Braz. j. . vol.81 número2

(1)

www.bjorl.org

Brazilian

Journal

of

OTORHINOLARYNGOLOGY

ORIGINAL

ARTICLE

Middle

ear

impedance

studies

in

elderly

patients

implications

on

age-related

hearing

loss

夽

Olusola

Ayodele

Sogebi

DepartmentofEarNoseandThroat,OlabisiOnabanjoUniversityTeachingHospital,Sagamu,Nigeria

Received1November2013;accepted12April2014 Availableonline8October2014

KEYWORDS

Acousticimpedance tests;

Pure-tone audiometry; Aged; Presbycusis; Acousticreflex

Abstract

Introduction:Controversiesarisewithrespecttofunctioningofthemiddleearovertime.

Objective: Toassesschangesinmiddleearimpedancethatmayberelatedtoaging,and/orif therewasanassociationofthesechangeswiththoseoftheinnerearintheelderlypatients.

Methods:Cross-sectional, comparative study of elderly patients managed in ear, nose and throatclinics.Astructuredquestionnairewasadministeredtoobtainclinicalinformation.Pure toneaudiometry,tympanometry,andacousticreflexeswereperformed.Comparative analy-seswereperformedtodetectintergroupdifferencesbetweenclinico-audiometricfindingsand middleearmeasures,viz.tympanogramsandacousticreflexes.

Results:Onehundredandthreeelderlypatientsparticipatedinthestudy;52.4%weremale, averagely70.0±6.3yearsold,age-relatedhearinglossin59.2%,abnormaltympanogramsin 39.3%,absentacousticreflexin37.9%.Therewasnoassociationbetweenageandgenderin patientswithabnormaltympanogramsandabsentacousticreflex.Significantlymorepatients withdifferentformsandgradesofage-relatedhearinglosshadabnormaltympanometryand absentacousticreflex.

Conclusion: Some abnormalities were observed in the impedance audiometric measures of elderlypatients,whichweresignificantlyassociatedwithparametersconnectedtoage-related hearingloss.

夽

Pleasecitethisarticleas:SogebiOA.Middleearimpedancestudiesinelderlypatients:implicationsonage-relatedhearingloss.BrazJ Otorhinolaryngol.2015;81:133---40.

E-mail:ayosogebi2000@yahoo.com http://dx.doi.org/10.1016/j.bjorl.2014.09.007

(2)

PALAVRAS-CHAVE

Impedânciaelétrica; Audiometriadetons puros;

Idoso; Presbiacusia; Reflexosacústicos

Estudosdeimpedânciadaorelhamédiaempacientesidosos;implicac¸õesnaperda auditivarelacionadaàidade

Resumo

Introduc¸ão:Existem controvérsiasnoqueserefereàsalterac¸õesfuncionaisdaorelhamédia comopassardosanos.

Objetivo:Avaliarasmudançasnaimpedânciadaorelhamédiaquepodemestarrelacionadas aoenvelhecimento,bemcomoqualquerassociaçãodessasalteraçõescomasqueocorremna orelhainterna.

Método: Estudoprospectivocomparativodepacientesidososatendidosemambulatórios espe-cializadosemotorrinolaringologiaeaplicaçãodequestionárioestruturadopara obtençãode informaçõesclínicas.Foramrealizadas audiometriadetonspuros,timpanometriaereflexos acústicos e análise comparativa para detectar as diferenças intergrupos entre os achados clínico-audiométricos.

Resultados: Participaramdoestudo103pacientesidosos:52,4%dogêneromasculino;idadede 70±63anos;perdaauditivarelacionadaàidadedetectadaem59,2%;timpanogramaanormal em 39,3%;ereflexoacústicoausenteem37,9%. Nãofoi encontradaassociac¸ão entreidade egêneroem pacientescomtimpanogramaanormal ereflexoacústicoausente. Umnúmero significantementemaiordepacientescomdiferentesgrauseconfigurac¸õesdeperdaauditiva relacionadaàidadeapresentoutimpanometriaanormalereflexoacústicoausente.

Conclusão:Algumasanormalidadesforamobservadasemmedidasdeimpedânciaaudiométrica empacientesidosos,queforamsignificantementeassociadoscomosparâmetrosligadosàperda auditivarelacionadaàidade.

Introduction

Hearing involves a complex interplay and integration of severalmechanisms,including conduction ofsound waves fromtheenvironmentthroughtheexternalauditorycanal, vibrations of the tympanic membrane, stimulation of the transformermechanism in the middle ear, aswell asthe sensoryhaircellsofthecochleathecentralneuronal con-nectionswithtermination at theprimaryauditory cortex. Thefunctionsofsomeofthesemechanismsareaffectedby agingandtendtomanifestashearingimpairment,whichis particularlycommonintheelderly.

Adeficit inhearingacuityis themost commonsensory disorderthathasbeenassociatedwithaging.1_In_fact,

stud-ieshaveshownthatapproximatelyone-thirdofadultsaged

between 61 and 70 years, and over 80% of those older

than85yearshaveclinicallyobviousdifficultyunderstanding

speechandfollowingconversationsinthepresenceof

back-groundnoise.2,3_On_the_average,_hearing_threshold_increases

byapproximately1dBperyearfor subjectsaged60 years

andabove,with atendency tofurtherdeterioration with

increasingage.4 _At _audiometry,_up _to_35% _of _elderly

sub-jectsabove 60 years had pure tone average threshold of

25dB HL or more at frequencies between 0.5 and 4kHz,

whichincreased furtherto50% inthe age groupbetween

70and80years.5_While_the_reported_prevalence_of_hearing

lossamongelderlysubjectsvaryindifferentlocations,itis

anestablishedfactthatitincreaseswithage.6

Traditionally,hearinglossisclassifiedasconductive,

sen-sory,neural,ormixed-type.Age-relatedchangesintheinner

earanditscentralconnectionshavebeenwelldocumented

amongelderlysubjects.Theseincludelossof sensoryhair

cells of the cochlea consequent upon generalized

degen-erative processes,dysfunction of the striavascularis (the

main blood supply to the organ of Corti), and

degenera-tion of the neurons of the cochlear nerve or its central

connections.7 _In _the _external _ear, _wax _impaction _in _the

externalauditorymeatushasbeenreportedtobe

dispropor-tionatelymorecommonintheelderlypatientsthaninother

groupsofpatients,causingconductivehearingloss.8_This_is

aconsequence of thegeneralizeddegenerationof

epithe-lia,includingthoseofthemicrocilia,affectingtheexternal

auditory canal without an accompanying reduction in the

rateofwaxproduction.Othercausesofconductivehearing

lossareoftenrelatedtothefunctioningofthemiddleear.

Comparedwithothercategoriesofpatients,little

atten-tionhasbeenpaidtotheconductivemiddleearcomponents

inelderlypatients.Controversiesariseconcerningthe

func-tioning of the middle ear as age advances. While some

studies concludedthat theconducting mechanismsof the

middleearremainnormalandfunctional,orthattheymay

play noseriousrole in thehearing impairmentassociated

withaging,9,10_others_observed_some_changes_in_the_dynamic

characteristics of the middle ear that may be related to

aging.11,12_This_might_have_resulted_from_different_types_of

instrumentsusedforassessingthemiddleearfunctions.As

partofthestudyontheepidemiologyofhearingimpairment

amongelderly patients, the authorperformed both

pure-toneandimpedanceaudiometries(tympanometry)toassess

thefunctionsoftheinnerandmiddleear,respectively.13_The

observationofcertainabnormaltympanometrictracingsin

(3)

supposedlypurelysensorineuralhearingloss(SNHL)

stimu-latedthisresearch.

Thisstudyaimedtoassesswhethertherewerechanges

inthemiddleearimpedancethatmayberelatedtoaging,

and/orwhethertherewereanyassociationofthesechanges

withthoseoftheinnerearintheelderlysubjects.Thisis

justifiablebecausehearinglossimpactsthequalityoflifeof

elderlysubjects.

Methods

Studydesign

Thiswasaprospective(cross-sectional),comparativestudy

ofelderlypatientsfollowed-upatspecializedear,nose,and

throat(ENT)clinicsforathree-yearperiod.

Setting/studylocation

This study was conducted at the ENT clinics of a

ter-tiaryreferralhospitalandofaprivate/missionaryhospital.

EthicsapprovalforthisstudywasobtainedfromtheHealth

Research and Ethics Committee, under approval number

OOUTH/DA.326/T/197.

Samplingcriteria/technique

The inclusioncriteriawereelderly patientsaged60 years

and above, who had no clinical middle ear disease,

attendedoneoftheENTclinics.Patientswereconsecutively

recruited.Thegeneralnature,significance,requirementsof

thepatients,includingthefactthatdecliningtoparticipate

in the study would not affect treatment, were explained

tothe patients.Consenting patientswere included in the

study.The categories of the patients that were excluded

were:thosewhodidnot consent,historyof recurrentear

discharges, and those with tympanic membrane

perfora-tions. Patients with wax impaction were treated before

the continuation of the study protocols. Patientswithout

complete investigations(bothforms ofaudiometry---pure

toneaudiometry[PTA]andtympanometry),with

asymmet-ricaudiograms,orevidenceofconductiveormixedhearing

lossintheirPTAsweresubsequentlyexcluded.

Studyperiod

Januaryof2010---Juneof2013.

Datasourcesandcollectionprocedure/technique

Dataweregeneratedusinginterviewer-administered

ques-tionnaires,dividedintothreesections.SectionAcomprised

socio-demographicinformation.Section Bconsistedof the

medical condition including questions on history of

per-ceived hearing loss, durationof hearing impairment, and

presentorpreviousearsurgeries,amongothers.

Section C wasdocumentation of the findings on

phys-ical examination, especially the status of the tympanic

membranes,andrecordsoftheaudiometricprofilesofthe

patients,whichincludedthePTA,tympanometry,and

acous-ticreflexes.

AtPTA,airconductionandbone-conductionevaluations

were performed in a commercial sound booth, using an

Amplivoxdiagnosticaudiometermodel 240,withstandard

earphonesenclosedinsupra-auralearcushions,anda

stan-dardbone-conductionoscillatorandheadbandtoevaluate

air-bonegaps.Tympanometrywasconductedbybroadband

middle earpower reflectance and measured using a

cali-brated,commerciallyavailablecomputer-controlledsystem

(InteracousticsmodelMT10.SN156607)thatincorporateda

high-qualityprobeassemblytotransducestimuliandrecord

acousticresponsesfromtheearcanal.Theacousticreflex

thresholdsweretestedwithcontralateralstapedialreflexes

forfrequenciesof500,1000,2000,and4000Hz;the

thresh-oldswereconsideredasnormalwhenelicitedbetween75

and110dBHL.

Main outcome measure: patients were paired into

dif-ferent categories based on the PTA findings as Normal

orAge-related hearingimpairment-presbycusis).The

tym-panogramswereclassifiedaccordingtoJergertypesA,As,

Ad,B,andC;14 _with_type_A_considered_as_normal,_and_any

other tympanographic types as abnormal, while acoustic

reflexeswereclassifiedasPresentorAbsent.

Dataanalysis

Descriptive analysis of the data was done and presented

in tabular and graphical forms. Comparative analyses

wereperformedtodetectinter-groupdifferencesbetween

the clinico-audiometric findings and different middle ear

measures, viz. tympanograms and acoustic reflexes, by

cross-tabulationwithcontingencytables.Categorical

varia-bles were presented as percentages and proportions and

analyzedusingChi-squaretest,whilecontinuousvariables,

presented asabsolute valuesand means, were compared

usingStudent’s t-test. The level of statistical significance

wassetatp<0.05.DataanalysiswasperformedusingSPSS

version19.0(Chicago,IL,UnitedStates).

Results

Onehundredandthree(103)elderlypatientsparticipated

in the study,which comprised 52.4% males, (M:F=1.1:1).

Theagesof thepatientsranged between61 and96years

withamean±SDof70.0±6.3years.Thesocio-demographic

characteristicsof thepatients areshown inTable 1.Over

half(59.2%) of thepatients hadaudiometric evidences of

ARHL,andtheSchuknechttypologyisrepresentedinFig.1.

Theimpedanceaudiometryfindingsbasedon

tympanomet-rictracingsaccordingtoJerger’sclassificationrevealedthat

onaverage,60.7% of theparticipants hadnormal (typeA

tympanograms),withahighconcordancebetweenthetwo

ears.The acousticreflexes werepresent inan average of

62.1%ofthepatients.Thedetailsoftheimpedance

(4)

Table1 Socio-demographiccharacteristicsofthepatients.

Variable n%

Agegroup(years)

61---65 27(26.2)

66---70 35(34.0)

71---75 25(24.3)

76---80 10(9.7)

≥81 6(5.8)

Mean±SD 70.0±6.3

Gender

Male 54(52.4)

Female 49(47.6)

Maritalstatus

Married 83(80.6)

Others(divorced/widowed) 20(19.4)

Educationlevel

Noformaleducation 3(2.9)

Primaryschool 21(20.4)

Secondaryschool 55(53.4)

Tertiary 24(23.3)

Occupationgroup

Unskilled 17(16.5)

Semi-skilled 44(42.7)

Professional 42(40.7)

Age,gender,andPTAfindingsofthepatientswere com-parativelyanalyzedagainst thetympanometric findingsin

Table 3. Based on the age distribution of the patients,

theyweresubdividedintotwogroups,≤70and>70years.

There were no statistically significant differences in the

tympanogramsregardingage(t=1.498,p=0.137)and

gen-der (2=1.837, p=0.175) of the patients. There was a

differencewhenthehearingstatus(PTAfindings)was

com-pared;significantlymorepatientswithage-relatedhearing

loss (ARHL) had abnormal tympanometric findings. These

werealsoobviouswhenconsidering thedifferentpatterns

ofaudiometricfindingsthatwereobservedinpatientswith

ARHL. Furtheranalysis of the PTA of patients withARHL,

consideringthedegreesofhearinglossescalculatedaspure

toneaverages(PTAv)indBHLatthelow(0.25,0.50,1.0kHz)

Normal, 40.8%

Normal

Type A, 13.6% Type B, 10.7%

Type C, 21.4% Type D, 13.6%

Type A Type B Type C Type D

Figure 1 Distribution of PTA findings of the patients. Schuknecht’stypologyonlyforpatientswithARHL.

and thehigh (2.0, 4.0,and 8.0kHz) frequencies was

per-formed.

Exploring the PTAv in the better ear at the low

(0.25---1.0kHz) frequencies revealed a mean of 28.7dB

HL (SD=18.0). Low frequency accentuationof the

audio-gram was taken as at least 40dB HL for the PTAv (WHO

classificationformoderatehearingloss)atthelow

frequen-cies.Atthehigh(2.0---8.0kHz)frequencies,computationof

thePTAvinthebetterear,resultedinameanof45.4dBHL

(SD=23.0).EstimateofthedifferencesinthePTAvbetween

thehightonesandlowtonesinthebetterearsrevealeda

meanof24.1dBHL(SD=10.1),thusa valueof≥25dBHL

differencewasusedasthecriterionforahightone

prepon-deranceoftheaudiogram.

ThePTAvatthelowandhighfrequencies inthebetter

ear andother parameters,namely low tone accentuation

Table2 Impedanceaudiometricfindingsinthepatients.

Variable Rightear(%) Leftear(%) Average(%)

Tympanometry(Jerger’stype)

A 60(58.3) 65(63.1) 62.5(60.1)

B 6(5.8) 7(6.8) 6.5(6.3)

C 14(13.6) 9(8.7) 11.5(11.2)

AS 22(21.4) 21(20.4) 21.5(20.9)

Ad 1(1.0) 1(1.0) 1(1.0)

Acousticreflexes

Present 65(63.1) 63(61.2) 64(62.1)

(5)

Table3 Relationshipbetweenclinico-audiometricandtympanographicfindings.

Clinico-audiometricparameter Tympanographicfindings

Normal Abnormal Statistic p-value

Age(mean) 69.2 71.1 1.498a _0.137

Sex

Male 46.6% 60.0% 1.837 0.175

Female 53.4% 40.0% 1.837 0.175

ARHL(allcases) 46.6% 75.6% 8.827 0.003

Schuknecht’stypeinARHL

TypeA 19.0% 6.7% 14.252 0.001

TypeB 3.4% 20.0% 13.542 0.001

TypeC 15.5% 28.9% 8.012 0.018

TypeD 8.6% 20.0% 6.641 0.036

PTAvinbestear

Lowfrequency(0.25---1.0kHz) 21.6 37.7 5.001a _<0.001

Highfrequency(2.0---8.0kHz) 38.2 54.6 3.833a _<0.001

Lowtoneaccentuation 11.1% 64.7% 17.872 <0.001

Hightonepreponderance 53.9% 29.4% 5.482 0.019

a _Statistic,_Student’s_t-test.

andhightonepreponderance,werecomparedwiththe

tym-panometricfindingsinpatients withARHL. Allparameters

presented statistically significantlydifferences for

tympa-nometricabnormalities,asshowninTable3.

A similarcomparativeanalysiswasperformed withthe

acousticreflexesastheoutcome variable.Similarto

tym-panometric findings, there were no associations between

ageofpatientsthathadabsentacousticreflexes(t=0.970,

p=0.334),andgender(2=0.363,p=0.549)inTable4.

Sta-tisticallysignificantdifferenceswereobservedforpatients

with ARHL, those with type B Schuknecht audiometric

pattern,thePTAvs,andalsoinpatientswithlowtone

accen-tuationoftheirPTAs.

Discussion

This study has demonstrated that elderly patients had

some functional anomalies in the middle ear impedances

andacousticreflexes.Impedanceaudiometricabnormalities

Table4 Relationshipbetweenclinico-audiometricfindingsandacousticreflexes.

Clinico-audiometricparameter Acousticreflex

Normal Abnormal Statistic p-value

Ageinyears(Mean) 69.5 70.8 0.970a _0.334

Sex

Male 54.8% 48.8% 0.363 0.549

Female 45.2% 51.2% 0.363 0.549

ARHL(allcases) 50.0% 73.2% 5.487 0.019

Schuknecht’stype

A 12.9% 14.6% 4.961 0.085

B 4.8% 19.5% 10.106 0.006

C 17.7% 26.8% 2.937 0.230

D 14.5% 12.2% 0.154 0.925

PTAvinbestear

Lowfrequency(0.25---1.0kHz) 24.1 35.9 3.326a _0.001

Highfrequency(2.0---8.0kHz) 39.3 54.5 3.448a _0.001

Lowtoneaccentuation 19.4% 63.3% 12.191 <0.001

Hightonepreponderance 48.4% 36.7% 0.856 0.355

(6)

were significantly higher in elderly patients with various

formsanddegreesofARHL,beingmorepronouncedinneural

andstrialtypes,andinlowfrequencyaccentuationofARHL.

Acousticstapedial reflexesappeared tobelessinfluenced

byARHLthantympanometry,anditmaybeamorereliable

indicatorofabnormalmiddleearfunction.

Researchersassessinghearinganditsimpairmentamong

elderly patients have focused disproportionatelyon ARHL

relatingtothesensorineuralaspectofhearing,with

appar-ent neglect of the conductive component. However, the

present study revealed that an average of 39.3% of the

elderly patients had abnormality in their tympanometric

tracings,andaverageof37.9%hadabsentacousticreflexes.

Itcannotbeconclusivelyascertainedwhetherthesemiddle

earabnormalitieswereduetoagingprocess,ormere

coinci-dentalfindings.Nondahletal.15_reported_a_small_degree_of

middle-earstiffeningoccurringovertheyearsamongolder

adults.Ananimalexperimentalsofoundstructuralchanges

inthemiddleearofmousethatwereattributabletoaging.16

Therewasnosignificantdifferencebetweentheagesof

elderlypatientswithnormalorabnormaltympanogramsand

betweenthosewithandwithoutacousticreflexes.Gaihede

and Koefoed-Nielsen17 _compared _compliance _and _middle

earpressuremeasured by tympanometry betweennormal

elderlysubjects (meanage 77 years)and normalyounger

patients (mean age 29 years);they observed that middle

earcompliancewasnotinfluencedbyvariationinage.

Sim-ilarly,noassociationwasfoundbetweenthegender ofthe

patientsandmiddleearmechanicsanalogoustofindingsof

theBlueMountains HearingStudyinAustralia.18 _These_are

atvariancewithreportsconcerningpresbycusis,whichwere

reportedtobesignificantlyassociatedwithadvancingage

andalsowiththemalegender.19

The prevalence of anomalies observed in the middle

ear mechanisms in this study were comparable to the

reportedprevalenceofARHL.20,21_This_may_suggest_a

simul-taneous or concurrent effect in both the inner and the

middle ear. The abnormal tympanometric findings of the

patients revealed that the Jerger’s typeAs tympanogram

wasthemost commonamongthepatients similartothat

found among centenarians in China,20 _providing _an

evi-dence of increased stiffness (reduced compliance) of the

conducting mechanisms.15 _This _was _followed _by _the _type

Ctympanogramsuggestiveofeustachiantubedysfunction.

Thus, it is hypothesized that common middle ear

func-tionalanomaliesmaybeattributabletoeitherofthesetwo

pathologies.Sometimesabnormalitiesoccurinthetympanic

membrane and in the bony ossicles, resulting in

signifi-cantmiddleearfunctionalimpairment.16_There_is_evidence

that,withadvancing age,thehumantympanicmembrane

exhibits a loss of vascularization, a reduction in collagen

structure, in elasticity,and greater rigidity in the middle

fibrouslayer.22_These_structural_changes_would_be_expected

toalter the compliance response of the middle ear. One

belatedinvestigationofairandboneconductionthresholds

hasobservedmiddle-earlossesofasmuchas12dBinelderly

patients.23

The possibilitythatARHL either initiates or aggravates

abnormalitiesintheimpedancecharacteristicsofthe

mid-dleearshouldalsobeconsidered.Theaudiometricpattern

ofelderlypatientswithARHLobservedinthepresentstudy

showeda preponderance of Schuknecht’s typeC, such as

in other Africanpopulations,24 _and _distinct_from_the

typi-calslopingpure toneaudiogram commonamongwhites.25

The finding that all Schuknecht’s audiometric patterns in

patients with ARHL were associated with tympanometric

abnormalities, suggested a link withthe etiopathogenesis

of these two entities in elderly patients. It is expected

that subjects with abnormal tympanograms should

mani-fest with hearing loss of conductive type. However, the

finding of these tympanometric patterns also in patients

with normaland sensorineural (ARHL) hearing loss should

stimulate further research into middle ear impedance

mechanisms.

UsingSchuknecht’stypologyinpatientswithARHL,two

particulartypes ofaudiograms(BandC)theoreticallyhad

accentuation at the low frequencies. In this study, these

twoaudiometrictypes comprisedoverhalf (33/61;54.1%)

ofthe audiometrictypesin patientswithARHL. Thus,the

association of low tone accentuation of audiograms with

abnormal tympanograms may derive from the

dispropor-tionate distribution of these two audiometric patterns in

the ARHL patients. Eustachian tube compliance has been

observedtochange withaging,26 _but_whether_this_change

is influencedmorebyneural orstrial typesofpresbycusis

remains to beascertained. Contrary toreports of Feeney

and Sanford,9 _the _present _findings _suggest _an _increase _in

middle-ear stiffness with specific types of ARHL. Thus,

these impedance middle earchanges may be particularly

commonintheAfricanpopulation,andneedfurther

clarifi-cation.

Itis noteworthy thatthere werediscordant findings in

someofthemiddleearmeasuresbetweentheears.These

suggestthat,despitetheearsbeingexposedtoalmostthe

sameconditions,theinfluencesandtheresponsesmightnot

beexactlysame.Thepossibilityofconfoundingfactors,such

asosteoarthritis(whichmightaffectossicularjointsofthe

earsunequally,producingtypeAstympanogram),mayalso

be considered. Asymmetrical audiograms have also been

reportedinpatientswithARHL.13,24

Manyexpertsconsider2.0kHzasbeginningofhigh

fre-quency, although the definition varies.4,27,28 _PTAv _at _high

frequencies andhigh tonepreponderanceHLwere

associ-ated withabnormalities in tympanometricfindings in this

study.Wileyetal.29 _reported_that,_for_younger_age_groups

(50---69years),thresholdchangeswerehigherforhigher

fre-quencies,whileinolderagegroups(70---89years),threshold

changes were higher for lower frequencies. Interestingly,

the agedistributionof thepresent patients is in-between

thesetwodivisions.Causesof high-frequencyhearingloss

have a wide variability,21 _and_there _is _a _possibility_of

co-existenceoffewoftheseinsomeofthepresent patients.

Thus,itispossiblethatnotenoughpatientswithpureARHL

werestudied.Conversely,lowfrequencyhearinglossisnot

easytoidentify,sinceittendstobeasymptomatic.Infact,

lowerfrequencysoundsdonothaveasmuchinformationas

soundsinthehigherfrequencies.30_One_of_the_few_clues_to

alow-frequencyhearinglossisthatthepersonhasdifficulty

hearingingroups orina noisyplace.It wasreportedthat

inertiaof themiddle earisnot animportant contribution

totheperception of boneconduction sounds for

frequen-ciesbelow1.5kHz,butappearstocontributeatfrequencies

between1.5and3.5kHz.30_However,_this_statement_may_not

(7)

The pathway involved in the acoustic reflex is

com-plexandcaninvolvetheossicularchain,cochlea,auditory

nerve,brainstem,facialnerve,andothercomponents.The

absence of acoustic reflex has been shown to effectively

detect hearing lossesexceeding 30dB in adult subjects,31

althoughitmaynotbeconclusiveinidentifyingthesource

of the problem.32 _Like _impedance _measures, _parameters

related to ARHL (namely Schnekcht’s type B audiogram,

PTAv, and low-tone accentuation) were significantly

asso-ciatedwithabsenceofthe acousticreflexes in thisstudy.

However, the absence of the acoustic reflexappeared to

be less influenced by parameters relating to ARHL, and

it may possibly be a more reliable parameter in

assess-ing the effect of ARHL on the functioning of the middle

ear.

Thisstudyhadsomelimitations.Firstisthelower

sensi-tivityoftheconventionaltympanometerinassessingmiddle

ear function compared with sweep frequency middle-ear

analyzer.The factthatmagnitudeof theacousticreflexes

wasnotascertainedis alsoa limitation.Furthermore,the

hospital-based nature of the study is prone to bias, as

patients may not represent a normal population of the

elderly. Despite these limitations, the study was able to

demonstrate that the middle ear functioning of elderly

patientsmaynotbefullynormal.

Conclusion

Someabnormalitieswereobservedinimpedance

audiomet-ric measures of elderly patients, which were significantly

associatedwithparameters relatedtoARHL. This arouses

suspicion of some middle ear changes that may be

attributabletoaging.Itisimperativethatelderlypatients

with hearing impairment have both their inner and

mid-dle ear assessed, in order to manage them optimally.

Community-based,longitudinal studies areneeded to

fur-therclarifythesefindings.

Conflicts

of

interest

Theauthordeclaresnoconflictsofinterest.

References

1.VanEykenE,VanCampG,VanLaerL.Thecomplexityof age-relatedhearing impairment: contributing environmental and geneticfactors.AudiolNeurootol.2007;12:345---58.

2.WallingAD,DicksonGM.Hearinglossinolderadults.AmFam Physician.2012;85:1150---6.

3.GlydeH,HicksonL,CameronS,DillonH.Problemshearingin noiseinolderadults:areviewofspatialprocessingdisorder. TrendsAmplif.2011;15:116---26.

4.LeeFS, MatthewsLJ,Dubno JR,MillsJH. Longitudinalstudy ofpure-tonethresholds inolder persons.Ear Hear.2005;26: 1---11.

5.Wiley TL, Cruickshanks KJ, Nondahl DM, Tweed TS. Aging and middle ear resonance. J Am Acad Audiol. 1999;10: 173---9.

6.PacalaJT,YuehB.Hearingdeficitsintheolderpatient:Ididn’t noticeanything.JAMA.2012;307:1185---94.

7.Bielefeld EC,Tanaka C,ChenGD, Henderson D.Age-related hearing loss: is it a preventable condition? Hear Res. 2010;264:98---107.

8.Sogebi OA. Profile of ear diseases among elderly patients in Sagamu, south-western Nigeria. Niger J Med. 2013;22: 143---7.

9.Feeney MP, Sanford CA. Age effects in the human mid-dle ear: wideband acoustical measures. J Acoust Soc Am. 2004;116:3546---58.

10.UchidaY, Nomura H, Itoh A, Nakashima T, Ando F,Niino N, etal.Theeffectsofageonhearingandmiddleearfunction.J Epidemiol.2000;101Suppl.:S26---32.

11.WadaH,KoikeT,KobayashiT.Theeffectofaging onmiddle ear dynamiccharacteristics. NipponJibiinkokaGakkaiKaiho. 1994;97:898---904.

12.Holte L. Aging effects in multifrequency tympanometry. Ear Hear.1996;17:12---8.

13.Sogebi OA, Olusoga-Peters OO. Clinical and audiomet-ric features of presbycusis in Nigerians. Afr Health Sci. 2013;13:886---92.

14.Onusko E. Tympanometry. Am Fam Physician. 2004;70: 1713---20.

15.NondahlDM,CruickshanksKJ,WileyTL,TweedTS,DaltonDS. 16-yearchangeinacousticadmittancemeasuresamongolder adults:datafromapopulation-basedstudy.JSpeechLangHear Res.2013.Epubaheadofprint].

16.DoanDE,ErulkarJS, SaundersJC.Functionalchangesinthe agingmousemiddleear.HearRes.1996;97:174---7.

17.Gaihede M,Koefoed-Nielsen B.Mechanics of themiddle ear system:age-relatedchangesinviscoelasticproperties.Audiol Neurootol.2000;5:53---8.

18.GoldingM,DoyleK,SindhusakeD,MitchellP,NewallP, Hart-leyD.Tympanometricandacousticstapediusreflexmeasures inolderadults:theBlueMountainsHearingStudy. JAmAcad Audiol.2007;18:391---403.

19.MaF,QuCY,WangT,YinJ,ZhangXD,MengJ,etal.Studyon hearingimpairmentamongelderlypopulationinthecommunity ofTaiyuancity,Shanxiprovince.ZhonghuaLiuXingBingXueZa Zhi.2009;30:247---51.

20.MaoZ,ZhaoL,PuL,WangM,ZhangQ,HeDZ.Howwellcan centenarianshear?PLOSONE.2013;8:e65565.

21.Cruz MS, Lima MC, Santos JL, Duarte YA, Lebrão ML, Ramos-CerqueiraAT.Self-reportedhearinglossamongelderly individuals in the city of São Paulo, Brazil: prevalence and associated factors (SABE Study, 2006). Cad Saude Publica. 2012;28:1479---92.

22.RuahCB,SchachernPA,ZeltermanD,PaparellaMM,YoonTH. Age-relatedmorphologicchangesinthehumantympanic mem-brane.Alightandelectronmicroscopicstudy.ArchOtolaryngol HeadNeckSurg.1991;117:627---34.

23.Nixon JC, Glorig A, High WS. Changes in air and bone conduction thresholdsas afunction of age.JLaryngol Otol. 1962;76:288---98.

24.OgunleyeAO,LabaranAS.PresbycusisinNigeriansatthe Univer-sityCollegeHospital,Ibadan.AfrJMedMedSci.2005;34:293---6.

25.ArlingerS.Audiometricprofileinpresbycusis.ActaOtolaryngol Suppl.1990;476:85---9.

26.KanekoA,HosodaY,DoiT,TadaN,IwanoT,YamashitaT.Tubal compliance----changeswithageandintubalmalfunction.Auris NasusLarynx.2001;28:121---4.

27.Frisina ST, Mapes F,Kim SH, Frisina DR,Frisina RD. Charac-terizationofhearinglossinagedtypeIIdiabetics.HearRes. 2006;211:103---13.

(8)

29.WileyTL,ChappellR,CarmichaelL,NondahlDM,Cruickshanks KJ.Changesinhearingthresholdsover10yearsinolderadults. JAmAcadAudiol.2008;19:281---92.

30.StenfeltS.Middleearossiclesmotionathearingthresholdswith airconductionandboneconductionstimulation.JAcoustSoc Am.2006;119(5Pt.1):2848---58.

31.MargolisRH.Detectionofhearingimpairmentwiththeacoustic stapediusreflex.EarHear.1993;14:3---10.