluntarily the vocal fold adductions or even the stridorous sound; therefore, it seems unlikely that malingering is present (Fields, et al., 1992). Patients with PVCD do not perpetuate the illness for secondary gain. Therefore, this disorder probably should not be considered factitious or malingering. Starkman and Appleblatt (1984) provide a description of four case studies that support

42 the theory that a psychogenic etiology is present. They note:

These patients had significant features in common. While three of the four gave no history of serious respiratory disease, respiratory problems had occurred in three of the families. A setting of psychosocial stress was associated with the onset of symptoms in three of our cases; for two of them, the severely disturbing incidence occurred only hours before the stridor began. All four patients had received psychiatric treatment for symptoms other than laryngospasm. Two of them had a history of psychiatric hospitalization, a third had been placed on tricyclic antidepressants by her family physician, and the fourth received psychiatric treatment after factitious illness had been documented during a subsequent medical hospitalization. The patients were resistant to psychological exploration and guarded about describing ongoing family difficulties (pp. 331-332).

These authors further noted that an abnormal dependency relationship can also be a part of the psychological spectrum of difficulties these patients may experience. Two of their patients developed dependency relationship with medical personnel. They noted that dependency features in PVCD are similar to those found in patients with asthma. They reported that patients with asthma demonstrate conflicts that stem from exaggerated dependency needs; actual or anticipated loss may play a role in the initial attack in some patients. Case studies have shown that PVCD has improved with the administration of bronchodilators. This is possible for two reasons: (1) the dilators served as a placebo and the act of administration provided a psychologic “cure” for the episode, (2) other respiratory illness such as mild asthma is present and the bronchodilators had an appropriate effect.

43 It is important, therefore, to investigate fully the patient’s respiratory status. Assuming that every case of PVCD is psychogenic, one would fail to identify those patients in which a mild asthma component was contributing to the symptoms. Kellman and Leopold (1982) wanted to provide additional characterization of this disorder by attempting to determine if malingering or purposefully producing the paradoxical vocal fold motion was possible. These authors were examined via indirect laryngoscopy. They contend that it was possible to produce the paradoxical motion, but noted that the task was strenuous and neither author could produce the motion for more than 30 seconds without reverting to normal respiration. Also, sustaining the motion produced pain in the larynx. Finally, these authors reported that the motion produced by the authors was not smooth or symmetrical, unlike the PVCD patients who demonstrated symmetry and fluidity in the production of paradoxical motion.

Psychiatric testing may provide evidence to support physicians’ suspicions that unrecognized emotional disturbances are present. Additionally, the recognition of underlying factors allows the individual to obliterate the need for an unconscious physical manifestation of emotional issues and permits the individual to begin dealing with the problems in a more appropriate fashion (Fields, et al., 1992).

44 Emotional factors vary from patient to patient. For example, sexual abuse has been associated with a broad range of psychopathology (e.g., multiple personality disorder, somatization, depression). Freedman, et al., (1991) found that in a group of 39 patients diagnosed with PVCD, 14 reported childhood sexual abuse, 5 suspected childhood sexual abuse, and 20 reported no history of sexual abuse. Patients with PVCD have been diagnosed with a variety of psychiatric disorders ranging from mild stress- related exacerbation of symptoms to obsessive-compulsive disorder; many patients with PVCD do not demonstrate the “typical” histrionic (hysterical) personality traits originally thought to be most prevalent. As stated earlier, the investigators of the present study have found patients’ stressors ranging from arguments with siblings, to an unplanned pregnancy, to long-term sexual abuse. The idea that the etiology of PVCD stems from psychogenic origins does have support. Patients with PVCD have been known to demonstrate behaviors which support suspicion of a psychogenic etiology (Kissoon, et al., 1988). These indicators include:

(1) precipitation of airway obstruction by suggestion, (2) lack of response to medical therapy, (3) relief of symptoms with verbal support, (4) demonstration of the absence of distress and a strikingly calm manner,

(5) ability to speak in sentences easily during an acute attack,

45 (6) failure to use oxygen willingly, (e.g., removal of oxygen mask

when medical personnel are out of the view),and (7) neck flexion during the attack. Neck flexion reduces the airway diameter (Kissoon, et al., 1988). A psychogenic etiology should be suspected when: (1) physical findings are negative for known respiratory illness, (2) the patient has a history of psychiatric illness, (3) the patient has a history of numerous hospital visits or requests for admission, and (4) a variety of medical treatments have failed (Kissoon, et al., 1988). Other patient characteristics that possibly indicate that PVCD etiology is psychogenic include a history of factitious disease, a history of other psychiatric illness, and malingering on diagnostic testing (Downing, et al., 1982). Seiner, Staudenmayer, Koepke, Harvey and Christopher (1987) describe three cases in which challenge testing was repeatedly administered during a course of psychotherapy to illustrate the psychogenic nature of the symptoms of PVCD. These authors provide an excellent description of how the symptoms of PVCD are used for primary gain and secondary gain.

Primary gain diverts an internal conflict into a psychological symptom; the anxiety that would be realized if that conflict were to surface is avoided. In their 32 y/o female, primary gain was revealed through attentional exercises which revealed to the patient repressed, state- dependent memories. She recalled being strangled by her father during an impulsive rage because she could not open an unlocked door. This may

46 have created a need for excessive achievement and perfection. The patient attempted to secure her mother’s attention through great accomplishment; when this failed, she turned to stridor symptoms because her mother responded to physical illness. Secondary gain avoids a particular condition that is noxious; the gain provides support, attention, sympathy, or material gain. Like primary gain, secondary gain works subconsciously and therefore, should not be confused with malingering. Secondary gain in this patient was revealed in the analysis of the stridorous events over an 18 month period. Each stridorous event, as well as other traumatic episodes (allergic reaction to penicillin), resulted in positive maternal support. Psychotherapy revealed that the patient viewed herself as the Cinderella of the family; she learned that she attempted to buy maternal affection with illness.

Finally, additional support for psychogenic etiology includes the success of psychotherapy as a treatment for PVCD. Psychotherapy is the most frequently recommended treatment: 33 out of 66 patients summarized in Table 2.4. The articles report anecdotally that psychotherapy is successful. Reports do not specify data on psychotherapy, number of sessions necessary, duration of therapy, etc.; without such data, it is difficult to determine exactly how psychotherapy helps these patients. Seiner et al., (1987) illustrated the benefits of psychotherapeutic counseling by administering multiple bronchial challenge tests to patients over the course of intensive psychotherapy. Two of their patients

47 demonstrated reduction and/or absence of dyspnic symptoms on the third challenge test administered after the start of counseling. The third patient did not resolve symptoms until another group of physicians diagnosed a glucose imbalance and recommended a special diet. After one week on the diet, all symptoms disappeared. Seiner et al, (1987) supposed that the patient preferred a physical diagnosis for her symptoms and once received, no longer needed the symptoms.

Type of Treatment Number of patients Psychiatry/Psychology 25 Speech Therapy 18 Tracheotomy 8 Heliox 7 Patient refused treatment 6 Reassurance 4 Sedatives/Antidepressants 4 Hypnotherapy 2 Relaxation Therapy 1 Pulmonary Therapy 1 None; symptoms ceased 1 Biofeedback 1 Not specified 2

NOTE: Some patients received combinations of treatments, therefore, the total number exceeds actual number of patients (66).

Table 2.4: Number of patients with PVCD receiving different treatments.

48 Learned Behavior/Compensatory Strategy It is possible that the paradoxical motion of the vocal folds is compensatory movement of the larynx to protect the airway or to facilitate more normal breathing. As stated earlier, the use of glottic closure to promote positive pressure in the lungs may aid in dilation of the bronchi. However, the glottic narrowing on inspiration in asthmatics has been shown to result in inspiratory dynamic compression of the trachea. In patients with asthma, compression of the trachea may be a cause of airway obstruction (Cohen, 1980).

if the compression of the trachea is the cause of the airway obstruction in asthmatics, then it is technically a lower airway abnormality and should be able to be identified as such on pulmonary function tests. As paradoxical vocal fold motion is an upper airway abnormality, it should be distinguishable from lower airway obstmction via PFTs. But, if the paradoxical vocal fold motion is co-occuring with tracheal compression as described, physiological tests need to be able to predict which behavior is contributing more to the dyspnea. Additionally, if the tracheal compression is a result of the learned behavior of the vocal folds as a physiological response to dilate the bronchi, the paradoxical closure may not be a behavior to resolve, but to promote.

Paradoxical closure may also be a compensatory maneuver in which the vocal folds are closing to protect the airway from an irritant. Such an irritant may be the acidic contents of the stomach that penetrate the larynx

49 when gastroesophageal reflux disease (GERD) is present. It is estimated that more than one third of the American population experiences symptoms of GERD on an intermittent basis. Approximately 10% of these patients have described pulmonary symptoms secondary to reflux. Pulmonary manifestations may be the only or the presenting symptoms of reflux (Barish, Wu, & Castell, 1985). Olson (1991) noted that many disorders are being related to GERD, including: posterior laryngitis, cricoarytenoid joint arthritis, subglottic stenosis, carcinoma of the larynx, nonproductive and irritable coughing, hoarseness, hyperkeratosis of the posterior larynx

(pachydermia laryngis), laryngospasm, cervical esophagitis, web formation, excess salivation, aspiration pneumonia, Zenker’s diverticulum, dental caries, ulceration of the mouth, sore throat, intubation granuloma and dysphagia. Bless and Swift (1995) reported that 34-89% of asthmatics have reflux and that 70% of asthmatics with reflux note an improvement in pulmonary symptoms with GERD is treated.

The typical symptoms of laryngeal manifestation of GERD include globus sensation (foreign body sensation in the throat), choking sensation, excessive throat clearing, weak voice, hoarse voice, neck pain, jaw pain, halitosis, and nocturnal apnea (Olson, 1991).

The laryngeal sensitivity to reflux may result in apnea, laryngospasm and respiratory arrest (Barish, Wu, & Castell, 1985). There are two theories which account for the laryngeal reaction to GERD: (1) pulmonary aspiration of refluxed gastric materials may produce acid-induced injury

50 and/or infection, (2) a neurally mediated reflex of bronchoconstriction secondary to the irritation of the esophageal mucosa may contribute to dyspnic-like symptoms. Abnormalities in esophageal motility and difficulty with clearance of refluxed gastric acid may contribute to the manifestation of symptoms.

Barish, et al. (1985) report that there is good evidence for the neural mechanism described above as one of the causes of GERD. They described patients which demonstrated an increased pulmonary flow resistance when gastroesophageal symptoms developed in response to intraesophageal acid. Further, antacid therapy reversed the respiratory changes. Mansfield, Hameister, and Spaulding (1981) studied dogs with esophagitis. They demonstrated a drop in respiratory conductance following intraesophageal acid infusion. This response was not seen in the dogs following bilateral vagotomy in the neck. They suggest a mechanism of stimulation of esophageal receptors triggering a vagally mediated bronchoconstriction.

The incompetence of the lower esophageal segment (LES) contributes to the manifestation of GERD symptoms. LES pressure varies throughout the day; food effects and other agents (alcohol, smoking) affect this pressure as well. Three mechanical causes of reflux due to pressure changes have been proposed; (1) transient LES relaxation; (2) increases in intra-abdominal pressure; and (3) spontaneous free reflux (Olson, 1991). Gastric juices, including acid, pepsin and bile have been shown to be damaging to esophageal mucosa. Increased acid secretion and increased

51 gastric volume have been documented to promote increased reflux. It is estimated that one-third of persons in the United States has intermittent reflux. Further, it is estimated that 10% of this group may have pulmonary symptoms including wheezing, cough, hoarseness or pneumonitis.

GERD has been suspected as a cause of intrinsic asthma; reflux should be part of the differential diagnosis whenever a respiratory disorder cannot be identified. Sokol (1993) stated that cases of vocal fold dysfunction associated with gastroesophageal reflux have reversed with treatment of the reflux. Neurological Differences

There are three possibilities of a neurological deficit causing a disruption in the performance of the aforementioned muscles and their neural control (Collett, et al., 1983): (1) Decreased activity of the glottic dilator muscles, (2) increased activity of the glottic constrictor muscles,

(3) both decreased activity of the glottic dilators and increased activity of the glottic constrictors. It is unlikely that decreased activity of the glottic dilators alone is the primary cause of the paradoxical motion. It is clear that the paradoxical movement of the vocal folds is due to altered neural output to the intrinsic laryngeal muscles during inspiration (Skinner & Bradley, 1989). Patients with bilateral vocal fold paralysis maintain a decreased activity level of the glottic dilators, but often do not produce an audible stridor during respiration. Kellman and Leopold (1982) explained

52 these three neurological theories:

One might postulate an etiology based on the proximity of adductor and abductor neurons to each other in the nucleus ambiguus. It is possible that the nearby inspiratory center is stimulating the adductor cells and inhibiting the abductor cells and vice versa for the expiratory center. (59)

Sokol (1993) reported that the pathophysiology of PVCD may be due to a lowered threshold for stimuli to produce vocal fold spasm due to altered tone in the laryngeal musculature. Electromyographic (EMG) studies are necessary to validate these assumptions. EMG studies may differentiate between the activity levels of the glottic constrictors and glottic dilators to help medical personnel determine which muscle group is the major contributor to the paradoxical motion. Ludlow (1990) summarizes the electromyographic assessment procedures currently available in laryngeal research. These procedures are already employed in the study of several neurological dysfunction syndromes including motor neuron diseases such as amyotrophic lateral sclerosis, or laryngeal movement disorders such as spasmodic dysphonia, vocal tremor, or Parkinson Disease. As PVCD visually appears to be laryngeal movement disorder, it is highly likely that these neurological techniques will refine what is known about PVCD and its relationship to laryngeal neurological function.

53 Kellman and Leopold (1982) also suggest the possibility of a brainstem abnormality causing the paradoxical motion. They reported on a patient who presented with dizziness, nystagmus to the left in all fields of gaze, paralysis of cranial nerves IX, X, XI, and XII on the right, and incoordination of his right arm and leg after head trauma. Indirect laryngoscopy demonstrated paradoxical motion of the unaffected vocal fold; the patient was not symptomatic for PVCD. An epidural hematoma was not substantiated by CT scan; conservative treatment resulted in resolution of the paradoxical motion within 24 hours and the other neurological signs within a few weeks. Kellman and Leopold (1982) also suggest that PVCD may be the result of cortical dysfunction. They describe an elderly female with chronic aspiration, persistent pneumonia, and organic brainstem syndrome secondary to viral encephalitis. Intermittent stridor was present as was hypoxemia; the hypoxemia worsened when the stridor increased. Indirect laryngoscopy documented the PVCD. CT scan demonstrated diffuse cortical atrophy and ventricular enlargement; however, the authors reported that significant brain stem pathology was not found. The patient was given a tracheotomy and normal laryngeal function returned. The authors noted that the chain of events for this patient was “obscure”; however, they offered the case as a possible description of a cortically based example of PVCD.

54 Woodson (1990) summarized briefly the assessment of sensation in voice disorders. She notes that research had demonstrated a variety of receptors present in the larynx. Fibers in the sensory branch of the superior laryngeal nerve react to upper airway pressure, transglottic airflow, and vocal fold motion. Studies have demonstrated the contribution of these receptors to vocal control. Conversely, studies have been unable to document any effect of laryngeal anesthesia on frequency range, loudness, vibratory pattern, or pitch stabilization. Other studies have demonstrated an effect of laryngeal anesthesia on glottal resistance, pitch perturbation, and phonation adjustment times (Woodson, 1990). It is possible that a laryngeal anesthesia facilitates inappropriate sensation of laryngeal, tracheal, or lung pressures thereby resulting in the paradoxical motion. It is also possible that a hypersensitivity of laryngeal receptors contributes to the paradoxical motion. Campbell, Mestitz, and Pierce (1990) suggest that throat irritation may sensitize laryngeal receptors causing attacks of laryngospasm. The report that patients who receive light anesthesia experience prolonged laryngeal closure. One patient they describe was a 72 y/o female who coughed violently following ingestion of an alcoholic drink; this induced episodes of sudden, complete respiratory obstruction followed by difficult respiration. Bronchoscopy showed complete vocal fold adduction. Maximum inspiratory flow loops were reduced and flattened. These authors suggest careful questioning about the sequence of events that occur prior to and concurrent with the laryngeal dysfunction. Ophir, Katz, Tavori, and Aladjem (1990) suggest that the striated

musculature of the upper airway is frequently involved in extrapyramidal disorders. This interferes with the muscles’ role in maintaining patency of the upper airway and leads to airflow limitation and stridor. However, no neurological deficits were detected in their patients; the literature lacks descriptions of neurological symptoms or neurological testing. Differential Diagnosis

Studies have reported generalized statements indicating that the clinical and physiological findings in the subjects were inconsistent with an asthma diagnosis (Downing, Braman, Fox, & Corrao, 1982). Many reports list the results of various clinical tests (e.g., blood gas levels,

spirometer readings, challenge tests) that rule out asthma, other respiratory conditions, and airway obstruction possibilities. Paradoxical closure of the

vocal folds is documented by transnasal laryngoscopy; however, the literature lacks other objective measurements that positively identify PVCD. Objective measures that differentiate PVCD from other disorders have not been identified.

56 The abnormal adduction of the vocal folds during an attack of PVCD is an observation which provides unequivocal proof that the disorder is present. This type of finding can only be discovered when the disorder is in the acute stage and the patient seeks treatment. This assumes that glottal narrowing occurs only when the patient is symptomatic. Examination of

200 subjects has provided evidence that paradoxical motion of the vocal folds during respiration is observed in patients with PVCD during asymptomatic periods. The literature lacks objective measures of persons with PVCD evaluated between attacks. The present study was designed to determine if objective measurements collected from subjects between attacks or when symptoms were not exacerbated could indicate the presence of PVCD. Diagnostic criteria based on presentation of symptoms have been categorized in an attempt to classify a patient who could be demonstrating PVCD. Fields, et al. (1991) report that PVCD is a diagnosis of exclusion. Differential diagnosis should begin with wheezing, which naturally includes asthma.

Logvinoff, Lau, Weinstein and Chandra (1990) stated that PVCD should be suspected whenever a patient presents in respiratory distress with discomfort at the neck level, is afebrile, demonstrates a fast respiratory rate, produces stridor, and has decreased breath sounds; neck and chest x- rays should be collected to document normal structure. If refractory asthma is suspected, PVCD should be investigated (Craig, et al., 1992).

57 Table 2.5 indicates the potential differential diagnosis of dyspnea and/or wheezing (Field,s et al., 1992; Craig, et al., 1992; Appleblatt & Baker, 1981; Sim, McClean, Lee, Naranjo, & Grant, 1990)

Upper Airway Endobronchial obstruction Tracheal stenosis Foreign body Laryngeal obstruction, anaphylaxsis Bronchogenic carcinoma Laryngeal spasm Bronchial adenoma Laryngeal edema, epiglottitis Vocal fold paralysis Bronchospasm Tonsil and adenoid enlargement

Goiter Asthma Laryngeal trauma Carcinoid Abscess of hypopharynx Congestive heart failure Laryngeal polyps, pappilomae

Emphysema Allergic reaction Infection Chronic diseases (Wegener’s granulomatosis, rheumatoid arthritis, sarcoidosis) Tracheal scarring from previous trauma or procedure Aortic aneurysm

Table 2.5: Differential diagnosis of wheezing/stridor.

Asthma must be completely investigated when respiratory distress and/or wheezing are present (Corren & Newman, 1992). The traditional definition of asthma includes reactive airways provoked by infection, exercise, stress, or aeroalergens in which the airway obstruction is

58 manifested as wheeze and reversibility of the obstruction with medical therapy is possible. Indicators that asthma is not present include: (1) the absence of chest symptoms during exercise or sleep (that is, if exercise does not cause respiratory difficulties),

(2) poor response to aggressive asthma therapy, (3) arterial-alveolar oxygen gradients within normal limits

(asthma demonstrates abnormalities), (4) normal pulmonary function tests (PFTs) two weeks post asthma exacerbation. Respiratory function normally remains depressed for as long as two to three weeks following an asthma attack, (5) negative histamine challenge test and

(6) flattened flow-volume loop on inspiration. If this profile is present, asthma is probably not the cause of the respiratory symptoms; PVCD should be considered in the differential diagnosis. Asthma, like PVCD, produces episodes of wheezing and dyspnea.

Rapid labored breathing with the use of the accessory muscles occurs. Widespread narrowing of the airways due to bronchospasm, mucosal edema and mucus plugging is observed. This leads to air trapping and ventilation-perfusion mismatching (Downing, et al., 1982). Positive physical findings for asthma can be documented. Signs that indicate asthma is present include:

59 (1) hyperinflation of the lungs (thoracic hyperinflation) (Downing, et al., 1982) observed via chest x-ray, (2) PFTs demonstrating obstruction to airflow,

(3) hyperactive airways in response to challenge testing; bronchial hyperreactivity is the sensitivity of the airways to physical, chemical and pharmacological stimuli as measured by the degree of bronchoconstriction occurring following inhalation challenge testing.

Methacholine inhalation is the most reliable because asthmatics consistently show greater constriction than normal, (4) wheezing predominantly in chest during auscultation, (5) PFTs showing reversibility of obstruction when bronchodilator medications are administered, (6) spirometric evidence of airflow obstruction, and (7) hypoxemia; arterial blood gas tensions have been shown to differentiate between PVCD attacks and asthma attacks (Goldman & Muers, 1991;

Craig, et al., 1992). McLNiven and Pickering (1991), however, reported on two cases of PVCD in which hypoxemia was present.

The possibility that PVCD and asthma co-occur exists. There is evidence that glottic narrowing is present in persons with asthma; however, unlike PVCD, this glottic narrowing is most prevalent during forced expiration. Glottic narrowing in PVCD is observed more frequently during inspiration. Goldman and Muers (1991) point out that the glottis

6 0 may contribute to the control of airflow in asthma and may effectively limit airway collapse and improve ventilation. This may be true if the narrowing occurs during expiration. Additionally, other parts of the upper respiratory system, (e.g., oropharynx) have been shown via fluoroscopic techniques to narrow during bronchoconstriction. This may suggest that the upper airway structures (e.g., muscles) play a part in ventilatory control. Meltzer, Orgel, Kemp, Welch, Ostrom, Park, and Keams (1991) summarized the diagnostic tests commonly performed to identify PVCD: (1) Physical examination: stridor, use of accessory muscles on

inspiration (2) Chest x-ray: normal; no evidence of infiltration or hyperinflation (3) Pulmonary function tests (PFTs) a. Within normal limits during symptomatic periods b. Within normal limits immediately following resolution of distress c. No bronchial reactivity via exercise testing, Methacholine or histamine challenge (4) Flow volume loops: may show abnormality on inspiratory or

inspiratory and expiratory portions; may show increased expiratory to inspiratory ratio

(5) Arterial blood gases; typically normal, may show hypoxemia if sufficient obstruction present

61 (6) Laryngoscopy

a. closure of true vocal folds during inspiration b. closure of true vocal folds when stimulated via contact c. closure of anterior two-thirds of vocal folds producing the diamond shaped chink (7) Gastroesophageal reflux studies It is interesting that these authors included 6b in their protocol. It is well documented that the true vocal folds will close when stimulated via contact (e.g. for example, the flexible fiberscope touching the folds). Therefore, it is not significant in an evaluation of PVCD if this normal reaction is present. Pulmonary Function Testing Pulmonary function testing (PFO has several important functions: (1) detection and quantification of respiratory disease, (2) documentation of the evolution of disease,

(3) documentation of the response of disease to therapy, (4) preoperative evaluation (to identify a high-risk patient or to

define extent of resectability), and (5) assessment of disability/impairment (Murray, 1985).

PFT is important to differentiate between other respiratory diseases, such as asthma, and PVCD. PFT testing is valuable because some respiratory diseases, including asthma, will demonstrate normal pulmonary functions between attacks, but during or shortly after an attack, completely normal

6 2 pulmonary function will not be present (Downing, et al., 1982). In the study of PVCD, this has been found not to be the case. Once an attack ceases, if pulmonary function does not return to normal within a certain

period of time, the probability that PVCD is the only cause decreases. PFTs typically includes flow volume loops, bronchial challenge tests,

endoscopic evaluation of airways, forced vital capacity with wedged spirometer, forced expiratory volume in 1 second (FEVp, arterial blood gas testing (ABGs) (Downing et al., 1982). Fields, et al. (1992) recommended using fiberoptic bronchoscopy to rule out cinatomic variants. Several studies, (Goldman & Muers, 1991; Fields, et al., 1992) reported diagnostic testing often reveals rapid breathing with low lung volume, absence of hyperinflation, auscultation of wheeze at the level of the larynx, blood gases within normal limits, variable spirometry readings, and flow volume loops showing extrathoracic obstruction. Barnes, Grob,

Lachman, Marsh, and Loughlin (1986) and Collett, et al., (1983) describe the loops as a flattening of the inspiratory portion of the maximal expiratory and inspiratory flow volume curves. Craig, et al., (1992) stated that the flow volume loops usually show flattening of the inspiratory

loop, a normal expiratory loop, and an increase in the ratio of expiratory to inspiratory flow during symptomatic episodes. Cormier, et al. (1980)

stated that pulmonary function testing (PFT testing) usually identifies a typical pattern of flow-volume loops: more obstruction to inspiratory flows for extrathoracic lesions and more obstruction to expiratory flows for intrathoracic lesions. Martin, et al. (1987) stated that many of these test results, for example, flow volume loops, are suggestive, not diagnostic. Flow volume loops do not confirm the disorder; the flow loops must be studied in conjunction with additional testing. During an attack, the flow volume loop may show abnormality during inspiration, expiration or both. A cough during the flow volume loop will open the folds and the expiratory loop will increase. Cohen (1980) reported a case study in which vital capacity was reduced (41% of predicted) and FEVj was diminished. Additionally, FEV/VC indicated severe airflow limitation typical of asthma. Peak flow was low (12%), which was also typical of asthma. However, peak flows during cough normalized. Following administration of bronchodilators, spirometry tested within normal limits. He reported that airway pressure flow curves are helpful is diagnosis because greater pressure is required to produce a given flow if the airway becomes obstructed. This causes a decrease in the slope of the curve (which is characteristic of airway obstruction). In general, when there is upper airway obstruction in asthma, resistance to flow in the upper airway is greater during inspiration than expiration. In persons without respiratory disorder, resistance is greater during expiration than inspiration due to minor expiratory glottic narrowing. With airway obstruction, pleural pressure becomes positive during expiration. Pressure in the trachea and main bronchi is less than pleural pressure. During expiration, these airways are compressed. In an instance of laryngeal narrowing, one would expect compression of extrathoracic trachea on inspiration as pleural pressure compresses the intrathoracic trachea on expiration. Typically, as flow increases during inspiration, intratracheal pressure decreases and tracheal compression increases (Cohen, 1980).

Laboratory data during asymptomatic periods versus symptomatic periods may be suggestive of PVCD. During asymptomatic periods, lung volumes, spirometry and blood gases are typically within normal limits. Blood gases and the alveolar-arterial oxygen difference typically remain normal during an acute attack. Spirometric tests may be highly variable. This pronounced variability in spirometric testing may be a useful clues in diagnosis. Persons with a confirmed respiratory disorder should not vary excessively in their spirometric performance (Goldman & Muers, 1991). Additionally, information from the patient should be incorporated into the diagnostic process. The patient should be asked to show where the airflow is being inhibited and should be questioned specifically about the airflow at the larynx. Auscultation of the laryngeal area is typically a poor indicator of vocal fold function (Martin, et al., 1987). Corren and

Newman (1992) echo the belief that auscultation of the neck and chest is not a reliable diagnostic procedure because some patients with PVCD have demonstrated wheezing predominantly over the chest although the vocal fold adduction has been observed via laryngoscopy.

65 Speech Pathology/Otolaryngology Testing At this time, flexible fiberoptic laryngoscopy is the only definitive study that can allow observation of the paradoxical motion in the “purest” manner (Corren & Newman, 1992). It is within the scope of practice for speech-language pathologists (SLPs) to perform endoscopic examination of the larynx. Transnasal laryngoscopy or rigid rod oral endoscopy can be used to visualize the larynx; transnasal laryngoscopy is preferred in diagnosis of PVCD to allow patients to use conversational speech during the exam and to avoid the possibly confounding motion of the vocal folds due to the gag reflex. Connected speech tasks are not possible via oral endoscopy as the tongue is typically fixed in the examiner’s hand. Ideally, laryngoscopy is done during an acute exacerbation. Laryngoscopy is necessary to document not only the vocal fold adductions, but also the lack of laryngeal pathology such as polyps, pappilomae, or neurological damage such as a fixed bilateral vocal fold paralysis (Corren & Newman, 1992). The testing protocol should include repetitive, rapid deep inspirations, panting, and phonation. Insertion of the scope below the epiglottis may trigger an attack. Exercise prior to examination may also trigger an episode (Martin, et al., 1987). At times, there is persistence of paradoxical motion of the vocal folds on indirect exam without the presence of symptoms. This may suggest an underlying physiological problem that may predispose patients to symptoms (Kellman

6 6 & Leopold, 1982). The present study was designed to test this hypothesis through the development of an aerodynamic protocol that identifies subjects with PVCD when they are not in an acute exacerbation of

symptoms. Conversely, Corren and Newman (1992) stated that for the diagnosis of PVCD, it is important that the flow-volume loops and

laryngoscopy are within normal limits during asymptomatic periods. This assumes that once the breathing attack has ended, the structure and function of the respiratory and laryngeal systems returns to normal. But, the definition of asymptomatic needs clarification. However, there are times when the patient does not complain of symptoms, but shows signs. Then, examination between attacks is not normal. This difference may indicate difference in etiologies. For example, it is possible that when a person demonstrates normal flow

volume loops and a normal larynx, the etiology may be psychogenic. In patients who demonstrate paradoxical vocal fold adduction between acute exacerbations and in the absence of stridor, an underlying neurological etiology or a compensatory habit may be perpetuating the abnormal movement.

It is highly unlikely, given the trauma to the systems during the attack, that laryngeal function can return to normal immediately. The constant contraction of the vocal folds may increase vocal fold swelling, mucous production, and facilitate an imbalance in respiratory function. It is possible that these mild changes in the respiratory and phonatory systems

67 could be detected during asymptomatic periods, offering evidence that an attack had just happened, or even that one is pending. According to Craig, et al., (1992), normal examination between attacks does not exclude the diagnosis. Therefore, the present study has been designed to attempt to identify these differences in the aerodynamic performance of persons with PVCD compared to controls.

Researchers have also noted wheeze-free intervals during general anesthesia or sleep or when the patient is distracted; this may support the theory of a psychogenic etiology (Bames, et al.,1986). Starkman and Appleblatt (1984) reported that among patients no case of stridor worsened and in one case stridor disappeared once consciousness was lost. This reaction contrasts stridor secondary to organic etiologies; stridor caused by organic etiologies typically worsens during anesthesia due to relaxation of laryngeal soft tissues. It is becoming clear that a multidisciplinary team approach is increasingly necessary to provide these patients with the most appropriate care. At a minimum, laryngology, speech pathology, psychiatry, and pulmonary medicine should be involved (Christopher et al., 1983). Aerodynamic Analysis Aerodynamics is a branch of mechanics dealing with pressures, forces, resistances, and movements and their reactions caused by motion between air and solid boundaries. Aerodynamics in the speech realm refers to the mean air pressures and airflows produced as part of the

68 mechanics of the respiratory, laryngeal, and supralaryngeal airways (Scherer, 1990). Research has demonstrated that the respiratory components of speech do follow physiologic regulating system principles. This has led to the use of pressure and airflow instrumentation. These instrumentations assess the physiologic responses to changes during speech production. Aerodynamic assessment is valuable for several reasons: airflow assessment (1) documents the extent of a structural deficit, (2) measures the effects of the deficit on temporal patterns during speech production, (3) identifies compensation responses/behaviors, and, (4) provides objective information gauging the effects of treatment on outcome. Laryngeal function can be described quantitatively via aerodynamic assessment (Warren, 1990; Scherer, 1990). Scherer (1990) describes airflow characteristics as “gross” and “fine.” Measures of fine characteristics are measurements which deal with short-term calculations often tens of milliseconds or less; these fine measures deal with aspects of pressure and flow within individual phonatory cycles. Examples include peak values, slopes at specific times, dynamic subglottal pressure, and intraglottal pressures. Measures of gross characteristics represent characteristics over longer periods of time such as hundreds of milliseconds or more. Examples include average subglottal pressure, mean airflow, flow resistance, sound pressure level, and acoustic efficient measures. The present study deals with gross measures of aerodynamic performance, including vital capacity, phonatory volume, and

69 mean airflow.

PVCD is primarily a respiratory disorder; the larynx is considered to be part of the phonatory system as well as the respiratory system. The creation of voicing is within the airflow which exits the glottis, and not in the motion of the vocal folds. The motion of the vocal folds helps to shape the characteristics of the airflow (Scherer, 1994). If the motion of the vocal folds in PVCD is aberrant, then it is logical to develop assessment techniques in the domain of aerodynamic measurements. The present study investigates the airflow of persons with PVCD compared to controls to determine if flows, and other related aerodynamic measures, differentiate the groups. It is not unlikely that aerodynamic variables in persons with PVCD are different from controls due to the extraneous laryngeal movements that occur during the acute attacks and between attacks. The paradoxical motion may not be as obvious or as severe when the subject is asymptomatic, but this motion has been observed and therefore, it is expected that some physiological measurement will demonstrate this atypical behavior. Also, it is likely that the excessive muscular contractions causing the paradoxical motion would increase the overall level of muscular activity or laryngeal tension. It is possible that elevated levels of muscular activity, or “tension,” could affect performance of these muscles when activated appropriately, for example, during phonation. Although the muscles, at this time, appear to be producing

“normal” phonation, it is likely that in some measurable variables, such as airflow, atypical performance can be assessed. Therefore, the present study utilizes an aerodynamic protocol to assess the theory that the presence of paradoxical motion of the vocal folds in an episodic manner will affect the coordination of the larynx during phonation and that these changes can be assessed via aerodynamic analysis. Proposed model of PVCD The literature outlined earlier proposes that persons with PVCD do not demonstrate signs of the disorder (specifically the paradoxical closure of the vocal folds) between episodes, and therefore, diagnostic testing will demonstrate results typical of persons without respiratory or voice disorders. The main hypothesis of the present study is that persons with PVCD do demonstrate physical signs (e.g., paradoxical motion of the vocal folds during respiration) when asymptomatic, or between attacks. This paradoxical motion during respiration has been observed in the 50 subjects in the PVCD group for the present study. It is therefore not unreasonable to assume that these physical signs will produce detectable effects in aerodynamic performance. These effects are likely to be subtle due to the fact that most persons with PVCD do not demonstrate laryngeal pathology. Laryngeal pathology is known to alter vibratory patterns of the vocal folds and is detectable by large variations if aerodynamic performance. Respiratory tasks that measure aerodynamic performance are more likely to demonstrate the suspected differences between persons with PVCD and controls. This is expected because PVCD is a respiratory disorder,

71 affecting the processes of respiration conspicuously. However, because the muscles of the larynx involved in respiration are also involved in phonation, it is possible that measures of aerodynamic performance collected during phonatory tasks will also demonstrate subtle differences in controls and persons with PVCD. It is expected, however, that respiratory tasks will be more efficient in differentiating the two groups. It is also possible that specific phonatory tasks will be better able to differentiate the two groups than other phonatory tasks. This is expected because persons with PVCD do not demonstrate laryngeal pathologies typically, and the muscular incoordination of PVCD is probably intermittent in nature on a gross level. It is possible that persons with PVCD are able to control the larynx for certain phonatory or respiratory maneuvers, but are unable to control the larynx for similar maneuvers.

Urgency of developing diagnostic methods It is with great urgency that the development of diagnostic methods should be developed for the identification of persons with PVCD. PVCD tends to be a recurrent disorder; the problem can be serious in that patients have demonstrated apnea or unconsciousness. There have been instances of tracheotomy or endotracheal intubation in an effort to provide relief to patients or to maintain a patient airway (Collett, et al., 1983). It is necessary to recognize the possibility of a psychogenic airway obstruction because these patients are at risk of intubation, tracheostomy, unnecessary hospitalizations or other unnecessary treatments such as

72 excessive steroid use or other potentially toxic medications (Bames, et al., 1986; Craig, et al., 1992). Iatrogenic Cushing’s Syndrome due to excessive use of steroids is one example of a treatment induced illness commonly seen in persons with PVCD (Goldman & Muers, 1991). Further, these patients present to emergency care on a regular basis, are admitted for lengthy hospital stays, and often cannot work due to their physical condition. Therefore, the present study was designed to begin to develop diagnostic criteria to assist in the earlier identification of persons with PVCD to prevent needless diagnostic testing and potentially harmful treatments.

73 Figure 2.1: Normal larynx during inspiration (top) and larynx demonstrating paradoxical vocal fold motion during inspiration (bottom). 74 CHAPTER 3

METHODOLOGY

The purpose of this chapter is to provide the methodology applied to obtain the aerodynamic measurements and to describe the statistical procedures used to analyze the measurements.

The present study was a combination of a retrospective file review and ongoing research in The Ohio State University Voice Center in the

Department of Otolaryngology. This out-patient clinic provides diagnostic and therapeutic speech-language pathology services to assess and treat voice/laryngeal disorders of all types, including PVCD. Subjects

PVCD group Patients subsequently diagnosed with PVCD were typically referred by a physician (e.g., pulmonologist, otolaryngologist, allergist) for evaluation. These subjects were evaluated by one of two speech-language pathologists

75 at The Ohio State University Voice Center. These patients were referred to this clinic for evaluation based on either objective analyses by their physicians or, at minimum, based on their medical history and/or history of complaints. Not all of the patients subsequently diagnosed with PVCD were used in the PVCD group. Only subjects who demonstrated the hallmark “paradoxical adduction” or narrowing of the glottis during inspiration or expiration at the time of evaluation were used for the present study. This strict criterion was used to ensure that the PVCD subjects definitively demonstrated the most salient characteristic of the syndrome. Subjects in the PVCD group were evaluated between July 1, 1994 and April 30, 1996. This criterion was based on evaluation of 85 persons with PVCD and 29 persons suspected of having PVCD (which could not be confirmed) prior to the onset of this study. In addition, 70 persons during the course of the study (in addition to the 50 subjects included in the present study) were determined to have PVCD, but were excluded from the analysis. These subjects were excluded for two reasons: (1) the subject demonstrated a laryngeal pathology other than or in addition to PVCD

(e.g., vocal nodules, contact granuloma, etc.) or (2) the subject did not demonstrate paradoxical closure of the vocal folds during any portion of the VLS examination. This subject may have been referred for treatment of PVCD based on other testing, but did not demonstrate the hallmark sign during examination.

76 At The Voice Center, persons suspected of having PVCD may be referred for laryngeal control therapy if one aspect of evaluation is typical of PVCD. The three portions of evaluation include (1) case history interview, (2) visual examination of the larynx, and (3) aerodynamic analysis. This procedure ensures false positives. For example, persons who may not have PVCD (and did not demonstrate PVCD endoscopically) may be enrolled in a treatment program based on other findings (e.g. case history, airflow or both). Other persons who demonstrated PVCD-like characteristics only during aerodynamic analysis were referred for the laryngeal control therapy. At the present time, over-referral for treatment is preferred as the professions studying the disorder are attempting to understand the disorder. Many of these patients have no other treatment options to try; therefore, laryngeal control therapy is their only option for treatment. However, as some of these patients were encouraged to seek treatment based on their airflow results, using them in the PVCD group would encourage data to fit the theories purported by the author of the present study. Therefore, these subjects have been eliminated from the analyses.

The evaluation protocol format for subjects with PVCD consisted of a case history interview, videolaryngostroboscopy (VLS), and transglottal airflow analysis (aerodynamic analysis). The videolaryngostroboscopy examinations were reviewed for subject selection. Only subjects who

77 demonstrated paradoxical vocal cord adduction or glottic narrowing during respiration (either inspiration or expiration) were included in the present study. This objective criterion was developed to ensure that subjects in the experimental group demonstrated PVCD, and to eliminate subjects with a borderline diagnosis. This group of subjects totaled 50; 38 female and 12 males. Demographic data (for both groups) can be seen in Table 3.1. Additional demographic data for control subjects and subjects with PVCD can be found in Table 3.2.

Demographic Data Female Male Total N PVCD 38 12 50 Control 38 12 50 Mean Age PVCD 47.5 (25.0-72.0) 48.5 (25.0-64) 47.0 Control 27.5 (19-52) 31.5 (23-46) 27.6

Table 3.1: Age and gender data for persons in PVCD and Control groups.

78 PVCD Control Female Male Female Male Asthma Yes 22 5 0 0 No 14 3 38 12 Unconfirmed 2 4 0 0 Smoking Yes 3 1 4 0 No 26 10 25 11 Former 9 1 9 1

Table 3.2: Asthma and smoking data for PVCD and Control groups.

The presence or absence of an asthma diagnosis was determined during the case history interview. If the physician did not provide the diagnosis of asthma in the referral documentation, the patient was asked if an asthma diagnosis had ever been made. The label of “unconfirmed” was applied to subjects who reported that the doctors were not sure if asthma was present, or if the subject could not remember if the diagnosis had been made. It is important to remember that this diagnosis of asthma is not based on objective testing (such as a methacholine challenge test) in all patients.

79 Persons with asthma were not excluded from the present study because asthma is a questionable diagnosis in persons suspected of having PVCD and may be a coexisting condition. The PVCD may masquerade as asthma and the subject may believe asthma is present, when in reality it is not. The unequivocal documentation of asthma for most of the patients in the present study was not available; most of these patients were referred to this clinic because traditional asthma therapy was not controlling the suspected disorder. Therefore, eliminating subjects because they carry the asthma diagnosis would be premature in the early stages of the investigation of PVCD. Control group

The control group was recruited from the population of the university. Volunteers responded to posters around campus and electronic mail (Internet) postings requesting persons with no vocal training, no history of asthma or other respiratory disorders and no complaints of voice disorder. Subject were not excluded based on any tobacco use. Due to university regulations, women were excluded from the study if they admitted to being pregnant at the time of the evaluation. Men and women were recruited to reflect similar proportions of the population of persons in the PVCD group. Control subjects were paid $20.00 for completing the case history, VLS, and aerodynamic analysis portions of the study.

Subjects were paid $10.00 if they could not complete the entire study for some reason. Reasons included: (1) the subject decided to terminate

80 participation in the study for personal reasons, (2) the larynx, during videolaryngostroboscopy, was found not to be within normal limits, and (3) the larynx could not be observed adequately due to posterior placement of the epiglottis or a hypersensitive gag reflex. Due to Human Subjects Committee guidelines, for the control subjects, no anesthesia was used during any portion of the evaluation. This decision was made to reduce possible physical risks to the subject. Persons with asthma were eliminated from the control group to ensure that aerodynamic testing of persons with no laryngeal or respiratory disorders took place. Persons with a history of tobacco use were not eliminated from the study to ensure that a sample typical of the general population was gathered. As mentioned in the review of the literature, researchers have suspected that persons in medical professions are more susceptible to PVCD. Table 3.3 lists the occupations of all subjects in the present study to compare to the literature. The number of persons with the same profession is in parentheses following the name of the occupation.

81 PVCD Control

Unemployed/disability (8) Graduate student (31) Medical transcriptionist University professor (2) Retired (9) Research associate Teacher’s aide Systems programmer Homemaker (5) Medical secretary Nurse (3) Phys. education teacher Assembly line worker (2) Attorney Clerical worker Curriculum advisor Factory worker Engineer (2) Collections agent Instrumental musician Retail store manager (2) Industrial engineer Personnel manager Otolaryngologist (2) Dietary technician Optical assistant Industrial worker Receptionist Tax coordinator Secretary (2) Case worker Balance lab technician Administrative assistant (2) Computer network mgr. Airplane dispatcher Audio producer Engineer Real estate broker Chemical plant worker Accountant Inmate Farm er Businessman

Table 3.3: Reported occupations for PVCD and Control groups.

82 Table 3.4 indicates the breakdown of nationality/ethnicity of the persons in each group. Ethnicity determinations were made by all individuals tested; each person was asked to indicate the ethnicity with which the person identified.

PVCD Control Caucasian (41) Caucasian (46) African American (8) Indian Hispanic African American Black Vietnamese

Table 3.4: Ethnic breakdown of all subjects in the present study. The literature also indicates that persons with PVCD typically demonstrate a normal voice between attacks. Table 3.5 illustrates the perceptual voice evaluations of persons with PVCD and controls at the time of evaluation. All persons with PVCD were not in an acute exacerbation and, if the literature has predicted appropriately, should demonstrate normal voicing. This was not the case. Over 50% (29) of the persons with PVCD were evaluated as having an abnormal voice. It is suspected that the decreased respiratory functions associated with the PVCD contribute to vocal deterioration resulting in dysphonia.

83 Voices were evaluated using the Wilson Scales (Wilson & Rice, 1977). WNL indicates normal laryngeal opening (LO), pitch (P), and intensity (I). The plus (+) sign indicates excessive function or increased parameters. A minus (-) indicates lack of function or decreased parameters. A +2 LO indicates excessive tension in the voice, also called hyperfunction. A -2 LO indicates lack of tension, or breathiness. A +2 P or +3 P indicates a fundamental frequency (pitch) higher than expected for the person’s age and sex. A -2 P indicates a pitch lower than expected. A -3 P indicates aphonia. A +2 I indicates intensity increased more than expected in normal conversational speech. A -2 I indicates intensity decreased more than expected. Voices are described with combinations of these perceptual ratings. Descriptors, such as persistent glottal fry, are sometime tagged onto the rating.

PVCD Control Voice Rating WNL 21 50 +2 LO 13 -2 P 5 +2 LO, -2 P 4 +2/-2 LO, -2 P 2 +2/-2 LO 2 -2 P, -2 I 2

Table 3.5: Perceptual voice ratings of persons in PVCD and Control groups.

84 Procedures The diagnostic protocol included a case history interview, indirect examination of the larynx, and aerodynamic analysis. Both groups participated in three sections of the evaluation with some modifications. Modifications are explained in the following three sections which describe the procedures in full detail. Informed Consent For all subjects, the session began with explanation of the study, written and verbal description of the procedures for VLS and airflow analysis, written and verbal description of the Informed Consent Form, and signing of the Informed Consent Form (see Appendix A). The data from the subjects with PVCD was part of a retrospective file review. Coincidentally during the duration of the present study, the Department of Otolaryngology instituted a “permission to test” form to be signed by all patients examined in the clinic. After this form became standard clinic practice (March, 1996), all patients were requested to sign this form prior to testing. At this time, the procedures were explained to the subjects (see Appendix B). Case History

The case history was obtained first from all subjects (see Appendices C & D). Subjects referred for PVCD were interviewed along with any attending family members or accompanying acquaintances. Individual

85 differences in case histories and circumstances surrounding referral to the

clinic required the interviews to be individualized for the subjects with PVCD. Diagnosis of asthma was discussed during all interviews with

subjects with PVCD. For these subjects, the presence of asthma was determined through one of several means. The subject was asked during the interview if asthma had ever been diagnosed and when the diagnosis was made. If the subject was unsure, any information sent to the clinic by the referring physicians was examined for an asthma diagnosis (e.g., letters from the physician, consults or pulmonary function reports). Unequivocal diagnosis of asthma is often difficult to determine in these patients as the suspected disorder, PVCD, mimics asthma. Case history information was collected from control subjects through a questionnaire (see Appendix C). This questionnaire requested the subject to provide the age, respiratory history and voice history. The examiner read the questionnaire before proceeding with testing to clarify

any ambiguous responses. The subject was eliminated from the study if the subject admitted to having a voice disorder at the time of the examination

or if the subject admitted to having asthma or suspected asthma or any other respiratory disorder (including transient upper respiratory infections i.e., common cold). The examiner rated the voice of the subject on the case history form using the Wilson Scales (Wilson & Rice, 1977).

86 If the subject did not receive a rating of “within normal limits,” the subject was eliminated from the study. Persons with mild vocal inefficiencies, such as intermittent glottal fry, were not excluded from the control group.

Videolarvngostroboscopv (VLS) Indirect examination of the larynx was performed either via oral endoscopy or transnasal fiberoptic endoscopy. PVCD subjects were evaluated using one or both methods; this was necessary to procure the maximum amount of information for the referring physician(s). Control subjects were examined only using oral endoscopy due to university regulations. Examination was performed with the Kay Elemetrics Rhino- Laryngeal Stroboscope Model 9100, Software Version 1.x. The Computer Integration Package Model 9141 and CCD Camera Model 9111 (Panasonic GP-KS152) were connected to the stroboscope. All examinations were recorded onto super VHS videotapes using Model 9213 Mitsubishi BV2000 VHS video cassette recorder.

If a control subject could not participate adequately through oral endoscopy, the subject was eliminated from the study. Oral endoscopy does not require anesthesia, but a topical anesthetic may make the exam easier to tolerate. If a subject with PVCD required anesthesia of the oral cavity or nasal cavity to reduce the gag reflex or to make the subject more comfortable, a topical 10% Xylocaine solution was applied to the posterior tongue, the soft palate, the posterior pharyngeal wall and the faucil pillars/tonsils. The use of topical nasal anesthetic was described to the

87 subjects when it was determined a transnasal examination was necessary. Anesthesia was applied to the nasal passages if a transnasal examination was being used and the subject agreed. Xylocaine was administered by a physician from the Department of Otolaryngology at The Ohio State University or the speech-language pathologist performing the evaluations within the guidelines established by the Department of Otolaryngology. This topical anesthetic affects sensation only, not motor function, of the laryngeal and oral mechanism. PVCD subjects requiring anesthetic were counseled about the potential allergic reactions to the anesthesia. Subjects consented verbally to application of the anesthetic or they did not receive it. Anesthesia was not administered to control subjects for any reason. During the VLS, the subject was required to sit in a straight backed chair with the feet flat on the floor. The subject held a flat contact microphone on one side of the neck at the thyroid lamina. The side of the neck on which the microphone is placed did not affect the test as long as the microphone continued to lie flat. The subject was instructed in flat placement. The examiner periodically checked the position of the microphone to ensure correct placement on the neck throughout the evaluation. This microphone detects the vibrations of the vocal folds and coordinates the strobe light to allow for stroboscopic capabilities. Training of vocal tasks was performed to check the positioning of the contact microphone and to prepare the subject. Subjects were asked to produce a sustained vowel /i/ for at least five seconds. The subject was told to

88 perform this vowel at a comfortable loudness level and pitch. The examiner demonstrated the vowel and instructed the subject to imitate. The examiner then demonstrated all the vocal tasks: (1) a voice glide up the scale, (2) a voice glide down the scale, (3) repeating /i/ four to five times, (4) repeating /hi/ four to five times, (5) alternating /hi/ productions with an inhalation, (6) quiet respiration, and (7) sustained /i/. Subjects practiced each vocal task and the examiner reinstructed, if necessary. The subjects were instructed to phonate in a self-selected, comfortable pitch unless the examiner asked the subject to produce a “high” pitch or a “low” pitch. Subjects were told that the examiner would reinstruct them while the endoscope was in the mouth or nose. During training, subjects were instructed to breathe through the mouth, keep their eyes open and not to pull the head away from the examiner. Subjects were given the opportunity to ask questions about the procedure during the training. All equipment was in view during the explanation and training.

For oral endoscopy, the subject was asked to extend the tongue forward and the examiner held the tongue with a piece of gauze using a gloved hand. The scope was inserted into the mouth typically without touching the anterior tongue or the front teeth. The examiner attempted not to make contact with any portion of the oral anatomy or pharyngeal walls during the exam; however, sometimes the tip of the endoscope came in contact with the soft palate, anterior tongue or posterior pharyngeal wall. If this happened, the subject might have coughed, gagged, or had no

89 reaction to the contact. If the subject did cough or gag or become uncomfortable at any point during the exam, s/he was instructed to pull the head backwards to indicate to the examiner to remove the endoscope from the mouth.

If the discomfort was prolonged or severe, the subject was given the opportunity to rest or quit the examination; PVCD subjects were encouraged to continue with the oral endoscopy or participate in transnasal examination. Re-entry of the scope into the mouth was not attempted again until the subject indicated to the examiner that s/he was ready. Each individual had a different experience with the oral endoscope examination; therefore, a rigid protocol for vocal productions was not used for either the PVCD group or the control group. Once the scope was in place in the mouth, the subject was asked to perform one of the vocal tasks as directed by the examiner. The scope was periodically removed from the mouth to give the subject a resting period. The resting period ended when the subject indicated s/he was ready to continue. Typical duration of the examination was approximately 15 minutes with a total videotaping time of 3-4 minutes. Transnasal laryngoscopy was used for 33 PVCD subjects.

Transnasal fiberoptic examination was performed in a similar manner except for insertion of the scope and grasping of the tongue. After anesthesia, if used, the scope was inserted into one nostril. The subject was instructed to breathe through the nose and to swallow as necessary. The

90 subject was told when the nasal scope was in place superior to the base of the tongue and epiglottis and was asked to perform one of the tasks from the protocol. Once the scope was inserted, it was not removed for resting periods as was done for the oral endoscopy. Resting periods were not provided in this manner because it is more uncomfortable to pass the scope repeatedly through the nose than for the vocal tasks to be performed and the examination to be completed with dispatch. The tongue was not held during transnasal examination. When the subject needed a rest period, the scope was held still while the subject relaxed. When the subject was ready to perform another vocal task, s/he indicated this to the examiner and the evaluation progressed.

The examination continued for the PVCD group until enough information was gathered to provide the referring physician with adequate information to make a positive or negative diagnosis of PVCD. Transnasal endoscopy typically took place for 5-7 minutes total including insertion and removal of the scope. The time difference occurs between transnasal and o ral endoscopy because oral endoscopy requires more resting periods.

Control subjects were not given the option of oral anesthetic due to potential allergic reactions; therefore, examinations were limited to 30 minutes if the examination was not proceeding in a typical fashion. In other words, if the client was having a difficult time with the examination (i.e., coughing, gagging) or the examiner determined that adequate pictures could not be obtained due to anatomical configurations, the exam was

91 terminated after 30 minutes or when the subject indicated s/he no longer wished to participate, whichever came sooner. Examples of anatomical configurations that prevent trans-oral endoscopy include a rigid tongue base which elevates during phonation, and a posteriorly placed epiglottis which approximates the pharyngeal wall and obscures view of the laryngeal vestibule. Eight potential control subjects were eliminated due to anatomical configurations preventing adequate observation of the larynx. All examinations, transnasal and oral, were conducted using the Kay Elemetrics Stroboscope. All examinations were video recorded and were reviewed with all subjects, family members and guardians/accompanying persons. Later, these videotapes were reviewed, without subjects present, to determine if the subject was eligible for placement into one of the subject groups. For the PVCD group, examinations were analyzed to determine if paradoxical vocal cord adduction during respiration was observed. If abnormal vocal fold adduction or narrowing of the glottis during respiration was observed on video, the subject was eligible for the PVCD group. Videos from subjects recruited for the control group were examined to determine if normal respiration behaviors were observed during the examination. Subjects for the control group were eliminated if any laryngeal abnormality was detected. Laryngeal abnormalities could include lesions such as nodules, polyps, or contact ulcers. If the larynx was judged as not within normal limits by the examiner, the subject was eliminated from the study.

92 The abnormality was explained to the subject and referral to an otolaryngologist was made. This did not occur during the course of the present study. Aerodynamic Analysis The next portion of the examination for all subjects was the transglottal airflow analysis. This examination served as the means for data collection for the dependent variables for this study. Exact procedures and tasks are outlined in the following measurements section. Measurements

All aerodynamic measurements were obtained via the Nagashima Phonatory Function Analyzer PS-77H with facemask, Nagashima Medical

Instruments, LTD. Richmond Virginia. The following is an excerpt from the Nagashima instruction manual which describes the function of the instrument: “PS-77H permits comprehensive evaluation of phonatory function, providing simultaneous measures of voice intensity, fundamental frequency, air flow rate, and flow volume of air usage. These measures can be read directly on panel meters and a panel-mounted LED display (flow volume) or plotted continuously on a multi-pen strip chart recorder [chart paper}. In addition, the instrument automatically measures the duration of sustained phonation (phonation time) and displays the value on a panel-mounted LED display” (p. 3).

93 The aerodynamic measure “air flow rate” represents the flow rate of the air consumed during phonation and was expressed in milliliters/second (ml/sec). The instrument determines air flow rate by the volume of air which was exhaled through the glottis in one second intervals during phonation or expiration. The instrument assumes that the air flow rate during phonation varies depending upon the states of glottis (glottal resistance) and the expiratory effort. The maximum phonation time represents the duration of time that the subject can sustain phonation without stopping and is expressed in seconds. Air flow rate on the Nagashima has a range of measurement from 0-1000 ml/sec. The Nagashima unit was calibrated semiannually during the course of the present study. These procedures are specified in the instruction manual with the exception that phonation volume was calibrated using a one liter syringe. Measurements from the Nagashima instrument are directed into a computer and analyzed via a software program developed at Vanderbilt

University (Patel, 1994). The software was developed as part of a master’s thesis. According to the unpublished thesis, “this system [the software] was designed to increase the efficiency with which phonatory testing is accomplished” (p. 16). The computer was a IBM clone 486 Laser Brand DX2 - 66 megahertz.

94 All aerodynamic measurements for the present study were part of an airflow analysis protocol designed to collect a comprehensive sample of measures for assessment and treatment of various voice disorders. The aerodynamic measures for the present study were chosen based on the clinical opinions of two speech-language pathologists using the protocol on a regular basis in the voice disorders clinic. These measures were specifically chosen because it is believed they differentiate persons with PVCD from controls. The literature describes PVCD as an episodic breathing disorder. Based on exposure to 75 patients prior to data collection for the present study, it is theorized that patients with PVCD are not laryngeally stable between breathing attacks. The airflow measures may demonstrate this laryngeal abnormality. The rationale for these hypotheses will be described in a section at the end of this chapter. The purpose of the present study is to determine the validity of these heretofore unsubstantiated clinical opinions.

All aerodynamic measures in the present study were direct measures or ratios of direct measures. Subjects were trained on all tasks and were allowed to repeat trials if a trial was determined not to be that individual’s best performance. This determination was made by the examiner and/or the subject based on impressions of the performance. The examiner modeled all tasks during training. Subjects were permitted to practice all tasks as many times as the subject requested. Subjects were instructed to inhale completely before most tasks (e.g., sustained phonation tasks);

95 reading and counting tasks did not require a deep inspiration before production. Subjects practiced with the face mask off. Feedback during training and data collection was achieved via two numeric displays on the Nagashima front panel. One display indicates the phonation time for the trial; the second display indicates airflow volume during the trial. Subjects were instructed to use either panel, or both, for feedback. Subjects were encouraged to “keep the numbers climbing” during the trials, when applicable. This type of feedback was not necessary during the reading, counting, /a/ repetitions and /ha/ repetitions. Subjects placed the face mask onto the face covering the mouth and nose. Subjects were told to place the mask over the face to maintain a seal around the mask (between the face and mask) for the duration of the task. The examiner administering the battery checked the seal of the mask against the face during the evaluation on an as needed basis. Subjects were instructed to remove the mask from the face when the task was completed

(i.e. when the subject finished expiration, or finished phonation of a sustained sound or reading/counting). Subjects were allowed to rest between trials and were instructed to let the investigator know when ready to perform another trial. This interval was typically 30-45 seconds and was not measured or controlled. The facemask served simply as a conduit to pass exhaled air over the necessary sensors. The mask did not impede respiration.

96 Data collection with the Vanderbilt software began when the investigator pressed the ‘return’ button on the keyboard of the computer approximately 1 second before exhalation. The investigator observed the subject’s inhalation and depressed the ‘return’ key at the moment the inhalation ceased, prior to the exhalation. There was no automatic start function on either the Nagashima instrument or the Vanderbilt software. Both experimenters developed the procedures for use of the Vanderbilt software with the measurement protocol and were in agreement on when to trigger data collection. If the key was depressed after exhalation had already begun, the investigator stopped the trial and the subject repeated the trial. The task was also repeated if review of the trial indicated that the trigger was “late.” The computer software provides the opportunity to set the duration of each task. The duration for each task was changed based on the individual’s trial performance. For example, if during a practice trial of sustained /a/, the subject sustained the vowel for 9 seconds, the program duration was set for 15 seconds. This provided an extended window of time for the subject to perform. If the subject sustained the production for less time than the pre-set duration, the subject took the mask down from the face so as not to breathe or speak into mask and corrupt the trial data. There was no function in the Vanderbilt software to stop the trial at the moment the subject finished the task. The preset duration was counted on a clock display via the software and automatically ends the data collection at

97 the end of the preset duration. If the subject produced a tone for longer than the preset duration, the trial was not counted. A longer duration was then preset into the software and the trial was repeated. The following speech, phonatory, and respiratory tasks were completed by the subjects. A definition of each task is provided along with the aerodynamic measurements collected from each task. VITAL CAPACITY

Subjects were asked to exhale completely for this task. They were instructed to inhale completely before placing the mask over their face.

Subjects were instructed not to renew their breath at the end of the production until the mask was removed from the fact. The task was modeled for 5-10 seconds by the examiner and the subject was asked to perform a training trial. Subjects were told not to force all of their air out in a short duration of time. Rather, subjects were told to exhale the air completely and slowly to maximize output. The subject could perform as many training trials as requested. Subjects were encouraged to use the LED display for volume for feedback to maximize output. The following measurements were collected from this task: Number of cessations of airflow

Vital Capacity (VC)

98 SUSTAINED /a/

Subjects were asked to sustain /a/ for as long as possible. They were instructed to inhale completely before phonation. Subjects were instructed not to renew their breath at the end of the production until the mask was removed from the face. The task was modeled for 5-10 seconds by the examiner and the subject was asked to perform a training trial. Subjects used a self-selected “comfortable” pitch and loudness. The subject could perform as many training trials as desired. Subjects were encouraged to use the LED displays (one for airflow, one for duration) as visual feedback. The following measurements were collected from this task: Mean airflow rate in milliliters/second

Duration of sustained production in seconds Number of cessations of airflow Phonatory Volume (PV) PV and duration were calculated by the software. Mean airflow rate is calculated by a spreadsheet in which all data were input using the formula: PV/Duration in seconds. Cessations of airflow were determined by examining the flow graph displayed by the software. If the flow wave crossed the x axis (which marks zero) at any point, that point was counted as one cessation. Cessations were not counted during a one second initiation and termination interval to allow for onset and offset incoordination.

99 READING

Subjects were asked to read the first paragraph of The Rainbow Passage (Fairbanks, 1960) (Appendix E) into the face mask. Subjects were instructed to take as many breaths as needed and not to attempt to read the passage on one breath, to speak at a comfortable pace, at a comfortable loudness level, and at a comfortable pitch. Subjects were instructed to read the paragraph to themselves and out loud before data collection to familiarize themselves with the reading and to allow the investigator to estimate task duration. The investigators provided correct pronunciation of words, if necessary. The following measurements were obtained from this task: Mean airflow rate in milliliters/second Number of spikes of airflow greater than 700 milliliters/second Mean airflow rate was calculated by the software. The number of spikes of airflow were counted by observing the flow wave displayed by the software. Spikes of airflow that surpassed the 700 ml mark were counted in this category. Spikes were not counted during a one second initiation and termination interval to allow for onset and offset incoordination. COUNTING

Subjects were asked to count from one to fifty into the face mask. Subjects were instructed to take as many breaths as needed and not to attempt to complete the task on one breath, to speak at a comfortable pace, at a comfortable loudness level and at a comfortable pitch. Typically, one

100 training trial of this task was collected to ensure appropriate performance (i.e., not speaking too fast) and to estimate task duration. The following measurements were obtained from this task:

Mean airflow rate in milliliters/second Number of spikes of airflow greater than 700 milliliters/second Mean airflow rate was calculated by the software. The number of spikes of airflow were counted by observing the flow wave displayed by the software. Spikes of airflow that surpassed the 700 ml mark were counted in this category. Sustained /s/ and /z/ tasks The subject was instructed to inhale deeply and to produce an /s/ or /z/ for as long as possible. Three trials of /s/ were collected first, then three trials of /z/. Sampling began and ended prior to and after production, but data were recorded only from production. The experimenter modeled the sounds for 5-10 seconds to begin training. The subject was then asked to produce at least one training trial of each phoneme. This allowed the investigator to ensure that the subject was performing the tasks correctly (e.g. using the correct phoneme) as well as estimate the time the subject needed to complete the task. Since the duration of time that the computer will collect data was set by the investigator, this estimate was used to set duration. Subjects typically performed one or two training trials before actual data collection, but were given the opportunity to perform an unlimited number of trials.

101 The following measurements were obtained during these tasks: Phonatory Volume /s/ Phonatory Volume /z/ Duration of sustained /s/ in seconds Duration of sustained /z/ in seconds Calculation of the S/Z ratio based on duration in seconds Mean airflow rate of /s/ in milliliters/second

Mean airflow rate of /z/ in milliliters/second Calculation of the S/Z ratio based on mean airflow rate in milliliters/second Number of cessations of airflow during sustained /s/ Number of cessations of airflow during sustained /z/ A cessation of airflow was defined as a point in the flow in which a value of 0 ml/sec was observed. This was determined via visual inspection of the airflow graph displayed by the software program. Only values of 0 ml/sec were counted as cessations of airflow. The first second of production and the last second of production were eliminated before cessations were tabulated. This was done to eliminate onset and offset variability. Duration was calculated by the Vanderbilt software immediately after the trial ended. Mean flow was calculated by dividing duration into PV.

1 0 2 /a/ AND /ha/ REPETITIONS

Subjects were asked to repeat /a/ or /ha/ syllables as quickly as possible for 4-5 seconds. The experimenter modeled the productions for

approximately 5 seconds and the subject imitated for practice. Subjects were instructed to produce the syllables quickly, but not so quickly that the productions sound like “a machine gun.” Subjects were also instructed not to slur the syllables. Subjects were instructed to produce the syllable completely, but quickly. When the investigator determined the subject was performing the task appropriately, the subject was instructed to begin with

a comfortable inhalation. An additional inhalation was permitted if /a/ or /ha/ could not be repeated quickly for 4-5 seconds on one breath. The middle two seconds of the total production were used for data analysis. These data were not processed through the Vanderbilt software. The Nagashima instrument contains the capability to produce a pen and ink chart representation of frequency, intensity, and airflow waves. The

Nagashima chart paper was used to draw a graph of these productions. The graph was analyzed via visual inspection by one of the speech-language pathologists. The following measurements were collected from these tasks:

Number of /a/ repetitions during middle two sec. of complete trial Number of /ha/ repetitions during middle two sec. of complete trial

Mean peak flow rate of /a/ productions during middle two seconds Mean peak flow rate of /ha/ productions during middle two seconds

103 Ratio of mean peak flow rate /a/:/ha/ during middle two seconds /a/ and /ha/ repetitions were calculated by counting the number of peaks in the flow graph during the middle two seconds of the total production. Mean peak airflow was calculated by determining the value of airflow (in ml) for each peak in the middle two seconds of the total production. These values were averaged to determine the mean peak airflow. Summary

The following tasks from the protocol were input directly into the Vanderbilt Phonatory Function software via the facemask: vital capacity, sustained /a/, reading, counting, sustained /s/, and sustained /z/. The mean airflow rate and duration of these tasks were computed and displayed by the software. Cessations of airflow and spikes of airflow were analyzed by visual inspection of the waveform which was displayed by the software. Ratios of dependent variables were calculated by formulae in the data spreadsheet. Laryngeal valving tasks (repeated /a/ and repeated /ha/) were collected on the Nagashima Phonatory Function Analyzer graph (chart) paper with four stylus pens that respond to the signals that were introduced via the facemask. (The stylus pens do not move for the tasks that were analyzed via the software program). The graph paper output was analyzed by hand. An airflow scale in milliliters was preprinted onto the chart paper and the graph was drawn over this scale as the subject produces the target behavior. The graph that was drawn was then examined visually to

104 determine appropriate values. For this task, subjects were asked to repeat quickly /a/ or /ha/ for approximately 4 seconds. The middle two seconds of repetitions was used for analysis. The sound repetitions typically demonstrate observable peaks and troughs on the graph. The airflow points for analysis were all of the peaks present in the two second sample.

These peaks were then averaged to compute the mean peak airflow for the trial. This was the only task in the present study analyzed from the graph paper rather than via the Vanderbilt software. Tasks were performed in the following order: Vital capacity, sustained /a/, reading, counting, sustained /s/, sustained /z/, repeated /a/, and repeated /ha/ (See Appendix F). The time allotted for complete collection of the data was different for each subject. Data collected from persons with PVCD was part of a diagnostic procedure. Subjects were given an opportunity to rest between trials and tasks. This was necessary for some subjects who were very ill (e.g., due to a recent, severe PVCD or asthma attack) and could not perform effectively without break periods between tasks and/or trials. Typically, controls did not require extensive rest periods or breaks. Administration of the protocol lasted approximately 30- 45 minutes per person depending on reading rate, counting rate, and sustained phonation abilities. Individuals with PVCD typically required 60-90 minutes for completion.

105 Statistical Analysis Table 3.6 displays the level of each dependent variable, the variable name and the unit of measurement.

Variable Name Unit of Measurement Level of Measure

Vital Capacity (VC) milliliters interval VC cessations quantity categorical /a/ Airflow milliliters/second interval /a/ Duration seconds interval /a/ Cessations quantity categorical PV /a/ milliliters/second interval /s/ Duration seconds interval /z/ Duration seconds interval S/Z Ratio (duration) based on seconds ratio /s/ Airflow milliliters/second interval /z/ Airflow milliliters/second interval S/Z Ratio (flow) based on airflow ratio /s/ Cessations quantity categorical /z/ Cessations quantity categorical PV /s/ milliliters/second interval PV/z/ milliliters/second interval S/Z Ratio (PV) milliliters interval /a/ Repetitions quantity/2 seconds interval /ha/ Repetitions quantity/2 seconds interval /a/ Rep Airflow milliliters/second interval /ha/ Rep Airflow milliliters/second interval /a:ha/ Ratio based on airflow ratio Counting Airflow milliliters/second interval Counting Spikes quantity categorical Reading Airflow milliliters/second interval Reading Spikes milliliters/second categorical

Table 3.6: Levels of measurement for dependent variables.

106 Cessations and spikes were treated as categorical data because the descriptive statistics did not meet the assumptions of an ANOVA. Therefore, the level of measurement was dropped from interval to categorical. Statistical Analyses

A multivariate analysis of variance (MANOVA) was used for the primary statistical analysis. Multivariate statistics are used to handle situations where sets of variables are involved either as predictors or as measures of performance (Harris, 1975). The dependent variables in the present study are measures of performance. MANOVA allows one to observe statistical significance among patterns of dependent variables or optimal combinations of variables. Multivariate statistical techniques are capable of two goals: (1) they provide rules for combining variables in an optimal way; this is a descriptive use of MANOVA; (2) They also allow multiple comparisons; this is an inferential use of MANOVA (Harris, 1975).

These data could have been analyzed using a series of univariate significance tests (i.e., t-tests). This would have consisted of one univariate test for each possible combination of the predictor variables with the outcome variables. Each univariate test is designed to produce a significant result a predicted number of times when the null hypothesis is correct using the following formula: a x 100% (where a is the significance level).

107 The probability of having one of the tests produce a significant result when chance variation produced the results, increases rapidly as the number of tests increases. Thus, using many univariate tests increases the likelihood of Type I error. Use of MANOVA controls the experimentwise error rate. MANOVA also provides for post hoc comparisons; these comparisons explore the statistical significance of possible explanations of the overall statistical significance of the relationship between predictor and outcome variables. A one-way MANOVA is applicable whenever there are several groups of subjects with more than one measure being obtained from each subject. A repeated measures ANOVA was used to assess which dependent variables within the variable groups contribute to the significant differences. Scheffe tests were used for post-hoc testing to determine critical differences between the means which contribute to the significant effects. A Chi square analysis was used to determine the statistical significance of the categorical data (cessations and spikes). Spearman rank order correlations were used to determine if connected speech mean rate of flow tasks correlated with spikes of flow.

108 Rationale for each dependent variable

The rationale for measurement of each dependent variable will be discussed in the following section.

Vital Capacity The size of the lungs helps to determine the management of airflow. Vital capacity(VC) is the largest volume measured on complete expiration after the deepest inspiration without forced or rapid effort (Ruppel, 1975) VC is measured in milliliters or liters. VC is measured by having the individual inspire completely and then exhale maximally, with no time limit. The exhalation is usually into a spirometer or other respiratory measurement device. VC can vary as much as 20% from predicted values in healthy individuals. VC can vary from trial to trial in an individual due to effort, body posture, or other changes in performance. VC has been shown to be positively correlated with height and negatively correlated with age; females typically have a smaller VC than males (Ruppel, 1975; Dawson, 1985).

VC may decrease due to a loss of lung tissue, bronchial obstruction, pulmonary edema, pneumonia, or similar respiratory maladies such as surgical excisions. Decreases in VC are observed when lung lesion is not evident; for example, depression of respiratory centers due to neuromuscular disease, hiatal hernia, or cardiac enlargement (Ruppel, 1975). The average adult maintains a VC of approximately 4-5 liters.

109 Vital capacity can be broken into three sub-volumes: (1) expiratory reserve volume, (2) tidal volume, and (3) inspiratory reserve volume. Residual volume , approximately 2 liters, is the volume of air never depleted unless the lungs collapse. Vital capacity and residual volume comprise total lung volume (Titze, 1994). VC for the present study is measured as total expiration into the facemask of the Nagashima instrument. It is important to measure this value in persons suspected of PVCD to determine overall integrity of the respiratory system. As Ruppel (1975) noted, VC will decrease due to changes in lung integrity. Analysis of this measure may help evaluators to determine if a person suspected of demonstrating PVCD is exhibiting a functional or organic disorder. The utilization of three trials of VC is indicated; VC has been shown to be highly repeatable with a small standard deviation. Repeated measures of VC typically approximate a normal distribution (Conrad, Kinasewitz & George, 1984). The use of extensive training and training trials is also indicated in the measurement of VC. VC increases with repeated performance over long periods of time. As VC is a maximal production, training will ensure this attribute. VC is also useful in determining whether subjects are performing maximum phonation duration (MPD) tasks appropriately as PV should approximate VC. Posture has been shown to affect lung volumes and the recommended position for collection of VC is erect; thus, the present study required

110 subjects to sit comfortably in a straight-backed chair. Studies have demonstrated VC decreasing in the supine position (Conrad, et al., 1984) due to changes in position of diaphragm and chest well dimensions.

Acute reversible obstruction of the airways (e.g., asthma) is associated with difficulty in exhalation. Residual volume increases while total lung capacity (TLC) remains unchanged; therefore, VC decreases in patients with obstruction (Dawson, 1985). As PVCD is an obstructive condition, VC may be expected to decrease in patients with PVCD. Although many patients state that difficulty with inspiration is their primarily complaint, many patients have noted difficulty with both inspiration and expiration. Therefore, if expiration is affected due to the lack of laryngeal control exhibited in PVCD, VC may demonstrate this lack of control. The VC task was also included to observe cessations of flow. The rationale for the dependent variable of cessations will be explained in a section titled “cessations” in this chapter.

Phonatorv Volume (PV) In the present study, PV measures were collected during sustained /a/, /s/, and /z/ tasks. The amount of air exhaled during maximum sustained phonation is called phonatory volume (Hirano, Koike, & von Leden, 1968). Per Kent, Kent, and Rosenbeck’s (1987) suggestion, the subjects in the present study were instructed to inhale maximally, then to phonate (/z/, /s/, /a/) for as long as possible using a comfortable pitch level (if phonation is required).

Ill PV varies with VC in a linear relationship. Several studies report formulae used to calculate PV based on VC. Yanigahara and von Leden (1967) used the following formula calculated in liters: Maximum Phonation Volume (MPV) = .86(VC) - .891 Kelman, Gordon, Simpson, and Morton (1975) used a different formula for this calculation (also reported in liters): MPV = .64(VC) +.22 Finally, Beckett (1971) recommended the following formulae which take into account the subject’s gender: Male PV = VC/100 x .67, Female PV = VC/100 x .59 The use of different formulae has not prevented researchers from demonstrating the same conclusion: empirically determined values for PV are typically less than the VC. Several studies have demonstrated expected percentages of VC representing PV. Table 3.7 illustrates the percentages of VC that constitute PV. The percentages represent the amount of VC expired during maximum sustained phonation.

112 Study Males Females Bless and Hirano (1982) 93% 91%

Inglis (1977) 88% 89% Isshiki, Okamura, & gender not specified: 68.7% - 94.5% Morimoto (1967)

Yanagihara & Koike, (1967) 50%-80% 45%-75% Taylor (1980) 85% 89%

Table 3.7: Percentages of VC that constitute PV.

PV was measured in the present study to determine if persons with PVCD and controls demonstrate different performance. Persons with PVCD may demonstrate decreased PV compared to persons without PVCD. It is possible that PV will be restricted in persons with PVCD compared to controls and compared to VC because of excessive laryngeal constriction during phonation. The valving action of the larynx is not functioning appropriately in persons with PVCD; this may affect phonation.

113 Maximum Phonation Duration (MPD)

MPD is the longest time during which phonation can be sustained. It is typically performed using a vowel sound, as “phonation” refers to voicing because of vocal fold vibrations. Frequently, the acronym MPD is used to label the maximum time any sound can be sustained, including voiceless sounds such as /s/. This usually occurs during collection of the s/z ratio (Boone, 1977). For the purposes of the present study, MPD refers to the maximum time a sound can be sustained following maximum inspiration. Three MPD values were collected: sustained /a/, /s/, and /z/. MPD requires the entire PV to be expended during production. MPD has been showed to be affected by several factors including age, sex, and stature (Kent, et al., 1987). MPD also depends on airflow through the larynx. Higher rates of flow per second will decrease MPD. MPD covaries with PV and airflow, and variability is large (Kent, et al, 1987). Hirano, et al. (1968) demonstrated a significant negative correlation between maximum phonation duration (MPD) and mean flow rate; therefore, the longer a sound is sustained, the less flow per second is expired.

A portion of this variability is due to practice effects. Many reports do not offer support for stability of MPD over fewer than 10 trials (Kent, et al., 1987). Neiman & Edeson (1981) reported that the average trial on which adults achieved MPD was 5.1, if the examiner modeled the production. The average trial number on which MPD was achieved if the

114 examiner did not model the production was 9.85. Stone (1983) found that a group of 21 adults showed increases in MPD through the 15th trial. Other researchers have reported that MPD requires repeated trials, visual feedback, careful instruction, and encouragement/reassurance. The present study utilizes these recommendations.

The subjects were asked to practice the MPD tasks at least once and were encouraged to perform multiple training trials if the examiner determined that maximum effort was not being produced (e.g. the subject ceased phonation then sighed or exhaled). Bless and Hirano (1982) reported that three trials were sufficient for collection of MPD provided appropriate instructions were given. Therefore, three trials of the sustained productions, plus the training trials were used to collect MPD data for the present study.

The examiner also modeled the production prior to having the subject perform. Visual feedback was provided via a digital display of airflow volume and phonation time on the Nagashima unit. For sustained /a/ and /z/, both displays (volume and time) could be used for visual feedback; the time display is a phonation time display and therefore cannot be utilized during sustained /s/ productions. During sustained /s/ productions, subjects were encouraged to watch the volume display and to “keep the numbers counting higher.” The Nagashima unit also contains three needle displays for the three parameters: frequency, intensity, and airflow. Subjects were also encouraged to keep sustaining the sound by

115 keeping the needles away from the zero point. Subjects were encouraged repeatedly to use whichever visual feedback mechanisms were most helpful. Finally, during productions, the subject was verbally reinforced to continue sustaining the production. The examiner pointed to the flow indicator or quietly told the subject to “keep it going, keep it going..keep the numbers climbing, etc.” Following the production, subjects were verbally reinforced for effort and were asked if the trial felt like a “complete expiration of all your air.” There is a great deal of “normative” data available for MPD. Table 3.8 delineates this information according to source and demonstrates the variability of values considered normal.

116 Source Subjects Gender Mean SD Range

Hirano et al., Adults M 24.8 _ 15.0-62.3 (1968) F 25.7 - 14.3-40.4

Hirano, (1981) Adults F 17.4-25.7

Canter, (1965) Adults M 20.6 - 14.8-42.4

Bless & Hirano, Adults M 33.6 11.4 16.7-58.4 (1982) F 26.5 11.3 11.6-60.5

Yanagihara & Adults M 30.2 9.7 20.4-50.7 Koike, (1967) F 22.5 6.1 16.4-32.90

Table 3.8: MPD published data reported in the literature.

Hirano (1981) states that MPD values are greater for males (25-35 seconds) than for females (15-25 seconds). Colton and Casper (1992) reported that MPD for adult males is approximately 20 seconds and for adult females is approximately 15 seconds. MPD is used frequently as an assessment tool in the diagnosis and treatment of voice disorders (Schmidt, Klingholz, & Martin, 1988).

Clinical observations support a correlation between MPD and presence of organic and functional voice disorders. The specific pathology or functional irregularity cannot be determined from MPD performance, but the severity or pervasiveness of a disorder may be gauged.

117 MPD should distinguish persons with PVCD from controls for several reasons. Similar to the rationale for a decreased VC in persons with PVCD, the larynx, due to paradoxical motion, may demonstrate chronic hyperfunction in all laryngeal functions. This excess tension may facilitate over-adduction during phonation, causing a decrease in overall flow rate. One would expect, then, for persons with PVCD to demonstrate longer MPD due to decreased flow rates (which are maintained for a longer period of time since PV remains constant). However, the excessive glottic constriction may impair the ability of the larynx to valve all of the PV through the vocal folds. It is possible that only a portion of the PV is used because the muscular incoordination of the larynx and possibly the entire respiratory system, prevent efficient valving. If a portion of PV is maintained in the lungs rather than expired through phonation, MPD will be reduced. Prior to the present study, MPD has not been investigated in persons with PVCD. Mean Airflow Rate in Sustained Tasks

The mean rate of airflow is defined as the average rate of flow passing via the glottis during phonation. The mean rate of airflow was measured during the following tasks for the present study:

Sustained /a/, sustained /s/, and, sustained /z/. Although a large range of mean flow has been reported (40-220 cc/sec) (Scherer, 1991) as normal, one would expect persons with PVCD to demonstrate lower rates of flow compared to controls for several reasons. First, the atypical adductions

118 during an acute exacerbation of PVCD may increase the overall muscle activation level in the larynx. If so, it is possible that persons with PVCD will adopt a hyperfunctional phonation posture due to the excess tension secondary to the paradoxical adductions. This hyperfunction may manifest as increased glottic constriction during phonation. Specifically, a longer closed phase of vocal fold oscillation may contribute to decreased mean flow rates.

Second, paradoxical narrowing or complete adduction of the vocal folds has been observed by the author of the present study in patients between attacks when the subject is apparently breathing normally and comfortably. These unnecessary motor behaviors may also increase or reflect the overall muscle tension level or muscle activation level in the larynx contributing to hyperadduction during phonation. Hyperadduction during phonation will lead to decreased mean flow rates. Men typically have greater airflows than women (Kent, et al., 1987). Table 3.9 illustrates several published reports of mean flow rates during sustained vowel productions. Special notes include von Leden, (1968) who stated that normal whisper has a mean rate of about 400 cc/s. All values have been rounded to the nearest whole number.

119 Source N Gender Flow SD Range

Bless & Hirano (1982) 60 M 160 37 85-252 F 162 47 62-249

Hirano, et al., (1968) 50 M 101 _ 46-222 F 92 - 43-197

Kelman, Gordon, 42 M 112 36 37-237 Morton, & Simpson F 94 32 37-187 (1981) von Leden (1968) n/a M 141 22 109-18: F 119 25 76-17:

Table 3.9: Mean airflow published data in the literature.

Mean Rate of Airflow during Connected Speech Tasks Mean rates of flow for the present study were also gathered from connected speech tasks (reading and counting). These values are expected to be restricted for the same reasons as described for sustained production tasks. The overall level of hyperfunction and the possible extended closed phase during vocal fold vibration may contribute to decreased flows during these functional speech production tasks. The flow values obtained from connected speech tasks should not be compared to the sustained production tasks as they are dramatically different speech behaviors.

1 2 0 S/Z Ratio

For the present study, the s/z ratio will be calculated for three dependent variable groups obtained during sustained production of /s/ and /z/: phonatory volume, mean airflow rate, and duration. The dependent variables will be specified with the variable name in parenthesis after the s/z ratio. For example, the ratio based on duration: s/z (duration.) The s/z ratio was derived as a measure that could indicate the presence of vocal fold lesions (Boone, 1977; Eckel & Boone, 1981). It was suspected that vocal fold function, specifically, laryngeal valving capabilities, could be measured through comparison of the MPD of sustained /s/ and sustained /z/. Boone (1977) also suggested that the s/z tasks may be a means of separating respiratory and laryngeal factors contributing to a dysphonia. For the present study, the s/z ratio of the three dependent variable groups is obtained by dividing the value for the /s/ production by the value for the /z/ production.

There are many studies describing the s/z ratio (duration) and reporting “typical” findings; to date, there are no studies in the published literature reporting findings for mean flow and PV. One unpublished manuscript (Trudeau and Forrest, in press) describes flow and volume for the s/z ratio in subjects with identified vocal cord lesions.

Colton and Casper (1990) indicate that subjects with normal larynges should sustain /s/ and /z/ for equal lengths of time. Boone (1977) stated that an s/z ratio in excess of 1.4 indicated laryngeal dysfunction. Eckel and

121 Boone (1981) found in a group of normal subjects s/z ratios ranging from .4 to 2.0. These data indicate that subjects with normal larynges could demonstrate an s/z ratio considered abnormal (i.e. >1.4). The s/z ratio based on duration was calculated in the present study for several reasons. First, data for 50 adult controls producing the sustained /s/ and /z/ will represent one of the largest studies to date in the study of the reliability and validity of the s/z ratio. Second, since there is some evidence confirming Boone’s hypothesis that the s/z ratio is useful for documenting a voice disorder, it may prove useful in documenting another laryngeal disorder: PVCD. One would expect each group to have an s/z ratio (duration) of 1.0. That is, the duration of /s/ and /z/ within groups should be equal. It is possible that the durations used to calculate S/Z (duration) will differentiate the groups. As stated earlier, MPD of /s/ and /z/ will differentiate the groups. However, use of the ratio allows accurate within-subject comparisons. This is especially important when considering the S/Z ratio of mean flow. The overall flow of a sustained fricative production may fall into the low normal region or the high normal region. This may be too narrow to differentiate the two groups if their productions are similar to “normal.” Simple comparisons of mean rates of flow may not demonstrate the variability that a ratio may demonstrate. Additionally, the ratio allows comparison across subjects when mean rates are significantly different.

122 Specifically, individual performance differences between both fricatives can be compared across subjects. The importance of investigating the airflow support of sustained s/z tasks has been documented. Hufnagle and Hufnagle (1988) investigated children with vocal nodules. They found that these children produced an s/z ratio that approximated 1.0. A group of children with dysphonia, but without glottal lesions, also demonstrated s/z ratios near 1.0. This finding contradicts the earlier reports of the capability of the s/z ratio as an indicator of glottal lesion. These authors questioned the phonation volumes as the variable which may affect the overall duration of a sustained consonant. Therefore, the present study attempts to document how PV affects s/z ratio in adult control subjects and persons with PVCD. The s/z ratio has demonstrated a “lack of congruence across studies” (Trudeau & Forrest, in press). Some studies have reported excellent sensitivity of the ratio to glottal lesions, while other studies have reported dramatic insensitivity. As mentioned before, these studies have investigated duration only, and have not studied PV or the airflow support of duration.

Therefore, the present study will contribute to the knowledge of the s/z ratio in the laryngeally normal population. Spikes of Airflow > 700 ml/sec

It is important to assess laryngeal function in connected speech (Baken, 1987). The connected speech tasks provide this functional assessment. During conversational speech production, the larynx rapidly

123 abducts and adducts in coordination with the respiratory, articulatory, and resonatory functions of speech. The coordination of phonation and respiration is paramount to optimum functioning of the larynx for both voicing and breathing. Spikes of flow > 700 ml/sec were observed during connected speech tasks. At this time, the frequency of these spikes in connected speech of persons with PVCD, persons with any other voice disorder, or controls is unknown. These spikes (a surge of flow >700 ml/sec) for the purposes of the present study) may be accounted for in two ways.

Excessive subglottal pressure is responsible for the increased flow during a spike. This pressure may occur as a result of (1) a hard glottal attack, (2) relaxation of the glottis during a pause in speech, or (3) relaxation of the glottis during a voiceless phoneme production. It is possible that subglottal pressure overall is excessive in persons with PVCD and therefore, when normal laryngeal functions occur (e.g. relaxation of the glottis during a pause or voiceless sound), increased flow passes through the glottis.

It may be expected that controls will infrequently demonstrate spikes since perfect control of subglottal pressures in the larynx is unlikely. The frequency of spikes may provide a clue not only to severity, but also whether or not a person is in the verge of a PVCD attack. This measure may be similar to the decreased peak flow measures in a patient about to have an asthma attack.

124 These “spikes” of airflow may be an indicator of laryngeal- respiratory incoordination. It is possible that a frequency count of these spikes may be a useful indicator of severity; they have been observed to occur in the connected speech of controls. The rate at which spikes occur in the connected speech of controls and persons with PVCD has not been investigated prior to the present study. The mean rate of airflow during connected speech also provides information about the overall level of hyperfunction in the larynx as described in the previous section. The mean rates of flow during reading and counting can be compared to assess variance across tasks. It is expected that persons with PVCD will demonstrate increased variance within task and across tasks due to the overall decreased coordination abilities. Cessations of airflow

A cessation of flow for the present study is defined as a point in which the airflow per second is measured as zero. Cessations of flow have been observed during the sustained production tasks and the sustained exhalation (vital capacity) task. It is theorized that each cessation indicates paradoxical closure of the vocal folds during a tasks in which the folds should remain abducted (VC) or should be maintaining stable airflow through the glottis. As theorized with the spikes of flow, it is possible that a frequency count of cessations may provide an indication of overall

125 severity of PVCD. Control subjects and persons with PVCD have been observed to produce cessations during sustained production tasks, but the rate at which cessations occur for each group has yet to be investigated. Cessations during the VC task and the sustained phonation tasks may provide different information.

Cessations during VC may indicate complete paradoxical closure during a time in which the vocal folds should remain at least partially abducted to facilitate complete emptying of the lungs. Cessations during the sustained production tasks (/s/, /z/, /a/) may indicate an excessively long closed phase of vocal fold vibration. The closed phase may be prolonged due the excessive adduction mechanisms (increased action of the glottic constrictors). Closed phase may also be prolonged due to decreased action of the subglottal pressure sensing mechanisms. If subglottal pressure is not detected accurately, the vocal folds will not be forced into oscillation per the aerodynamic-myoelastic theory of vocal fold vibration. Rapid vocal fold adductions

The group that developed the Nagashima unit devised a set of tasks and proposed measures for flow. The rapid repetitions of /a/ and /ha/ were included as a measure of laryngeal diadochokinesis (DDK). The mean flow rates of these productions may provide information about the overall valving performance of the larynx during rapid adductions. The rapid repetitions of /a/ provide complete closure of the glottis and may not allow for release of increased subglottal pressure.

126 The /h/ prior to an /a/ provides a relatively open glottis and may allow for such a release. The /ha/ syllable was used to compare to /a/ because the /h/ is a known airflow facilitator. It is frequently used during voice therapy to facilitate easier vocal fold adduction to decrease vocally abusive phonatory maneuvers. For the purposes of the present study, it is theorized that this airflow facilitating phoneme /h/ will promote increased flow levels in rapid laryngeal valving. The introduction of this phoneme may facilitate the laryngeal incoordination suggested to be present in persons with PVCD. In that sense, the production of a /ha/ may be analogous to a spike and airflow may be excessive. This will increase the overall mean flow rate of the /ha/ syllable. The comparison of the mean peak flow of /ha/ to /a/ derives the /ha/:/a/ ratio. This ratio may provide valuable information about the difference between productions of the phonemes. Similar to the s/z ratio, it may be possible to differentiate persons with PVCD from controls. It may also provide an indicator of severity as well as an indicator of baseline on which to gauge progress once treatment begins. The ratio is more likely to reflect subglottal differences and is distinct to the individual subject. Overall flow in an individual may be excessive compared to someone else, but a ratio allows for comparison across subjects when mean rates are different. Further, mean flow in an individual may be low normal or high normal, and thus, will still be generalized to the “normal” category.

127 This may not be broad enough to differentiate groups on the extremes of normal. The use of the ratio may allow for demonstrability of variability moreso than simple comparisons of mean rates of flow.

128 CHAPTER 4

RESULTS AND DISCUSSION

In this chapter the results and their statistical analyses will be discussed. Results will be divided into sections based on dependent variables. Descriptive statistics will be demonstrated first, followed by the MANOVA and post-hoc analyses. Two variables were analyzed using Chi square analyses because the data did not meet the assumptions of an ANOVA. Spearman Rank Order Correlations were used to determine if connected speech flows varied with spikes of flow. Discussion of the findings is included in each section with the analyses. Implications of these findings and suggestions for future research are discussed in Chapter 5. Explanation of analyses

A multivariate analysis of variance (MANOVA) was performed on the groups of dependent variables:

(1) volume measures (ml): VC, PV /a/, PV /s/, PV /z/

129 (2) mean flow (ml/sec) measures in single sustained phonemes sustained /a/, sustained /s/, sustained /z/ (3) mean flow (ml/sec) measures in connected speech: Rainbow Passage (RBP) and counting (1-50) (4) mean peak flow measures (ml/sec): repeated /a/, repeated /ha/ (5) duration measures (seconds): sustained /a/, sustained /s/, sustained /z/ (6) ratio calculations: s/z ratio duration, s/z ratio flow, s/z ratio PV A Chi square analysis was used for two measures because the data did not meet the basic assumptions of ANOVA. Chi square analysis was followed by Spearman Rank Order correlations to determine if one variable varied with another. These measures used with Chi square are

(1) frequency of cessations in flow measures: sustained /a/, sustained /s/, sustained /z/, VC, and

(2) frequency of spikes in flow measures: reading RBP, counting (1-50). Spearman Rank Order correlations were used to determine if spikes of flow correlated with mean flow rates during the connected speech tasks. A two way (ANOVA) was used to analyze one dependent variable

that could not be grouped: ha:a ratio. 2 between, 1 within repeated measures ANOVAs were used to analyze the grouped dependent variables to aid in interpretation of the MANOVAs. Based on these effects or interactions, a Scheffe test was used for post-hoc analysis comparison of means.

130 Volumes measures The following dependent variables are volume measures: Vital capacity (VC), phonation volume sustained /a/ (PV /a/), phonation volume sustained /s/ (PV /s/), and phonation volume sustained /z/, (PV /z/). The design for the MANOVA included two between subjects factors: group (PVCD or Control), gender (Male or Female) and four within subjects volume-dependent variables (VC, PV /a/, PV /s/, PV/ /z/). All values for volumes are in milliliters. Table 4.1 provides all the mean volume data with standard deviations for all tasks and groups.

Task PVCD. F PVCD. M Control. F Control. M n = 38 n = 12 n = 38 n = 12

VC mean 2093.66 2637.06 3281.87 4864.64 SD* 724.99 906.80 724.24 1170.64

PV/a/ mean 1864.69 2539.92 2804.58 4067.50 SD 614.87 1129.21 780.46 1455.29

PV/s/ mean 1723.02 2483.86 2812.48 4501.56 SD 603.62 1013.67 774.79 1300.11

PV/z/ mean 1551.90 2204.72 2638.82 4236.69 SD 576.378 1068.14 723.57 1223.48

*SD = standard deviation

Table 4.1: Mean volume data for all volume tasks and groups.

131 MANOVA revealed a significant interaction for group X gender. Table 4.2 lists the MANOVA results of all analyses. Figure 4.1 illustrates the significant effect of group X gender. Table 4.3 lists the means and standard deviations for the groups and genders.

Wilk’s Lambda F ratio df p Group .472 26.021 4,93 .0001 Gender .688 10.529 4,93 .0001 Group X Gender ______J581 ______3.150 4.93 .0178

Table 4.2: MANOVA table for dependent variable volumes.

PVCD Control

n = 12 n=12 Males mean 2466.39 4418.58 SD 1012.31 1296.39

Females n=38 n=38 mean 1808.32 2884.43 SD 657.10 781.66

Table: 4.3: Means and standard deviations for interaction group X gender for the dependent variable volumes.

132 MANOVA revealed a significant main effects for group and gender. Tables 4.4 and 4.5 list the data for these effects. Figures 4.2 and 4.3 demonstrate these effects visually.

Group n Mean (ml) §D* PVCD 50 1966.26 805.64 Control 50 3252.39 1133.73

*SD = standard deviation

Table 4.4: Mean volume data for group.

Group n Mean (ml) SD*

Male 24 3441.99 1512.44 Female 76 2346.37 900.07

*SD = standard deviation

Table 4.5: Mean volume data for gender.

133 This analysis demonstrates that there is a volume difference across groups. The persons with PVCD did not expire as much air during exhalation or phonation as did the controls. One explanation for this finding supports the proposed model. It is possible that persons with PVCD demonstrate an increased level of muscle tension in the larynx which prevents complete expiration of air during respiration and phonation. A second explanation for this effect is that the persons with PVCD also demonstrate a concomitant asthma disorder. It is known that persons with asthma will demonstrate decreased lung volumes (Goldman &

Muers, 1991; Fields et al., 1992). It is possible that the presence of asthma in 26 persons with PVCD in the present study contribute to the overall decreased volumes measures. Next, a repeated measures ANOVA determined several significant effects. The ANOVA table 4. 6 follows.

134 Source df ss MS F P Group i 167163433.32 167163433.32 71.268 .0001 Gender l 8759808.743 87579808.743 37.339.0001 Group X Gender l 13968046.811 13968046.811 5.955 .0165

Residual 96 2.252E8 2345555.435 Volumes 1 12204880.940 4068293.647 30.902 .0001* Volumes X Group 1 2184440.275 728146.758 5.531 .0018* Volumes X Gender 1 632667.923 210889.308 1.602 .1948*

Volumes X Group X Gender 1 535020.876 178340.292 1.355 .2590*

Residual 288 37915876.381 131652.349

*Geiser-Greenhouse p value

Table 4.6: Repeated measures ANOVA table for volumes.

There is a significant effect for group, gender, and a significant interaction for group X gender. Table 4.4 lists the data for the effect for group. Table 4.5 lists the data for the effect for gender (these are the same means tables used to illustrate the effect described in the MANOVA section). Table 4.3, also in the MANOVA section, lists the data that relate to the significant group X gender interaction. Figure 4.1 illustrates the interaction. Figures 4.2 and 4.3 illustrate the main effects for group and gender, respectively. These figures were already pointed out in the MANOVA section.

135 The interaction of group X gender is interesting because it indicates a departure from parallelism. The gender effect might indicate that males will have a higher volume than females, but the group effect shows that controls have a greater volume than persons with PVCD. The means table demonstrates the departure from parallelism in that male controls demonstrated the greatest volumes, with female controls the next largest volumes, not the males with PVCD as might have been expected. This accounts for the interaction of group X gender.

There is a significant effect for the variable of volumes. This indicates that there is a significant difference between one or more of the levels of the dependent variable in this group: VC, PV /a/, PV /s/, PV /z/. The means table for the main effect volumes is illustrated in Table 4.7.

Figure 4.4 illustrates this main effect.

136 Task n Mean (ml) SD*

VC 100 2942.88 1189.96 PV /a/ 100 2567.22 1109.02 PV /s/ 100 2561.74 1188.90 PV /z/ 100 2365.45 1150.31

*SD = standard deviation

Table 4.7: Mean volume data for volumes effect.

There was also a significant interaction between volumes X group. This indicates a significant difference exists between one or more levels of the dependent variables within the subject groups, PVCD and Control. Table 4.8 and Figure 4.5 illustrate these data.

Group n VC PV/a/ PV/s/ PV /z/

PVCD 50 2224.07 2026.75 1905.62 1708.58 SD* 797.77 810.31 783.29 765.70

Control 50 3661.69 3107.69 3217.86 3022.31 1081.66 1110.05 1167.79 1098.45

* SD = standard deviation

Table 4.8: Mean volume data for significant effect volumes X group.

137 A Scheffe test was performed to determine which levels of the dependent variable contribute to the significant differences found for the effects. Scheffe test was necessary to determine significant differences in (1) the main effect of volume and (2) the interaction effect of volumes X group. Table 4.9 displays the volumes differences which exceed the minimum significant difference for the volumes effect.

Task Task Difference (507.97 ml) VC PV /z/ 2942.88 2365.45 577.43

Table 4.9: Difference between means which exceed critical value as determined by Scheffe test for volumes effect.

Subjects demonstrated significantly higher volumes for vital capacity than for the phonatory volumes tasks. This supports what is already known about volumes measures. As discussed in Chapter 3, phonation volumes are estimated to be approximately 80% of VC. The percentages for the measures in the present study are listed in Table 4.10. This information does provide further confirmation about what is known regarding volumes. However, knowing that both controls and persons with

PVCD use approximately 80% of VC for PV does not help to differentiate the groups.

138 Task Task % of VC VC PV /a/ 2942.88 2567.22 87.23%

VC PV /s/ 2942.88 2561.74 87.10%

VC PV /a/ 2942.88 2365.45 80%

Table 4.10: Percentage of vital capacity made up by the

phonation volume across tasks for all subjects.

Scheffe testing was done for the volumes X group interaction to determine which pairs of tokens were contributing to the significance. Table. 4.11 displays the significant differences between means as determined by Scheffe testing for the volumes X group interaction. The minimum significant difference equals 359.139.

139 Group Task Task Difference(359.139^

PVCD VC /z/ n=50 2224.07 1708.58 515.49

Control VC /a/ n=50 3661.69 3107.69 554.0

VC /a/ 3661.69 3217.86 443.83

VC /z/ 3661.69 3022.31 639.38

Table 4.11: Mean significant difference for volumes X group.

These minimum significant differences demonstrate that the persons with PVCD in the present study expired significantly less air during these tasks than did controls. Each token (VC, /a/, /s/, fzf) contributes to the effect because all four exceeded the minimum significant difference. However, the volumes X group interaction is accounted for primarily based on the performance of the control subjects. Control subjects produced significantly higher volumes for vital capacity than they did for all three phonatory volume tasks, but maintained the same basic proportion of PV to

VC. The subjects with PVCD did not demonstrate this same basic

140 proportion as they demonstrated a fatiguing of performance across the volumes tasks.

However, subjects with PVCD produced significantly higher vital capacity volumes compared only to the phonatory volume /z/. The interaction is significant; however, some means comparisons did not meet the minimum significant difference. It is difficult to know exactly what this means at this time because there is not a great deal of information available about phonatory function in persons with PVCD. These findings indicate that phonation is different in persons with PVCD than controls, but the exact nature of that difference cannot be discerned from this one variable.

The research question, “is there a significant difference in volumes between persons with PVCD and controls” must be answered yes. Persons with PVCD used less air across all four volumes measures than did controls. It is possible that the laryngeal incoordination in persons with PVCD is contributing to this effect. As stated earlier, an increased degree of laryngeal constriction may prevent efficient transglottal flow.

Therefore, during a task which requires maximum transfer of flow from the lower airways to the vocal tract, persons with PVCD can not perform efficiently. It is also possible that the presence of asthma contributes to decreased volume in persons with PVCD.

141 To determine if asthma contributed to decreased volumes measures, MANOVA was used with the presence of asthma as the independent variable. Table 3.2 lists the gender breakdown for the presence of asthma in persons with PVCD. Of the 50 persons with PVCD, 27 have a “diagnosis” of asthma, 17 did not, and 6 persons could not confirm or deny the presence of asthma. MANOVA did not demonstrate a significant difference in volumes between persons with an asthma diagnosis and persons without a diagnosis. Table 4.12 lists the MANOVA table for this non-significant effect. Table 4.13 lists the data for each token and subject group.

Wilk’s Lambda F ratio df j> Asthma .803 1.276 8,88 .2664 n=50 [27 + asthma, 17 - asthma, 6 unknown]

Table 4.12: MANOVA table for dependent variable volumes with asthma independent variable.

142 Task + ASTHMA - ASTHMA UNKNOWN n = 27 n = 17 n = 6 VC mean 2102.12 2306.55 2539.17 SD 778.63 770.14 981.83

/a/ mean 1900.16 2031.19 2584.00 SD 806.02 647.10 1121.25

hi mean 1907.49 1827.18 2119.61 SD 815.39 749.50 825.86

/z/ mean 1713.93 1568.08 2082.61 SD 790.55 699.83 832.75

*SD = standard deviation

Table 4.13: Data for token and groups based on presence of asthma.

Thus, it is noted that the persons with PVCD and a diagnosis of asthma did not necessarily produce decreased volumes measures compared

to persons with PVCD without an asthma diagnosis. Therefore, the difference in volumes discussed earlier can be attributed to the presence of PVCD. Controls and persons with PVCD can be differentiated via volumes

measures.

143 MANOVA (Table 4.2) also indicated a significant effect across gender for the volumes tasks. Males expired significantly more air than did females. This is confirmation of what is known about lung volume. It is correlated with height, and as most men are taller than most women, it is not surprising to find men consistently demonstrated higher volumes on these tasks. This does not contribute to the goal of differentiating the two subject groups, however. There was also a significant effect for the grouped volumes tasks. VC demonstrated a larger mean than the PV tasks. Scheffe post hoc testing confirmed that VC is significantly different from the other volumes measures in the present study. Again, this confirms what is known about the relationship between VC and PV. The percentages of VC that constitute PV for the data in the present study are approximately 80%. This is similar to the literature reported in Chapter 3.

Therefore, these tasks are useful in the diagnosis of persons with PVCD, as they demonstrate differences from respiratorally and laryngeally normal controls. Vital capacity measures are typically part of pulmonary function testing. Why is it, then, that measurement of VC in this study demonstrated decreased results for persons with PVCD, whereas the literature reports that these patients test WNL between attacks? The method of collecting VC may be the difference. In the present study, persons were encouraged to exhale slowly and steadily with visual feedback to facilitate maximal lung emptying. They were instructed not to be

144 excessively forceful until the end of the trial where they needed to push out all air. It is possible that the PFT methods are more accurate for forceful expirations such as FEV (forced expiratory volume). Mean Flows of Sustained Tasks It was important to use sustained tasks during a the present study to attempt to validate an easily obtained clinic measurement used widely with the field of speech-language pathology. At the present time, the literature does report on findings of sustained tasks (flows and durations), but often, the sample sizes are not adequate for powerful statistics. Therefore, the reliability and validity of the measures must continue to be questioned. A large sample such as was used for the present study attempts to provide information that the literature presently lacks. The sustained phonation tasks, /a/, /s/, /z/, were grouped for analysis. Table 4.14 lists the mean flow and standard deviations of flow for all tasks and groups. MANOVA did not demonstrate significant differences for group, gender, or group X gender: Table 4.15 displays the MANOVA table.

145 Task PVCD. F PVCD. M Control. F Control. M n = 38 n = 12 n = 38 n = 12

/a/ mean 146.24 122.08 146.58 144.56 SD 66.93 30.76 55.56 68.34

/s/ mean 151.60 170.63 161.85 225.37 SD 69.84 84.72 50.11 122.24

/z/ mean 126.22 117.36 134.51 146.31 SD 43.70 44.76 37.86 63.67

*SD = standard deviation

Table 4.14: Mean and SD data for sustained phonation tasks.

Wilk’s Lambda F ratio df E Group .951 1.610 3.94 .1923

Gender .925 2.548 3.94 .0605 Group X Gender .979 .677 3.94 .5680

Table 4.15: MANOVA table for dependent variable mean flow.

These findings differ from what the literature generally indicates. The literature reports that males demonstrate higher flow than females. The groups in the present study did not follow this pattern. Males with PVCD or male control subjects were not more likely to use more air per

146 second during sustained phonation tasks than were females. Kent, Kent, and Rosenbeck (1987) provide an extensive review of the literature on mean flow during sustained tasks and state “Considering first nongeriatric men and women, it is clear that airflow is sex dependent. Men have somewhat greater airflows than women.” (page 368). Hirano, Koike, and von Leden (1968) tested 50 “normal” controls. They found ranges from 46-222 ml/sec for males and 43-197 ml/sec for females. The data from the present study do not support the statement that males use more flow during sustained tasks than do females. Significance of these findings is questionable, however, because the researchers did not employ large N studies with powerful statistics. Therefore, it is difficult to know if the trends they report generalize to other samples. The research question, “does mean rate of airflow during sustained production tasks differ persons with PVCD from controls,” must be answered no. These data do not indicate that the two groups perform differently during these tasks. This does provide evidence that mean flow during sustained tasks may not be related to either VC or PV. Males did differ from females on VC and PV, but these differences are not transferred to transglottal flow.

147 Durations of sustained phonation tasks The sustained phonation tasks, /a/, /s/, /z/, were grouped for analysis. Duration was recorded in seconds. Table 4.16 lists the data for each token across group and gender. MANOVA demonstrated a significant effect for group and gender. There was not a significant effect for the interaction group X gender. Table 4.17 illustrates the MANOVA table for these analyses.

Task PVCD. F PVCD. M Control. F Control. M MPD n = 38 n = 12 n = 38 n = 12

/a/ mean 14.59 21.87 20.76 30.78 SD 6.55 9.66 6.21 9.67

/s/ mean 12.40 16.74 18.28 24.59 SD 4.16 9.62 5.52 12.28

/z/ mean 13.17 20.79 20.57 21.64 SD 5.02 10.45 6.16 9.77

*SD = standard deviation

Table 4.16: Duration (in seconds) data for sustained phonation tasks.

148 Wilk’s Lambda F.ratip df c Group .742 10.917 3,94 .0001 Gender .721 12.105 3,94 .0001 Group X Gender .988 .385 3.94 .7644

Table 4.17: MANOVA table for dependent variable mean flow.

These data indicate that persons with PVCD can be differentiated from controls via duration of sustained tasks. These data also indicate that males can be differentiated from females via duration of sustained tasks.

The means tables for these analyses are listed below. Table 4.18 delineates the mean duration in seconds for the three tasks for each group. Figure 4.6 illustrates this main effect. Table 4.19 delineates the mean duration in seconds across gender. Figure 4.7 illustrates the data for this main effect.

PVCD Controls n=50 n=50 Mean 14.92 22.06

SD 7.24 8.38

Table 4.18: Mean duration and standard deviations in seconds

across groups.

149 This relates directly to the research question, “can sustained phonation duration differentiate persons with PVCD from controls? The answer is yes. These results indicate that controls can sustain a phonatory target for longer durations than persons with PVCD. This is probably related to the significant difference in volume discussed earlier, as mean rate of flow was found to be not significant.

Males Females n=24 n=76 Mean 24.40 16.63 SD* ______11.28 ______6 J 6 ______

Table 4.19: Mean duration and standard deviation in seconds across gender

The difference in duration between genders is most likely directly related to the significant difference in volume discussed earlier. Males have a larger volume of air for phonatory tasks, and therefore are able to sustain a phonatory target for a greater length of time than are females.

This finding is interesting in that it supports the gender difference of volume; however, it does not directly relate to the research question for the present study.

150 A repeated measures ANOVA was performed to determine which subtle differences contributed to the significant effects found in the MANOVA. Table 4.20 provides the ANOVA table.

Source df s s MS F P

Group l 3368.518 3368.518 31.869.0001

Gender i 3308.182 3308.182 31.299 .0001

Group X Gender i 101.067 101.067 .956 .3306

Residual 96 10146.958 105.697

Tokens I 697.958 348.979 16.947 .0001*

Tokens X Group 1 49.433 24.716 1.2 .2995*

Tokens X Gender 1 167.903 83.952 4.077 .0233*

Tokens X Group X Gender 1 5.013 2.507 .122 .8589*

Residual 192 3953.703 20.592

*Geiser-Greenhouse p value______

Table 4.20: Repeated measures ANOVA table for durations.

Similar to the MANOVA, there is a significant main effect for group and a significant main effect for gender. The means tables referred to for the MANOVA also provide the data to illustrate these significant effects

(Tables 4.18 and 4.19 respectively). Similar to the MANOVA the interaction group X gender was not significant. Two other significant

151 effects were found: the main effect of tokens and the interaction of tokens

X gender. Table 4.21 indicates the data for the interaction of tokens X gender. Figure 4.8 illustrates the interaction.

M IsL IzL Males Mean 26.32 20.67 26.21 SD* 10.49 11.51 11.34 Females Mean 17.67 15.34 16.87 SD 7.06 5.69 6.71

Table 4.21: Mean duration and standard deviations in second across tasks and gender.

A post-hoc Scheffe test was used to determine the significant differences defining the interaction. Using these values in the formula, the minimum significant difference equals 5.19. Using this value, the comparison of means for this interaction yielded differences which account for the significance. These differences are delineated in Table 4.22.

152 Task Task Gender Difference (5.19 sec) MPD /a/ MPD /s/ Males 26.32 20.67 5.65

MPD /s/ MPD /z/ Males 20.67 26.21 5.54

Comparisons among females were not signficant.

Table 4.22: Critical differences for the durations X gender interaction.

A repeated measures ANOVA indicated a significant main effect for tokens. Table 4.23 indicates the data for that interaction. Figure 4.9 illustrates the interaction.

M M M Mean 19.75 16.62 19.11 SD* 8.78 7.78 8.95

Table 4.23: Mean duration and standard deviations in seconds across tasks.

153 A post-hoc Scheffe test was used to determine which specific tasks contributed to the significant differences found in the interaction. The minimum significant difference equals 6.35. Using this minimum significant difference, the comparisons yielded no significant means differences. Mean Flow of Connected Speech Tasks The connected speech tasks, reading the Rainbow Passage (RBP) and counting from 1-50 (Counting) were grouped for analysis. The data for each group, gender, and task are listed in Table 4.24. MANOVA results are listed in Table 4.25.

Task PVCD. F PVCD. M Control. F Control. M

n = 37 n = 8 n = 38 n = 12 RBP mean 137.99 167.92 121.66 160.36 SD 38.08 35.67 34.82 28.16

Count ing mean 133.62 192.75 124.65 160.28 SD 45.01 60.81 27.68 34.66

*SD = standard deviation

Table 4.24: Mean airflow (ml/sec) and standard deviations across group,

gender, and task for the significant effect of task X group X gender.

154 n=95 Wilk’s Lambda F ratio df £ Group .954 2.161 2,90 .1211

Gender .799 11.333 2,90 .0001 Group X Gender ______,960 ______1.874 2.90 .1594

Table 4.25: MANOVA table for dependent variable connected speech tasks.

MANOVA analysis demonstrated a significant effect for gender. The data for this effect are listed in Table 4.26 and the effect is illustrated in Figure 4.10.

n Mean (ml/secl SD

Males 20 163.38 30.70 Females 75 131.18 34.52

Table 4.26: Mean airflow in ml/sec across gender for the significant effect of gender during connected speech tasks.

155 A repeated measures ANOVA was used to determine which subtle differences contributed to the main effects demonstrated by the MANOVA. The ANOVA results are listed in Table 4.27.

Source df s s MS F P

Group 1 8217.216 8217.216 3.577 .0618

Gender 1 50853.683 50853.683 22.136 .0001

Group X Gender I 428.497 428.497 .187 .6669

Residual 91 209058.718 2297.349

Connected Speech Tasks 1 1020.809 1020.809 2.020 .1587*

Tasks X Group 1 605.512 605.512 1.198 .2766*

Tasks X Gender 1 1279.907 1279.907 2.533 .1150*

Tasks X Group X Gender 1 2022.392 2022.392 4.002 .0484*

Residual 91 45990.558 505.391

*Geiser-Greenhouse p value

Table 4.27: Repeated measures ANOVA table for connected speech tasks.

The repeated measures ANOVA demonstrated a significant effect for gender. Table 4.26 provides the data for the effect; this is the same table which described the main effect found via MANOVA.

Repeated measures ANOVA demonstrated a significant effect for the interaction connected speech tasks X group X gender. The data for this interaction are listed in Table 4.24 (seen earlier in this section to provide

156 summary data); the interaction is illustrated in Figure 4.11. A Scheffe test was done to determine which differences in the interaction connected speech tasks X group X gender contributed to the effect. The minimum significant difference equals 22.26 ml/sec. Table 4.28 illustrates the differences between the volumes means which

contribute to the significant effect.

Task Task Group.Gender Difference (22.26 ml/sec) Counting RBP PVCD, Males 192.75 167.92 24.83

Other comparisons within group and gender were not significant. Comparisons across genders would be significant, however this is explained by the main effect of gender which is significant and demonstrated above.

Table 4.28: Significant critical differences which account for the effect for connected speech tasks X group X gender.

The research question, “does the mean flow of connected speech tasks differentiate persons with PVCD from controls?” must be answered no. Persons with PVCD did not demonstrate a significant difference (a constriction of flow was predicted) from controls during these connected

speech tasks. There was a significant effect for gender, however. Males expired significantly more air per second than did females during connected speech. Why the males in the present study used more air for these tasks in not understood. It was demonstrated prior that males expired

157 larger volumes than did females; however, during flow regulation for connected speech, volume should not contribute to increased flow per second. Again, this provides evidence that males and females are not homogeneous groups. Also, males with PVCD performed unlike the other groups, most notably, females with PVCD. It is possible that males and females with PVCD are two different populations and need to be treated differently. The gender bias of more females in the PVCD population (3 females : 1 male) also supports the suggestion that females with PVCD are unlike males with PVCD,

The repeated measures ANOVA did demonstrate a significant interaction for tasks X group X gender. The males with PVCD performed differently across tasks. One might consider that the Rainbow Passage contains several constraints which may make it a more “complex” task. These constraints include syntax, prosody, intonation, and pause time. A counting task such as the one used in the present study does not maintain constraints like the reading task. Counting is essentially a simpler task. Why increased flow would occur because a task is simpler is not understood. One would expect a complex task, like reading, to inhibit coordination, and thus, inefficient use of airflow. This was not the case in the present study. This incoordination may also be reflected in the presence of spikes of flow (which will be discussed in a later section). It is possible that mean flow during connected speech is related to frequency of spikes during the passage.

158 A larger frequency of spiking behavior would explain an increased mean flow rate. Repetitions of /a/ and ha/ The analysis of the frequency of repetitions (repetitions) will be discussed first, then the mean peak flow (peak flow) will be explained, followed by the results for the analysis on the ha:a ratio (ratio). Repetitions

Table 4.29 provides the mean number of repetitions for each group, gender, and task. Table 4.30 provides the MANOVA table. The MANOVA analysis indicated a main effect for group for the task of repetitions (both /a/ and /ha/). Table 4.31 lists the data for this group effect. Figure 4.12 illustrates the effect.

Task PVCD. F PVCD. M Control. F Control. M 00 G n = 31 n = 7 II n = 12 /a/ reps mean 5.38 6.59 4.39 4.50 SD 2.52 1.63 .77 .72

/ha/ reps mean 5.17 6.67 4.50 4.19 SD 2.47 1.77 .73 1.02

*SD = standard deviation

Table 4.29: Data for /a/ and /ha/ repetitions across groups, genders and tasks. 159 n=88 Wilk’s Lambda F ratio df £

Group .866 6.426 2,83 .0025 Gender .974 1.092 2,83 .3403

Group X Gender ______.939 ______2.677______2.83 .0747

Table 4.30: MANOVA table for frequency of repetitions /a/ and /ha/.

n Mean (#) SD

PVCD 38 5.52 2.39 Control 50 4.43 .78

Table 4.31: Mean frequency count and standard deviations for the main effect of repetitions.

These data indicate that the research question, “does the number of repetitions of /a/ and /ha/ differentiate persons with PVCD from controls?” must be answered yes. Persons with PVCD tended to produce more syllable repetitions than did controls. This is opposite of the expected outcome. It was theorized that persons with laryngeal incoordination may

160 also demonstrate articulatory incoordination which could be measured via a diadochokinetic task. These data indicate that persons with PVCD were able to produce more syllables per second than were laryngeally normal controls. Mean peak flow of /a/ and /ha/ repetitions Table 4.32 provides the data for mean peak flow (in ml/sec) for all groups, genders, and tasks. Table 4.33 provides the MANOVA table for the analyses.

Task PVCD. F PVCD. M Control. F Control. M r»1 00 c II n= ll n=38 n=l 2

/a/ Mean 143.13 223.92 129.84 215.13 SD 76.25 187.39 47.83 137.28

/ha / Mean 482.85 620.31 580.36 785.68 SD 187.06 262.22 198.63 224.43

Table 4.32: Mean peak flow (ml/sec) and standard deviations for task, group, and gender for mean peak flow during /a/ and /ha/ repetitions.

161 n=99 Wilk’s Lambda F ratio £lf p Group .913 4.477 2,94 .0139 Gender .827 9.809 2,94 .0001 Group X Gender ______.995 ______.239 ______2.94 .7881

Table 4.33: MANOVA table for mean peak flow (ml/sec) for repetitions

/a/ and /ha/.

The data to support the significant effect of group are listed in Table 4.34 and illustrated in Figure 4.13.

n Mean fmO SD PVCD 49 339.04 243.47

Control 50 389.97 293.02

Table 4.34: Mean peak flow in milliliters across groups for the main effect of group.

162 MANOVA analysis also indicated a main effect of gender. Table 4.35 lists the data to support this effect and Figure 4.14 illustrates the effect.

n Mean (ml) SD Males 23 462.96 322.76 Females 76 335.05 245.67

Table 4.35: Mean peak flows (ml) and standard deviations across gender for the main effect of gender.

The group effect allows the research question, “does the mean peak flow of /a/ and /ha/ repetitions differ persons with PVCD from controls?” to be answered yes. Examinations of the means in Table 4.32 indicate that when the mean peak flows of /a/ and /ha/ are combined, control subjects demonstrated a higher rate of flow than did persons with PVCD. This may support the prediction that persons with PVCD demonstrate a higher degree of constriction during certain phonatory tasks thereby inhibiting airflow.

163 The gender effect, although interesting, does not contribute to differentiating persons with PVCD from controls. As there are no data in the literature describing the typical performance of each gender during a syllable repetition task such as the ones utilized in the present study, comparison to such findings cannot be made at this time. An ANOVA table for the repeated measures analysis can be found in

Table 4.36.

Source df s s MS F *G-G p

Group I 123569.024 123569.024 4.107 .0479

Gender 1 561715.665 561715.665 18.260 .0001

Group X Gender 1 12853.385 12853.385 .418 .5196

Residual 91 2922467.320 30762.814

Repetitions Peak Flow 1 6773986.183 6773986.183 3.33 .0001

Repetitions Peak Flow X Group 1 184012.084 184012.084 9.049 .0034

Repetitions Peak Flow X Gender 1 71970.149 71970.149 3.539 .0630

Repetitions Peak Flow X Group X Gender 1 7766.103 7766.103 .382 .5381

Residual 95 1931826.616 20335.017 *Geiser-Greenhouse p value

Table 4.36: Repeated measures ANOVA table for repetitions peak flow.

164 Like the MANOVA, the repeated measures ANOVA indicates a group effect and a gender effect for the variable mean peak flow. Table 4.34 provides the data for the group effect and Table 4.35 provides the data for the gender effect. These tables were referred to during the MANOVA explanation.

Repeated measures ANOVA indicated a significant effect for repetitions peak flow. Table 4.37 lists the data to support this effect and Figure 4.15 illustrates the effect.

n Mean (mil SD /a/ 99 157.27 99.99 /ha/ 99 572.26 223.02

Table 4.37: Mean peak flow (ml/sec) across tasks for the main effect of repetitions peak flow.

These data confirm that fhj is an airflow facilitator as more airflow was used for productions of /ha/ than for /a/. Repeated measures ANOVA also indicated an interaction effect of repetitions peak flow X group. Table 4.38 lists the data and Figure 4.16 illustrates the effect.

165 Task n PVCD Control

/a/ 49 Mean 164.37 150.31 SD 113.37 85.51

/ha/ 50 Mean 513.71 629.64 SD 211.32 221.23

Table 4.38: Mean peak flow across group and task for interaction effect repetitions peak flow X group.

A post-hoc Scheffe test was used to determine the minimum significant difference which contributed to the interaction. The minimum significant difference equals 199.64. Using this value, the comparison of means for this interaction did not yield any significant differences between the groups.

It is apparent from the ANOVA that mean peak flow of /ha/ repetitions is more sensitive to PVCD than is /a/. The research question, “does mean peak flow of syllable repetitions differentiate persons with PVCD from controls?” can be answered yes due to the sensitivity of /ha/ mean peak flow. Interestingly, though, the effect demonstrated by the data is opposite of what was expected. It was hypothesized that persons with

PVCD would demonstrate increased mean peak flows during /ha/ syllable repetitions because of the airflow facilitation characteristics of /ha/

166 combined with the suspected laryngeal incoordination. According to these data, persons with PVCD used less air during /ha/ repetitions than did controls. Rather than identifying laryngeal incoordination demonstrated via increased flow, these data may be demonstrated the excessive constriction of flow persons with PVCD may demonstrate during some phonatory tasks. /ha:a/ Ratio A two-within, one between ANOVA was used to determine if the /ha:a/ ratio differentiated the groups or genders. The ANOVA table can be found in Table 4.39.

Source d f s s MS F P

Group l 22.805 22.805 2.792 .0981

Gender i 4.660 4.660 .570 .4520

Group X Gender l 1.032 1.032 .126 .7231

Residual 95 776.059 8.169

Table 4.39: ANOVA table for ha/a ratio.

167 Table 4.40 provides the data for each group, and gender.

PVCD. M PVCD. F Control. M Control. F n=ll n=38 n=12 n=38

Mean 3.655 3.928 5.307 4.551 SD 2.045 2.262 3.610 2.385

Table 4.40: Group and gender data for /ha:a/ ratio.

The research question, “does the /ha:a/ ratio differentiate persons with PVCD from controls?” must be answered no. According to these data, the two groups utilize airflow in generally the same manner for rapid repetitions of /a/ and /ha/ syllables. It was expected that an increased /ha/ mean peak flow would facilitate an increased ratio for persons with PVCD. However, as seen in the previous section, persons with PVCD actually demonstrated decreased /ha/ peak flow compared to controls. This is confirmed in the increased mean ratio demonstrated in the above table for the control group. Although the means for the controls are increased compared to persons with PVCD, the difference between means is not significant.

168 S/Z Ratio The s/z ratio has been calculated for three different variables obtained through the sustained /s/ and /z/ tasks: phonation volume (PV), duration, and mean flow. The MANOVA table for the three grouped ratios can be seen in Table 4.41. Figure 4.17 demonstrates the data graphically. MANOVA with the three ratios demonstrated a main effect for gender. There was no significant effects for group or for the interaction group X gender. Data for group, task, and gender can be seen in Table 4.42. The data for the gender effect are listed in Table 4.43.

n=100 Wilk’s Lambda F ratio d£ U

Group .933 2.239 3,94 .0888 Gender .903 3.356 3,94 .0221 Group X Gender .969 1.008 3.94 .3928

Table 4.41: MANOVA table for three s/z ratios.

169 PVCD. M PVCD. F Control. M Control. F

n = 12 n = 38 n = 12 n = 38 s/z Phonation Volume 1.197 1.301 1.066 1.080 s/z Duration .929 1.031 .770 .924 s/z Mean Flow 1.668 1.282 1.559 1.267

Table 4.42: Data for three s/z ratios for group and gender.

Females Males Mean 1.148 1.198 SD .588 .640

Table 4.43: Mean s/z ratio (duration, PV, and flow) for the main effect of gender. These data indicate a gender effect. Production of s/z varies according to gender. A repeated measures ANOVA was performed to determine which differences contributed to this effect. Table 4.44 provides the ANOVA table.

170 Source d f s s MS F P

Group i .837 .837 1.786 .1846

Gender i .140 .140 .299 .5858

Group X Gender l .005 .005 .010 .9196

Residual 96 45.013 .469

Ratios 1 10.284 5.142 19.607 .0001*

Ratios X Group 1 .122 .061 .232 .7661*

Ratios X Gender 1 2.312 1.156 4.408 ,0171*

Ratios X Group X Gender 1 .083 .042 .159 .8277*

Residual 192 50.352 .262

Table 4.44: ANOVA table for s/z ratios.

These data do not support the expectation that one of the three forms of the s/z ratio would differentiate persons with PVCD from controls.

There was no significant group effect via MANOVA or repeated measures ANOVA. There was a gender effect for s/z ratios, via MANOVA but not ANOVA. However, this does not provide support in relation to questions regarding PVCD.

171 Repeated measures ANOVA did demonstrate a significant effect for the ratios variable. Table 4.45 lists the data for this effect.

11=100 Mean SD

s/z PV 1.176 .693

s/z Duration .947 .332 s/z Flow 1.356 .643

Table 4.45: Mean s/z ratio data for the main effect of ratios.

Repeated measures ANOVA also indicated a significant interaction for ratios X gender. Table 4.46 lists the data for this interaction. Figure 4.18 illustrates these data.

Males Females n=24 n=76

PV Mean 1.132 1.191 SD .187 .788

Duration Mean .850 .977 SD .362 .318

Flow Mean 1.613 1.275 SD .888 .525

Table 4.46: Mean data for the interaction ratios X gender.

172 The primary finding from these analyses indicate that the s/z ratio for the three measurements, (duration, flow, PV) demonstrates a gender effect. This indicates that flow, duration, and PV vary as a function of gender. All three measurements are related, therefore it is not surprising to find the effect across all three. A Scheffe post-hoc test was used to determine which levels of the dependent variable contributed to the effect. The minimum significant difference equals .585. Table 4.47 lists the significant differences

Task & Gender Task & Gender Difference (.585)

Duration, Males Flow, Males .763 Duration, Females Flow, Males .636

Table 4.47: Critical differences for the ratios X gender interaction.

Frequency of Spikes during Connected Speech

A single case Chi square was used to analyze the frequency of spikes during connected speech. This analysis was used because the data from the present study provide a good estimate of spiking behavior in a normal population. The question to be asked is “do persons with PVCD correspond to this expectation?” This test was used because the data did not meet the basic assumption of an ANOVA that the data must be distributed on a normal curve.

173 Table 4.48 lists the data for the frequency of spikes during both connected speech tasks. This table demonstrates the lack of a normal distribution.

PVCD.F PVCD.M Control.F Control. M

Rainbow Passage Mean 1.76 5 .974 4.33 SD 3.27 6.164 1.619 6.827

Counting Mean 2.76 13.71 .395 1.75 SD 5.22 19.46 .946 3.28

Table. 4.48: Means and standard deviations of spike of flow during reading and counting for group and gender.

Table 4.49 lists the observed and expected frequencies of spikes during counting (1-50). Table 4.50 lists the observed and expected frequencies of spikes during reading (RBP).

174 PVCD Cpntrol Gender O E Q E Males n=9 n=12 125 15.75 21 8.64

Females n-31 n=38

100 12.24 15 27.36

Total 225 27.98 36 36 Chi square = 1387.25 (p< .001) Chi square = 23.26 (p < .001)

Table 4.49: Chi square for frequency of spikes during counting (1-50).

The Chi square of 23.26 for the control subjects indicates that there is a significant difference in the performance of males and females in the production of spikes during the counting task. Male control subjects produced more spikes than did female control subjects. This provides additional evidence that males and females are not a homogeneous group. This difference may be exacerbated in the PVCD disorder. The Chi square of 1387.25 indicates that persons with PVCD are significantly different from their control counterparts in the production of spikes of flow during the counting task. Therefore, the research question, “does frequency of spikes of airflow during counting differentiate persons with PVCD from controls,” can be answered yes. Persons with PVCD

175 were more likely to produce spikes during this task than were controls. Persons with PVCD produced eight times more spikes than did controls of the same gender. Spikes of flow, in the present study, are sensitive to the presence of PVCD and further study of this phenomenon is indicated. Men with PVCD were differentiated from the other groups during this task. Males with PVCD produced more spikes than any other group. Men were four times more likely to produce spikes > 700 ml than were females. They also demonstrated higher rates of flow during these connected speech tasks. It is difficult to determine from the present study if a higher rate of flow facilitates the production of spikes, or if the production of spikes produces the higher rate of flow. Chi square analyses were also performed for the spiking of flow during the reading task. First, a Chi square was done to determine the typical performance of control subjects. Then, persons with PVCD were compared to this typical pattern. Table 4.50 provides the observed and expected frequencies along with the Chi square values for these analyses.

176 PVCD Control

Gender Q E Q E Males n=7 n=12 35 30.33 52 21.36 00 C Females n=29 II

51 28.23 37 67.64

Total 86 58.56 89 89 Chi square = 19.068 (p< .0011 Chi square = 57.83 fp < .0011

Table 4.50: Chi square for frequency of spikes during reading of the Rainbow Passage.

The Chi square of 57.83 indicates that the control subjects are not similar in their production of spikes of flow during reading of the Rainbow

Passage. Males produced significantly more spikes than did females. Again, this gender difference may be intensified when laryngeal disorder, such as PVCD, is present. The Chi square of 19.068 indicates that persons with PVCD did not perform like controls in the production of spikes of flow during the reading task. In the above table, 29 women with PVCD produced 51 spikes, while 7 men produced 35 spikes, whereas 38 female controls produced 37 spikes, and 12 male controls produced 52 spikes. Persons with PVCD produce more spikes on average than do their control

177 counterparts. If one looks only at the frequency counts and not the proportions, at first, it appears the control subjects produced more spikes than did the subjects with PVCD. Also, subjects were more likely to produce spikes » during the counting task than during the reading tasks. The grammatical constraints of reading include syntactic constraints, prosody and intonation constraints, and pauses. These same constraints are not present in a counting task in which the subject is told to count at a comfortable pitch, pace, and loudness. Although the subjects were told to read the passage comfortably, grammar constraints are still present. These constraints make reading the RBP a more complex task. Counting can be considered a simple connected speech task. The cognitive skills used during reading may allow for better control over the respiratory system during the task.

The same cognitive control may not be present in a simple, rote connected speech task like counting, therefore, cognitive control of respiration is also not present. Therefore, it is possible that the frequency of spikes during counting demonstrate this lack of control over the respiratory system. Frequency of Cessations during Sustained Phonation and Vital Capacity Tasks

Again, Chi square was used to determine the typical performance in a normal population to then compare to the PVCD population. Tables 4.51 through 4.55 list the data for the total frequency of cessations during all tasks, and for each token (VC, /a/, Is/, /z/).

178 PVCD Control

Gender O E Q E Males n= 10 n=12 48 25.4 39 30.48 r*i 00 G Females n=37 II

161 93.98 88 96.52

Total 209 118.18 127 127 Chi square = 67.90 (p < .001) Chi square = 3.133 fp > .05)

Table 4.51: Chi square for frequency of cessations during all tasks (VC, /a/, /s/, /z/).

The Chi square of 3.133 for the control group indicates that males and females in the control group did not differ significantly in their production of cessations for across all tasks. Therefore, there is no apparent gender affect in the normal population for the production of cessations of flow during sustained expiration tasks. The Chi square of 67.90 was significant and thus indicates that the group of persons with

PVCD performed differently from the controls. By examining the observed number of cessations, one can see that the persons with PVCD produced more cessations of flow during these tasks than the controls. Females with PVCD produced a greater number of cessations overall than did males with PVCD (or controls). Proportionately, however, each person

179 with PVCD produce approximately 4 cessations (31 females produced 4.35 cessations on average, while males produced 4.8 cessations on average). This was significantly different than the controls (39 females produced 2.32 cessations on average, males produced 3.25 cessations on average). Thus, it appears that cessations are sensitive to PVCD. Each token (VC, /a/, /s/, /z/) was analyzed for cessations of flow. The tables of data follow.

PVCD Control Gender 0 E O E Males n=10 n=l 2 25 17.8 26 21.36 oo c Females n=37 li

81 65.86 63 67.64

Total 106 83.01 89 89 Chi square = 6.392 fp < .011 Chi square = 1.326 (p > .051

Table 4.52: Chi square for frequency of cessations during VC.

The Chi square of 1.326 indicates that control subjects did not differ significantly in their production of cessations of flow during expiration of the vital capacity. There is no apparent gender affect for this task. The Chi square of 6.392 indicates that performance of persons with PVCD in

180 the production of cessations of flow for vital capacity did not correspond to the expected performance demonstrated by the controls. The frequency of cessations of flow during vital capacity does differentiate the two groups; this task is sensitive to the presence of PVCD. By examining the observations of cessations, one can see that again, females with PVCD produced more cessations during this task than did males with PVCD. This may be further evidence that males with PVCD and females with PVCD are not demonstrating the same disorder.

PVCD Control

Gender a e Q E Males n -9 n=12 16 .18 0 .24 oc c c II Females II

37 .66 1 .76

Total 53 .84 1 1 Chi square = 3391.3 fp < .0011 Chi square = .315 fp >.051

Table 4.53: Chi square of cessations of flow during sustained /a/.

The Chi square of .315 does not reach significance. Therefore, cessations of flow during sustained /a/ does not demonstrate a gender effect for laryngeally normal adults. Males and females performed similarly

181 during this task relative to cessations of flow. The Chi square of 3391.3 indicates that persons with PVCD did perform differently from controls. Cessations of flow during sustained /a/ are sensitive to the presence of PVCD. Proportionately, males and females with PVCD produced approximately the same number of cessations during sustained /a/ (2.5 and

2.18, respectively).

PVCD Control

Gender O E O E Males n=8 n=12 6 5.76 13 8.64 Tt c Females II n=38

26 24.48 23 27.36

Total 32 30.24 36 36 Chi square = .104 (n > .05'I Chi square = 2.894 (p > .05)

Table 4.54: Chi square for frequency of cessations during /s/.

The Chi square of 2.894 did not reach significance and therefore indicates that male and female controls did not differ in their performance of cessations of flow during sustained /s/. Females did produce more

182 cessations than did males, however, this difference was not statistically significant. The Chi square of .104 did not reach significance indicating that persons with PVCD did not perform differently than expected compared to the controls. This, it appears that cessations of flow during sustained /s/ productions is not sensitive to PVCD or to gender.

PVCD Control Gender O E 0 E Males n=8 n=l 2 1 .16 0 .24 m 00 c c Females II II

17 .34 1 .76

Total 18 .84 1 1 Chi square = 396.09 (p < .001) Chi square = .316 fp > .05)

Table 4.55 Chi square for frequency of cessations during /z/.

The Chi square of .316 was not statistically significant, indicating that male and female control subjects did not perform differently in the production of cessations of flow during sustained /z/. The Chi square of 369.09 was statistically significant indicating that subjects with PVCD did perform differently from controls in the frequency of cessations of flow during sustained /z/. Females with PVCD contributed primarily to this

183 effect in that 34 females produced 17 cessations, while 8 males produced 1 cessation. Again, cessations of flow are sensitive to the presence of PVCD in females moreso than in males. Correlation of Spikes and Flow One final analysis with spikes of airflow and mean airflow was performed after the observation of significant effect with spikes and mean airflow during the connected speech tasks. It appeared the mean flow during connected speech tasks, specifically counting, was related to frequency of spikes. This was tested using Spearman Rank Order correlations to determine if spikes of airflow during connected speech tasks varied with mean airflow of these tasks. The correlation tables for all subjects, PVCD subjects only, and control subjects only, are seen in Tables 4.56, 4.57, and 4.58. Significance levels are in parenthesis to the right of the correlation value (r). 1! z OC 4^ RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .706 (.01) 1.000

RBP Spikes .434 (.01) .334 (.05) 1.000

Counting Spikes .306 (.05) .430 (.05) .505 (.01) 1.000

Table 4.56: Spearman rank order correlation table for all subjects for comparison of spikes and mean flow during connected speech tasks.

184 The strongest correlation is counting flow and reading flow (.706). This moderate-strong correlation is significant at the .01 level. This correlation indicates the subjects were ranked similarly in mean rate of flow for both connected speech tasks. The correlation of spikes during reading of the Rainbow Passage and spikes during counting was weak, but significant (.505). This may demonstrate a weak trend for spiking behavior across tasks. The other correlations across all subjects, although significant at either the .05 or .01 level, demonstrated coefficients of less than .50 and for most practical purposes do not demonstrate a linear relationship between the attributes. cn Z 11 RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .669 (.01) 1.000

RBP Spikes .430 (.05) .430 (.05) 1.000

Counting Spikes .294 (N S) .596 (.01) .569 (.01) 1.000

Table 4.57: Spearman rank order correlation table for PVCD subjects.

185 Table 4.57 looks at the PVCD subjects only. There was a moderate relationship between flow during counting and flow during reading. The mean rates of flow across tasks were ranked similarly according to the Spearman calculations. There was also a weak-moderate correlation of the mean rate of flow during counting and the number of spikes during counting. The liklihood to produce spikes does not necessarily rank similarly to the liklihood of producing a higher mean rate of flow during counting. A stronger correlation was expected because the spikes contribute bursts of flow > 700 ml which do get averaged into the mean when calculated. There was also a weak-moderate correlation of spikes during reading and spikes during counting (.569). This was significant at the .01 level indicating that persons with PVCD who produce spikes in one connected speech tasks will likely produce spikes in the other connected speech task.

N=50 RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .754 (.01) 1.000

RBP Spikes .402 (.05) .229 (NS) 1.000

Counting Spikes .319 (.05) .278 (NS) .447 (.01) 1.000

Table 4.58: Spearman rank order correlation table for control subjects.

186 Controls subjects demonstrated a strong, significant correlation between mean rates of flow during both connected speech tasks (.754). Like the persons with PVCD, it is likely that control subjects will produce rates of airflow during two connected speech tasks that can be ranked similarly. Controls did not demonstrate any other moderate or strong correlations of behaviors in this analysis. Controls subjects did not demonstrate a practical correlation between number of spikes in one task compared to number of spikes in the other task. Persons with PVCD did demonstrate a moderate correlation between spikes in both tasks. This is more evidence that spikes of flow during connected speech tasks are successful in differentiating persons with PVCD from controls and deserve continued investigation.

The correlation tables for each group and gender follow (Tables 4.59 - 4.63).

N = 12 RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .580 (.01) 1.000

RBP Spikes .366 (.05) -.118 (N S) 1.000

Counting Spikes .607 (.01) .416 (.05) .424 (.01) 1.000

Table 4.59: Spearman rank order correlation table for control males.

187 There was a moderate correlation between mean rates of flow during reading and counting (.580). There was a moderate-strong correlation between number of spikes of flow during counting and mean rate of flow during reading (.607). This across task correlation probably offers little clinical significance considering that other related correlations were not strong ( e.g., spikes during counting and spikes during reading, or spikes during counting and counting flow). It is helpful to compare controls performance across genders to determine if the two genders are performing similarly.

N =38 RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .732 (.01) 1.000

RBP Spikes .300 (NS) .227 (NS) 1.000

Counting Spikes .159 (NS) .127 (NS) .464 (.01) 1.000

Table 4.60: Spearman rank order correlation table for female controls.

188 There is strong, significant correlation for counting flow and reading flow for female controls (.732). Again, these subjects demonstrated similar rankings of flow during both connected speech tasks. There is also a weak correlation for spikes during counting and spikes during reading. Although this weak correlation was significant at the .01 level, it may offer no practical relationship between these variables.

N = 5 RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .690 (.01) 1.000

RBP Spikes .600 (.01) .255 (NS) 1.000

Counting Spikes .294 (NS) .857 (.01) .202 (NS) 1.000

Table 4.61: Correlation table for males with PVCD.

There was a strong significant correlation between reading flow and counting flow for males with PVCD. There was also a strong correlation between number of spikes during reading and mean rate of flow during reading (.600). This strong correlation was also seen in the counting task. The number of spikes during counting and the mean rate of flow during counting were positively related (.857). These correlations support the point that mean rate of flow during connected speech tasks is related to number of spikes. Interestingly the number of spikes during reading and

189 the number of spikes during counting did not demonstrate a significant correlation (.202). One caution in interpreting these data concerns the number of subjects. Due to missing data, only 5 males with PVCD were used for these analyses. This small number of subjects may not allow generalization of these data; however, these data may represent a trend in need of further exploration.

N=29 RBP Flow Counting Flow RBP Spikes Counting Spikes

RBP Flow 1.000

Counting Flow .540 (.01) 1.000

RBP Spikes .325 (.05) .401 (.05) 1.000

Counting Spikes .186 (NS) .463 (.01) .591 (.005) 1.000

Table 4.62: Correlation table for females with PVCD.

Females with PVCD demonstrated a moderate significant correlation between mean rate of flow during counting and mean rate of flow during reading (.540). This trend was observed for all groups analyzed. The mean rates of flow across connected speech tasks are related. Females with

PVCD also demonstrate a moderate significant correlation between spikes of flow during counting and spikes of flow during reading (.591). Females who produced spikes in one task are likely to produce spikes in another

190 task. The other correlations in this analysis were either non-significant, or were weak, and therefore, of no practical significance. Therefore, it can be seen that males and females performed differently because males with PVCD demonstrate more strong, significant correlations during these tasks than did the females. This indicates again, that males and females with PVCD may be demonstrating different disorders, or more likely different variants of the same disorder. Spikes of flow are an operationally defined variable measured for the present study based on the observance of the phenomenon during preliminary analysis of patients with PVCD. To date, no study which reports spikes or spike-like measures has been published. Therefore, these data can not be compared to what is already known. These data provide a new, potentially beneficial measurement to the field of aerodynamic speech production. There are several considerations that must be explored now that preliminary data identifying and describing spikes in a normal population and a disordered population have been presented. First, the height of the spike must be considered. 700 ml/sec was chosen as a lower limit for the definition of a spike because during observation of the airflow wave at the time of data collection, these sudden bursts of flow are more conspicuous than other smaller bursts of flow that are present in connected speech. It is possible that counting the frequency of spikes > 600 ml/sec may be even more sensitive to the presence of PVCD than 700 ml/sec. It is also possible that spikes of flow >800 ml/sec

191 will be the most sensitive to identifying persons with this disorder. Now that the behavior has been identified and is potentially a valid diagnostic criterion for persons with PVCD, the measurement must be scrutinized and studied carefully to determine the exact nature of the behavior in controls and the precise differences that distinguish persons with PVCD from controls. The location of the spikes in the passage should also be investigated. If persons adapt to a task and are better able to handle a task the longer they produced the behavior, one would expect fewer spikes at the ends of passages. However, if a fatigue factor has an effect on the production of the behavior, it is possible that by the end of a connected speech task, people will produce more spikes. The location of spikes in connected speech tasks must be compared between controls and persons with PVCD to determine if there are opposing patterns. Summary of Typical Adult with PVCD

Table 4.63 lists all significant comparisons and the statistical test which determined significance. Following this table, there are description of the typical adult person with PVCD. There are two descriptions because based on the data of the present study, it is likely that males with PVCD and females with PVCD are demonstrating two variants of the same disorder.

192 Or, it is possible that the gender differences illustrated via aerodynamic performance are exacerbated by the present of PVCD. If this is the case, and the two genders are not displaying different variants, each gender must still be considered separately as different criteria will affect diagnosis of males and females.

193 GROUP EFFECTS

Effect Task Measurement/Interaction Comparison Stat,

Group \61um es Con > P V C D MANOVA& Rep. ANOVA Group \61umes (X Gender) Con > P V C D MANOVA& M > F Rep. ANOVA

Group Durations Con > PVCD MANOVA& Rep. ANO VA

Group Number o f /a/ & /ha/ repetitions PV C D > Con MANOVA Group M ean Peak flow /a / & /ha/ reps Con > P V C D MANOVA Group Mean Peak flow (X Group) PVCD > Con /a/ Rep. ANO VA PV C D < Con /ha/

Group Spikes in Rainbow Passage PV C D > Con Chi square Group Spikes in Counting PV C D > Con Chi square

Group Cessations in sustained tasks PV C D > Con Chi square Group Cessations in VC PV C D > Con Chi square Group C essations in /a/ PV C D > Con Chi square Group C essations in /sf PV C D > Con Chi square Group Cessations in /z / PV C D > Con Chi square

GENDER EFFECTS Gender \blumes M > F MANOVA & Rep. ANOVA

Gender Durations M > F MANOVA & Rep. ANOVA

Gender Mean Flow Connected Speech M > F MANOVA & Rep. ANO V A

Gender Mean Peak Flow /a, ha/ reps M > F MANOVA & Rep. ANOVA

Gender S/Z Ratio M > F MANOVA

Gender S/Z Ratios ( X Gender) F > M PV Rep. ANOVA F > M Duration M > F Flow

Table 4.63: Significant effects and interactions for all measurements in the present study.

194 Table 4.63: Significant effects and interactions for all measurements in the present study, continued

GENDER EFFECTS CONTINUED

G ender Spikes in Rainbow Passage M > F C hi square G ender Spikes in Counting M > F C hi square

G ender Cessations in sustained tasks F > M C hi square G ender Cessations in VC F > M Chi square Gender Cessations in /a/ F > M Chi square Gender Cessations in /s/ M > F Chi square Gender Cessations in /z/ F > M Chi square

MAIN TASK EFFECTS and INTERACTIONS

\filumes \blumes V C > /a / > /z / > /s / S ch effe \blumes \blumes (X Group) PVCD: VC > z S ch effe Con: VC>/a, s, z / S ch effe Durations Durations /a/ > /z/ > /s/ S ch effe Durations Durations (X Gender) Males: a > z > s S ch effe Peak Flows Repetitions Peak Flows /a/ & /ha/ /ha > /a / Rep. A N O V A Ratios S/Z Ratios Flow > PV > Dur S ch effe Conn. Speech Task X Group X Gender PVCD Males: Counting > RBP S ch effe

SIGNIFICANT CORRELATIONS

Correlation PVCD. M PVCD. F Con. M C on F

RBP Flow & Count. Flow yes, strong y es, m od y e s, m od yes, strong RBP Spikes & Flow yes, strong y es, w eak y e s, w eak no Counting Spikes & Flow yes, strong y e s, w eak y e s, w eak no Count, Spikes & RBP Spikes no y es, m od y es, w eak y es, w eak

195 The effects and interactions in the above table will now be used to describe the typical female with PVCD and the typical male with PVCD. Comparisons to the normal population will be made when appropriate. This summary will in effect be an aerodynamic diagnostic model of persons with PVCD. The purpose of such a model is to utilize the physiologic measurements to assist in the diagnosis of PVCD. Adult Female with PVCD

The adult female with PVCD will most likely demonstrate a vital capacity below normal limits. Phonatory volume during sustained tasks will probably also be low. She will expire approximately 80% of her air for phonation tasks that is available for vital capacity productions (although vital capacity will be restricted). Phonatory volumes of voiced sounds may be greater than voiceless sounds. The durations of the sustained tasks from which phonatory volume is derived will be decreased compared to adult females without PVCD (or other respiratory disorder). She will be able to sustain voiced sounds for greater periods of time than voiceless sounds. The difference between voiced and voiceless sound durations will be smaller than the difference a male with PVCD will produce. Mean rate of flow during these tasks will be equal. During diadochokinetic tasks

(i.e., rapid syllable repetitions), she will be able to produce syllables at a normal rate; her laryngeal articulatory maneuvers are probably not affected by the PVCD. Airflow during rapid repetitions will probably be

196 constricted compared to males with PVCD but not controls. This may be related to an overall level of hyperfunction that is difficult to control during rapid speech productions. During connected speech tasks, she will demonstrate instances of control inhibition which will be evidenced as spikes of flow. The more complex the task, the less likely the presence of spiking behavior. If there is a large number of spikes in a given connected speech passage, it is likely that her mean rate of airflow during that passage will demonstrate normal or above normal airflow. During sustained phonation and expiration tasks, she will abruptly stop airflow. This behavior differentiates her not only from control subjects, but also from males suspected of having PVCD. Similarly, she will not produce as many spikes during connected speech tasks as her male counterparts. Also, her mean rate of flow may or may not be correlated to the number of spikes of flow during a connected speech task. This is different from males with PVCD who will probably demonstrate a positive correlation of spikes to flow across tasks. Ratios of performance will be similar to those of persons without PVCD. Two such measures are 1) the ratio of /ha/ airflow to /a/ airflow and 2) the s/z ratio based on either flow, volume, or duration. Although her flow s/z ratio will be similar to other adults who do not have PVCD, her ratio will be decreased compared to males with PVCD. She will probably demonstrate a higher s/z phonation volume ratio and duration ratio than her male counterparts indicating that their productions and sustained /s/ and sustained /z/ are different.

197 In summary, the adult female will differ from adult female control subjects as well as adult males with PVCD. The differentiation of males and females with PVCD will be clarified in the following section describing the typical male with PVCD. Adult Male with PVCD The adult male with PVCD will demonstrate a restricted vital capacity compared to adult males without respiratory disorders. Although this volume measure will be restricted, it will still be greater than for adult

females with PVCD. Phonatory volume will be the expected percentage of vital capacity. He will expire approximately 80% of his air for phonation tasks that is available for vital capacity productions (although vital capacity will be restricted). He will not be able to sustaine phonation for as long as his normal male counterparts; he will be able to sustained voiced sounds for longer periods of time than voiceless sounds. This difference will be

more prominent than the difference a female with PVCD would produce. The mean rate of flow will be generally equal for both kinds of sounds, however. This will be reflected in a more restricted phonation volume for voiceless sounds than voiced sounds. He will be able to produce rapid syllable repetitions at the same rate as adults without respiratory disorders and females with PVCD. His peak flow during syllable repetitions will be increased compared to controls when an airflow facilitator is not present. When an airflow facilitator is present, airflow will be decreased compared

198 to controls. During connected speech tasks, he will produce spikes of flow. Rates of flow will be correlated with these spikes, and the rates of flow across connected speech tasks may not be equal. He will probably produced more spikes during a connected speech task than an adult female with PVCD.

During sustained phonation tasks, he will produce cessations of airflow. He will not produce as many of these as females with PVCD. It appears that spikes are more sensitive to PVCD in males and cessations of flow are more sensitive to PVCD in females. Spikes of flow and mean rate of flow during connected speech tasks will likely be positively correlated in all tasks measured. Ratios of measurements will be equal to controls, but may be higher than females.

199 4800 -j-

4400-

4000- PVCD

8 3600- Control 3200-

2800-

2400-

2 0 0 0 -

1600- r i M G e n d e r

Figure 4.1: Mean volume data for the significant effect of group X gender. Volume in milliliters 0 0 0 2 3000- 2500- 3500 1500 significant effect of group. of effect significant Figure 4.2: Mean volume data for the for data volume Mean 4.2: Figure - r l tro n o C D C V P oup u ro G 201

Volume in milliliters 3250- 2750- 3000- 2250 - 2250 2500- significant effect of gender. of effect significant Figure 4.3: Mean volume values for the for values volume Mean 4.3: Figure le a M i 202 r e d n e G le a m e F l

Volume in milliliters 3000 2800- 2900- 2700 2600 2500 2300 2400- effect. Figure 4.4: Mean volume data for volumes for data volume Mean 4.4: Figure 1 ... C V i— P V /a / P V /s/ V P / /a V P 203 k s a T

z/ /z V P 4000

3500

PVCD 3000 - Control

2500 -

2000

1500 -1- , , ------1----- VC PV /a/ PV /s/ PV /z/ T a s k

Figure 4.5: Mean volume data for the significant effect volumes X group

204 Mean duration in seconds 2 2 24 ~i 24 0 2 18------( J 4 1 16- sustained phonation tasks for each group. each for tasks phonation sustained Figure 4.6: Mean duration (sec) for three for (sec) duration Mean 4.6: Figure - -

r l tro n o C D C V P ------205 oup u ro G . r

------Mean duration in seconds 1.18- 1.16- 1.12 - 1.14 sustained phonation tasks for gender. for tasks phonation sustained Figure 4.7: Mean duration (sec) for three for (sec) duration Mean 4.7: Figure 1.2 t es es le a m e F s le a M r e d n e G 206 T

Mean duration in seconds 27.5 5- .5 2 2 17.5- 12.5- duration X gender. X interaction duration significant the for gender and Figure 4.8: Mean duration (sec) across task across (sec) duration Mean 4.8: Figure 25 0 2 - 5 1 -

es Femal s le a m e F s le a M r e d n e G 207 O

----

the significant interaction of duration. of interaction significant the Figure 4.9: Mean duration (sec) across tasks for tasks across (sec) duration Mean 4.9: Figure Mean duration in seconds 1.14- 1.18- 1.12 -J 1.12 1.16 1.2 es Femal s le a m e F s le a M i i k s a T 208

Mean flow (m l/sec) 170 150- 160- 130- 140- 120 effect of gender. of effect Figure 4.10: Mean airflow (ml/sec) for the main the for (ml/sec) airflow Mean 4.10: Figure

es es le a m e F s le a M 209 r e d n e G

200

180 -

120 -

1 0 0 J 1------1— RBP Counting

T a s k

Figure 4.11: Mean airflow (ml/sec) across group, gender, and task for the significant effect of task X group X gender.

210 Mean num ber of re p e titio n s 5.5- 4.5- groups for /a/ and /ha/ repetitions. /ha/ and /a/ for groups Figure 4.12: Number of repetitions across repetitions of Number 4.12: Figure 5- D C V P 211 oup u ro G r l tro n o C

Mean peak flow (m l) 400 380- 360- 340- 320 for the significant effect of group. of groups effect across (ml) significant flow the for peak Mean 4.13: Figure D C V P p u o r G 212 r l tro n o C

Mean peak flow (m l) 450- 500 350- 300 for the main effect of gender. of effect main the for Figure 4.14: Mean peak flow (ml) across gender across (ml) flow peak Mean 4.14: Figure es le a M r e d n e G es le a m e F

Mean peak flow (m l) 600 400- 0 0 2 100 the main effect of repetitions peak flow. peak repetitions of effect main the Figure 4.15: Mean peak flow (ml) across task for task across (ml) flow peak Mean 4.15: Figure - a/ /a 214 r e d n e G ha/ a /h

Mean peak flow (m l/sec) 600- 400- 500- 700 300- 0 0 2 100 for the main effect of repetitions peak flow. peak repetitions of effect main the for Figure 4.16: Mean peak flow (ml) across tasks across (ml) flow peak Mean 4.16: Figure - a/ /a sk a T 215 ha/ a /h

G r l tro n o C D C V P -G • - 1.75

1.5- PV

~0----- D uration

1.25- -A Flow

1 -

0.75 PVCD, F PVCD, M Control, F Control, M

Group and Gender

Figure 4.17: Comparison of s/z ratios for group and gender.

216 Ratio value 1.8 0.8 1 1.4- 1 . . 6 2 - - Figure 4.18: Interaction of s/z ratios X gender. X ratios s/z of Interaction 4.18: Figure V P i n tio a r u D n e k o T 217 ow lo F O males em F -O ales M CHAPTER 5

DISCUSSION

Limitations of the present study The present study does contribute to what is known about persons with PVCD as well as adults without laryngeal or respiratory disorders. It is an initial attempt to begin to quantify the performance of adults with

PVCD in an arena in which no data exists to describe this population. However, with this goal in mind, it is necessary to recognize the limitations of the present study to ensure that continued research avoids or controls situations that could nullify or weaken conclusions drawn about persons with PVCD. One limitation of this present study is the lack of a specific asthma diagnosis in the persons with PVCD. It is paramount that this disorder be accurately distinguished from asthma so that persons with a true asthma

218 condition receive appropriate care and persons without asthma do not receive unnecessary care. Determination of a true asthma diagnosis requires collaboration of speech-language pathology with pulmonology. Pulmonologists are trained in the diagnosis and treatment of asthma and are the medical professionals who determine the reliability and validity of an asthma diagnosis. The criteria pulmonologists use must be investigated first to determine reliability and validity, and then, the most robust measures can be used to collect a group of subjects with a confirmed diagnosis of asthma. It is then that persons with PVCD and persons with asthma can be reliably compared on aerodynamic measures. Although the one MANOVA in the present study determined that volumes measures were not affected by the presence of asthma, this is only one comparison. It cannot be stated that all the measures in the present study were not affected by the presence of asthma based on the one analysis. Further analysis like the MANOVA could be performed; however, without the reliability of the asthma diagnoses, the results would not be reliable, either. Another limitation of the present study is the number of subjects in each gender group. Although 38 females most likely represents an adequate sample of adult females with and without PVCD, 12 males in each group probably may not be an adequate sample. Continued collection of data on adult males (both control and PVCD) should continue, with re analysis of the data, to determine if the effects found in the present study hold true in larger samples. The use of larger sample sizes, particularly

219 males, will ensure generalizability of the data to all persons with PVCD (or all persons like the subject groups used). Collection of larger sample groups will also allow for larger groups in age breakdowns (e.g., 30’s, 40’s, 50’s etc.). It is possible that persons of different ages manifest PVCD in different ways and thus, will produce differing aerodynamic measurements. Age differences are also a limitation of the control group of the present study. As noted in Chapter 3, the mean age of persons in the PVCD was in the fourth decade, while the mean age of persons in the control group was in the 2nd decade. Although there is little evidence in the literature that demonstrates a significant difference in respiratory function, it is possible that decreased respiratory capabilities in the aging person contributed partially to the effects found in the present study. Data collection on laryngeally normal persons over age 40 is necessary to determine if age effects were found in the present study.

Another limitation of the control group was the inadequate observation of the glottis during respiration. Most subjects with PVCD

(33) were evaluated via transnasal fiberoptics, while none of the controls were evaluated via nasendoscopy. Nasendoscopy is the preferred method of assessment of laryngeal behaviors during respiration because the scope rests above the laryngeal mechanism and does not interfere with respiration (or phonation). This is not necessarily true for oral endoscopy which was the method used to evaluate the laryngeal status of the controls.

220 Paradoxical closure of the true vocal folds may be present intermittently in laryngeally normal persons. Spiking behavior and cessations of flow were noted in the control population; it is thought that paradoxical behavior enables these phenomena to occur. Therefore, it is reasonable to suggest that adults without laryngeal or respiratory disorders may demonstrate paradoxical closure of the vocal folds intermittently during the respiratory cycle.

Transnasal fiberoptics were not used during analysis of control subjects in the present study because of Human Subjects Committee recommendations to avoid the use of invasive testing. It is possible that other research bodies will be able to collect this data for further analysis. Directions for Future Research Directions for future research on PVCD will lead researchers into

several areas. First, research must still focus on positive identification of the disorder so that differential diagnosis can distinguish it from other respiratory disorders, specifically, asthma. This will require testing of not only persons with identified PVCD, but also additional measurement of control subjects via the pulmonary tests used to diagnose asthma. Also, additional testing of persons with all variants of asthma are necessary.

Persons with asthma must be assessed via videolaryngostroboscopy or at least laryngoscopy to determine the typical laryngeal function of persons with asthma. As described in Chapter 2, it is suspected that persons with asthma utilize paradoxical closure of the vocal folds to inflate the lungs.

221 This paradoxical behavior must be documented and described to determine if it is similar to the paradoxical motion of PVCD. Also, the respiration behaviors of persons without respiratory disorders must be evaluated via laryngoscopy, as well. This is a difficult task as human subjects committees are reluctant to allow invasive testing such as transnasal fiberoptic laryngoscopy which is the preferred method for assessing respiratory function via endoscopy. Without accurate documentation of respiratory function in persons without respiratory disorders and persons with asthma, the exact nature of PVCD will remain unknown. Persons with concomitant asthma and PVCD will remain undertreated or overtreated. Another population which must be considered for research when studying PVCD is the psychiatric/psychologic population. If psychogenesis is a suspected etiology of PVCD, then persons with confirmed psychogenetic disorders must be evaluated in terms of their respiratory, laryngeal, and phonatory behaviors. If neurotransmitter dysfunction is contributing to the psychologic disorder (e.g. schizophrenia), then it is possible that neurotransmitter dysfunction is contributing to the paradoxical muscle contractions in PVCD. The respiratory patterns of persons with psychogenesis must be documented to determine if dyspnea is a common complaint of this population or if it is specific to conversion disorders like PVCD (if PVCD is in fact a conversion disorder).

222 Research must also determine if several different groups exist within the population of persons with PVCD. The data in the present study suggest that males with PVCD are unlike females with PVCD. If this is the case, the exact nature of the difference should be identified. This would require testing larger groups of males on the same protocols as females. Persons with PVCD may fall into different groups based on the presence of asthma, presence of reflux, presence of psychogenic component, presence of allergies, or other unknown factors. These factors may be different for males and females with the disorder; these factors may be different for persons of different ages who have confirmed PVCD. Further research into the 0-18 age group must also occur, along with research with adults with PVCD. As etiology of the disorder is unknown, it is important for this aspect to be studied. These investigations should be multi-focused and should include neurological testing, psychological testing, and behavioral/physiological testing. Correlations of behavioral performance with neurological and psychological testing may provide evidence of suspected etiologies interacting to precipitate the PVCD attacks or the development of the disorder.

Specifically related to aerodynamic performance, studies of laryngeal resistance and subglottal pressure may provide evidence of a neurologically based pressure sensing deficit. These studies may also show findings similar to controls, which may provide evidence that the majority

223 of persons with the disorder are suffering from a psychological difficulty. Research must continue to focus on persons with PVCD when they are between attacks so it can be determine what triggers an attack, what physiological performance is like before an attack, and how quickly physiology returns to baseline following an attack. With this type of information, it may be possible to manage the disorder similar to asthma in which persons monitor their physiological performance daily and alter medication dosage based on these tests. Finally, research must begin to document and assess treatment programs so that medical professional have accurate information about prognosis, response to treatment, and recurrence of the disorder. Research must focus on the effects of pharmacological agents typically used to treat an attack (e.g. sedatives) as well as behavior treatments (e.g. speech therapy, laryngeal control therapy). Information about treatment which is most efficacious is paramount to effective treatment of the disorder. The precedent of mismanagement of the patient with PVCD has been set for the past 15 years that it has been treated as asthma. Research into appropriate treatment programs will facilitate effective care for persons with PVCD.

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Woodson, G. (1991). Assessment of sensation in voice disorders. Assessment of speech and voice production: research and clinical applications. NIDCD Monograph. Conference proceedings. Bethesda: National Institutes of Health.

Yanagihara, N., Koike, Y. (1967). The regulation of sustained phonation. Folia Phoniatrica. 19. 1-18.

Yanagihara, N., von Leden, H. (1967). Respiration and phonation. Folia Phoniatrica. 19. 153-166.

232 APPENDIX A INFORMED CONSENT FORM

233 INFORMED CONSENT FORM

The Ohio State University Protocol No. 95H0295

CONSENT TO INVESTIGATIONAL PROCEDURE

I, ______, hereby authorize or direct Kathleen Treole, MA or Michael D. Trudeau, PhD or associates or assistants of his/her choosing to perform the following procedure. I will permit examination of my oral cavity and larynx (voice box), will provide answers on a questionnaire about my voice usage and will speak into a face mask for collection of measures of air flow during speech.

The experimental portion of the treatment is the measurement of airflow through the face m ask.

This is done as part of the dissertation research for Kathleen Treole. This investigation is titled “Differentiation of Persons with and without Paradoxical Vocal Cord Dysfunction via Aerodynamic Measurement.”

1. The purposes of the procedures are as follows: a. The purpose of this procedure is to compare various aerodynamic measures between persons with Paradoxical Vocal Cord Dysfunction and persons without Paradoxical Vocal Cord Dysfunction. b. The goal of this study is to create an aerodynamic assessment tool to diagnose Paradoxical Vocal Cord Dysfunction in person’s suspected to have the disorder.

2. The possible alternative procedure is not to participate in the study.

3. The possible discomforts and risks reasonably to be expected include minor gagging or coughing during examination of the vocal cords.

4. Possible benefits to you and society include for you: free examination of your vocal cords and analysis of your air flow use for speech. Benefits to society include understanding the nature of the disorder of paradoxical vocal cord dysfunction and its treatment.

5. The anticipated duration of the procedures for each subject is 2 hours.

1 hereby acknowledge that Kathleen Treole or Michael D. Trudeau or his/her associates have provided information about the procedures described above, about my rights as a subject, and that any questions have been answered to my satisfaction. I understand that I may contact Kathleen Treole should I have additional questions. He/She has explained any risks involved and I understand them; she/he also has explained all possible risks or complications. I understand that the most common risks include coughing or gagging during the videolaryngostroboscopy; I understand that I may choose not to participate in the study at any time.

I understand that, where appropriate, the US Food and Drug Administration may inspect records pertaining to the study. 1 further understand that record obtained during my 234 participation in this study may be made available to the sponsor of this study and that the records will not contain my name or other personal identifications. Beyond this, I understand my participation will remain confidential.

I understand that 1 am free to withdraw my consent and participation in this project at any time after notifying the project director without prejudicing future care. No guarantee has been given to me concerning this procedure. I understand that I may contact Kathleen Treole at 436-6692 should I have additional questions regarding my participation in this study.

I understand in signing this form that, beyond giving consent, I am not waiving any legal rights that I might otherwise have, and I am not releasing the investigator, the sponsor, the institution, or its agents from any legal liability for damages that they might otherwise have.

In the event of injury resulting from participation in this study, I also understand that immediate medical treatment is available at University Hospitals of The Ohio State University and that the costs of such treatment will be at my expense; financial compensation beyond that required by law is not available. Questions about this should be directed to the Office of Research Risks at 292-5958.

I have read and fully understand the consent form. I sign it freely and voluntarily. A copy has been given to me.

D a t e : ______Tim e:______Signed______(Subject signature)

W itness:

1 certify that I have personally explained this form to the subject before requesting the subject to sign it.

Signed: ______Kathleen Treole or authorized representative

235 APPENDIX B

PROCEDURES SCRIPT

236 Videolarvngostroboscopv This examination is a procedure that will take a video picture of your vocal cords. You will be sitting in a chair with your feet flat on the floor. You will be leaning approximately 45 degrees forward from your hips. The examiner will be holding your tongue with a piece of gauze and you will be holding the contact microphone up to your neck. The camera will go in your mouth and will rest above your tongue. Typically, the camera will not come in contact with any portion of your mouth, but if it does, you may feel a slight pressure on the back of your throat. This pressure may make you gag or cough. That is the typical reaction. If that happens, the camera will be removed from your mouth and you can rest. The examination will continue when you are ready. Once the camera goes in your mouth, it does not have to stay there. For any reason, if you want the camera out of your mouth, just pull your head back and I will remove the camera. During the examination, you will be most comfortable if you breathe through your mouth and keep your eyes open. Both of these behaviors will decrease the chances that you will cough or gag. You can have a drink of water at any time during the examination. There is no rush and we will proceed at your pace. The entire examination typically takes 10 minutes to perform. If we do not get adequate pictures of your voice box after 30 minutes, we will not continue the examination. When we are done, I will show you the video examination and will explain the parts of your voice box to you. At this time, I will also inform you if you are eligible for the airflow portion of the study. Do you have any questions?

Airflow analysis For this examination, I will ask you to speak or breathe into a face mask. The face mask is placed around your nose and mouth. You will be holding the face mask throughout the examination and can remove the mask from your face at any time. I will ask you to perform a variety of breathing and speaking tasks into the mask. I will describe and model each task before I ask you to do it; you will have an opportunity to practice each task. During the time when you are not performing a task, the mask does not have to be up to you face. When you complete a task, you may remove the mask and wait for your next direction. You will be able to inhale and exhale completely when the mask in on your face. This portion of the exam should take approximately 30 -45 minutes. Do you have any questions?

237 APPENDIX C CONTROL SUBJECT CASE HISTORY FORM

238 CASE HISTORY QUESTIONNAIRE

Case History Information SUBJECT NUMBER

1. What is your gender? MALE FEMALE

la. If you are female, are you pregnant? YES NO If YES, you do not have to finish the questionnaire and will not be asked to participate in this study. Thank you for your time.

2. What is your age? ______

3. Do you feel you have a problem with your voice? YES NO If, YES, please explain.

4. Do you have asthma? YES NO

5. Do you feel you have a problem with your breathing? YES NO If YES, please explain.

6. Do you smoke? YES NO

7. What is your occupation?

8. What do you consider your ethnicity/race?

NOTE: If you are a student your grade(s) for any class will not be affected by participation or lack of participation in this study. Your participation will not be reported to any departments or professors. This is also true if you choose to drop out of the study without finishing.

239 APPENDIX D

PVCD SUBJECT CASE HISTORY FORM

240 PARADOXICAL VOCAL CORD DYSFUNCTION CASE HISTORY INTERVIEW GUIDE Patient Name: Number: BREATHING Describe breathing difficulties. General shortness of breath or episodes? Describe episodes (quantity/week, severity, stridor, wheezing). Imitate noises if possible. What makes them better? Worse? Does it feel like asthma? Is asthma confirmed diagnosis? Other respiratory disorders?

REFLUX Is there a chronic cough? throat clearing? bitter/acid/metallic taste in mouth? night chokes? hoarseness in mornings? feeling of heartburn? how often? taking anything? ever been diagnosed with reflux, hernia? When, by whom? What are the eating habits? Caffeine?Alcohol? Smoking? Water intake? Any dysphagia? What, when?

VOICE Any voice difficulties on daily basis? During attack? After attack? What makes it better? What makes it worse? Aphonia? How is voice today? RATE VOICE VIA WILSON SCALES.

EMOTIONS/STRESS Any stress lately? Any stress at time of attacks? Any stress at time when symptoms first appeared? Any history of abuse: verbal, physical, sexual? Any treatment for admitted difficulties? When, where, how long, is it resolved?

241 APPENDIX E READING SAMPLE THE RAINBOW PASSAGE

242 RAINBOW PASSAGE

WHEN THE SUNLIGHT STRIKES RAINDROPS IN THE AIR, THEY ACT LIKE A PRISM AND FORM A RAINBOW. THE RAINBOW IS A DIVISION OF WHITE LIGHT INTO MANY BEAUTIFUL COLORS. THESE TAKE THE SHAPE OF A LONG, ROUND ARCH WITH ITS PATH HIGH ABOVE AND ITS TWO ENDS APPARENTLY BEYOND

THE HORIZON. THERE IS, ACCORDING TO A LEGEND, A BOILING POT OF GOLD AT ONE END. NO ONE EVER FINDS IT.

WHEN A MAN LOOKS FOR SOMETHING BEYOND HIS REACH, HIS FRIENDS SAY HE IS LOOKING FOR THE POT OF GOLD AT THE END OF THE RAINBOW.

243 APPENDIX F

AIRFLOW ANALYSIS DATA COLLECTION WORKSHEET

244 AIRFLOW ANALYSIS DATA COLLECTION WORKSHEET Subject No: ______Date:______TRIAL 1 2 3 Vital Capacity (ml)______Cessations of flow (#) ______M P D /a/ Phonation volume (ml) ______Duration (sec) ______Rate of airflow (ml/sec) ______F 0 (H z) ______Intensity (dB) ______Cessations of Flow (#) ______Rainbow Passage (Reading) Airflow (ml/sec) ______F 0 (Hz) ______Intensity (dB) ______Duration (expired) ______Duration (total) ______Spikes >700 ml/sec ______Counting (1-50) Airflow (ml/sec) ______F 0 (Hz) ______Intensity (dB) ______Duration (expired) ______Duration (total) ______Spikes >700 ml/sec ______M P D is/ & /z/ Phonation Volume /s/ ______D u ra tio n is! ______Rate of airflow /si ______Cessations of flow ______Phonation Volume /z/ ______Duration /z/ ______Rate of airflow ht ______Cessations of flow ______/a/ and /ha/ repetitions are collected next on the Nagashima chart paper.

245 APPENDIX G HUMAN SUBJECTS COMMITTEE APPROVAL FORM

246 BIOMEDICAL SCIENCES REVIEW COMMITTEE _x_ Original Review RESEARCH INVOLVING HUMAN SUBJECTS _ Continuing Review THEr OHIO STATE UNIVERSITY _ Five-Year Review Amendment

ACTION OF THE REVIEW COMMITTEE

With regard to the employment of human subjects in the proposed research:

95H0295 DIFFERENTIATION OF PERSONS WITH AND WITHOUT PARADOXICAL VOCAL CORD DYSFUNCTION USING AERODYNAMIC MEASUREMENTS, Michael D. Trudeau, Kathleen Treole, Speech and Hearing Science

_ APPROVED _ DISAPPROVED

_x_ APPROVED WITH STIPULATIONS* _ WAIVER OF WRITTEN CONSENT GRANTED

*Stipulations stated by the Committee have been met by the investigator and, therefore, the protocol is APPROVED>

It is the responsibility o f the principal investigator to retain a copy of each signed consent form for at least three (3) years beyond the termination of the subject’s participation in the proposed activity. Should the principal investigator leave the University, signed consent forms are to be transferred to the Human Subjects Committee for the required retention period. This application has been approved for the period of one year. You are reminded that you must promptly report any problems to the Review Committee, and that no procedural changes may be made without prior review and approval. You are also reminded that the identity of the research participants must be kept confidential.

Date: October 16. 1995 Signed (Judrperson HS-025H (Rev. 2/94)

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