WHISPER AND PHONATION: AERODYNAMIC COMPARISONS ACROSS ADDUCTION AND LOUDNESS LEVELS Ramya Mohan Konnai A Dissertation Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2012 Committee: Ronald C. Scherer, Advisor Lewis Fulcher Graduate Faculty Representative Roger Colcord Alexander Goberman © 2012 Ramya Konnai All Rights Reserved iii Ronald Scherer, Advisor ABSTRACT The purpose of the present project was to compare the aerodynamics of whisper and phonation. The novel aspect was to have subjects produce both whisper and phonation for nine different conditions, three qualities relative to levels of adduction (breathy, normal, and pressed) and three levels of loudness (soft, medium, and loud). The study reports subglottal pressure (Ps), airflow (F), and laryngeal flow resistance (Rf, the ratio Ps/F) for all conditions. Three males and five females between 20 and 30 years of age whispered and phonated smooth syllable strings of /baep/. This resulted in 18 treatment combinations (i.e., 3 adductions x 3 loudness levels x 2 genders). A regression analysis was performed using a Proc-mixed procedure with SAS statistical software. Results relative to laryngeal source (phonation vs. whisper): Ps was not significantly different between whisper and phonation (except for the breathy soft condition in females, where Ps was greater in phonation). Flow typically was higher for whisper than phonation (except for soft conditions, where flow was about the same). Rf tended to be greater for phonation than for whisper for females, but not for males (where Rf was about the same between phonation and whisper). Results relative to loudness: Ps increased with loudness (soft, medium, loud) at each of the three adduction levels for both phonation and whisper. Flow tended to increase with loudness in whisper at each level of adduction, but flow results were varied for phonation. In phonation, Rf increased with loudness at each level of adduction, but there was no general pattern for whisper (being relatively constant across loudness levels for each gender). iv Results relative to adduction: Ps increased from normal to breathy to pressed at each level of loudness for phonation, and similarly for whisper (except Ps was about the same for normal and breathy whisper productions). Breathy adduction had the greatest flow at each level of loudness for both phonation and whisper. Flow was about the same in both phonation and whisper for normal and pressed productions. Rf increased from breathy to normal to pressed at each level of loudness (although for whisper, Rf was similar for breathy and normal productions) Results relative to gender: Ps tended to be higher in males than females for all nine conditions for phonation and whisper. Males tended to have greater flow for phonation but lower flow for whisper for all conditions. Males produced greater Rf values for whisper across adduction, but lower Rf values (relatively small differences, however) for phonation across adduction levels. While there are some clear and understandable trends for the aerodynamic measures relative to changes in loudness and adduction for whisper, phonation, and gender, the results are best taken as testable hypotheses for future research. v This dissertation is dedicated to: The memory of my beloved grandfather, M. Elumalai. You encouraged me to pursue my dreams. My husband, Asai. You make my dreams come true! vi ACKNOWLEDGEMENTS This project would not have been possible without the guidance of Dr. Scherer, my advisor. Dr. Scherer, you took a genuine interest in my learning and challenged me in my academic program. I will always remember our lengthy brainstorming discussions (not necessarily all the content), the long hours spent making figures on excel, and above all our ability to laugh away even at the eleventh hour of meeting a deadline. You taught me not just about the larynx but lessons for life. Thank you! Sincere thanks to my committee members- Dr. Goberman, Dr. Colcord, and Dr. Fulcher for their time and input on my project. I am grateful to Amy Peplinski and Dr. Kenneth Ryan from the Statistical Consulting Center, BGSU for their immense help with the data analysis. A big “Thank you” to Jason Whitfield for assisting me with data collection. Special thanks to Dr. Fari Alipour, University of Iowa, for providing solutions with technology issues in the lab whenever we needed. Thanks also go to Dr. Hewitt for supporting my transition from University of Cincinnati and helping me throughout my program at BGSU. I am thankful to the College of Health Sciences and the Graduate College, BGSU and University of Cincinnati for the financial support of my education. I am indebted to my husband, Asai, for being patient, supporting, and encouraging throughout this tough and long journey. Special thanks to my son, Aarya, for bringing absolute joy into my life and constantly reminding me to enjoy the simple moments every day! I cannot thank my brother and parents enough for all their care and support throughout my life. Thanks to my cohorts- Haidee Tan, Biji Philip, Emily Rusnak, Scott Palasik, Eric Swartz, Farzan Irani, Charlie Hughes, and Stephanie Hughes for lending their ears day and night and helping me to get to the end of this program. Friends, Sabiha Parveen, Purnima Gopalakrishnan, Siva “akka,” vii Sethu Karthikeyan, and Vijay Ramachandra deserve special thanks for accommodating my needs at Bowling Green when I needed it the most. Thanks also go to friends from Cincinnati, Venkat, Prodipto, Ritesh, Renuka, Anu “didi”, Rohit, and Chris for making me feel at home when I was 10,000 miles away from home. Last but not the least, thanks to Dr. Alice Silbergleit, Henry Ford Health System for her encouraging comments and being flexible with my work schedule. viii TABLE OF CONTENTS Page CHAPTER 1. INTRODUCTION…………………………………………………………1 1.1 Phonation types ...........................................................................................1 1.2 Whisper vs. phonation.................................................................................3 1.3 Significance of whisper ..............................................................................3 1.4 Loudness and intensity ...............................................................................5 1.5 Aerodynamics .............................................................................................6 1.6 Whisper characteristics ...............................................................................9 1.7 Proposed research .....................................................................................13 CHAPTER 2. METHODOLOGY .....................................................................................14 2.1 Subjects ....................................................................................................14 2.2 Equipment .................................................................................................14 2.3 Syllables for analysis ................................................................................15 2.4 Procedure ..................................................................................................15 2.5 Data analysis .............................................................................................20 2.6 Significance ..............................................................................................22 CHAPTER 3. RESULTS .................................................................................................23 3.1 Research question 1 ..................................................................................30 3.2 Within-subject and between-subjects variability ......................................42 3.3 Research question 2 ..................................................................................44 3.4 Research question 3 ..................................................................................55 3.5 Values for variables ..................................................................................65 ix CHAPTER 4. DISCUSSION ...........................................................................................66 4.1 Subglottal pressure ....................................................................................66 4.2 Airflow .....................................................................................................69 4.3 Flow resistance ........................................................................................72 4.4 Other observations ....................................................................................74 CHAPTER 5. SUMMARY ..............................................................................................75 CHAPTER 6. CONCLUSION ........................................................................................90 REFERENCES ..................................................................................................................95 APPENDIX I. Table of physical characteristics of subjects............................................105 APPENDIX II. Flow mask and oral pressure calibrations ..............................................106 APPENDIX III. Figures of pressure vs. flow for each subject ........................................113 APPENDIX IV. Consent form.........................................................................................133 x LIST OF TABLES Table Page 1 Proc Mixed Model Terms for