www.bjorl.org
Brazilian
Journal
of
OTORHINOLARYNGOLOGY
ORIGINAL
ARTICLE
Sequential
bilateral
cochlear
implant:
results
in
children
and
adolescents
夽
Gabriela
Felix
Lazarini
Almeida
a,∗,
Marcella
Ferrari
Martins
b,
Lucas
Bevilacqua
Alves
da
Costa
b,
Orozimbo
Alves
da
Costa
c,
Ana
Claudia
Martinho
de
Carvalho
aaUniversidadedeSãoPaulo(USP),FaculdadedeMedicina(FM),SãoPaulo,SP,Brazil bAlfaInstitutodeComunicac¸ãoeAudic¸ão,SãoPaulo,SP,Brazil
cUniversidadedeSãoPaulo(USP),FaculdadedeOdontologiadeBauru(FOB),Bauru,SP,Brazil
Received5May2018;accepted24July2018 Availableonline18August2018
KEYWORDS Cochlearimplant; Hearing; Hearingloss; Child; Speechperception Abstract
Introduction:Theuseofthebilateralcochlearimplantscanpromotethesymmetrical
devel-opmentofthecentralauditorypathways,thusbenefitingthedevelopmentofauditoryabilities
andimprovingsoundlocalizationandtheabilityofauditoryspeechperceptioninsituationsof
competitivenoise.
Objective:To evaluate the ability of speech perception in children and adolescents using
sequentialbilateralcochlearimplants, consideringtheassociationofthesevariables:ageat
surgery,timeofdeviceuseandintervalbetweensurgeries.
Methods:Atotalof14individualsbetween10and16yearsofage,whodemonstratedsurgical
indicationfortheuseofsequentialbilateralcochlearimplantsasinterventionintheauditory
habilitationprocess,wereassessed.Thespeechperceptionabilitywasassessedthrough
sen-tencelistsconstructedinthePortugueselanguage,presentedintwosituations:insilence,with
fixedintensityof60dBSPL,andincompetitivenoise,withasignal-to-noiseratioof+15dB.
Theevaluationwasperformedunderthefollowingconditions:unilateralwiththefirstactivated
cochlearimplant,unilateralwiththesecondactivatedcochlearimplantandbilateralwithboth
devicesactivated.
Results:Theresultsofthespeechperceptiontestsshowedbetterperformanceinbothsilence
andinnoiseforthebilateralcochlearimplantconditionwhencomparedtothe1stcochlear
夽 Pleasecitethisarticleas:AlmeidaGF,MartinsMF,CostaLB,CostaOA,MartinhodeCarvalhoAC.Sequentialbilateralcochlearimplant:
resultsinchildrenandadolescents.BrazJOtorhinolaryngol.2019;85:774---9.
∗Correspondingauthor.
E-mail:gflazarini@gmail.com(G.F.Almeida).
PeerReviewundertheresponsibilityofAssociac¸ãoBrasileiradeOtorrinolaringologiaeCirurgiaCérvico-Facial. https://doi.org/10.1016/j.bjorl.2018.07.008
1808-8694/©2018Associac¸˜aoBrasileiradeOtorrinolaringologiaeCirurgiaC´ervico-Facial.PublishedbyElsevierEditoraLtda.Thisisanopen accessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).
implantandthe2ndcochlearimplantalone.A worseresultofspeechperceptionwasfound
usingthe2ndcochlearimplantalone.Nostatisticallysignificantcorrelationwasfoundbetween
ageatthesurgicalprocedure,intervalbetweensurgeriesandthetimeofuseofthe2ndcochlear
implant,andtheauditoryspeechperceptionperformanceforallassessedconditions.Theuse
ofa hearing aid priorto the2nd cochlearimplantresultedinbenefits for auditory speech
perceptionwiththe2ndcochlearimplant,bothinsilenceandinnoise.
Conclusion: Thebilateralcochlearimplantprovidedbetterspeechperceptioninsilenceandin
noisesituationswhencomparedtotheunilateralcochlearimplant,regardlessoftheinterval
between surgeries, ageat thesurgical procedureandthe time ofuse ofthe2nd cochlear
implant. Speechperceptionwiththe1stcochlearimplantwassignificantlybetterthanwith
the2ndcochlearimplant,bothinsilenceandinnoise.Theuseofthehearingaidpriortothe
2ndcochlearimplantinfluencedspeechperceptionperformancewiththe2ndcochlearimplant,
bothinsilenceandinnoise.
© 2018 Associac¸˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Published
by Elsevier Editora Ltda. This is an open access article under the CC BY license (http://
creativecommons.org/licenses/by/4.0/). PALAVRASCHAVE Implantecoclear; Audic¸ão; Perdaauditiva; Crianc¸a;
Percepc¸ãodafala
Implantecoclearbilateralsequencial:resultadosemcrianc¸aseadolescentes
Resumo
Introduc¸ão: Autilizac¸ãodoimplantecoclearbilateralpodepromoverodesenvolvimentodas
viasauditivascentraisdemaneirasimétrica,beneficiando,assim,odesenvolvimentodas
habili-dadesauditivasemelhorandoalocalizac¸ãosonoraeahabilidadedepercepc¸ãoauditivadafala
emsituac¸õesderuídocompetitivo.
Objetivo: Avaliarahabilidadedereconhecimentodefalaemcrianc¸aseadolescentesusuários
doimplantecoclearbilateralsequencial,considerandoarelac¸ãodasvariáveis:idadecirúrgica,
tempodeusododispositivoeintervaloentreascirurgias.
Método: Foramavaliados14indivíduosentre10e16anos,quereceberamindicac¸ãocirúrgica
paraautilizac¸ãodoimplantecoclearbilateralsequencialcomoformadeintervenc¸ãono
pro-cessodehabilitac¸ãoauditiva.A habilidadedereconhecimentodefalafoiavaliadapormeio
delistasdesentenc¸asconstruídasnalínguaportuguesa,apresentadasemduassituac¸ões:no
silêncio,comintensidadefixade60dBNPS,enoruídocompetitivo,comarelac¸ãosinal/ruído
de+15dB.Aavaliac¸ãofoifeitanasseguintescondic¸ões:unilateralcomo1◦implantecoclear
ativado,unilateral como2◦ implantecoclearativadoebilateral comambososdispositivos
ativados.
Resultado: Osresultadosdostestesdereconhecimentodefalademonstrarammelhor
desem-penhotantonosilêncioquantonoruídopara acondic¸ãoimplantecoclearbilateral,quando
comparadoao1◦ implantecocleare2◦implantecoclearisoladamente.Umpiorresultadode
reconhecimentodefalafoiencontradocomousodo2◦ implantecoclearisoladamente.Não
foiencontradacorrelac¸ãoestatisticamentesignificanteentreidadecirúrgica,intervaloentre
ascirurgiasetempodeusodo2◦ implantecocleareodesempenhodepercepc¸ãoauditivada
falapara todasascondic¸õesavaliadas.Ousodoaparelhodeamplificac¸ãosonora individual
anteriorao2◦ implantecoclearbeneficiouosresultadosdepercepc¸ãoauditivadafalacomo
2◦implantecoclear,tantonosilêncioquantonoruído.
Conclusão:O implante coclear bilateral proporcionou melhor reconhecimento de fala em
situac¸ões de silêncio e de ruído, quando comparado com o implante coclear unilateral,
independentementedointervaloentreascirurgias,daidadecirúrgicaedotempodeusodo
2◦implantecoclear.Oreconhecimentodefalacomo1◦implantecoclearfoisignificativamente
melhordoquecomo2◦implantecoclear,tantonosilêncioquantonoruído.Ousodoaparelho
deamplificac¸ãosonoraindividualanteriorao2◦implantecoclearinfluenciouodesempenhode
reconhecimentodefalacomo2◦implantecoclear,tantonosilêncioquantonoruído.
© 2018 Associac¸˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Publicado
por Elsevier Editora Ltda. Este ´e um artigo Open Access sob uma licenc¸a CC BY (http://
Introduction
Evenconsideringallthetechnologyappliedtothecurrent generationofcochlearimplantsandthefactthatunilateral cochlearimplant(CI)usersshowspeechcomprehensionin silentenvironmentsandreportimprovementsinthequality of life after the implantation, some difficulties in every-daysituationshavebeenreportedbyusersofunilateralCI, suchassoundlocalization andspeechperception in noisy environments,1,2functionsthatrequirethebinauralability
andmaynotbefavoredwiththeuseoftheunilateralCI.3
Inrecentyears,thebilateralCIhasbeenfavoredinthe internationalcontext,andalsoasanalternativetopromote binauralfunction. Studieshave demonstratedspeech per-ceptionimprovementwithbilateralCI,thuscontributingto soundlocalizationimprovement4andbetterspeech
percep-tioninnoise.5
Theclinicalandscientificliteraturehashighlightedthree reasonstoimplantthesecondear:toensurethatthebest earisstimulated;toprovidebackupifdevicefailureoccurs, aswellastoprovidethebenefitsofbinauralhearing, allow-inganimprovementinthelocalizationofsoundsourcesand intheauditoryperceptionofspeechinnoisyenvironments.6
BilateralCIsurgerycanbeperformedsimultaneouslyor sequentially.Inasimultaneousprocedure,thetwodevices areimplantedduringasinglesurgicalevent;inasequential procedure,theseconddeviceisimplantedmonthsoryears afterthefirstsurgery.Forsequentialimplantationcases,a questionrelatedtotheimpactofthetimeintervalbetween the first and second surgeries regarding the post-surgical resultshasbeendiscussedbyresearchersinthearea.7
The bilateralCIis areality inBrazil, andthepatients’ interestinthesecondCIsurgeryamongthosewhouse uni-lateralCIisincreasing.Therefore,theseindividualsundergo bilateral CI surgery sequentially, with intervals between surgeriesthatmaybemonthsoryears,anditisoftheutmost importancetoevaluatetheperformanceofauditory abili-tiesintheseindividualsover timeaswellastoverifythe aspectsthatcaninfluence theseresults.However,studies inthescientificliteratureabouttheBrazilianexperienceof bilateralCIusersarescarce.
Inthiscontext,itisofgreatimportancetoevaluatethe benefitsofbilateralCI,aswellastheinfluenceofthe varia-bles:ageat thesurgicalintervention, timeof deviceuse, timeintervalbetweenthesurgeriesanduseofahearingaid priortothe2ndCIforspeechperceptiontohelpinthe indi-cationofnewcandidates,aswellasinthemanagementof thespeech-languagetherapyprocess.
Objective
To evaluatethe speech perception abilityin children and adolescentswithsequentialbilateralCIandtoanalyzethe influenceofthevariables:ageatsurgicalprocedure,timeof deviceuse,timeintervalbetweensurgeriesandhearingaid usepriortothe2ndCIforspeechperceptionperformance withthe2ndCIandwithbilateralCI,insilenceandinnoise.
Methods
Across-sectionalstudywascarriedoutinacochlearimplant center of the private health care network of the city of SãoPaulo, in 14children and adolescentswithsequential bilateralCIs,whoseagerangedfrom10to16yearsandhad receivedthe1stCIatameanageof29months,withamean intervalbetween surgeriesof 91 months.Nine individuals
(64.3%)usedhearingaidpriortothe2ndCIandfivedidnot useit(35.7%).
Patientselection andevaluationprocedureswere initi-atedaftertheappropriateethicalprocesses:authorization wasobtainedfromtheinstitutionwherethestudywas car-riedout,approvalbytheResearchEthicsCommitteeofthe institution(n.1754869)andsigningoftheFreeandInformed Consentformbythepatients’parentsorcaregivers.
Thefollowinginclusioncriteriawereusedtodetermine thestudysample:severetoprofoundbilateralsensorineural hearingloss;firstCIprocedureupto36monthsofage; inter-valbetweenthefirstandsecond CIsurgeries≥12months; timeofuseofbilateralCI≥12months;effectiveuseof bilat-eralCI(minimumof8hdaily)andpost-surgicalmedicaland speech-languageandaudiologyfollow-up.
Speechperceptionassessmentwasperformedby
apply-ing lists of sentences constructed for the Portuguese
language,8availableinmaterialrecordedonaCDplayerand
presentedinaacousticbooth,usingatwo-channel audiome-terconnectedtoanamplifierinfreefieldwiththeindividual within1meterofthespeaker.Inthesilencesituation,the sentenceswerepresentedinaloudspeakerat0◦azimuth,at thefixedintensityof60dBSPL.Forthenoisesituation,the sentenceswerepresentedinaloudspeakerat0◦azimuth,at thefixedintensityof60dBSPL,andthecompetitivenoise (partynoise) presentedat 180◦ azimuth, witha signal-to-noiseratio(SNR)of+15dB.9Thetestresultswereobtained
inpercentage(%),withscoresrangingfrom0to100%,and
the higher the score, the better the performance in the
speechperceptionability.
Thespeechperceptionresultsinsilencewerecompared to those obtained in noise, at the conditions 1st CI, 2nd CI,andbilateralCI.Descriptivemeasures(meanand stan-darddeviation)wereused,aswellasPearson’scorrelation coefficientandthenonparametricWilcoxontestforpaired samples.
Adescriptiveanalysis of thespeech perception results withthe2ndCIandthebilateralCIinsilenceandinnoise wasperformedbetweentheindividualswhousedhearingaid priortothe2ndCIandthosewhodidnotuseconventional amplification.Forthecomparisonoftheresultsobtainedin eachgroup,anon-parametricanalysiswasperformed,using the Mann---Whitney test for independent samples. Tukey’s
method was used tocompare the means of the
percent-agesofcorrectanswersinsilenceandinnoisebetweenthe groups.
Results
Betterspeechperceptionwasobservedwiththeuseof bilat-eralCI,whencomparedtotheresultsofthe1stCIandthe 2ndCIseparately,bothinsilence(respectively,p=0.011and p=0.003)andinthepresenceofcompetitivenoise(p=0.002 andp=0.001,respectively).Theperformancewiththe1stCI wassignificantlybetterthanwiththe2ndCI,bothinsilence andinnoise(Fig.1).
The analysis of the association between the variables: surgical interval,ageat surgical procedure forthe 2ndCI
and time of use of the 2nd CIfor the speech perception
results with the 2nd CI and withthe bilateral CI showed nostatisticallysignificantcorrelationbetweentheauditory performancewiththe2ndCIandthebilateralCIandsuch variables,bothinsilenceandinnoise(Table1).
Regardingthespeechperceptionabilityinsilenceandin noiseandtheuseofthehearingaidpriortothesecondCI surgery,abetterperformancewiththesecondCIaloneand withabilateralCI,bothinsilenceandinnoise,wasfound
Bilateral 1st CI Bilateral 1st CI 2nd CI 2nd CI 100% 100% 80% 80% 60% 60% 40% 40% 20% 20% 0% 0% Silence Noise
Figure1 Percentageofcorrectanswersinspeechperceptiontestsinsilenceandinnoiseinthethreeassessedconditions:1st CI,2ndCIandbilateralCI.
Table1 Correlationofthepercentagesofcorrectanswersforspeechperceptioninsilenceandinnoisewiththe2ndCIand
bilateralCIandsurgicalinterval,ageatthe2ndCIsurgeryandtimeofuseof2ndCI.
Situation Intervalbetweenthe
1standthe2ndCI Ageatthe2nd CIsurgery Timeofuse ofthe2ndCI Speechperception withthe2ndCI Silence r=−0.28 r=−0.35 r=−0.06 p=0.339 p=0.214 p=0.852 Noise r=−0.33 r=−0.43 r=−0.03 p=0.251 p=0.128 p=0.922 Speechperception withbilateralCI Silence r=0.50 r=0.56 r=−0.48 p=0.067 p=0.035 p=0.084 Noise r=0.38 r=0.48 r=−0.52 p=0.178 p=0.080 p=0.054
CI,CochlearImplant;r,Pearson’scorrelationcoefficient;p,p-value.
forthegroupofindividualswhousedthehearingaidprior tothe2ndCI(Fig.2).
A statistically significant differencewas found for the speechperceptionresultswiththeuseofthe2ndCI,bothin silenceandinnoise,forthegroupthatusedthehearingaid priortothesecondsurgery(p=0.001andp=0.002, respec-tively).WhenevaluatingperformancewiththebilateralCI, nostatisticallysignificantdifferenceswerefoundregarding speechperceptionbetweensilenceandnoiseinindividuals whousedanddidnotusethehearingaidpriortothesecond surgery(p=0.606andp=0.364,respectively).
Discussion
WiththeconsolidationoftheunilateralCIbenefits,the pos-sibilityofindicatingsequentialbilateralCIhasbecomepart ofthecurrentclinicalscenario,sinceasignificant number ofindividualswhoreceivedCIinthefirstyearsoflifemay bepotentialcandidatesforsequentialbilateralCI.
The scientificliteratureoftheareahashighlighted the benefitsofbilateralCIinchildrenandadultsconcerningthe soundlocalizationandspeechperceptionabilitiesin com-petitivenoisesituations.
FortheindicationofsequentialbilateralCI,aconsensus hasnot yet been established regarding the desirable and necessarysurgical intervaltoobtain thebenefits of bilat-eralstimulation.Additionally,theageatthefirstCIsurgery
might be able to influence the speech perception results
withbilateralCI.7,10,11
In the present study, all subjects received the 1st CI beforetheageof3,duringtheperiodofmaximalneuronal plasticity, thus allowing the developmentof the auditory skillsthatareessentialfororallanguagedevelopment. Espe-ciallyinthepediatricpopulation,thesurgicalageatwhich thechildwassubmittedtothe1stCIcanbeconsidereda predictorofauditoryandlanguageskilldevelopment.12,13
Regardingauditory performancewiththe CI,all ofthe researchsubjectsshowedspeechperceptionwiththe1stCI
(≥70%). However,despite the goodperformance withthe
unilateral CI, greater difficulty wasfound for the speech perceptiontaskinthepresenceofcompetitivenoise,thus demonstratingtheauditorychallengesfacedinsituationsof complexday-to-daylisteningthatmayhavemotivatedthe decisionforabilateralCI,evenwithalongintervalbetween thesurgeries.14
The results of the present study demonstrated that
auditoryperformancewiththebilateralCIwassuperiorto thatwiththe 1stCIand 2ndCIalone, withastatistically
Recognition of sentences - Silence
Recognition of sentences - Noise
With PSAP With PSAP 94,0% 86,4% 90,2% 95,1% 13,6% 14,0% 66,4% 80,2% 100% 20% 0% 40% 60% 80% 100% 20% 0% 40% 60% 80% 100% 20% 0% 40% 60% 80% 100% 20% 0% 40% 60% 80% Without PSAP Without PSAP 2nd CI 2nd CI Bilateral CI Bilateral CI Bilateral CI Bilateral CI 2nd CI 2nd CI
Figure2 Individual andmean values ofthe percentage of correct answers inspeech perceptiontests insilenceand in noisewiththe2ndCIandwiththebilateralCIaccordingtothe useofhearingaidpriortothe2ndCI.
significant difference for the bilateral CI condition when comparedtotheotherassessedconditions(Fig.1).
These results corroborate the data found in the lit-erature, of which auditory speech perception results are significantlybetterwiththeuseofbilateralwhencompared tounilateralCI.6,10,15---17
Evenwithsignificantbilateraladvantages,astatistically significantdifferencewasfoundwhencomparingthe perfor-mancebetweenthe1standthe2ndCIinsilenceandinnoise,
therefore suggesting an asymmetry between the auditory
pathways and apredominance of the firstimplanted side
inrelationtothesecondone.Thesefindingsarein agree-mentwiththe scientificliterature, inwhich children who usedaunilateralCIformanyyearsbeforereceivingthe2nd CIshowedauditorypathwayandcorticalfunction asymme-tries,whichresultedinadifferenceinauditoryperformance withthe2ndCI.18
Anotheraspecttobeconsideredandthatremains contro-versialintheclinicalandscientificcommunityreferstothe idealageforthe2ndCI,aswellastherecommended inter-valbetweensurgeriestoachievegoodhearingoutcomes.In
thepresentstudy,theintervalbetweensurgeries,theage atthe2ndCIsurgeryandthetimeofthe2ndCIusedidnot influencespeechperceptionresultsinsilenceandinnoise withthe2ndCIandwiththebilateralCI(Table1).Thesedata areinagreementwithotherstudiesthatdescribedspeech perceptionbenefits,eveninindividualswithlongintervals betweensurgeries.7,11,17,19Itislikelythattheageatwhich
individualsweresubmittedtothe1stCIpositivelyinfluenced theresultsofthisstudy,sincethestimulationprovidedby the 1stCI during theperiod of maximalneuronal plastic-ityallowedtheauditoryaccessandthedevelopmentofan auditorysystemmorepreparedforthestimulationwiththe 2ndCI,evenafteralongsurgicalinterval.7,20,21
Ontheotherhand,thelongintervalbetweensurgeries andtheageatwhichthe2ndCIisperformedcandirectly impact the results of auditory perception of speechwith thebilateral CI,in additiontothe factthata late2ndCI
might not favor adequate neural connections, generating
inferiorresultsforthesecondimplantedearandadecrease inmotivationregardingtheuseofanotherdevice,whichdid notattaintheperformanceofthe1stCI.12,13,19However,it
remainsunclearwhetherthereisacriticalageand/orperiod fortheindicationofthesecondCIinthisgroupofchildren withprelingualhearinglosswhohaveusedunilateralCIfor manyyears.15,20,21
Theuseofhearingaidpriortothe2ndCIpositively
influ-enced the speech perception results with the use of the
2ndCI,sincebetterresultswerefoundbothinsilenceand innoise forthegroupthatusedthehearingaid(Table1). ForthebilateralCI,eventhoughtherewasnostatistically significantdifference,atrendtowardbetterspeech percep-tionperformanceinsilenceandinnoisewasobservedinthe groupthatusedconventionalsoundamplification(Fig.2).
Inclinicalpractice,agreatvariabilityisobserved regard-ingtheuseofthehearingaid,anditisnotpossibletodefine thepercentageofpatientswhousecombinedelectricaland acousticstimulationafterthe1stCI.Inaninternational mul-ticenterstudy,thetotalofbimodalusersaccountedforonly 32%ofthetotal.22
Although the scientific literature has not described in detailtheinfluence ofbimodalhearingonspeech percep-tionafterthe2ndCI,authorshavepointedoutthattheuse ofhearingaidpriortothe2ndCIcanbeconsidereda pre-dictorforbetterspeechperception withthe2ndandwith thebilateralCI.TheyalsoemphasizethatunilateralCIusers shouldbeencouragedtocontinuetheuseofsound amplifica-tioncontralateraltothe1stCItomaintainauditorypathway stimulation.20,23
Forallsubjects in the present study,improved speech perceptionskillswithbilateralCIstrengthenedand consoli-datedtheuseofbothdevicesinacontinuousandeffective manner.However,theindicationfor asequential bilateral CIinchildrenandadolescentswithalongintervalbetween surgeries should be considered in a cautious and careful manner.
Detailedinformationshouldbeprovidedtotheapplicants ofthesequentialbilateralCIandtheirfamiliesconsidering thevariability ofthe resultsfound inthe scientific litera-ture.Evenconsideringtheencouragingresults,itisessential to assess the bilateral advantages over time, as well as analyzetheseveralfactorsthatcaninfluencethebinaural benefitstobeobtainedfromtheuseofbilateralCI.
Conclusions
Better speechperception performance wasobservedwith
comparedtothe1stCIandwiththe2ndCIalone.Speech perceptionwiththe1stCIwassignificantlybetterthanwith the2ndCI,bothinsilenceandinnoise.
Nostatisticallysignificantcorrelationwasfoundbetween ageatthetimeofthe2ndCIsurgery,thetimeofuseofthe 2nd CIand theinterval between thesurgeries for speech perceptioninsilenceandinnoisewiththe2ndCIandthe bilateralCI.
The use of a hearingaid prior tothe 2nd CIpositively influencedthespeechperceptionperformancewiththe2nd CI,bothinsilenceandinnoise.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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