Table Of ContentTHE ACOUSTIC
REFLEX
Basic Principles
and Clinical Applications
Edited by
SHLOMO SILMAN
Audio logy and Speech Pathology Service
Veterans Administration Medical Center
East Orange, New Jersey
Department of Otolaryngology
University of Medicine and Dentistry
of New Jersey
Newark, New Jersey
Department of Communication
Arts and Sciences
New York University
New York, New York
With a Foreword by Donald D. Dirks
1984
ACADEMIC PRESS, INC.
(Harcourt Brace Jovanovich, Publishers)
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COPYRIGHT © 1984, BY ACADEMIC PRESS, INC.
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ACADEMIC PRESS, INC.
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United Kingdom Edition published by
ACADEMIC PRESS, INC. (LONDON) LTD.
24/28 Oval Road, London NW1 7DX
Library of Congress Cataloging in Publication Data
Main entry under title:
The acoustic reflex.
Includes index.
1. Audiometry. 2. Acoustic reflex. I. Silman, Shlomo.
[DNLM: 1. Reflex, Acoustic. WV 272 A1855]
RF294.A26 1983 617.8 83-22318
ISBN 0-12-643450-6 (alk. paper)
PRINTED IN THE UNITED STATES OF AMERICA
84 85 86 87 9 8 7 6 5 4 3 2 1
Contributors
Numbers in parentheses indicate the pages on which the authors' contributions begin.
MICHAEL BENNETT1 (35), Department of Mechanical Engineering, Brunei
University, Uxbridge, England
MICHAEL G. BLOCK (387), Department of Speech Pathology and
Audiology, University of Wisconsin Hospital and Clinics, Madison,
Wisconsin 53706
ERIK BORG (63, 413), Department of Audiology, Karolinska Hospital, and
Department of Physiology II, Karolinska Institute, S-104 01, Stockholm,
Sweden
ANDREA BOSATRA (301), Ear, Nose, and Throat Clinic, University of
Trieste, Trieste, Italy
S. ALLEN COUNTER (63), Department of Neurology, Harvard Medical
School, and the Massachusetts General Hospital, Boston, Massachusetts
02114
STANLEY A. GELFAND (137, 187), Audiology and Speech Pathology
Service, Veterans Administration Medical Center, East Orange, New Jersey
07019; and Department of Neurosciences and Surgery, New Jersey Medical
School, University of Medicine and Dentistry of New Jersey, Newark, New
Jersey
KATHLEEN W. GREEN (275), Department of Speech Pathology and
Audiology, State University College at Cortland, Cortland, New York
13045
'Present address: Nicolet Biomedical, 5225-4 Verona Road, Madison, Wisconsin 53711-0287.
xi
xii CONTRIBUTORS
RHÖN A HELLMAN (469), Communication Sciences Laboratory, Boston
University, Boston, Massachusetts 02215
DAVID J. LILLY2 (101, 329), Department of Otolaryngology Head and Neck
Surgery, and Kresge Hearing Research Institute, University of Michigan,
Ann Arbor, Michigan 48104
A AGE R. M0LLER (1), Department of Neurological Surgery, Presbyterian
University Hospital, University of Pittsburgh School of Medicine,
Pittsburgh, Pennsylvania 15213
CHARLES A. MANGHAM (441), Subsection of Otology and Neurotology,
The Mason Clinic, Seattle, Washington 98101
ROBERT H. MARGOLIS (275), Communicative Disorders Program,
Syracuse University, Syracuse, New York 13210
ROLAND NILSSON (413), Research Department, Project Lindholmen,
Göteborg, Sweden S-402 75
NEIL PIPER (187), Audiology and Speech Pathology Service, Veterans
Administration Medical Center, East Orange, New Jersey 07019
GÜNTER RÖSLER (63), Department of Physiology II, Karolinska Institute,
S-104 01 Stockholm, Sweden
MARIO RUSSOLO (301), Ear, Nose, and Throat Clinic, University of
Trieste, Trieste, Italy
BERTRAM SCHARF (469), Auditory Perception Laboratory, Northeastern
University, Boston, Massachusetts 02115
JANET E. SHANKS (329), Audiology Section, Veterans Administration
Medical Center, Long Beach, California 90822; and Division of
Otolaryngology/Head-Neck Surgery, University of California-Irvine,
Irvine, California 92717
SHLOMO SILMAN (187, 225), Audiology and Speech Pathology Service,
Veterans Administration Medical Center, East Orange, New Jersey 07019;
Department of Otolaryngology, New Jersey Medical School, University of
Medicine and Dentistry of New Jersey, Newark, New Jersey; and the
Department of Communication Arts and Sciences, New York University,
New York, New York
CAROL ANN SILVERMAN (187, 301), Department of Speech Pathology
and Audiology, Mary mount Manhattan College, New York, New York
10021
TERRY L. WILEY (387), Department of Communicative Disorders,
University of Wisconsin-Madison, Madison, Wisconsin 53706
2Present address: Audiology Department, Good Samaritan Hospital, Portland, Oregon 97210.
CONTRIBUTORS xiii
RICHARD H. WILSON (329), Audiology Section, Veterans Administration
Medical Center, Long Beach, California 90822; and Division of
Otolaryngology/Head-Neck Surgery, University of California-Irvine,
Irvine, California 92717
LESLIE VAN FRANK3 (187), PhD. Program in Speech and Hearing Science,
Graduate School and University Center, City University of New York, New
York, New York 10036
3Present address: 52 Carolin Road, Montclair, New Jersey 07043.
Foreword
Although the middle-ear muscles in humans were described anatomically
more than 400 years ago, the purpose of the middle-ear reflex continues to be the
subject of scientific interest and considerable speculation. During the past 40
years significant technological advancements in instrumentation have enabled
investigators and clinicians to make increasingly more precise measurements of
the response from middle-ear muscle activation. In general, results from these
experiments have led to elimination of some of the older theories of middle-ear
muscle function; however, a definitive and comprehensive theory concerning the
role of the middle-ear muscles in hearing awaits further development and inves-
tigation.
The response of the middle-ear muscles, especially to loud sound, acquired
new significance following the now classic monograph of Metz in 1946 concern-
ing the use of impedance measurements in the diagnosis of auditory impair-
ments. Subsequently, investigators, particularly in the Scandinavian countries,
developed and investigated methods for the clinical measurement of the middle-
ear muscle reflex. In the late 1960s, and thereafter, interest and investigations in
the diagnostic use of the middle-ear muscle response grew rapidly here in the
United States. As a consequence, the measurement of the middle-ear muscle
reflex has become a routine clinical procedure in nearly all comprehensive eval-
uations of hearing impairments. The widespread use and investigation of this
powerful objective technique has expanded so rapidly in the past decade that a
critical and comprehensive review of the significant experiments and theories of
middle-ear muscle function in one volume have become highly desirable, if not
necessary. These considerations became the primary impetus for the current book
devoted to the theory and clinical implications of the middle-ear muscle reflex.
xv
xvi FOREWORD
This book contains chapters that amply characterize the international and
multidisciplinary interest in the middle-ear muscle reflex. The contributors are a
group of international experts with academic backgrounds in engineering, au-
diology, medicine, and physiology. As a consequence, the chapters reflect the
impressive diversity of approaches to the basic and clinical investigation of the
middle-ear muscles. In this sense, the book represents a genuine multidiscipli-
nary appraisal of the middle-ear reflex in man.
A concerted attempt has been made in this volume to present a balanced
evaluation of the current knowledge concerning the middle-ear muscle reflex.
Besides chapters on the basic neuroanatomy and physiology of the middle-ear
muscles, the reader will find comprehensive reviews of the various characteris-
tics of the reflex that are predictive of the anatomical site of an auditory lesion or
may be employed in the objective estimation of auditory threshold. In addition,
the reader will quickly recognize that the purpose and utility of the middle-ear
muscles in man go far beyond clinical diagnosis. For example, chapters are
included that describe the protection afforded the middle-ear muscle reflex
against the adverse effects of industrial noise, the possible enhanced detection
and recognition of auditory signals embedded in a high-intensity interfering
masker, and the complicated and controversial relationship of the reflex response
to loudness.
This book will no doubt have special interest to professionals involved in
auditory diagnosis. However, the comprehensive approach taken in the book
should provide significant background and stimulation for researchers and stu-
dents interested in the auditory system.
DONALD D. DIRKS
Head and Neck Surgery
UCLA School of Medicine
Preface
Since Metz's finding in 1946 that the acoustic reflex is a potential tool in
clinical diagnosis of otic pathology, worldwide research on the acoustic reflex
has rapidly proliferated. Subsequent research has revealed new parameters, and a
body of knowledge concerning its clinical utility has amassed. The results of the
investigations have been made known in the journals of various disciplines—
otolaryngology, neurology, physiology, audiology, hearing science, psychology,
etc. So many facts about the acoustic reflex have been revealed that they cannot
be described even in a few chapters. A complete book on the acoustic reflex is
warranted. The need for dissemination of recent findings is evident in the ever-
growing number of courses, seminars, and workshops on this topic.
Although previous books on impedance have provided excellent coverage of
the acoustic reflex, they have not discussed the following topics, which are
comprehensively detailed in this book: (1) methods and instrumentation for
controlling the occurrence of artifacts during ipsilateral stimulation; (2) acoustic-
reflex magnitude in differential diagnosis; (3) normative data for the contralateral
acoustic-reflex threshold, the acoustic-reflex latency and interaural latency, and
acoustic-reflex adaptation; (4) the temporal characteristics of acoustic-im-
mittance devices; and (5) prediction of mild, high-frequency, and nonorganic
hearing-loss ears from the acoustic reflex. Furthermore, the effects of drugs and
systemic disease on the acoustic reflex has never been the topic of a chapter in
previous books on impedance. Moreover, previous books on impedance have
concentrated on the concept of impedance during the resting state. In this book,
the concept of impedance during acoustic-reflex contraction and the interaction
of the impedance components with various probe tones in infants and adults are
described. In various studies, the relation between loudness and the acoustic
reflex has been debated, but the issue in its physiological and psychoacoustic
xvii
xviii PREFACE
aspects has never been fully explored as it is here. A controversy exists regarding
the role of the acoustic reflex in noise. In this book, research evidence is pre-
sented that details the role of the acoustic reflex in noise and discusses its
potential as an index of noise susceptibility. Although previous books have
covered the classical theories of acoustic-reflex function, it is here that the
classical concepts are integrated into one comprehensive theory. Coverage of
diagnostic acoustic-reflex and nonacoustic-reflex profiles in this book is based on
the results of the most recent investigations. Because of the dimensions of this
book, it was necessary to include a chapter that expanded on the neurophysiology
of the acoustic reflex so that phenomena such as latency, magnitude, fatigue,
adaptation, and temporal integration could be more fully understood.
Clinicians and researchers in audiology, deaf education, engineering, hear-
ing science, neurology, otolaryngology, physiology, and psychology will find
this book invaluable for enriching their knowledge of clinical diagnosis of otic
pathology, as well as for guiding future research on the acoustic reflex. This book
can also serve as a reference text in a course on impedance.
I am indebted to Dr. Roy Sullivan, who was my first professor of impedance
and who stimulated my interest in this area; to Dr. Gerald R. Popelka, who was a
great influence on my research on the acoustic reflex and who served on my
doctoral committee; to Dr. Maurice H. Miller, my very dear friend and colleague
and former professor who has continually supported and encouraged my profes-
sional development; to Dr. Stanley A. Gelfand, my best friend and colleague,
who enlightened me with his wisdom; to the staff at the East Orange Veterans
Administration Medical Center—John Lutolf, Neil Piper, Jean Sullivan, Theresa
Showers, Ella Taliaferro, Valerie Adams—and lastly, but not least, to my
colleague and friend, Dr. Carol Ann Silverman, for her constructive and thought-
ful advice on this book.
Neurophysiological Basis of the
Acoustic Middle-Ear Reflex
AAGE R. M0LLER
ANATOMY OF THE STAPEDIUS-REFLEX ARC
DIRECT PATHWAYS
It has long been known that the two middle-ear muscles are innervated by two
different cranial nerves: the facial nerve (Ν VII) innervates the stapedius muscle,
whereas the trigeminal nerve (Ν V) innervates the tensor tympani muscle (Pol-
itzer, 1861). Although it may be inferred from earlier work that the superior
olivary complex is most likely the reflex center (Hammerschlag, 1899, 1901),
the details of the reflex arc have not been studied until relatively recently (Borg,
1973).
The anatomical organization of the reflex arc for the acoustic middle-ear reflex
(for both the tensor tympani and stapedius muscles) has been studied mostly
through experiments in rabbits (Borg, 1973). Contrary to what is believed to be
the case in humans, the tensor tympani muscle in the rabbit contracts in response
to sound as an acoustic reflex. In these rabbit experiments, lesions were made at
various locations on the ascending auditory pathway. After sufficient time had
THE ACOUSTIC REFLEX 1 Copyright © 1984 by Academic Press, Inc.
All rights of reproduction in any form reserved.
ISBN 0-12-643450-6
