Perturbation and Harmonics to Noise Ratio as a Function of Gender in the Aged Voice THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Arts in the Graduate School of The Ohio State University By Meredith Margaret Rouse Hunt Graduate Program in Speech and Hearing Science The Ohio State University 2012 Master's Examination Committee: Michael Trudeau, Advisor Michelle Bourgeois Copyrighted by Meredith Margaret Rouse Hunt 2012 Abstract The purpose of this investigation was to explore possible differences as a function of gender in perturbation (jitter and shimmer) and harmonics to noise ratio (HNR) among aged male and female speakers. Thirty normal aged adults (15 males; 15 females; over age 60) prolonged the vowel /a/ at a comfortable loudness level. Measures of jitter (%), shimmer (%), and HNR were used to compare vocal function between aged gender groups. No significant differences were found between genders on any of the measures. Findings are discussed relative to other published studies on similar measures and support data that aged voices exhibit increased variability. Future suggestions for research are discussed. ii Dedication This manuscript is dedicated to my husband, Ryan, for his unfailing patience, support, and humor during the completion of my thesis and in all aspects of my life. iii Acknowledgments I would like to acknowledge Michael Trudeau, Ph. D., CCC-SLP, my academic and thesis advisor, for his gentle and persistent guidance. His dedication to teaching and patience with students has allowed me to become adept at critical evaluations of research and treatment methodology. More importantly, his love of voice science and care for his clients has shaped my future professional career as speech-language pathologist. I cannot thank him enough for the opportunities and mentorship he has provided me. I would also like to acknowledge Michelle Bourgeois, Ph. D., CCC-SLP, for her unending enthusiasm for research; without whose passion and support I would not have attempted a thesis project. Thank you for making research and methods understandable and attainable. I would like to acknowledge Kerrie Obert, M. A., CCC-SLP, the principle investigator. The document that follows could not have been possible without her generosity in allowing me to take part in her research. Finally, I would like to acknowledge the Department of Speech and Hearing Science for graciously providing lab space to complete the data collection process. iv Vita 2005................................................................B.A. in Liberal Studies with a focus in Communication Sciences and Disorders, Northern Arizona University 2010 to present ..............................................Graduate Clinician, Department of Speech and Hearing Science, The Ohio State University Fields of Study Major Field: Speech and Hearing Science; Speech-Language Pathology v Table of Contents Abstract ............................................................................................................................... ii Dedication .......................................................................................................................... iii Acknowledgments.............................................................................................................. iv Vita ...................................................................................................................................... v List of Tables ................................................................................................................... viii Chapter 1: Introduction ...................................................................................................... 1 Chapter 2: Methods ........................................................................................................... 10 Screening Procedures .................................................................................................... 10 Participants .................................................................................................................... 11 Equipment ..................................................................................................................... 14 Measures........................................................................................................................ 15 Procedures ..................................................................................................................... 17 Reliability ...................................................................................................................... 17 Chapter 3: Results ............................................................................................................. 21 Chapter 4: Discussion ....................................................................................................... 25 vi References ......................................................................................................................... 31 Appendix A: Informed Consent ........................................................................................ 34 Appendix B: Participant Questionnaire ............................................................................ 40 Appendix C: Screening Protocol Form ............................................................................. 41 Appendix D: Study Participant Raw Data ........................................................................ 42 Appendix E: Test-Retest Reliability Data......................................................................... 43 vii List of Tables Table 1. Reported participants, ages (mean), shimmer (dB), jitter (%), harmonics to noise ratio (HNR), and recording conditions for genders only on /a/ phonations........................ 7 Table 2. Descriptive male participant characteristics. ...................................................... 13 Table 3. Descriptive female participant characteristics. ................................................... 14 Table 4. Intra-judge ratings comparison for GRBAS scale. ............................................. 19 Table 5. Inter-judge ratings comparison for GRBAS scale. ............................................. 20 Table 6. Group means (SD) and t-test results for Jitter (%), Shimmer(%), and harmonics to noise ratio (HNR) (dB) ................................................................................................. 21 Table 7. Revised group means (SD) and t-test results using only subjects where G = 0. 22 Table 8. Group means (SD) for subjects aged 60-69 years. ............................................. 23 Table 9. Group means (SD) for subjects aged 70-79 years. ............................................. 24 Table 10. Study participant raw data ................................................................................ 42 Table 11. Test-retest data for sustained /a/ task averaged across three recorded trials. ... 43 Table 12. Test-retest data for continuous speech sample. ................................................ 44 Table 13. Test-retest data for maximum performance tasks ............................................. 45 viii Chapter 1: Introduction As the population in the United States ages and the elderly population growth outpaces growth in other age groups it is necessary to understand the effects of aging on the voice (Brock, 1990). With the increasing number of elderly clients seeking services from speech-language pathologists due to complaints of voice changes or difficulties, clinicians must be able to delineate whether those changes are part of the normal aging process of the voice or a disorder of aging. Many avenues are available for clinicians to judge voice parameters, yet there is a lack of sufficient normative data for the aged voice. Anatomical and physiological changes in the larynx due to the aging process have been reported and reviewed by several researchers. Established age-related changes to the larynx include ossification and calcification of the laryngeal cartilages, degeneration of the cricoarytenoid joint, decreased blood supply, bowing of the vocal folds, reduction and degeneration of nerve fibers innervating the laryngeal musculature, and a reduction in vital capacity of the lungs (Colton, Casper, & Leonard, 2011; Kahane, 1987 & 1990). These changes in the aging larynx may alter the perceptual, acoustic, and physiologic characteristics of phonation. Research in gerontology and the aging of the larynx and peripheral speech mechanism has outlined measurable change in all humans across the life-span. The research has regularly defined that those degenerative changes occur earlier in the life- span in men than in women (Kahane, 1990). Changes are also thought to be of greater 1 extent in male anatomy versus female anatomy. This may lead one to logically deduce that there should be greater perturbation in the aged male voice than the aged female voice. Kahane‟s 1990 review of relevant literature on age-related structural and physiological changes in the speech mechanism provides some of the most comprehensive information regarding the ways this integrated mechanism shows its age. However, the body of research concerning how anatomical evidence may predict differences in older speakers is equivocal (Awan, 2006; Ferrand, 2002; Bohnenkamp & Hageman, 2011; Harnsberger, Shrivastav, Brown, Rothman, & Hollien, 2008; Linville & Fisher, 1985). Structural changes in the larynx and peripheral speech mechanism may