v

Contents

Foreword by Charles Berlin viiPreface xiii

SECTION I: THE EARLY YEARS 1

1 The Pioneers 3The Saga of Average Normal Hearing 4The Audiogram Recording Form 5The First Audiologist 6

2 Origins of the Words “Audiology” and “Audiologist” 11

3 The Military Programs During and After World War II 15

4 The VA Program 19

SECTION II: SIX DIVERGENT PATHS 23

5 Diagnosis 25The Alternate Binaural Loudness Balance (ABLB) Test 25The Intensity Difference Limen 26Békésy Audiometry 27Pseudohypacusis 28Dichotic Tests 29Impedance (Immittance) Audiometry 30Auditory Evoked Potentials 31Otoacoustic Emissions 35

6 Rehabilitation 39Hearing Aids 39Auditory Deprivation and Acclimatization 44Binaural Aids 44Digital Signal Processing and Microphone Technology 45Accountability 46The Saga of Barry Elpern 48Assistive Devices 49Cochlear Implants 50

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Auditory Training 52Clear Speech 54

7 Pediatric Audiology 55Screening in Newborn Babies and Infants 55Assessing Young Children 57

8 Auditory Processing Disorder 61Divergence Begins 63The Audiologic Approach 63The Psycho-Educational Approach 64The Language Processing Approach 65

9 Tinnitus Evaluation and Therapy 67

10 Hearing Conservation 71

SECTION III: PROFESSIONAL GROWTH 75

11 The Medical Connection 77

12 Audiologic Education 79The Au.D. Degree 80Practice Management 81

13 Professional Organizations 83American Speech-Language-Hearing Association (ASHA) 83The Academy of Rehabilitative Audiology (ARA) 84The Academy of Doctors of Audiology (ADA) 85The American Auditory Society (AAS) 85The American Academy of Audiology (AAA) 86

14 Research Support for Audiology 89

15 Looking Back 91

Sources and Suggested Readings 93Index 99

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vii

Foreword

Before you go any farther, read what Jim haswritten about me on page xiii in his Preface.There is an axiom in academia—“any bookthat cites my work in admiration is a finepublication worthy of worldwide distribu-tion.” So I must in all honesty ask that JimJerger’s name be substituted for mine onceagain.

Why do I say “once again”? In Decem-ber of 2002, Jim Jerger kindly came to LSU to applaud my career at a retirement party.To paraphrase this witty clever man, whomI have always admired from the beginningof our association, he said something like:

It is a pleasure and an honor to speak inglowing terms about a man whose influ-ence on our field has been immeasurable,whose leadership and originality haveset the stage for the development of astrong and powerful profession . . .

And as he went on and on, I muttered in abarely audible fashion ”Jim that soundsmuch more like you than me.” At the end ofhis encomium, he smiled and said “ . . . Butenough about me, we are here to celebrateChuck’s retirement.”

No one laughed louder or longer than I did. It is to Jim we owe the popular accept-ance of much of our modern audiologic prac-tice differentiating cochlear from retrocochleardisease, starting with Békésy types, SISI,SPAR, tone decay, and so on and, of course,the ubiquitous test battery principle whichnow is the cornerstone of good audiology.

My honor, respect, and admiration forboth Jim and Susan have only grown over the

years. But it should come as no surprise thatmy view of our profession’s history wouldhave a slightly different twist based on dis-coveries made in intellectual streams quitedifferent from those that formed the basis ofaudiology as Jim lived it. Other members of our profession were more strongly influ-enced by NIH and its training and researchprograms. Jim and Susan both played strongroles in promoting Audiology and its scien-tific validity in halls of NINDB and ultimatelyNIDCD. I daresay, without his support, someof my own grant applications would neverhave been approved.

Sadly, only a few of our audiologic col-leagues have held NIH grants, but thosewho have, are leaders in our field and havepublished in the most prestigious journals in the world, including Science and Nature.Brenda Ryals of James Madison University,for example, published some of the germinalpapers on hair cell regeneration and, work-ing with Ed Rubel, helped discover thatchicks regrow hair cells after noise trauma.That opened a remarkable chapter in audi-tory science, which uncovers new findingsalmost weekly.

Through my personal early postdoctoraltraining, underwritten by NIH, my notion ofthe first audiologists included C. C. Bunch.But I must add his anatomist-colleague-mentor Stacy Guild Ph.D. who learned aboutthe WE 1-A from Bunch (or perhaps the otherway around—history is unclear) and thenrolled the first Western Electric audiometeraround the wards of the Johns Hopkins,doing bedside audiograms on dying patients.He then collected their temporal bones and

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showed that high-frequency hearing loss(measured albeit tenuously to 16,384 Hz withBakelite headphones!) was associated withloss of hair cells and nerve fibers at the basalturn of the cochlea. That publication dove-tailed with von Békésy’s first publication ontraveling wave theory, meshed with Weverand Bray’s findings on cochlear electricalevents, and spawned immediate attempts torecord human action potentials and cochlearmicrophonics instead of audiograms. Thesearch for the objective audiogram hadalready begun before there were even normsor very many official practitioners. Theirattempts to record these events from humanears unfortunately were technically prema-ture, despite von Békésy’s and Lempert’sbest efforts. Merle Lawrence, and later JoeHawkins, were among the leaders who ush-ered in a new era of correlating electricallyextracted audition with physiology andanatomy. This was the slightly differentstream into which I fell as part of my earlyNIH-supported postdoctoral training. With-out NIH support, I feel our field would havetaken a somewhat less scientific turn.

It was one of my responsibilities as apostdoctoral fellow at the Johns Hopkins totest terminal patients bedside, get permis-sion to harvest their temporal bones, and getthe bones and fix them for subsequent study.It was there I first realized that what Jim andhis colleagues already knew, that the puretone audiogram did not always mesh withwhat textbooks taught about the underlyingcochlear anatomy and physiology. My audi-ologic brain was expanding and people likeWever, Lawrence, Schuknecht, Lempert, andGuild, not to mention Ira Hirsh (none ofwhom would ever qualify for ASHA certifi-cation—sigh) were really teaching us impor-tant things about our patients from anentirely nonclinical perspective.

And Jim is, of course, also responsiblein part for that expansion because he intro-

duced me to, and captivated me with, thewritings of Edward de Bono. (The Five DayCourse in Thinking and Serious Creativity aretwo of my personal favorites.) Let me explain.de Bono taught us ways of thinking toaddress both the “quite impossible” and the“incredibly mundane” as worthy of someattention. So, in much of my teaching of med-ical students, neuroscientists, audiologists,and colleagues I ask the rhetorical question“Why Is the Sky Dark at Night?” The com-mon and expected answer is: “Because thesun’s on the other side of the earth.” Well,that explains why the earth is dark at night,but why don’t we see the light of the sunbypassing the earth on its way out to space?Is the earth casting a huge shadow thatblocks out everything but somehow managesto skip the moon, the stars, and any planesor satellites passing by way up in the sky?Obviously not. The (partially) correct answeris that the sky is brilliantly lit with infraredlight visible to cats, rats, mice, and so on butnot to humans. The sun’s light is movingaway from us at the speed of light andundergoes a Doppler shift, which causes itto appear as infrared instead of visible spec-trum light.

Why is this an important thinking exer-cise? We don’t mull over this dark sky para-dox because we have a logical answer thatsatisfies us, even though it is wrong. Oncewe make up an answer that satisfies us, westop looking. The nature of the human brainis that we make up stories to fit the facts thatwe observe (cf. Gazzaniga and the EthicalBrain), which in turn dampens our curiosity.

For example, why do we have a middleear muscle reflex and what does it have to do with the audiogram? We were taught(or taught each other) that it is a protectivemechanism for “loud noises” and we elicit itwith a loud sound to the ear. But virtually allmammals and many other species have sucha reflex. Why would Nature (my apologies

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to the Intelligent Design folks) anticipate theindustrial revolution and introduce a protec-tive device that attenuates low frequenciesby virtue of its increase in stiffness of theossicular chain. In humans the middle earmuscle reflex is invoked 50 msec in anticipa-tion of the onset of the voice, and in part as aprotective device for the almost 115 dB SPLlow frequencies generated in the vocal tract.In many mammals (bats, for example), it is a tool to modulate echo returns and keepthem from impinging on pinging soundsemitted from the vocal tract.

I include this homily in honor of Jim andhis contribution to our profession. He makesus think, and come up with new answers.What’s more, his own relentless attempts toseparate cochlear from retrocochlear disor-ders has an orderly interlaced lattice-likestructure, which allows its ultimate reconfig-uration once new facts are discovered.

Let me clarify. Because of the history ofour profession and its reliance on the puretone audiogram as a gold standard, we nowhave one of our most critical problems fac-ing us. “If your only tool is a hammer, thewhole world looks like a nail.” Our primarytool was the pure tone audiogram and wethought that, once we obtained it, “our jobwas done.” As Jim quite rightly notes in thetext, some of our otolaryngology colleagueswould like to relegate us to that role, or auto-mate us out of our work. We must revisemuch of our thinking about the audiogramand learn instead to interpret it throughmodern concepts of physiology which wedidn’t have even 15 years ago.

To amplify, most of the work publishedin our journals views the ABR and middleear muscle reflexes through the prism of the“getting the audiogram” or diagnosing atumor, rather than the underlying physiol-ogy. In the late 1960s and early 1970s. HenrySpoendlin showed that it was the inner haircell that mediated virtually all the auditory

nerve activity in mammals. So the audiogram,the middle ear muscle reflexes, the ABR, andall of our understanding of speech percep-tion and the articulation index reviewed inthis book that were championed by HarveyFletcher et al. now have to be re-examinedfrom the point of view of the integrity of the inner hair cell, its dynamic range of only65 dB, and the synchrony of the nerve fiberswhich it subtends. People with nearly nor-mal audiograms can in fact have no ABRsbecause they lack synchrony, and, similarly,people with very poor audiograms can havenormal emissions because their inner hair cellsand/or nerve fibers are not functioning well.These observations demand that we put the quest for the “objective audiogram” and“objective hearing measurement” in a differ-ent light.

David Kemp’s discovery of otoacousticemissions allows us to study the outer haircell almost in isolation. We recognize theouter hair cell has a wide dynamic rangecochlear amplifier and, therefore, in the pres-ence of normal emissions, an additional hear-ing aid is certainly not physiologically calledfor in the selected frequency ranges. Thus,we as audiologists are the only professionthat can noninvasively dissect the cochlea intoinner and outer hair cell function in livinghumans, and manage them from a physio-logic perspective rather than exclusively fromtheir audiograms. Unfortunately, the two-stage test of emissions first, followed by ABRsecond, described here by Jim as a majorachievement in our profession has to be re-examined in the light of recent findings. Itshould be ABR first, and emissions second,because almost 40% of NICU babies will havenormal emissions and absent or abnormalEcochGs or ABRs. They will escape properdiagnosis and management (Rea & Gibson)if emissions are done first.

Outer hair cells can be tested with oto-acoustic emissions and cochlear microphonics.

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Inner hair cell integrity can be inferred fromfive test results: A synchronous N1 in theEcochG, a similarly synchronous Wave I inthe ABR, recordable Summating potentials,brief cochlear microphonics (again becausethey come from any hair cell) and robustmiddle ear muscle reflexes at or less than 95dB HL regardless of the audiogram. Anabsent reflex in the presence of normal emis-sions, or an absent ABR in the presence ofnormal emissions are cardinal signs of audi-tory neuropathy/dys-synchrony, a set ofconditions that apply in at least 15% of ourhearing-impaired children and many of our adults who are inexplicably poorhearing aid users or who have “dead zones”(Brian C. J. Moore).

With this armamentarium, why do westill fit hearing aids based on the audiogramwithout testing the underlying physiology?Because we think we know why the sky isdark at night and don’t think beyond thepure tone audiogram the way Jim has alwaysexhorted us to do. This is the core of a newway to look at audiology. It complementsand plays a reprise to all of our audiologicforebearers, and ties together many looseends which, at the time of original report,had only limited physiologic explanations.

By applying the Jerger and Hayes cross-check principle, we can study each newpatient physiologically with tympanometry,reflexes, and emissions. This trio predictswhat the audiologic results should be butprevents us from viewing the audiogram asthe gold standard of hearing. The sameaudiogram can lead to entirely differentauditory perceptions when and if inner haircells and/or nerve fibers are disabled.Therefore, “fixing or compensating for theaudiogram,” as suggested by many of ourforebearers is appropriate only if the outerhair cells and, in part, the cochlear battery(endocochlear potential) are the culprits.

When inner hair cells and/or nervefibers underlie the poor audiogram (andsometimes their accompanying audiogramscan be nearly normal!), we have an entirelynew way to classify their problems. Whatlooks like auditory processing disorder (APD)may really be cases of auditory neuropathy/auditory dys-synchrony (AN/AD), withnearly normal audiograms, poor hearing innoise, and poor performance on the SCANor any of the dichotic procedures commonlyapplied to make the APD diagnosis. It is herethat assistive technologies, which essentiallyenhance the signal-to-noise ratio become ourstrongest weapons. Inner hair cell and nervefiber losses, often revealed by extraordinar-ily poor hearing in noise scores, ultimatelywill yield to FM enhancement, assistive lis-tening devices (ALDs), or cochlear implants,provided the impairment does not stem fromthalamic, cerebellar, or cortical impairment.C.C. Bunch’s patient, whom Jim thoughtmight have Ménière’s disease, could just aseasily have had temperature-sensitive audi-tory neuropathy/dys-synchrony. But theadvent of anything that enhances signal-to-noise ratio can just as easily be viewed in thecontext of ameliorating inner hair cell andnerve fiber loss.

So the six streams of audiology that Jimhas so elegantly outlined in this book all willconverge in the future on the underlyingphysiology and genetics of our patients.

Why genetics?Within the next few years, chips will be

available that can sample droplets of bloodfrom our patients and tell us whether theyare homozygous or heterozygous for manydifferent genetic forms of deafness. (Seehttp://webh01.ua.ac.be/hhh/ for almostdaily updates on the status of genes anddeafness.) Knowing the underlying geneticcauses of various types of hearing loss willliberate us from categorizing hearing loss as

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simply “conductive or sensorineural.” Wewill certainly be able to understand and bet-ter manage the underlying mechanisms ofvarious hearing losses and both apply anddevelop new tools for assessment. The mostimportant tools of the future will be bothgenetic and physiologic, especially if we candevelop a noninvasive or nondestructivemethod for evaluating the endocochlearpotential in humans. Knowing the status ofthe cochlear battery will open new vistas forboth diagnosis and management.

So, in summary, my favorite audiologistof all time, the man in our field I hold in thegreatest of respect, has brought us to a placewhere we can liberate ourselves from thesearch for the all elusive Holy Grail of theaudiogram. We can now amend all of ourpractices with physiologic and mechanisticunderpinnings to better treat our patientsand work with our professional colleagues

to better understand some of the mysterieswe encounter.

We certainly cannot say that once we“get the pure tone audiogram,” we now knowall there is to know about Why the (audio-logic) Sky Is Dark at Night, Jim Jerger hashelped us reach a new place, a new prom-ised land, where we have all the “hallmarksof a robust and growing profession with aremarkable history.”

Charles Berlin, Ph.D.

Reference

Rea, P. A., & Gibson, W. P. (2003). Evidencefor surviving inner hair cell function in con-genitally cleat ears. Laryngoscope, 113(11),2030–2034.

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3

1The Pioneers

Harvey Fletcher (Figure 1–1) was oneof the true pioneers of research in speechcommunication. After teaching physics forfive years at Brigham Young University inProvo, Utah, Fletcher moved to New York tocarry out research in sound at the WesternElectric Company. Here he participated in thedevelopment of the Western Electric hearingaid, the first to employ vacuum tubes; theinitial model was delivered to none otherthan Thomas A. Edison. Harvey Fletcher’sbook Speech and Hearing for many years was

the accepted standard guiding research inspeech communication. As director of phys-ical research at the Bell Telephone Laborato-ries in New Jersey, Fletcher set the stage forwhat later became the concept of the articu-lation index, and, more recently, the speechintelligibility index. He helped to found, andserved as first president of, the AcousticalSociety of America.

The Western Electric 1-A audiometer wasquite large by today’s standards and fairlyexpensive ($1500.00). As Figure 1–2 shows, it was hardly portable, but a later model, theWE 2-A, was smaller and lighter. It was soldmainly for use in otolaryngology practices.Within two years the Sonotone Jones-KnudsonModel 1, became commercially available.Otolaryngologists were the primary users ofaudiometers in the 1920s and 1930s. Theirenthusiasm was tempered, however, by thefact that there was no common standard forcalibrating the devices. Each manufacturerrelied on its own laboratory data, usuallybased on results from a few people availablearound the laboratory. Thus, the same patientmight show somewhat different losses ontwo different audiometers. The problem wasthat no one was quite sure what were theSPL levels corresponding to average normalhearing in the population.Figure 1–1. Harvey Fletcher.

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The Saga of Average Normal Hearing

In 1935 The United States Public Health Ser-vice (USPHS) undertook a fairly massiveeffort for the time, a survey of hearing sen-sitivity in the United States. Willis Beasley, apublic health officer, was appointed to carryout the survey during the years 1935-1936; in subsequent years it became known as the“Beasley survey.” Considering that no onehad ever undertaken such a study before,the planning, execution, and reporting wereremarkably sophisticated. The SPL levelsobtained by the Beasley survey provided,for the first time, large-sample data defining

average normal hearing over the frequencyrange from 128 Hz to 8192 Hz.

The first standard for the calibration ofaudiometers in the United States was pub-lished in 1951 by the American StandardsAssociation, a voluntary group of consumers,manufacturers, engineers, and specialists. Thesound pressure levels (SPL) values from theBeasley survey corresponding to averagenormal hearing at each test frequency (thezero HTL line on the audiogram) became, in 1951, the basis for the calibration of allaudiometers in the United States. And, be-cause no other country had undertaken asimilar survey, the ASA-1951 standard (whichcame to be known as the “American stan-dard”) was adopted by many other countries

4 AUDIOLOGY IN THE USA

Figure 1–2. The Western Electric Model 1-A audiometer.

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as the basis for calibrating their audiometers.But in the early 1950s two other hearing sur-veys were carried out, one in the UnitedKingdom (UK), the other in Japan. The twosurveys were in agreement: both found aver-age normal hearing to be about 10 dB betterthan the American standard. In an effort tounderstand what might account for theapproximately 10-dB discrepancy betweenthe ASA-51 and the UK findings, the Re-search Center of the Subcommittee on Noisein Industry, in Los Angeles, authorizedAram Glorig to plan and execute anothersurvey of average normal hearing in whichthe exact methods and procedures employ-ed in the Beasley survey would be carefullyrepeated. Audiometers and audiometricbooths were set up at the Wisconsin State Fairin 1954, and 3500 fairgoers were tested audio-metrically. Results essentially replicated theBeasley findings. This prompted Glorig togo back to the Wisconsin State Fair, in 1955,and carry out another survey, but using whathe termed “laboratory methodology,” in whichthreshold was crossed at least three times ineach direction. This time results were about10 dB better, and in agreement with theUK/Japan results. Glorig concluded that thedifference lay in the technique of thresholddetermination. Apparently, the differencebetween, on the one hand, the Beasley and1954 Wisconsin State Fair results, and on theother hand the UK/Japan and the 1955 Wis-consin State Fair results, could best be attrib-uted to better audiometric testing technique.It seemed that experience over the period fromthe 1930s to the 1950s, especially as a resultof World War II military programs, hadimproved threshold seeking technique, re-sulting in more accurate threshold estimates.

After a good many international meet-ings, checks, and counterchecks on possibleprocedural and/or calibration microphone,earphone, and coupler differences, and manyother possible reasons for the discrepancy,

all finally agreed, in an international meet-ing at Rapallo, Italy, that the InternationalStandards Organization (ISO) should issue,in 1964, a new standard that all could agreeon. This became known as the ISO-64 stan-dard. It was essentially based on the findingsof the UK and Japan surveys. From thatpoint on, audiometers worldwide could becalibrated to the same standard.

This change in the basis for calibratingthe zero HTL line on the audiogram had amajor impact on a number of agencies in thiscountry, particularly the military and the Vet-erans Administration. Because compensationfor service-induced hearing loss was basedon audiometric hearing threshold levels, achange of the zero loss level of 10 dB, had thepotential to increase compensation benefitsnationwide to a financially alarming degree.There was a long transition period duringwhich reporting degree of hearing loss in theUnited States required that the calibrationstandard of the particular audiometer usedfor the measurement (ASA-51 or ISO-64) bereported as well. Eventually, however, all ofthese problems were resolved. Later, in 1969,the ASA (newly renamed the AmericanNational Standards Institute [ANSI]), madesome minor adjustment to the ISO-64 stan-dard, resulting in the ANSI-69 standard, andstill later the ANSI-96 standard, which is nowthe basis for the calibration of audiometersin the United States. Although other detailsof these standards have changed slightlyover the years, the ISO-64 SPL levels haveremained virtually unchanged.

The Audiogram Recording Form

The year 1922 also saw the design of whatwe now know as the pure-tone audiogramrecording form. It was conceived jointly by

THE PIONEERS 5

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scientists Fletcher and Wegel and by an otolaryngologist, Edmund Prince Fowler(Figure 1–3) of Columbia University, the latter one of the great pioneers of otologicmedicine. Unfortunately, they made twodecisions that have continued to haunt usfor the past 50 years. First, they proposedthat “hearing loss” at each test frequency be expressed relative to “average normalhearing,” a sound pressure level (SPL) thatvaries with frequency. Second, they thoughtthat degree of loss ought to be plotted down-ward on the graph. All of this probablyseemed like a good idea at the time, but ithas caused unremitting problems in relatingthe audiogram to the performance of ampli-fication devices, where performance at eachfrequency is expressed relative to a commonSPL reference and is plotted upward on thegraph in conformity with standard scientificpractice. But at this point the practice is soingrained that all efforts to bring reason tothe situation have failed utterly.

The First Audiologist

The first genuine audiologist in the UnitedStates was undoubtedly Cordia C. Bunch. Asa graduate student at the University of Iowa,late in the World War I, Bunch came underthe influence of Carl Seashore, a psycholo-gist who was studying the measurement ofmusical aptitude, and Lee Wallace Dean, anotolaryngologist. Together they convincedBunch to undertake a five-year project onthe practical application of methods for test-ing hearing. Because audiometers were notyet available commercially, Bunch devel-oped his own instrument, called the “pitchrange audiometer.” It covered the frequencyrange from 30 to 10,000 Hz and intensitiescapable of reaching threshold in one directionand pain in the other. With this audiometer,Bunch plotted what he called the “hearingfields” of Dean’s patients, from thresholds ofhearing to thresholds of discomfort.

After obtaining his Ph.D. degree, Bunchstayed on briefly at Iowa, then moved for ashort time to Johns Hopkins University, asAssociate in Research Otology. In the mean-time, L. W. Dean had moved from the Uni-versity of Iowa to Washington University inSt. Louis and invited Bunch to rejoin himthere. Bunch accepted and was appointed Pro-fessor of Applied Physics of Otology at theWashington University School of Medicine.For the next two decades Bunch gathered a massive number of air-conduction audio-grams on Dean’s patients, analyzed them, andwrote up his findings. Over the years from1919 to 1943, Bunch published papers cover-ing an astonishing range of topics. He wroteon the use of the audiometer, the importanceof measuring sensitivity in the range of frequencies above the conventional audio-metric range, the effect of age on audiomet-ric thresholds, occupational and traumaticdeafness, traumatic loss from firecracker

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Figure 1–3. Edmund Prince Fowler.

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explosion, progression of loss in otosclerosis,deafness in aviators, conservation of hearingin industry, hearing aids, race and sex vari-ations in hearing thresholds, otitis media,effect of removal of one entire cerebral hemi-sphere, calculating percentage of loss formedicolegal purposes, and the effect of ab-sence of the organ of Corti on the audiogram.

Bunch carried out the first systematicstudies of the relation between types of hear-ing loss and audiometric patterns. Thesepioneering efforts were published in 1943 ina slender volume entitled Clinical Audiometry,which is now a classic in the field. The titlepage is shown in Figure 1–4. One case studyfrom the book illustrates how his insights

THE PIONEERS 7

Figure 1–4. The title page of C. C. Bunch’s classic volume,Clinical Audiometry, published by C. V. Mosby in 1943.

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foreshadowed ideas that did not come tofruition until many years later. In the bookhe presents the audiogram of a 42-year-oldman with what may very well have beenMénière’s disease (Figure 1–5).

Bunch noted that the audiogram maynot always help in the selection of a hearingaid and, indeed, may even lead to the wrongrecommendation. In this case, he advised anaid with uniform frequency response, butsubsequent evaluation showed that thepatient understood very little in spite of theamplification afforded by the aid. Then hetried a Y-cord arrangement to both ears, butthe patient could still understand very little.At this point, he began to suspect that some-thing was out of order. He returned to theaudiometer, presented tones at suprathresh-old levels, and simply asked the patient to

make pitch comparisons of the tones. Usingthis procedure he discovered that tones at128, 256, and 512 Hz all were heard at theappropriate pitch and in the proper order,but that tones at frequencies of 1024, 1448,2048, and 2896 Hz “all sounded alike andlacked tonal quality.” Bunch speculated thatthe hearing aid was useful only in the lowfrequency range below 512 Hz, but of littlevalue in the frequency region important forunderstanding speech. Bunch then made theprescient observation that, if it had been pos-sible to administer simple speech audiomet-ric testing, then the discrepancy between theaudiogram and the patient’s actual ability tounderstand speech could have been detectedand the patient would not have had to go tothe expense of purchasing a hearing aid thatwas not very helpful.

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Figure 1–5. Audiogram of a Bunch patient who fared poorly with hearing aids.

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Here, we can almost see the thinking of the consummate clinician/investigator atwork. With only the pure-tone, air-conductionaudiometer as test equipment, he senses apuzzling disagreement between his test resultsand the patient’s ability to function withamplification. Determined to explore the mat-ter, he does rudimentary pitch comparisonsand discovers that all tones above 512 Hzhave lost tonal pitch quality. He speculatesthat this may be the result of a unique auralpathology of which he is apparently unaware.He speculates that standardized speech audi-ometric tests, which, of course, were not avail-able in 1938, would have been helpful inidentifying the problem and thereby avoid-ing an inappropriate hearing aid fitting.

Bunch was probably the first to suggestthat, in seeking threshold, the tonal stimulusshould be keyed on and off rather than lefton continuously, the first to suggest that test-ing should begin at 1000 Hz, and the first to

suggest that total unilateral malingeringwould be revealed by the absence of anappropriate “shadow curve” on the presum-ably deaf ear.

After Dean’s retirement, Bunch brieflybecame Associate Director of the CentralInstitute for the Deaf in St. Louis. In 1941 heaccepted an offer from the School of Speechat Northwestern University to come to Evan-ston as Research Professor in Education ofthe Deaf, and to teach courses in hearingtesting and hearing disorders. There he metand did a bit of mentoring of a young facultymember in speech science, Raymond Carhart.In June of 1942 Bunch unexpectedly died atthe age of 57. In order to proceed with thecourse, the NU administration tapped Carhartto teach Bunch’s courses. And the rest, asthey say, is history. Carhart told me, yearslater, that no single person had had moreinfluence on his career than C. C. Bunch.

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39

6Rehabilitation

Throughout much of the history of mod-ern audiology the principal rehabilitativeweapons have been wearable hearing aids,assistive devices, cochlear implants, andauditory training. Their paths have becomeinterestingly intertwined.

Hearing Aids

Leland Watson, president of the Maico Com-pany, and Thomas Tolan, an otolaryngolo-gist, traced, in their volume, Hearing Testsand Hearing Instruments, the early history ofthe development of the wearable hearingaid. The following is based on their compre-hensive review.

Alexander Graham Bell played a signif-icant role in the invention of the first electricalhearing aid. In an effort to help his hearing-impaired wife, he experimented with theelectrical properties of carbon granules. Bellfailed to succeed with the hearing aid proj-ect, but his work with carbon granules leddirectly to the invention of the telephone.The first viable hearing aid based on carbongranule technology was actually developedby a Viennese physician, Dr. Ferdinand Alt,in 1900. American versions were produced in1902 by Miller Reese Hutchinson in Mobile,Alabama and C. W. Harper in Boston. Carbon-

granule based hearing aids were widelyavailable in the 1920s and 1930s, but theyhad many problems, not the least of whichwas fairly poor sound quality. Vacuum tubeamplifiers were a giant step forward. The firstvacuum tube-based aid in the United Stateswas produced by Art Wengel in 1937. It wascalled the “Stanleyphone.” But it remainedfor the Aurex company to make the technol-ogy widely available. These aids stretched thedefinition of portable to an extreme degree.They were powered by a separate batterypack. The amplifying unit was mountedsomewhere on the upper body, the batterypack either strapped to the midsection or onone leg. How a contemporary woman mightoutfit herself in the 1930s is illustrated inFigure 6–1.

The truly wearable hearing aid was madepossible by the invention, and systematicimprovement, of the miniature vacuum tubein the late 1930s. The filaments of the tubeswere heated by a 1.5-volt “A” battery, theplate biased by a 22- to 30-volt “B” battery.These aids, about the size of a package ofcigarettes, could be worn in a shirt pocket or in a cloth pocket suspended from theneck. They were connected by thin wire to asmall transducer, curiously referred to as a “receiver,” mounted in the ear canal by atotally occluding earmold. Such aids weremade available to the aural rehabilitative

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programs of the various services during and after World War II and were widely dis-tributed to returning servicemen. Examplesof these “all-in-one” aids are shown in Figure 6–2.

Sound quality, in these aids, was stillmarginal. Figure 6–3 shows the frequencyresponse of one such aid at various tone con-

trol settings. The wide-band, flat responsewas still a few years away.

The military programs generated a long-standing debate, which at times becamequite contentious, over what might be calledthe “philosophy of fitting” an aid. On theone hand were the exponents of “hearingaid selection,” a procedure promoted mostnotably by Raymond Carhart and his manystudents. The rationale here was that theaudiologist must seek, through objectivetesting of speech understanding, the aid thatbest matches the unique shape and degree ofthe serviceman’s loss. This was achieved bymanipulation of gain and tone control of eachof several candidate aids in search of opti-mal word intelligibility. As outcome mea-sures of this approach Carhart adapted, forthis purpose, the speech audiometric scoresbased on the spondee and PB word listsdeveloped at the Harvard PsychoacousticLaboratory during the war. The underlyingassumption of the hearing aid selection pro-cedure was that individuals differed in theunique details of their losses and that the bestaid was the aid that complemented theshape of the loss, especially in terms of itsfrequency response. It was assumed that thespeech audiometric scores would order theaids appropriately.

As early as 1946, however, an alterna-tive philosophy emerged from two sources:(1) the British Medical Research Council(MEDRESCO) hearing aid, and (2) the Har-vard Report. The MEDRESCO aid was devel-oped by British engineers to meet the needs ofthe nascent British National Health Service.They were convinced that a single, relativelyflat, frequency response was sufficient formost hearing-impaired individuals. Thus,they allowed for only minimal adjustment ofthe tone control of the aid.

The Harvard Report was generated by agroup of scientists, including as noted earlier,Hallowell Davis, working on the National

40 AUDIOLOGY IN THE USA

Figure 6–1. How a hearing aid was worn inthe 1930s. The amplifying unit, mounted onthe chest, was supplied by batteries strappedto one leg, and was connected by a long, flex-ible wire to the transducer mounted in a fullyoccluding earmold. (Reprinted from Hearingand Deafness, first edition, Murray Hill Books,1947.)

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Defense Research Council (NDRC) AuralRehabilitation Project at Harvard Universityduring the last years of World War II. Theytested a number of hearing-impaired indi-viduals with a master hearing aid, in whichthe frequency response could be manipulatedover a wide range. Their report, published in1946, reinforced the MEDRESCO philosophyin concluding that selective amplification wasof little value. A uniform (flat) frequency re-sponse, or a response slightly tilted upward

in the high frequencies, almost always yieldedthe best speech understanding scores. Thus,elaborate selection procedures were not war-ranted. For the next several decades, livelydebate ensued between proponents of thetwo conflicting philosophies. Traditionalistscontinued to carry out hearing aid selectiontesting in the Carhart manner while youngturks called for reform, but usually to littleavail. It must be said, however, that thephysical characteristics of the aids of that era

REHABILITATION 41

Figure 6–2. Five hearing aids popular in 1948, compared with four hearing aids popular in1998. Fifty years of miniaturization.

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did not permit very precise control over thefrequency response of any aid. In retrospect,it is doubtful that either side could haveamassed very much hard evidence in sup-port of its position.

A similar conclusion was reached asearly as 1949 by none other than HarveyFletcher himself. He opined, at the SecondCongress of the International Society ofAudiology, that the appropriate frequencyresponse of an aid ought to simply mirrorthe audiometric threshold levels, but thatthere would be little difference in wordrecognition scores between such an aid andone with a flat frequency response, so that,for all practical purposes the aid with a flatresponse should be suitable for everyone.He did concede, however, that if the audio-gram sloped downward by more than 20 dBbetween 500 and 2000 Hz, then the responseof the aid should slope upward at about onethird the slope of the audiometric contour.

In the early 1950s the transistor wasdeveloped and its value in the design of wear-able aids was immediately apparent. Tran-sistors were certainly a good deal smallerthan miniature vacuum tubes, but the mainadvantage was the elimination of the needfor the bulky, high-voltage “B” battery. Tran-sistors could manage the same amplificationpowered only by a small 1.5-volt “A” bat-tery. This additional miniaturization made itpossible to move the amplifier unit from thechest to a location over and behind the auri-cle, the behind-the-ear unit, and ultimatelyinto the ear canal itself. Miniaturization alsomade bilateral fittings feasible, permittingfor the first time the capability of exploitingthe several advantages of two-eared hearing.

One of the early attempts in this direc-tion was the development of the “eyeglassaid” in the 1960s. In this novel arrangementall of the components of an aid were builtinto the eyeglass frames, one aid on each

42 AUDIOLOGY IN THE USA

Figure 6–3. The frequency response of an inexpensive hearing aid popular in the 1940s atfour positions of the tone control. (Reprinted from Hearing Tests and Hearing Instruments,Williams & Wilkins, 1949.)

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side. It was a clever idea, but never reallycaught on, perhaps because it complicatedthe process of taking the glasses off and put-ting them back on. In those days, heavyframes were in vogue, but as that fad passedaway, and only thin wire frames remained,there was no longer space for the hearingaids and the era of the eyeglass aid passedaway with little fanfare.

An interesting innovation in hearingaid configuration was suggested by EarlHarford (Figure 6–4) and Joseph Barry in1965. Persons with severe or profound uni-lateral loss were not considered suitable forhearing aid fitting because of the normal ornear normal hearing on the better ear. Butthese individuals frequently complained ofdifficulty when the talker was on the side of the poorer hearing ear and difficulty intelling the direction from which a sound wascoming. Harford and Barry reasoned thatsuch a person might be helped by a fitting inwhich the aid and its microphone weremounted on the poorer hearing ear but thesignal was actually routed to the better hear-ing ear. They called this arrangement CROS,standing for “contralateral routing of sig-nal.” Several innovative arrangements of theCROS principle were subsequently devised,

including FM transmission of the signalfrom one side of the head to the other. In1966 Harford further suggested that an indi-vidual with loss in both ears, but substan-tially more loss in one ear than the other,might benefit from a BICROS arrangementin which two aids are fitted but both signalsare routed to the better ear.

The development of real-ear measure-ment of hearing aid performance was pio-neered by Earl Harford. In the early 1970s,the advent of the miniature Knowles micro-phone raised the possibility of actuallyrecording the sound pressure level of a sig-nal within the human ear canal. Up to thistime, hearing aid performance typically hadbeen measured on a 2-cc coupler. But thisapproach failed to take into account the vari-ations in response due to differences in realear canals, transducer placement, and so forth.In 1973, William (Bill) Austin and DavidPreves of Starkey Laboratories broughtsamples of the new microphone to Harford’slab at Northwestern University and the trioran numerous tests, using themselves assubjects, of what we now know as real-ear-measurement techniques. Austin and Prevescontinued to provide even smaller Knowlesmikes as Harford continued his work testinghundreds of patients at the University ofMinnesota. The first paper on the subject waspresented by Harford at an InternationalSymposium on Sensorineural Hearing Lossin Minneapolis in 1979. His first publishedpaper, entitled “The Use of a Probe Micro-phone in the Ear Canal for the Measurementof Hearing Aid Performance,” appeared ayear later in Ear and Hearing. By 1985 clini-cally useful real-ear measurement systemswere widely commercially available. In thealmost 30 years since the original publica-tions, real-ear measurement of hearing aidperformance has become an essential ele-ment in the fitting of aids.

REHABILITATION 43

Figure 6–4. Earl Harford.

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In addition to his seminal studies ofbone conduction calibration and measure-ment, and his fundamental studies of speechrecognition, the research of Donald Dirks(Figure 6–5), in particular, will be remem-bered for his development, with Sam Gilman,of a probe tube used to establish the effects ofstanding waves in the external ear canalover a wide range of frequencies. They wereextremely useful in the subsequent develop-ment of clinical methods for real-ear mea-surement via probe microphones.

Auditory Deprivation andAcclimitization

In 1984 Shlomo Silman (Figure 6–6), StanleyGelfand, and Carole Silverman published aseminal paper on auditory deprivation. Whena person was aided monaurally, the aidedear maintained its speech-understandingcapacity over time, whereas the unaided eargradually declined. The late Stuart Gatehouse,in Scotland, later expanded the concept toinclude acclimatization, the tendency for theaided ear to improve slightly over time com-pared to the unaided ear. This importanttheoretical development has provided strongsupport for the fitting of aids to both earswhenever possible, even when there is asubstantial difference between sensitivitylevels on the two ears. It has also alertedresearchers to take the initial period ofacclimatization into account in hearing aidoutcome research.

Binaural Aids

The fitting of independent bilateral aids, oneto each ear, has had an interesting history.

The idea that both ears ought to be aided inorder to take advantage of the benefits oftwo-eared hearing was commonly assertedfrom the very earliest days of hearing aid fit-ting. But it was not until the advent of tran-sistors that miniaturization made it practicalto mount the aids, and their microphones inor near the two ears. Such fittings were orig-inally called “binaural,” but the late Dennis

44 AUDIOLOGY IN THE USA

Figure 6–5. Donald Dirks. (Courtesy of LaraineMestman.)

Figure 6–6. Shlomo Silman.

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Bryne of the National Acoustic Laboratoryin Sydney, Australia suggested that a more ap-propriate term would be “bilateral” in recog-nition of the fact that bilateral aids do notnecessarily restore normal binaural function.

In spite of accumulating research evi-dence that bilateral hearing was, on average,superior to unilateral hearing in persons withnormal two-eared hearing, for many years,there was considerable resistance in the mar-ketplace to the fitting of an aid to each ear,probably for two principal reasons: (1) theadditional cost of the second aid was a deter-rent for many potential users, and (2) con-ventional speech audiometric test materialsseldom reflected, in hearing-impaired indi-viduals, the two-eared advantage so welldocumented in persons with normal hear-ing. As this situation improved, with thedevelopment of more sensitive tests; how-ever, another problem surfaced. As more andmore bilateral aids were fit, especially to eld-erly persons, it became evident that not allindividuals benefited from bilateral fittingsto the same degree. Indeed, in some individ-uals, the presence of the second aid seemedto actually make matters worse. The problemwas noted as early as 1939 by Vern Knudsenof UCLA, and by Leland Watson and ThomasTolan. Watson and Tolan reported that theirobservations led them to suspect some kindof conflict between the two ears.

The phenomenon of binaural interfer-ence, described by Jerger and by Shlomo Silman in the 1980s and 1990s seemed to beat fault. In 2005 the problem was highlightedin a landmark study by Therese Walden andBrian Walden at the Walter Reed Army Med-ical Center. They showed that some elderlyhearing aid users did, indeed, perform betteron a test of speech understanding in compe-tition when only one ear was aided. Perfor-mance was often poorest when both ears wereaided. We still await data on the prevalence

of this binaural interference phenomenon inthe entire population of hearing-impairedindividuals. It is certainly the case that themajority of hearing aid users of all ages per-form better with a bilateral fitting, but thelesson for audiologists has been that allpotential users, but especially elderly users,must be evaluated under both unilateral andbilateral fitting conditions.

Digital Signal Processing andMicrophone Technology

No engineering advance in the past half cen-tury has had greater impact on the wearablehearing aid than the advent of digital signalprocessing in the late 1980s and early 1990s.Now, for the first time, it was possible toactually manipulate the fine grain of the fre-quency response of an aid in order to matchit to the shape of the audiometric contour.This capability, combined with digital com-pression/expansion and various adaptivealgorithms fueled a resurgence in interest inselective amplification. At the same time,studies by David Pascoe and Margo Skinner,at Washington University in St. Louis, byLarry Humes (Figure 6–7) at Indiana Univer-sity, and by many other investigators, haveemphasized the critical impact of the exactdegree and configuration of high-frequencysensitivity loss on speech understanding.These two forces have lent such strong sup-port to the philosophy of selective amplifica-tion that it has become the virtual rule inhearing aid fitting. Additionally, the labori-ous testing characterizing Carhart’s originalconcept of hearing aid evaluation havegiven way to emphasis on fine tuning asmaller number of aids, with heavy relianceon the real-ear measurement of their physi-cal characteristics.

REHABILITATION 45

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Confluent with advances in digital sig-nal processing, microphone technology hasadvanced to a point permitting the develop-ment of a truly directional microphone inwhich directivity patterns favoring inputfrom a particular direction have been imple-mented. Although there have been voices ofdissent, the available evidence seems tofavor the use of directional microphones inmost listening situations involving compet-ing speech or noise.

In the months and years to come, it iscertain that continuing advances in hearingaid technology will broaden our rehabilitativecapabilities. Indeed, we are already seeingaids that learn a client’s preferred volumesetting, and switch among programs forquiet listening, music, listening to speechalone, and listening to speech in a noisybackground. And there are aids that willautomatically switch to the directionalmode when background noise is detected,aids that can be recharged, and even aidsthat can be individually programmed to suita particular lifestyle.

Accountability

As hearing aids and other amplificationdevices have become more sophisticated,there has been a growing sense that the fieldstands in need of better outcome measuresto assess how well a particular interventionactually helps the hearing-impaired person.For many years, the only outcome measureavailable was the ubiquitous aided PB score.But Harvey Fletcher’s prediction in 1949,that existing word recognition tests were notreally capable of differentiating among aids,became ever more evident.

The efficacy of word discriminationtesting, as it was then called, was challengedas early as 1960 by Irvin Shore, Robert Bilger,and Ira Hirsh at Central Institute for theDeaf. For the next two decades, there wasgrowing unease about whether PB scoreswere acceptable as measures of account-ability. Finally, in 1983, a study by BrianWalden and his colleagues at Walter Reedreinforced the growing feeling that worddiscrimination scores were just not up to the task.

Further development took three direc-tions. First, there was a concerted effort to design more sophisticated measures ofspeech understanding such as the speechperception–in-noise (SPIN) test by Kalikow,Stevens, and Elliott in 1977 and its revisedversion by Bilger, Nuetzel, Rabinowitz, andRzeczkowski in 1984, the hearing-in-noisetest (HINT) by Nilson, Soli, and Sullivan in1994, the BKB-speech-in-noise (BKB-SIN)test by Killion et al. in 1997, and its abbrevi-ated version, the QUICKSin test in 2004.New tests will eventually replace the old PBlists, but progress is painfully slow.

A second major development has beenthe construction of assessment questionnairessuch as the Hearing Handicap Inventory forthe Elderly (HHIE) by Ira Ventry and Barbara

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Figure 6–7. Larry Humes. (Courtesy of Indi-ana University Photo Services.)

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Weinstein in 1982, the Abbreviated Profile ofHearing Aid Benefit (APHAB) by Robyn Coxand Genevieve Alexander in 1995, the Client-Oriented Scale of Improvement (COSI) byHarvey Dillon in 1997, the Satisfaction withAmplification in Daily Life (SADL) scale byCox and Alexander in 1999, and the Interna-tional Outcome Inventory for Hearing Aids(IOI-HA) by Cox and Alexander in 2002.Researcher Robyn Cox (Figure 6–8), at theMemphis Speech and Hearing Center at the University of Memphis, has been one of the foremost supporters of accountabilitythrough evidence-based practice in audiology.Craig Newman (Figure 6–9), of the ClevelandClinic, has been particularly active in the con-struction and evaluation of questionnaires ina number of areas including hearing handi-cap in the elderly, tinnitus evaluation, andquantifying hearing aid benefit.

A third development has been theapplication of cost-benefit analysis to auralintervention by Harvey Abrams and his colleagues at the VA Medical Center in BayPines, Florida.

Finally, there is the intriguing develop-ment of the concept of acceptable noise levelas a predictor of a successful fitting by AnnaNabelek (Figure 6–10) and her colleagues

and students at the University of Tennessee-Knoxville.

Many audiologists have made signifi-cant contributions to research on hearing aidsover the years. Space limitations preclude anexhaustive list, but a sampling of entrants to

REHABILITATION 47

Figure 6–8. Robyn Cox. (University of Mem-phis, courtesy of L. Lissau.)

Figure 6–9. Craig Newman. (Courtesy of theCenter for Medical Art and Photography, Cleve-land Clinic.)

Figure 6–10. Anna Nabelek.

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the hearing aid hall of fame would surelyinclude Ruth Bentler, Donald Dirks, DavidHawkins, Mead Killion, Sam Lybarger,David Pascoe, David Preves, Todd Ricketts,Margot Skinner, Wayne Staab, Pat Stelma-chowicz, Gerald Studebaker, Tom Tillman,Michael Valente, and Laura Wilber.

The Saga of Barry Elpern

No history of audiologists and hearing aidswould be complete without an account ofthe adventures and misadventures of BarryElpern (Figure 6–11). Barry was an audiolo-gist at the University of Chicago in the1960s. One cold mid-winter evening in 1967,he was driving home from work on Chicago’ssouth side in the midst of a record-settingmidwestern blizzard. Snow and freezingwind swirled around his car as he made hisway, slowly and stressfully, along the free-way. But it soon became impassable. Afterspending the night in his car, he had to walk

the rest of the way home in cold, waist-deepsnow. He describes a moment of epiphany,during this walk, in which he asked himself,“Is this any way for a reasonable person to live?” As soon as he reached home heinstructed his family to pack up as they weremoving to Arizona.

In Phoenix, Barry joined a group ofengineers who had formed a company toimprove hearing aid performance. As part of the operation, they established a dispen-sary to test-market new products and toassist in corporate cash flow. Because of hisaudiologic background, Barry was chosen tooperate the dispensary. But the AmericanSpeech and Hearing Association (ASHA) hadlong decreed that dispensing hearing aids,by a member, was unethical, and it roundlydrummed Barry out of the organization(which in those days was tantamount toejecting you from the profession). But Barrypersisted, and soon other individuals hold-ing a long pent-up concern that ASHA’s eth-ical code was not helpful to the professionbegan to exert pressure on ASHA to changeits ethical stance. It took some time, but in1979 the ASHA Code of Ethics was finallymodified to permit the dispensing of aids.

Nowadays the dispensing of hearingaids and other amplification devices is sucha cornerstone of the profession that we haveto be reminded of what it was like before theASHA code was changed. After you hadspent hours in audiometric testing and theevaluation of several aids, you could onlysend the client off to a hearing aid dealerwhose code of ethics was less burdensome.It was very unlikely that you would ever seethat client again. You never really knewwhether they had even acquired an aid or whether they were successful users. Therewas very little feedback and no accountabil-ity. Only in the VA and the military clinics,where the audiologist was permitted to bethe dispenser, did the audiologist have any

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Figure 6–11. Barry Elpern.

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sense of closure, any feel for the ultimateconsequences of his or her work. It is fair tosay that, today, audiology is a very differentprofession as a result of Barry’s defectionleading to that pivotal decision by ASHA in1979. It provided a key part of the frame-work for the rise of private practice, a devel-opment so essential to the viability of anindependent profession.

Assistive Devices

Audiologists have long been familiar withFM systems employing remote microphones,and tend to equate these with all assistive lis-tening devices (ALDs). But Cynthia ComptonConley (Figure 6–12), of Gallaudet Univer-sity, reminds us that there are a wide varietyof devices designed to improve the commu-nication skills, the well-being, and the qual-ity of life of hearing- impaired and deafenedpersons, and that not all such devices involve“listening.” Thus, although the term ALD isstill being used, a more appropriate umbrella

term, hearing assistance technology (HAT),refers to both auditory and nonauditoryassistive technology. Historically, the firstwere alerting devices, designed to assist theindividual to be aware of and identify envi-ronmental sounds and relevant or dangeroussituations. These include systems that flasha light or vibrate a transducer when the door-bell rings, when the baby cries, and so forth.

A second category of assistive devicesincludes systems to assist in telephone com-munication, for example, devices to amplifythe telephone signal.

Third are devices to assist in the enjoy-ment of broadcast and other media. In thesesystems, the audio signal from the broadcastsource is amplified and delivered to thehearing-impaired person either via a hard-wired amplification system, such as couplinga portable music player to one’s hearing aidsor implant via direct audio input or induction,or via wireless transmission. The wireless,devices may be of three types: (1) Infrared(IR), (2) FM carrier, or (3) induction (audioloop). Each of these systems consists of atransmitter and a wireless receiver. Althoughthe transmitter can be connected to the soundsource via a microphone, usually the trans-mitter is simply plugged into the soundsource directly.

The history of remote-microphone tech-nology can be traced back to the availabilityof the very first commercially available vac-uum tubes in the 1920s. In 1949 Leland Watsonand Thomas Tolan, in their comprehensivevolume, Hearing Tests and Hearing Instruments,noted that, in the early 1930s multiple vac-uum tube hearing aids were widely installedin schools for the deaf, leagues for the hardof hearing, churches, and theaters. Foreshad-owing the later development of the wirelessremote microphone, a microphone was placedin close proximity to the source of sound(loudspeaker or live speaker) and hard wiredto the multiple aids. To their amazement

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Figure 6–12. Cynthia Compton Conley. (Cour-tesy of Gallaudet University.)

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77

11The Medical Connection

Throughout its history, audiology hasbeen strongly influenced by related medicalspecialties, particularly otolaryngology. Earlypioneers included Los Angeles otologistIsaac Jones who collaborated with legendaryacoustician Vernon Knudsen, head of thephysics department at UCLA in the 1920s, todevelop the first audiometer with bone con-duction testing capability; otolaryngologistL. W. Dean, who mentored the young C. C.Bunch; otolaryngologist Walter Hughson,who collaborated with speech pathologistHarold Westlake in the development of thewell-known “Hughson-Westlake” protocolfor obtained a pure-tone audiometric thresh-old; and, of course, physiologist HallowellDavis, whose many contributions havealready been discussed.

Many long-standing and fruitful collab-orations between audiologists and otolaryn-gologists arose from a common interest inpatients with medically treatable hearing dis-orders. The development of the fenestrationoperation, by Julius Lempert in 1938, and sub-sequent techniques of stapes mobilizationpioneered by Sam Rosen in the early 1950s,created an unusual opportunity for a mutualcollaboration between otologic surgeons andaudiologists in documenting and quantify-ing the improvement in hearing provided bysurgical intervention. One example was thecollaboration between Raymond Carhart,

head of the audiology program in North-western University’s School of Speech, andGeorge Shambaugh, chairman of the depart-ment of otolaryngology in Northwestern’sSchool of Medicine. Shambaugh was one ofthe pioneers of the fenestration operation, in which a surgeon creates an opening in asemicircular canal to bypass the middle earmechanism immobilized by otosclerosis.Throughout the decade of the 1950s, Carhartand Shambaugh jointly staffed a weeklyotology/audiology clinic in which Carhartand his audiology students carried out audi-ologic assessments and Shambaugh and hisresidents carried out the medical evaluationsof a small number of patients from Sham-baugh’s practice. Then the patients werejointly counseled by Carhart and Shambaugh.It was an excellent example of how the twodisciplines could collaborate in an atmosphereof mutual respect, for the benefit of hearing-impaired persons: and, it was a teachingexperience of unparalleled value to all whoparticipated. It was this collaboration thatresulted in the now famous “Carhart notch,”the characteristic depression in the boneconduction threshold at 2000 Hz in personswith otosclerosis.

Another example of early collaborationbetween audiologists and otolaryngologistsoccurred at the Louisiana State University(LSU) Medical School in New Orleans. Here

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audiologist Charles Berlin and otolaryngol-ogist Merv Trail collaborated on a researchand clinical program of unusual productiv-ity for over 20 years.

At the University of California at LosAngeles (UCLA), audiologist Donald Dirkscollaborated, first with otolaryngologist Vic-tor Goodhill and later with Goodhill’s suc-cessor, Paul Ward, in the development of anaudiologic research program of internationalrenown.

The success of these early collaborationsconvinced many audiologists and otolaryn-gologists that they could take maximum ad-vantage of each other’s expertise by workingtogether in the same medical department.Such collaborations continue to flourishtoday in many academic medical settings.

Unfortunately, the course of these inter-actions has not always been smooth: frictionshave sometimes arisen. In his classic book,Clinical Audiometry, published in 1943, C. C.Bunch noted that an otologist had publiclystated that he had no confidence in audio-metric tests because he had been sent threeentirely different audiograms of the samepatient by three different testers. Bunch sug-gested that a report of this sort would havebeen impossible if the tests had been carriedout under proper conditions by trainedexaminers, using standardized audiometersand careful testing technique.

A particular point of contention intoday’s world has been the reaction of someotolaryngologists to audiology’s attempts to upgrade the qualifications of its practi-tioners. Because a significant percentage ofaudiologists are employed in medical set-tings, and usually in departments headed byotolaryngologists, there is a persistent con-cern among our medical colleagues whoview audiologists as valued but nonetheless

technicians, and fear that upgrading to the Au.D. degree will both increase the costof employing audiologists and result inoverqualified personnel. Periodically, theyhave threatened to train their own audio-metric technicians to fill the roles presentlyplayed by audiologists with master’s andAu.D. degrees. Indeed, they have recentlydeveloped a program known as CPOP (Cer-tificate Program for Otolaryngology Person-nel) with an initial concentration on thetraining of audiometric technicians. Theextent to which such activities among themedical ranks will impact audiology dimin-ishes as our field moves more and more inthe direction of private practice.

In general, collaboration between audi-ologists and otolaryngologists historically hasbeen most successful when the audiologistheld the Ph.D. degree, and least successfulwhen the audiologist held only a master’sdegree. In the former case, mutual respectwas more easily achieved than in the lattercase. One of the theoretical benefits of up-grading from the master’s degree to theAu.D. degree was the idea that this wouldhelp to foster an atmosphere of coequality inmedical settings. Whether this hope will fallvictim to the financial concerns noted aboveonly time will reveal.

In summary, the strong relationshipsand good will built between audiology andotolaryngology in the early years remain inforce in many medical settings, certainly tothe advantage of both disciplines. But as ourprofession matures and moves in new direc-tions there have been, and will undoubtedlycontinue to be, strains and frictions betweenthe two arenas. Hopefully, the issues under-lying any conflicts will be resolved amicablyso that each discipline can continue to bene-fit from mutual interaction.

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