This dissertation has been microfilmed exactly as received SHALLOP, Jon Kent, 1939- A STUDY OF ACOUSTIC IMPEDANCE AND MIDDLE-EAR FUNCTION. The Ohio State University, Ph.D., 1965 Speech-Theater University Microfilms, Inc., Ann Arbor, Michigan A STUDY OF ACOUSTIC IMPEDANCE AND MIDDLE-EAR FUNCTION DISSERTATION Presented In Partial Fulfillment of the Requirements of the Degree Doctor of Philosophy In the Graduate School of The Ohio State University by- Jon Kent Shallop, B .S ., M.A, The Ohio State U n iversity 1965 Advisers Department of Speech VITA December 21 , 1939 Born - Erie, Pennsylvania. 1961 B.S. Ed., Edinboro State College Edinboro, Pennsylvania 1961-1963 Instructor of Speech, Edinboro State College 1963 M.A., Kent State University 1963-1964 Communications Fellow , The Ohio State U n iv e rs ity , Columbus, Ohio 1964-1965 United States Public Health Service Train ee, The Ohio S tate U n iv e rs ity . ii TABLE OF CONTENTS Page VITA ....................................................................................................................................... II TABLE OF CONTENTS.........................................................................................................i l l LIST OF TABLES.............................................................................................................. Iv LIST OF FIGURES .......................................................................................................... v CHAPTER r— I INTRODUCTION ...................................................................................................... 1 The Problems ................................................................................................. 4 Nul 1 Hypotheses .................................................... .................................. h D e fin itio n s of Terms ...... 5 II REVIEW OF THE LITERATURE.................................................................................10 Function of the Middle Ear ........................................................................10 Function of the Middle-ear Muscles .............................. 15 Measurement o f Acoustic Impedance . ........................... 22 Otosclerosis and Stapedectomy ......................................................... 29 111 INSTRUMENTATION AND PROCEDURES ............................................................... 36 Selection of Subjects ........................................................................... 36 Instrumentation .................................. 37 Procedures .......................................................................................................... J+3 IV RESULTS AND DISCUSSION.....................................................................................52 Hypothesis 1: Acoustic Impedance Measures .....................................52 Hypothesis I I ; Hearing S e n s itiv ity and Impedance .... 72 Hypothesis III: Acoustic Reflex Time Delay ............................. 76 V SUMMARY AND CONCLUSIONS.....................................................................................80 APPENDIXES A Test-retest Measures of Acoustic Impedance ...................................... 83 B Raw Scores fo r Normal Hearing Subjects .......................................... 85 C Raw Scores fo r Stapedectomized Subjects .......................................... 89 D Raw Scores for Otosclerotic Subjects. .... ............................. 93 E Raw Scores of Relative Air-bone Gap ...................................................... 97 F Raw Scores for Acoustic Reflex ....................................................................98 BIBLIOGRAPHY ................................................................................................... 99 H i LIST OF TABLES Table Page 1. A lis tin g of means, standard deviatio n s, and medians determined from the measures of Impedance, compliance, and resistance for ail subjects ......................................................... 56 2. Values associated with J>tests showing the differences between the comparisons o f mean measures of equivalent compliance obtained from all subjects ..................... 64 3* Values associated with J:-tests showing the differences between the comparisons o f mean measures of a rb itra ry resistance obtained from all subjects .............................................66 4 . Values associated with Jt-tests showing the differences between the comparisons o f mean measures of to ta l impedance obtained from all subjects ....................................67 5* H-values associated with the Kruskal-Wal1 Is one-way analysis of variance showing the differences between the compari­ sons of mean measures o f to ta l impedance, compllance, and resistance obtained from all subjects ........................... 70 6. Spearman rank correlation coefficients for test retest compliance and resistance measurements ................................... 84 iv LIST OF FIGURES F ig u re Page 1. Schematic representation of mechanical impedance as a function of frequency ..................................................................... 7 2. A drawing of the middle ear ........................................ I I 3. A schematic cross-section drawing showing the close approxi­ mation of the stapes footplate within the oval window of the Inner e a r ................................................ 14 4. Schematic cross-section drawing of the Zwislocki Acoustic B r id g e ...................................................................................................... 23 5 . Comparative impedance measures fo r one ear without an incus, one normal e a r, and one ear diagnosed as oto sclerosis • 26 6. Schematic drawing of the stapes and three replacement prostheses .........................................................................................3] 7* Instrum entation fo r the measurement o f acoustic impedance . 38 8 . The Zwislocki Acoustic Bridge with the monitoring stethescope. .........................................................................................39 9 . Instrum entation fo r the measurement of an acoustic r e fle x , shown schematically. .................. 40 10. Cai ibration of the noise stimulus as viewed on an oscilloscope screen ............................................................................ 43 11. A schematic diagram showing the analysis of instrumentation time delays fo r the measurement o f an acoustic re fle x as detected by a change of acoustic impedance ................... 44 12. Placement of the ear speculum fo r the measurement of ear canal volume .................................................................................47 13* Measurement o f the ear canal volume p rio r to the measurement of acoustic impedance ............................................ 47 14. The Zwislocki Acoustic Bridge in position for the measure­ ment of acoustic impedance .............................................................. 48 15* The apparatus used for supporting the acoustic bridge during the recording of the acoustic reflex response . • 50 v LIST OF FIGURES ( c o n t.) F ig u re Page 16. A graph showing the re la tio n s h ip between the equivalent volume measurements obtained w ith the Zwislocki Acoustic Bridge and re a c tiv e acoustic impedance in acoustic ohms. ....................54 17. A graph showing the re la tio n s h ip between the a rb itra ry resistance measurements obtained w ith the Zw islocki Acoustic Bridge and resistive impedance in acoustic o h m s .............................................................................. 55 18. Median scores of to ta l impedance fo r the three subject groups shown graphically as a function of the four test frequencies ..........................................................................................58 19. Mean scores of total impedance for the three subject groups shown graphically as a function of the four te s t frequencies. .........................................................................60 20. Median scores of compliance and resistance for the three subject groups shown graphically as a function of the four test frequencies ................................ 6 1 21. Mean scores of compliance and resistance for the three subject groups shown graphically as a function of the four test frequencies ......................................................................62 22. A s c a tte r diagram of measures of to ta l impedance vs. relative air-bone gap obtained from all subjects at 250 c p s .............................................................................................................73 23. A s c a tte r diagram of measures of to ta l impedance vs. relative air-bone gap obtained from ail subjects a t 500 cps ...................................................................... 7k 2A. Examples of sing le impedance change responses from one normal h e a rin g -s e n s itiv lty subject and one stapedectomized subject ....................................................................... 77 vl CHAPTER I The purpose of this study was twofold: (a) to investigate some aspects of acoustic impedance measured at the eardrum of subjects w ith normal-hearing sensitivity, subjects with otosclerosisJ and subjects after stapedectomy surgery; and (b) to study the reflexive responses of the mlddle-ear muscles of some subjects during stimulation of their contralateral ear with acoustic noise. It Is acknowledged that a function of the middle ear is to transmit sound