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www.bjorl.org

Brazilian

Journal

of

OTORHINOLARYNGOLOGY

ORIGINAL

ARTICLE

LS

CE-Chirp

®

vs.

Click

in

the

neuroaudiological

diagnosis

by

ABR

Michelle

Cargnelutti

a,∗

,

Pedro

Luis

Cóser

b

,

Eliara

Pinto

Vieira

Biaggio

b,c

aUniversidadeFederaldeSantaMaria(UFSM),DistúrbiosdaComunicac¸ãoHumana,SantaMaria,RS,Brazil bClinicaCoserdeOtorrino,SantaMaria,RS,Brazil

cUniversidadeFederaldeSantaMaria(UFSM),SantaMaria,RS,Brazil

Received24December2015;accepted6April2016 Availableonline31May2016

KEYWORDS

Hearing;

Electrophysiology;

Auditorybrainstem

response

Abstract

Introduction:The chirpstimuluswas developedseekingtocounterbalance thedelayofthe soundwave onitsjourneythroughthecochlea, allowingthehair cellstodepolarizeatthe same time.Theresultis asimultaneous stimulation providingbetterneuralsynchronyand, consequently,therecordingofresponseswithgreateramplitudes.

Objective: TocomparetheabsolutelatencyofwavesI,IIIandV,theinterpeakintervalsI---III, III---VandI---V,amplitudevaluesofwave VanditsassociationwiththeamplitudeofwaveI, andtheinterauraldifferenceV---Vintheauditorybrainstemresponse(ABR)usingClickandLS CE-Chirp®stimulitodeterminewhethertheresponsesevokedbyLSCE-Chirp®couldbeapplied

toneuroaudiologicaldiagnosis.

Methods:Cross-sectionalstudywith30normal-hearingindividuals.Theparametersusedwere: intensityof85dBnHL,alternatingpolarity;17.1stimuli/sand100---3000Hzfilters.

Results:TheabsolutelatenciesofwavesI,IIIandVobservedwithLSCE-Chirp®andclickdidnot

showsignificantdifferences.SignificantlyhigheramplitudesofwaveVwereobservedwiththe LSCE-Chirp®.TheinterauraldifferencebetweenthewaveVlatenciesbetweenstimulishowed

nosignificantdifference.

Conclusion: TheLSCE-Chirp®stimuluswasshowntobeasefficientastheclicktocaptureABR

athighlevelsofstimulation,withtheadvantageofproducinggreater-amplitudeVwaves. © 2016 Publishedby Elsevier Editora Ltda. onbehalf of Associac¸˜ao Brasileira de Otorrino-laringologiaeCirurgiaC´ervico-Facial.ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/4.0/).

Pleasecitethisarticleas:CargneluttiM,CóserPL,BiaggioEP.LSCE-Chirp® vs.ClickintheneuroraudiologicaldiagnosisbyABR.BrazJ Otorhinolaryngol.2017;83:313---7.

Correspondingauthor.

E-mail:michellecargnelutti@gmail.com(M.Cargnelutti).

PeerReviewundertheresponsibilityofAssociac¸ãoBrasileiradeOtorrinolaringologiaeCirurgiaCérvico-Facial.

http://dx.doi.org/10.1016/j.bjorl.2016.04.018

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PALAVRAS-CHAVE

Audic¸ão; Eletrofisiologia;

Potenciaisevocados

auditivos

LSCE-Chirp® vs.CliquenodiagnósticoneuroaudiológicopeloPEATE

Resumo

Introduc¸ão:O chirp foi desenvolvidobuscandocompensar oatraso da ondasonora em seu trajetopela cóclea,possibilitandoqueascélulas ciliadasdespolarizemaomesmotempo.O resultadoéumaestimulac¸ãosimultâneaproporcionandoumamelhorsincronianeurale conse-quentementeoregistroderespostasocorrecommaioresamplitudes.

Objetivo:CompararalatênciaabsolutadasondasI,IIIeV,osintervalosinterpicosI---III,III---Ve I---V,osvaloresdeamplitudedaondaVesuarelac¸ãocomaamplitudedaondaI,eadiferenc¸a interaural V---Vno PotencialEvocadoAuditivode TroncoEncefálico, utilizando osestímulos CliqueeLSCE-Chirp®,afimdedeterminarseasrespostasevocadasporLSCE-Chirp®poderiam

teraplicabilidadenodiagnósticoneuroaudiólogico.

Método: Estudotransversalcom30indivíduosnormo-ouvintes.Osparâmetrosutilizadosforam: intensidadede85dBnNA,polaridadealternada;17,1estímulo/sefiltrosde100---3000Hz.

Resultado:Aslatências absolutasdasondasI,IIIeV observadascomLSCE-Chirp® eclique

nãotiveramdiferenc¸assignificativas.AmplitudessignificativamentemaioresdaondaVforam observadascomoLSCE-Chirp®.A diferenc¸ainteraural entreaslatênciasdaondaV entreos

estímulos,nãomostroudiferenc¸asignificativa.

Conclusão:OestímuloLSCE-Chirp®mostrou-sesertãoeficientequantoocliquenacaptac¸ão

doPotencialEvocadoAuditivodeTroncoEncefálico,emníveiselevadosdeestimulac¸ão,coma vantagemdeproduzirondasVdemaioramplitude.

©2016Publicado porElsevier EditoraLtda.em nome deAssociac¸˜ao Brasileirade Otorrino-laringologia eCirurgiaC´ervico-Facial.Este ´eum artigo OpenAccess sobuma licenc¸aCC BY (http://creativecommons.org/licenses/by/4.0/).

Introduction

Theauditorybrainstemresponse(ABR)examinationrecords

responsesoftheneuralpathway,andisusefulinthe assess-mentof theauditory system integrity.It isclinically used toestimate hearingthresholds of adults and infants1 and

todetect nervous system disorders at the peripheral and

central level.2 It is historically recorded with a transient

clickstimuluswitharapidonsetandshortduration(100␮s).

The compositionof thisstimulus is broadband,with

max-imum peak power in the regions from 1000 to 4000Hz.3

Considering the cochlear tonotopy when the click

stimu-lusis presentedatthe cochlea,eachregionofthebasilar

membraneisstimulated,oneafteranother,fromthebase

to the apex. Thus, the transient stimulus stimulates the

high-frequencyregionearlier thanthose correspondingto

low frequencies. Because the low-frequency components

providedelayedresponsepeakstobeaddedtotheresponse

tohigh-frequencycomponents,muchinformationislostin

theoverallresponsesum.Therefore,theresultsofthe exci-tationofdifferentnervefibersatdifferenttimesdecreases theneuralsynchrony,whichisnecessarytoevokeahearing potential.4

Fromthis perspective, in orderto compensate for the

sound wave delay on its trajectory through the cochlea,

researchers have designed a stimulus which they named

chirp. This stimulus hasa duration upto10.33ms,which ismuchlongerthan theclick.It wasdesignedsothatlow

frequencies are presented before the high ones, so that

differentregions offrequencies reachtheir specific place

at thebasilar membrane simultaneously.Consequently, in

thisway,thecochlearneuralresponseismoresynchronized

andagreateramplitudeofwaveVisdisplayedattheABR

recording.4---6

Severalchirpmodelshavebeenproposedandtested,4,6---9

andoneoftheresearchers’aimsistofindthemostadequate stimulusforwaveVrecodingoftheABRatlowintensities.

Whenstudying7 severalchirpmodels,chirpresearchers

found that short-duration chirps were more effective at

highintensities andlong-durationchirpsweremore effec-tive at low intensities, and that the stimulus intensity is directlyrelatedtothewaveVamplitude.Giventhesefacts, ClausElberlingandhisgroupofresearchersconcludedthat

the CE-Chirp® model, based only onthe durationof time

required for the soundwave totravelthroughthe

differ-entcochlearfrequencyregions,isinadequatetogeneratea

robustABRresponseinadultswithnormalhearing.

There-fore,theyimprovedthestimulusdesignandcreatedamodel called‘‘directapproach’’.10Thisnewmodeltookinto

con-sideration the sound travel time in the cochlea and also

differentlevelsofintensity.UnliketheCE-Chirp®andothers thatprecededit,thisnewchirphasnofixeddurationatall intensities; itwascreatedwithvariabledurationforeach stimulusintensity,thuscomprisingtwentystimuliof differ-entdurationsthatchangeevery5dB.Thisnewstimuluswas calledlevelspecificCE-Chirp® (LSCE-Chirp®)andhasbeen

tested, purporting toovercomethe limitationsof the

CE-Chirp®,11 whichevokedonlyaverysmallwaveVamplitude

anddidnotallowtheidentificationofwavesIandIIIathigh stimulationintensities.

The few literature articles on this stimulus11,12 only

discussed its advantage in detecting wave V with high

amplitudeevenat high intensityand mentionedthat only

(3)

subjects. Therefore, we decided to measure the values of absolute latencies of waves I, III and V, the interpeak intervalsI---III,III---VandI---V,theamplitudevaluesof wave

V and its association with the amplitude of wave I, and

the V---V interaural difference in the auditory brainstem

response (ABR) using Click and LS CE-Chirp® stimuli to

determine whether thisnewstimulus couldbe appliedto

neuroaudiologicaldiagnosisbyABR.

Methods

Thiswasacross-sectionalstudywithadescriptivedesign,

associatedtoawiderprojectapprovedbytheethics

com-mitteeonhumanresearch,accordingtoopinionN.610506,

onApril8,2014,andCAAE14804714.2.0000.5346.Itshould benotedthatitfollowedResolutionN.66/12,whichdeals

with human research. All subjects were informed of the

studyaim,aswellastheproceduresinvolved andall

sub-jectssignedthefreeandinformedconsentform,agreeing

toparticipateinthisstudy.

Inclusion criteria were: individuals with no history of

otologicalor neurologicaldisease andaudiometric thresh-olds≤25dBHLfor the250---8000Hz frequencies.Thestudy included30individuals(18womenand12men)aged12---42 yearswithnormalhearing.

The ABR records with Click and LS CE-Chirp® stimuli

wereperformedusingtheEclipseEP25ABRsystem®

equip-ment, manufacturedby Interacoustics A/S, Denmark.The

parametersusedfortherecordingswere:alternating polar-ity, presentation rate of 17.1stimuli/s; passband filterof 100---3000Hz for the Click and LS CE-Chirp® stimuli,

10-millisecond (ms) window, stimulation using ER-3A insert

earphonesattheintensityof85dBnHL,withnoadditional filteringbeingmadeafterresponseacquisition.

The subjects were placed ona stretcher, so that they

were comfortably lying down. The electrode attachment

siteswerecleanedwithNuprepabrasivepasteandthe elec-trodeswereattachedtotheskin.Thereferenceelectrodes wereplacedontheright(A2)andleft(A1)mastoidsandthe

active (Fz) and ground (Fpz) electrodes on the forehead.

Therecordingonlystartedwithelectrodeimpedancebelow

3k.

TheABRrecordingwasmonaural,startingattherightear withtheClickstimulusand,afterthat, therecordingwas performed in theleftear. Subsequently,theLS CE-Chirp® stimuluswasused,alsostartingwiththerightearandfinally, intheleftear.

The recordingwasinterruptedwithaminimumof1000

stimuliandtheduplicationofeachrecordwascarriedout toensurethereproducibilityandreliabilityofthewaves.

Thepresence/absenceofwavesI,IIIandVwasanalyzed,

comparing theabsolute latency values of waves I, III and

V;amplitude valuesof waveV andwave Iandthe values

ofinterpeaklatencies (IPLs) I---III,III---V,I---Vandthe inter-auraldifference V---V between theLS CE-Chirp® and click stimuli.

Tocomparethelatencyandamplitudevariablesbetween

thestimuli,Student’sttestwasusedforindependent sam-ples.At theanalysisofthevariablesinterauraldifference V---V andV/I ratio,the Mann---WhitneyUtest wasusedto comparetheclickandLSCE-Chirp®stimuli.

Table1 Descriptivestatisticsfortheabsolutelatenciesof wavesI,IIIandVofABRwithClickandLSCE-Chirp®stimuli,

at85dBnHLinnormalhearingadults(n=60).

Variables Stimuli p-Value

Click LSCE-Chirp®

WaveI 1.29(±0.09) 1.29(±0.13) 0.921

WaveIII 3.42(±0.15) 3.42(±0.18) 0.978

WaveV 5.27(±0.18) 5.19(±0.24) 0.885

ABR, auditorybrainstemresponse; dBnHL,decibelfor normal hearinglevel.

Table 2 Descriptive statistics for I---III, III---V and I---V interpeaklatenciesofABRbetweenClickandLSCE-Chirp®

stimuliat85dBnHLinnormalhearingadults(n=60).

Variables Stimuli

Click LSCE-Chirp®

Mean(SD) Mean(SD)

I---III 2.13(±0.14) 2.13(±0.14)

III---V 1.85(±0.18) 1.77(±0.22)

I---V 3.98(±0.21) 3.90(±0.25)

ABR, auditorybrainstemresponse; dBnHL,decibelfor normal hearinglevel;SD,standarddeviation.

Forall analyses, the significance level wasset at 0.05

(5%)andconfidenceintervalswerebuiltwith95%statistical

confidence.

Results

When comparing the results of the absolute latencies of

waves I, III and V and the amplitude of wave V between

therightandleftears,itwasobservedthatthedifferences

betweentheearswerenotsignificantforbothClickandLS

CE-Chirp®stimuli.Thus,thevaluesofbothearswerealways

consideredfordataanalysis,doublingthesamplesize.

Table1 comparesthe absolutelatencies of waves I,III

and V between the stimuli, at an intensity of 85dBHL,

withnostatisticallysignificantdifferenceinthecomparison betweentheClickandLSCE-Chirp® stimuli.

ThemeanvaluesofInterpeaklatenciesI---III,III---VandI---V forthestimuliusedinthisstudyareshowninTable2.

Table3shows thatattheintensity assessed,85dBnHL,

the amplitude of wave V in ABR recordings with the LS

CE-Chirp® stimuluswasgreater thantheamplitude ofthe

Table3 DescriptivestatisticsforwaveVamplitudeatABR withClickandLSCE-Chirp® stimuli,at85dBnHLinnormal

hearingadults.

Stimuli p-Value

Click LSCE-Chirp®

WaveVamplitude 0.50(±0.19) 0.61(±0.23) 0.004

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Right ear

Click Click

I I

I

III III

III

III

III

III

LS CE-Chirp LS CE-Chirp

I I

0 2 4 6 8 0 2 4 6 8 10

I

I V

V

I

III

III V

V

V

V V

V

Left ear

Figure1 ExampleofABRrecordingwithClickandLSCE-Chirp® stimuliinonesubject.Observethemuchhigheramplitudeof

waveVinresponsetotheLSCE-Chirp®andsimilarlatenciesinresponsetoClickandLSCE-Chirp®onbothsides.

Table4 DescriptivestatisticsfortheV/IratioofABRwith ClickandLSCE-Chirp®stimuli,at85dBnHLinnormalhearing

adults.

Stimuli p-Value

Click LSCE-Chirp®

V/Iratio 1.63(±1.3) 2.07(±1.3) 0.004

ABR,auditorybrainstemresponse; dBnHL,decibelfor normal hearinglevel.

recordingswiththeclickstimulus,withasignificant differ-ence.

When comparing the amplitude values of V/I ratio

betweenthe stimuli,statistically significant higher values

wereelicitedbytheLSCE-Chirp®stimulus(Table4).

Table5showsthatnostatisticallysignificantdifference

wasobserved when comparingthe interaural latencies of

waveVbetweenthestimuliusedinthisstudy.

Accordingtotheresultsobtainedinthisstudy,itis

sug-gested that the values shown in Table 6 can be used as

maximumvaluesofnormality(meanvalueplus2standard

deviations) for neuroaudiological diagnosis, for both the

clickandtheLSCE-Chirp®stimuli,presentedat85dBnHL.

Table5 DescriptivestatisticsbetweenV---VbetweenClick andLSCE-Chirp®stimuliatABR,at85dBnHLinnormal

hear-ingadults.

Stimuli p-Value

Click LSCE-Chirp®

MeanSD MeanSD

V---V 0.08(±0.09) 0.10(±0.09) 0.273

ABR,auditorybrainstemresponse; dBnHL,decibelfor normal hearinglevel;Sd,standarddeviation.

Table6 Maximumvaluesforabsolutewaveandinterpeak latencies ofABRfor neuroaudiologicaldiagnosis withboth stimuli---ClickandLSCE-Chirp®,at85dBnHL.

Latencies WaveI WaveIII WaveV

1.55ms 3.79ms 5.67ms

Intervals I---V I---III III---V V---V

4.40ms 2.40ms 2.20ms 0.28ms

ABR,auditorybrainstemresponse;dBnHL, decibelfornormal hearinglevel;ms,milliseconds.

Fig.1 shows theABR recordingsregisteredwiththe LS

CE-Chirp® andclickstimuliinoneofthestudysubjects.

Discussion

This study showed that in all ABR recordings the waves

I, III and V were identified both with Click and LS

CE-Chirp® stimuli, at astimulation level of85dBHL.Another

study12 recorded ABR in normal-hearing adults, using the

stimuli: Click, CE-Chirp® and LS CE-Chirp®, and observed

that at 80dBnHL, all peaks of waves I, III and V were

identified when using the Click and LS CE-Chirp® stimuli. WhenusingtheCE-Chirp®stimulusatthisstimulationlevel,

wave I was not observed in any of the records, wave III

appearedin35%andwaveVin90%ofrecordings.Another

investigation13 comparedABR records using click and

CE-Chirp® innormal-hearingadults.Theresearchersanalyzed thepresence/absenceofwavesI,IIIandVat80dBnHLand

concluded that waves I andIII tended todisappear when

(5)

However,inastudy recordingABR at80dBnHL,waveV

latencies werelonger for theLS CE-Chirp® stimulus when

comparedtoClick.Accordingtothestudyresearchers,this resultwasdue tothefactthat inthe LS CE-Chirp®,most

frequencycomponents,reachthecochlea1.5mslaterthan

thecorresponding componentsinthe Clickand, thus, the

latency at ABRwiththe LS CE-Chirp® stimulus washigher

whencomparedtoClick.12

However,thecommercialversionofLSCE-Chirp®,when

using the Eclipse EP25 ABR system® equipment

manufac-turedbyInteracoustics, changedthewayLS CE-Chirp®,is presented,usingaspointzeroofthestimulusthelocationof thechirpcorrespondingtothe2500Hzfrequency,insteadof thelocationofthefinalfrequencyof10,000HzoftheLS CE-Chirp® usedinresearch.Thischangeresultedinresponses withlatenciesequaltothoseobtainedwiththeclickinits severalintensities.RegardingtheamplitudeofwaveV,we foundsignificantlyhighervaluesintherecordingswiththe LSCE-Chirp® stimulus.Theseresults areconsistent witha

studythatcomparedtheamplitudebetween LSCE-Chirp®

and Click and concluded that the LS CE-Chirp® stimulus

in ABR recordingsprovides significantly higheramplitudes

when compared to Click, at higher levels of stimulation

(80dBnHL).12

The current study corroboratesseveral studies4,13 that

alsoobservedahigherresponsetowaveVamplitudewhen

usingthechirpstimulusinABRrecordingsinnormal-hearing adults.

ItisworthmentioningthatstudiesusingtheLSCE-Chirp®

stimulus are carried out in individuals with cochlear and

retrocochlearpathologytobetterassesstheircontributions toclinicalpractice.

Conclusion

The LS-CE Chirp® stimulus is as efficient as the click in

obtaining waves I, III and V of the auditory brainstem

response test, at high levelsof stimulation. This stimulus maybeusefulinneuroaudiologicaldiagnosisbecauseunlike CE-Chirp®thatmostofthetimeevokesonlywavesIIIandV, theLS-CEChirp®stimulusevokesthethreewavesneededfor thistypeofdiagnosis,withtheaddedadvantagethatwave

Vhasgreateramplitudethanwhenevokedbytheclick.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

References

1.HecoxK,Galambos R.Brainstemauditoryevokedresponses in human infants and adults. Arch Otolaryngol. 1974;99: 30---3.

2.StarrA,AchorJ.Auditorybrainstemresponsesinneurological disease.ArchNeurol.1975;32:761---8.

3.Hall JW. Effect of stimulus factor. In:Handbook of auditory evoked responses. Massachusetts: Allyn & Bacon; 1992. p. 104---76.

4.Dau T, Wegner O, Mellert V, Kollmeier B. Auditory brain-stem responses with optimized chirp signals compensating basilar-membrane dispersion. J Acoust Soc Am. 2000;107: 1530---40.

5.ElberlingC,DonM,CebullaM,StürzebecherE.Auditory steady-state responses to chirpstimuli basedon cochlear traveling waredelay.JAcoustSocAm.2007;122:2772---85.

6.Fobel O, DauT. Searchingfor the optimal stimulus eliciting auditory brainstem responses in humans. J Acoust Soc Am. 2004;116:2213---22.

7.Elberling C,Don M.Auditory brainstemresponsesto a chirp stimulus designed from derived-band latencies in normal-hearingsubjects.JAcoustSocAm.2008;124:3022---37. 8.ElberlingC,DonM.Adirectapproachforthedesignofchirp

stimuliusedfortherecordingofauditorybrainstemresponses. JAcoustSocAm.2010;128:2955---64.

9.Gøtsche-RasmussenK,PoulsenT,ElberlingC.Referencehearing thresholdlevelsforchirpsignalsdeliveredbyanER-3Ainsert earphone.IntJAudiol.2012;51:794---9.

10.Elberling C, Callo J, Don M. Evaluating auditory brainstem responsesto differentchirpstimuli atthreelevelsof stimu-lation.JAcoustSocAm.2010;128:215---23.

11.Kristensen SG. Comparing three broad-band stimuli: click, CE-chirp, LS-chirp. Available from: http://www.dtas.info/ SinnetGBKristensen.pdf[cited10.10.11].

12.Kristensen SGB,ElberlingC.Auditorybrainstemresponsesto level-specificchirpsinnormal-hearingadults.JAmAcadAudiol. 2012;23:712---21.

Imagem

Table 2 Descriptive statistics for I---III, III---V and I---V interpeak latencies of ABR between Click and LS CE-Chirp ® stimuli at 85 dBnHL in normal hearing adults (n = 60).
Figure 1 Example of ABR recording with Click and LS CE-Chirp ® stimuli in one subject

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