www.bjorl.org
Brazilian
Journal
of
OTORHINOLARYNGOLOGY
ORIGINAL
ARTICLE
Impact
of
adenotonsillectomy
on
vocal
emission
in
children
夽
,
夽夽
Spyros
Cardoso
Dimatos
a,∗,
Luciano
Rodrigues
Neves
a,
Jéssica
Monique
Beltrame
b,
Renata
Rangel
Azevedo
c,
Shirley
Shizue
Nagata
Pignatari
aaDepartmentofOtolaryngologyandHeadandNeckSurgery,UniversidadeFederaldeSãoPaulo(UNIFESP),SãoPaulo,SP,Brazil bHumanCommunicationDisorders,DepartmentofSpeechTherapy,UniversidadeFederaldeSãoPaulo(UNIFESP),SãoPaulo,SP,
Brazil
cDepartmentofSpeechTherapy,UniversidadeFederaldeSãoPaulo(UNIFESP),SãoPaulo,SP,Brazil
Received8September2014;accepted1February2015 Availableonline14December2015
KEYWORDS Voice; Tonsillectomy; Adenoidectomy; Pharyngealtonsil; Palatinetonsil
Abstract
Introduction:Adenotonsillectomyisthemostcommonsurgeryperformedbyotolaryngologists inpediatricage,andoneofthemostfrequentlyaskedquestionsaboutthepostoperativeperiod iswhetherthereisapotentialforchangeinvocalpatternofthesechildren.
Objective: Toevaluate the impact of adenotonsillectomy in the voice emission pattern of childrenwithhypertrophyofpalatineandpharyngealtonsils.
Methods:Thisisaprospectivestudyinwhichwecarriedoutperceptualauditoryassessments andacousticanalysisof26childrenwithadenotonsillarhypertrophyatthreetimepoints:before surgery,onemonthandthreemonthsaftersurgery.Thefollowingacousticparameterswere esti-matedusingthePraatsoftware:fundamentalfrequency,jitter,shimmer,andharmonic---noise ratio.
Results:A statistically significant change was found between shimmer and harmonic---noise ratioduringvowel/u/productionbetweenthepreoperativeand1stmonthpostoperativetime points.Nosignificantdifferencesweredetectedforacousticparametersbetweenpreoperative analysisandthatofthe3rdmonthpost-operation.
夽
Pleasecitethisarticleas:DimatosSC,NevesLR,BeltrameJM,AzevedoRR,PignatariSSN.Impactofadenotonsillectomyonvocalemission inchildren.BrazJOtorhinolaryngol.2016;82:151---8.
夽夽Institution:DepartmentofOtolaryngologyandHeadandNeckSurgery,UniversidadeFederaldeSãoPaulo(UNIFESP),SãoPaulo,SP,
Brazil.
∗Correspondingauthor.
E-mail:sdimatos@hotmail.com(S.C.Dimatos). http://dx.doi.org/10.1016/j.bjorl.2015.11.005
Conclusion:Transient changes in acousticparameters occur in children with adenotonsillar hypertrophy submittedto adenotonsillectomy,progressing tonormalization inthe3rd post-operativemonth.
© 2015 Associac¸ão Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).
PALAVRASCHAVE Voz;
Tonsilectomia; Adenoidectomia; Tonsilafaríngea; Tonsilapalatina
Impactodaadenotonsilectomianaemissãovocalemcrianc¸as
Resumo
Introduc¸ão:Adenotonsilectomia é o procedimento cirúrgico mais realizado pelos otorrino-laringologistasem pacientespediátricos, e entreas dúvidasmais frequentesa respeito do pós-operatório,inclui-seapossibilidadedemodificac¸õesnopadrãovocaldessascrianc¸as.
Objetivo:Avaliaroimpactodaadenotonsilectomianopadrãodeemissãovocaldecrianc¸ascom hipertrofiadetonsilaspalatinasefaríngea.
Método: Trata-se de estudo prospectivo, em que foramrealizadas a avaliac¸ão perceptiva-auditiva e a análiseacústica da voz de 26 crianc¸as com hipertrofia adenotonsilar em três oportunidades:nopré-operatórioeno1◦e3◦mesesapósoprocedimentocirúrgico.Os
parâmet-ros acústicos frequência fundamental, jitter, shimmer e proporc¸ão harmônico-ruído foram avaliadospormeiodoprogramaPraat.
Resultados: Houveumaalterac¸ãoestatisticamentesignificanteentreoshimmereaproporc¸ão harmônico-ruídodaemissão davogal/u/entre operíodo pré-operatório eo1◦ mêsdo
pós-operatório.Nãohouvediferenc¸assignificantesdosparâmetrosacústicosentreaanálise pré-operatóriaeaquelarealizadano3◦ mêsdopós-operatório.
Conclusão:Crianc¸ascom hipertrofiaadenotonsilar submetidas àadenotonsilectomiacursam comalterac¸õestransitóriasdosparâmetrosacústicos,evoluindocomanormalizac¸ãodos mes-mosno3◦mêsdopós-operatório.
© 2015 Associac¸ão Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Publi-cado por Elsevier Editora Ltda. Este é um artigo Open Access sob a licença CC BY (https://creativecommons.org/licenses/by/4.0/deed.pt).
Introduction
Thevoiceisbasicallyaproductofthreephysiological pro-cesses: a constant expiratory airflow controlled by chest muscles; production of glottal sound throughvibration of thevocal folds,andachangeinthissoundwith amplifica-tionandmuffling ofsound frequencies resultingfromthe action of pharyngeal, oral and nasal resonant structures (vocaltract).1
Adenotonsillectomy is the most common surgery per-formedbyotolaryngologists,especiallyinchildren.Among themostfrequentlyvoiced concernsregardingthis proce-dure are questions about changes in vocal patternsafter surgeryandwhethertheyaretemporaryorpermanent.
According toMora et al.,hypertrophic palatine tonsils reduce the oropharyngeal air space and push the tongue forward, causing mouth breathing,abnormal nasalityand amuffledvoice.2Itisalsoreportedthatadenoidandtonsil
hypertrophycauseobstructionofthenasopharyngealregion anda decreased mobility of velopharyngeal muscles (i.e.
softpalate).2
Althoughitisthemoststudied, nasalityisnottheonly formofvoicealterationthatcanoccurafter adenotonsillec-tomy.Withvocaltractmodification,therecanbechangesin voicequalityduetophonationinstability,asaconsequence ofchangesinthevibrationpatternofthevocalfolds.2,3
However,todate,fewstudieshaveassessedvocal emis-sionafteradenotonsillectomy,andmostofthesedidsousing onlysubjectivemeasures(perceptual-auditoryvoice analy-sis).
Theaimofthisstudyistoassesstheimpactof adenoton-sillectomyonthepatternofvocalemissionofchildrenwith hypertrophyofpalatineandpharyngealtonsils.
Methods
This is a prospectivestudy with surgical intervention and postoperativemonitoring,whichbeganinJanuary2009and endedinDecemberofthesameyear.Twenty-sixchildren, between5and10yearsofage,sufferingfrompalatineand pharyngealtonsilhypertrophyandwithpriorindicationfor adenotonsillectomy,weremonitored.
This study was approved by CEP, according to Resolu-tion196/96 ofthe NationalEthics inResearchCommittee ---CONEP,dealingwithguidelinesandregulatorystandards forresearchinvolvinghumansubjects.
Our children were submitted to otorhinological exam-ination, which consisted in a detailed history, physical examination,andtransnasalfiberopticlaryngoscopy.
Table1 Perceptual-auditoryassessment(VAS).
Perceptual-auditory assessment
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 1.442 1.087 0.200 3.900 0.500 0.850 2.225 0.002 T30 26 1.988 1.052 0.300 4.000 1.000 2.100 2.925
T90 26 1.473 0.981 0.200 3.200 0.700 1.200 2.500
proposed by Brodsky,4 pharyngeal tonsil hypertrophy with
>70% obstruction of the nasopharynx diagnosed by direct visualizationwiththeuseofnasalfiberopticendoscopyand dueconsentofthelegalrepresentativeforthechild’s partic-ipationinthestudy,accordingtotheproposedmethod,and afteradetailedstudyexplanationandtheFreeandInformed ConsentTerm(FICT)signature.
Patients with dysphonia or changes in vocal emission, upper or lower airway infection, previously submitted to speech therapy, with craniofacial malformation, or with neurologicalsyndromeswereexcluded.
All children underwent adenotonsillectomy carried out by the same medical team, always underthe supervision oftheresearcher.Thesurgicaltechniqueconsistedofcold steel adenotonsillectomy, and hemostasis wascarried out withsimplesutureswithabsorbablesuture(Catgut2.0).
Thevocalemissionrecordingswereperformedinaquiet environment with the use of a Samson C03 professional microphone (Samson Technologies, USA) at a distance of approximately 5cm from the child’s mouth; the material obtained was edited in Sound Forge 8.0 software (Sony, Japan),fromwhichemissionpartsofthesustainedvowels /a/, /i/ and/u/ and partsof chained speech (automatic sequenceandspontaneousspeech)wereextracted.
The vocalemissionsof thesechildren wererecordedin threecircumstances,namely:
• 1stTimepoint(T0)---preoperativeperiod; • 2ndTimepoint(T30)---1monthafterthesurgery; • 3rdTimepoint(T90)---3monthsafterthesurgery.
The perceptual-auditory evaluation of voice quality (spontaneous speech and automatic sequence) was per-formedbythreeexperiencedspeechtherapists(blindedfor thisstudy),andthevisualanalogscale(VAS),validatedby Yamasakietal.,5wasusedastheevaluatorparameter.
TheVAScorrespondstoa100mm-longlineinwhichthe judgeisencouragedtomarkapointthatrepresentshis/her experiencedfeelingatthemomentinregardstothevoice recordingpresented.On VAS,eachmillimetercorresponds toonedegreeofdeviation,wheretheextremeleft repre-sentsabsenceofvocalchange,andtheextremerightisthe maximumdegreeofchange.Thecutoffvaluetodiscriminate betweenanormalandalteredvoiceis35.5mm.5
Acomputerizedacousticanalysisofthechild’svoicewas carriedoutforevaluationofvowels/a/,/i/,and/u/,with theuseofthePraatsoftware(PhoneticSciences,University ofAmsterdam,Netherlands).6
Theacousticparametersanalyzedwerethefollowing:
• Fundamental frequency (Fo) --- The number of glottic
cycles per second, reflecting the biomechanical char-acteristics of the vocal folds and their relation with subglotticpressure;
• Jitter(J)---Cycle-to-cyclevariationsoffundamental
fre-quency;
• Shimmer(S) --- Ameasure that quantifiescycle-to-cycle
fluctuationsintheintensityoftheglottalexcitation;and
• Harmonic---noiseratio(HNR)---Anestablishedrelationship
betweenthesoundsproducedbythelarynxversusnoises thatinterferewithvoiceproduction.
Astatisticalanalysiscomparingpreoperativeand postop-erativedatawasconducted,andthesignificancelevelwas set at 5% (p<0.05). For this purpose, the following tests wereapplied:
Friedmantestforeachvariable,inordertoverify possi-bledifferencesamongthethreeobservationtimepoints.
Wilcoxon test using Bonferroni correction, in order to observeinwhattheobservationaltimepointschosendiffer fromtheothers,wheninapairwisecomparison.
Results
Twenty-six children aged between 5 and 10 years (mean=7.15 years)(16males and10 females) were eval-uated.
Perceptiveauditoryvoiceevaluation
FortheperceptualauditoryanalysiscarriedoutusingaVAS, astatisticallysignificant differenceamongthe threetime pointswasfound(Table1).
By applyingthe Wilcoxon test using Bonferroni correc-tion,wefoundastatisticallysignificantdifferencebetween the assessment carried out at the 1st month after the surgeryand thatundertaken inthe 3rdmonth postopera-tively(p=0.005)andatrendshowingthatthetimepoints beforethesurgeryandat1monthpostoperativelyare sta-tisticallydifferent(Table2).
Table2 Perceptual-auditoryassessmentanalysis.
Pairofvariablesanalyzed Significance(p)
T30---T0 0.039
T90---T0 0.903
T90---T30 0.005a
Table3 Fundamentalfrequency---Vowel/a/.
Fundamental frequency
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 238.403 30.873 201.259 310.992 215.525 225.529 256.087 0.382 T30 26 240.826 31.719 190.438 324.569 219.385 237.142 252.817
T90 26 232.375 36.962 137.915 305.835 211.768 230.933 257.945
Table4 Jitter--- Vowel/a/.
Jitter n Mean Standard deviation
Minimum Maximum Percentile25 Median Percentile75 Significance(p)
T0 26 0.887 1.017 0.192 4.155 0.352 0.526 0.899 0.707 T30 26 0.698 0.358 0.205 1.899 0.470 0.628 0.834
T90 26 0.595 0.340 0.239 1.493 0.391 0.467 0.685
Table5 Shimmer---Vowel/a/.
Shimmer n Mean Standard deviation
Minimum Maximum Percentile25 Median Percentile75 Significance(p)
T0 26 8.621 4.564 2.521 20.449 4.482 8.451 10.816 0.607 T30 26 5.893 2.608 1.254 11.903 3.880 5.766 7.617
T90 26 6.965 3.674 2.618 16.795 4.392 6.026 7.425
Table6 Harmonic---noiseratio---Vowel/a/.
Harmonic---noiseratio
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 14.098 4.367 4.234 20.818 12.821 14.289 17.018 0.857 T30 26 14.966 3.619 7.393 22.320 12.377 14.876 17.256
T90 26 14.940 3.179 8.043 22.237 13.572 14.875 17.358
Table7 Fundamentalfrequency---Vowel/i/.
Fundamental frequency
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 260.239 40.543 217.994 375.138 231.627 250.910 272.441 0.048a
T30 26 256.229 38.329 190.388 353.938 227.330 250.870 277.795
T90 26 245.710 34.407 192.366 316.837 219.197 239.116 274.424
aBonferroni’salpha=0.016667.
Computerizedacousticvoiceanalysis
Vowel/a/
Regardingthevowel/a/,nostatisticallysignificant differ-encewasfoundamongthestudiedparameters(fundamental frequency,jitter,shimmer,andHNR)inthethree observa-tionaltimepoints(Tables3---6).
Vowel/i/
Theanalysisofthe emissionof sustainedvowel /i/atthe threeobservational timepointsshoweddifferencesinthe
fundamentalfrequencyofthevoicebetweenthe preopera-tiveperiodand3monthspostoperatively(Tables7and8).
Statisticallysignificantchangeswerenotidentifiedinthe remainingparameters(jitter,shimmer,HNR)(Tables9---11).
Table8 Fundamentalfrequencyanalysis(Fo)---Vowel/i/.
Pairofvariables Significance(p)
T30---T0 0.501
T90---T0 0.009
Table9 Jiitter---Vowel/i/.
Jitter n Mean Standard deviation
Minimum Maximum Percentile25 Median Percentile75 Significance(p)
T0 26 0.907 1.066 0.190 5.585 0.310 0.618 1.007 0.240 T30 26 0.478 0.228 0.197 1.239 0.341 0.456 0.515
T90 26 0.507 0.353 0.142 1.968 0.310 0.450 0.542
Table10 Shimmer---Vowel/i/.
Shimmer n Mean Standard deviation
Minimum Maximum Percentile25 Median Percentile75 Significance(p)
T0 26 7.033 4.625 2.479 20.331 3.181 6.146 8.910 0.089 T30 26 4.151 2.399 0.651 12.832 2.931 3.694 4.729
T90 26 4.864 3.424 1.551 19.216 3.151 3.788 5.876
Table11 Harmonic---noiseratio---Vowel/i/.
Harmonic---noiseratio
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 18.693 4.769 4.601 27.854 15.402 18.436 22.023 0.341 T30 26 20.755 2.712 15.465 25.920 19.308 21.325 22.186
T90 26 20.575 3.870 8.925 28.471 18.303 20.193 23.446
Table12 Fundamentalfrequency---Vowel/u/.
Fundamental frequency
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 261.170 44.299 174.045 347.238 229.347 252.526 290.321 0.764 T30 26 264.623 50.040 204.910 426.145 223.374 257.706 283.011
T90 26 256.735 38.025 207.698 327.897 222.196 247.372 284.049
Vowel/u/
Regarding the vowel /u/, no statistically significant dif-ferencewasdetectedinfundamental frequencyandjitter (Tables12and13).
A statistically significant difference was detected for shimmer and HNR measures between the preoperative recordingandthat undertakenatthe 1stmonthafter the surgery(Tables14---17).
Discussion
The vocal tract can be defined as the set of anatomical structureslocatedabovetheglottisthatmodifiesthesounds
producedbyvibrationsofthevocalfolds,becauseof reso-nanceeffectsonthosesoundsduetophysicalattributesof thetract.7
This resonance is the product of a three-dimensional configuration of the vocal tract, the tone of its walls, characteristics of the mucosal lining and its viscoelastic properties.8
Anychangeinthesefeatureswillimpactthesound propa-gationandthedefinitionofvocalformants.Thefrequencies thatdefinethefirstformant,forinstance,mayvary accord-ingtochangesinjawpositioning,whilethesecondformant is influenced by the tongue position.7 The third formant
relatestoresonance of the regionabove the vocal folds; thisareaconsistsofthelaryngealventricles, aryepiglottic
Table13 Jitter---Vowel/u/.
Jitter n Mean Standard deviation
Minimum Maximum Percentile25 Median Percentile75 Significance(p)
T0 26 1.134 1.435 0.227 6.867 0.388 0.724 1.025 0.076 T30 26 0.531 0.225 0.273 1.007 0.371 0.458 0.615
Table14 Shimmer---Vowel/u/.
Shimmer n Mean Standard deviation
Minimum Maximum Percentile25 Median Percentile75 Significance(p)
T0 26 8.117 5.282 2.908 22.404 4.448 5.968 9.990 0.019*
T30 26 4.557 2.302 0.808 11.614 3.251 4.138 5.088
T90 26 6.296 4.179 2.126 19.265 3.474 4.829 7.926
* p<0.05.
Table15 Harmonic---noiseratio--- Vowel/u/.
Harmonic---noiseratio
n Mean Standard deviation
Minimum Maximum Percentile 25
Median Percentile 75
Significance(p)
T0 26 19.175 6.271 4.529 27.033 16.010 21.208 24.214 0.004*
T30 26 23.761 3.230 15.513 30.059 22.222 24.158 26.103
T90 26 22.116 4.090 10.796 28.865 20.470 22.847 25.045
* p<0.05.
Table16 Analysisofshimmer(S)---Vowel/u/.
Pairofvariables Significance(p)
T30---T0 0.003a
T90---T0 0.159
T90---T30 0.058
aBonferroni’salpha=0.016667.
folds and vestibularfolds, while the fourth and fifth for-mantsaremoredependent onthe vocaltractlengththan onthearticulators’position.7
Itisassumedthatchangesinvocaltractanatomy result-ingfromsurgicalproceduresmaymodifythesubject’svocal characteristics.
Moraetal.relatedthatthepresenceofhypertrophic ton-silsreduces the oropharyngeal space, project the tongue forwardandcausehypernasality,mouthbreathingand muf-fled voice. In their study, 40 children with ages ranging from4 to 14 years were submitted toan acoustic analy-sisbeforeand30daysafteradenotonsillectomy.Afterthe surgery, these authors observed a statistically significant improvementinallparameters:fundamentalfrequency, jit-ter,shimmer,andHNR,aswellasothers.2
Consideringthattheadenoidtissueisaspace-consuming structure, Salami et al. proposed that its removal would resultinchangesinthenasopharyngealanatomy.Similarly, enlargedtonsilsandadenoidscanblockthenasopharyngeal airflowandinfluencesoftpalatemobility.Afteracoustically analyzingchildreninthepreoperativeperiodand1month
Table17 Harmonic---noiseratio(HNR)---Vowel/u/.
Pairofvariables Significance(p)
T30---T0 0.004a
T90---T0 0.069
T90---T30 0.026
aBonferroni’salpha=0.016667.
afteradenotonsillectomy,theseauthorsfoundimprovement invoicequalityandintheentiregroupofacoustic parame-tersanalyzed.3
Jarboeetal.studiedtheimpactofadenotonsillectomy inprofessionalsingers.Theseauthorsretrospectively eval-uated through telephone questionnaires 23 patients in a late postoperative periodand found that the vast major-ityshowed improvementin vocal qualityaftersurgery; in onlyfivepatientsdidtheyidentifyalossofvocalqualityin theearlypostoperativeperiod(1---4months),andall expe-riencedrecovery.Despitetheresultsoftheirstudy,Jarboe etal.pointoutthat,animprovementinvoicequalitydoes notpersejustifyanindicationofadenotonsillectomy.9
Ontheotherhand,Chumaetal.,inaprospectivestudy of 23 children who underwent acoustic analysis before and 3 months after adenotonsillectomy, concluded that theremovaloftissuefromtheoropharynxexertsminimal quantitativeandqualitative(perceptual)impactonseveral aspectsofvocalfunction.10
Subramanianetal.evaluatedtheeffectsoftonsillectomy withorwithoutadenoidectomythroughanacousticanalysis of20patients.Theseauthorsrecordedthevocalregisterthe daybeforetheprocedureandat 1monthpostoperatively, andfounddecreasesinshimmer.However,theirpatientsdid notundergoalong-termacousticanalysis;thus,thisfinding maycorrespondtoatransientpost-surgicalchange.Unlike thepresent study,the authorsalsoevaluatedthenasality andobservedthatthisfactordiminishedafterthesurgery.11
Karaetal.conductedananalysisoftheeffectsofsurgical removalofpharyngeal tonsilsontheir patients’voiceand speech.Theseauthors evaluated36 childrenwith pharyn-gealtonsilhypertrophybeforeand3monthsaftersurgery, andfoundasignificantchangeinnasalityandalsointhe3rd and4thformants.Inlinewithourstudy,nochangein funda-mentalfrequency,shimmerandHNRwasfound.Theauthors statethatadenoidectomyproceduresmayaffectvocal res-onanceandnasality,bymodifyingtheshapeandsizeofthe nasopharynxandupperrespiratorytract.12
Theseauthorsstudied vocaloutcomesin67children after adenotonsillectomyandconcludedthatthosepatientswith tonsil and adenoid hypertrophy preoperatively exhibited hyponasality,adeeperpitchandhigherperturbation meas-ures,comparedtothecontrolgroupandtoapostoperative evaluation. However, there was no significant change in fundamental frequency before and after surgery, thus demonstratingvocaltractinterferenceinthe psychoacous-ticsenseoffrequency.13
In ourstudy,thegroupof patientsstudiedconsistedof childrenwithhypertrophyofthetonsilsandadenoids,aged between 5 and 10 years old. It was decided to exclude childrenunder5yearsbecausetheycouldfacedifficulties executingthe required tasks, since their oral code is not yetfullyestablished.Childrenolderthan10yearswerenot included in our study due tothe proximity totheir voice change,afactthatcouldinterferewiththeanalysisofthe collectedresults.
Foraproperinvestigationofthevocalpatternofthese children,twotestswerechosen,namely: perceptive audi-toryandacousticvoiceanalysis.
Theperceptiveauditoryvoiceanalysisallowsan assess-ment of vocal perception for two vocal aspects: glottal sourceandresonantfilter.7Ifcarriedoutduringachained
speech(countingnumbers,narratingmonthsoftheyear,or readingapredefinedtext),thisanalysisismore comprehen-siveandalsoincludesvocalaspectsrelatedtoarticulation and resonance, thus being considered by many authors as the gold standard of vocal assessment.7 This kind of
analysis allows the characterization of vocal quality and the quantificationof phonationdeviation in theface of a given stimulus.Being an essentiallyacousticphenomenon ofsubjectivenature,itsutilizationrequiresprevious train-ingandexperienceofthoseprofessionalsinchargeof the evaluation.7
We found a statistically significant differencebetween theassessmentsinthe1stand3rdmonthsafterthesurgery; wealsonoticedatendencyinfavorofadifferencebetween timepointsbeforeandatthe1stmonthafterthesurgery. Thesefindings supportthehypothesis that adenotonsillec-tomyproceduresareresponsiblefortransientchangesinthe patternofvocalemission,creatingatemporaryphonation instability, that disappears throughout the postoperative period.
Theacousticanalysisofhumanvoiceraisesgreater inter-est, by involving objective, observer-judge-independent measures. According to Vieiraet al., thesemeasures can helpintherapeuticmonitoring,contributingdirectlyby ver-ifyingtheeffectivenessofaparticularstrategyorproposed therapeutic approach. Vieira et al.also state that acous-ticregistersandmeasurementscanbolsterthedefenseof the physicianor speechtherapist in legal disputeswhere the effectiveness of a vocal treatment outcome is being questioned.8
In thisstudy,thevowels/a/,/i/and/u/ werechosen tocarryoutthecomputerized acousticanalysis,and data onfundamental frequency,jitter,shimmer,andHNR were collected.
Thesethreevowelswerechosenbecausetheyformthe verticesofthepolygonrepresentingtheaverageofthe fre-quencies of the first two formants of oral vowels of the BrazilianPortugueselanguage,asdefinedbyBehlauetal.7
Thevowel/a/isanoral,central,low,andopenvowel; thevowel/i/isanoral,anterior,high,closed,not-rounded vowel;andthecharacteristicsofvowel/u/arethoseofan oral,posterior,high,closed,androundedvowel.
Intheanalysisofthedataproduced,wefoundstatistical differencesonlyinrelationtoshimmerandHNRforvowel /u/betweenthepreoperativeevaluationandthatcarried outat1monthaftersurgery.However,thismodificationmay betransitory, since no statistical difference between the preoperativeevaluationand thatperformed threemonths aftersurgerywasfound.
By being a posterior vowel, /u/ proved to be most affected by modifications of the anatomy stemmed from adenoid/tonsillar tissue removal at the end of the first month of the postoperative period--- a fact compensated later,inourlongerpostoperativetimepoint.
Likewise, the only statistically significant difference found in the sustained emissionof vowel /i/ was due to theobservationofthefundamentalfrequencybetweenthe preoperativeassessmentandthatcarriedoutthreemonths afterthesurgery.
Theresultspresentedinthispaperdemonstrateapartial agreement with the results of other studies that eval-uated the effects of adenotonsillectomy at one month postoperatively; these studies found significant differ-ences in all parameters (fundamental frequency, jitter, shimmer and HNR).2,3 Perhaps some methodological and
sample standardization variations may justify this varia-tion of data. However, these studies did not carry out a medium-term (time point=3 months) assessment of the children.
Theresultsof thisstudy providedatathatsuggestthat children with enlargedtonsils and adenoids submitted to adenotonsillectomyexhibittransientchangesintheirvocal quality/acousticparameters,butexperiencethereturnto preoperativelevels90daysaftersurgery.
Conclusion
Childrenwithadenotonsillarhypertrophysubmittedto ade-notonsillectomyareaffectedbytransientchangesoftheir acousticparameters,progressingtonormalizationinthe3rd monthpostoperatively.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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