Braz. j. . vol.81 número3

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www.bjorl.org

Brazilian

Journal

of

OTORHINOLARYNGOLOGY

ORIGINAL

ARTICLE

Swallowing

and

pharyngo-esophageal

manometry

in

obstructive

sleep

apnea

夽

,

夽夽

Luciana

Almeida

Moreira

da

Paz

Oliveira

a,b,∗

_,

_Luiz

_Henrique

_de

_Souza

_Fontes

c

_,

Michel

Burihan

Cahali

a,d

a_Department_of_{Otorhinolaryngology,}_Hospital_do_Servidor_Público_Estadual_de_São_Paulo,_São_Paulo,_SP,_Brazil b_Health_Sciences,_Hospital_do_Servidor_Público_Estadual_de_São_Paulo,_São_Paulo,_SP,_Brazil

c_Department_of_{Gastroenterology,}_Hospital_do_Servidor_Público_Estadual_de_São_Paulo,_São_Paulo,_SP,_Brazil

d_Department_of_{Otorhinolaryngology,}_Hospital_das_Clínicas,_Faculdade_de_Medicina,_Universidade_de_São_Paulo_(USP),_São_Paulo,

SP,Brazil

Received16February2014;accepted29June2014 Availableonline30March2015

KEYWORDS Obstructivesleep apnea;

Deglutitiondisorders; Manometry;

Pharynx; Esophagus

Abstract

Introduction:Upperairwaynerveandmuscledamageassociatedwithobstructivesleepapnea mayimpairthestrengthanddynamicsofpharyngealandesophagealcontractionsduring swal-lowing.

Objective:To evaluate the presence of alterations in pharyngoesophageal manometry in patientswithobstructivesleepapneawithandwithoutoropharyngealdysphagia.

Methods:Thisstudyprospectivelyevaluated22patientswithobstructivesleepapneawithout spontaneouscomplaintsofdysphagia,usingaquestionnaire,fiberopticendoscopicevaluation ofswallowing,andpharyngoesophagealmanometry,includingmeasurementoftheupperand loweresophageal sphincterpressuresandmean pharyngealpressuresatthreelevelsduring swallowing.

Results:Thedysphagiagroupconsistedof17patients(77.3%)inwhomswallowing abnormali-tiesweredetectedonfiberopticendoscopicevaluationofswallowing(n=15;68.2%)and/orin thequestionnaire(n=7;31.8%).Thefiveremainingcasescomprisedacontrolgroupwithout oropharyngealdysphagia.Inallcasesofabnormalitiesonfiberopticendoscopicevaluationof swallowing,therewas prematurebolusleakageinto thepharynx.Therewasnostatistically significantdifferencebetweenthegroupsregardinganyofthepharyngoesophagealmanometry measurements,age,orseverityofobstructivesleepapnea.

夽

Pleasecitethisarticleas:OliveiraLA,FontesLH,CahaliMB.Swallowingandpharyngo-esophagealmanometryinobstructivesleepapnea. BrazJOtorhinolaryngol.2015;81:294---300.

夽夽

Institution:HospitaldoServidorPúblicoEstadualdeSãoPaulo,SãoPaulo,SP,Brazil. ∗_{Corresponding}_author.

E-mail:[email protected](L.A.M.d.P.Oliveira).

http://dx.doi.org/10.1016/j.bjorl.2015.03.006

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Conclusion: Pharyngoesophageal manometry detected no statistically significant difference betweenthegroupswithandwithoutoropharyngealdysphagia.

PALAVRAS-CHAVE Apneiadosonotipo obstrutiva;

Transtornosde deglutic¸ão; Manometria; Faringe; Esôfago

Deglutic¸ãoemanometriafaringoesofágicanaapneiaobstrutivadosono

Resumo

Introdução: Lesõesneurogênicasemuscularesassociadasàapneiaobstrutivadosonopodem comprometeraforçaeadinâmicadascontraçõesfaríngeaseesofágicasduranteadeglutição.

Objetivo: Verificarseháalterac¸õesnamanometriafaringoesofágicadepacientescomapneia obstrutivadosonocomesemdisfagiaorofaríngea.

Método: Foram avaliados, prospectivamente, 22 pacientes com apneia obstrutiva do sono sem queixaespontânea dedisfagia, utilizando questionário, videoendoscopiada deglutic¸ão emanometriafaringoesofágica,commedidasdaspressõesdoesfíncteresofagianoinferiore superiorepressãomédiadafaringeemtrêsníveisduranteadeglutic¸ão.

Resultados: 17pacientes(77,3%)formaramogrupocomdisfagia,porapresentaremalterações de deglutição navideoendoscopia dadeglutição (n=15; 68,2%)e/ou noquestionário (n=7; 31,8%).Oscincorestantescompuseramogruposemdisfagiaorofaríngea.Emtodososcasos comalteraçõesnavideoendoscopiadadeglutiçãohouveescapeprecocedoboloalimentarpara afaringe.Nãohouvediferençasignificanteentreosgruposcomesemdisfagiaemrelaçãoa todasasmedidasdemanometria,idadeegravidadedaapneiaobstrutivadosono.

Conclusões: A manometria faringoesofágica não demonstrou diferenc¸a significante entreos gruposcomesemdisfagiaorofaríngea.

Introduction

Neurallesionsin thesoftpalateandoropharynxaresome ofthealterations foundinpatients withobstructivesleep apnea(OSA) andprimarysnorers.1---3_Some _authors_believe that these lesions are triggered by low frequency vibra-tions producedby snoring or intermittenthypoxia related toOSA.4---6 _The_soft_palate _mucosa_in_primary_snorers_with OSAshowsanincreasednumberofabnormalnerveendings.1 Thepalatopharyngeal muscle,both inprimarysnorersand inpatientswithOSA,showsmorphologicalalterationsthat aretypicalofperipheralnerveinjury,suchasgroupingof tis-suesbyfibertype,clustersofatrophiedareas,andfascicular atrophy.2

Thepresenceofneurologicaldisordersinthepharynxof patientswithOSAcancauseswallowingprocessdysfunction, astheinitiationoftheswallowingreflexandpropagationof the foodbolus depends onadequate sensitivity(afferent) andpharyngealfunction.Additionally,itisbelievedthatthe perpetuation ofOSA impairsneuromuscularafferent stim-ulation of the upper airways and the central integration betweenswallowingandbreathingfunctions.7---12

The evaluation ofswallowing usingvideofluoroscopyor fiberoptic nasal endoscopy shows a high prevalence of alterationsinpatients withprimarysnoringor OSA.These alterationscanbesymptomatic orasymptomatic and con-sistmostlyofprematurebolusleakage(fromtheoralcavity into the pharynx) and food residue in the pharynx after swallowing.9,10,13,14

Pharyngoesophageal manometry assesses the compres-sivemuscleforceofthepharyngealandesophagealmuscles duringswallowing,aidingintheunderstandingofthe phys-iopathologyoforopharyngealdysphagia.15---17_{Hypothetically,} neurologicaland muscular disorders of the upper airways associatedwith OSA18 _can _impair _the_force _and _dynamics ofpharyngoesophagealcontractionsduringswallowing, con-tributingtothedysphagiaobservedin manycasesofOSA. Tothebestoftheauthors’knowledge,nostudieshave per-formedmanometricevaluationsofthepharyngealphaseof swallowinginpatientswithOSA.

TheobjectiveofthisstudyofpatientswithOSA,wasto evaluatewhetherswallowingpressuresinthepharynxand esophagusarelowerinpatientswithoropharyngeal dyspha-giacomparedtothosewithoutoropharyngealdysphagia.

Methods

Subjects

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thosewithclinicallyknowndysphagiawereexcluded.This studyalsoexcludedpatientswithneuromuscularor rheuma-tological disease, Downsyndrome, acquired or syndromic facialdeformities,useofdrugsthatinterferedwithmuscle tone, previous esophageal surgery, and those with symp-tomsofgastroesophagealrefluxdisease.Thisstudyispart of a research protocol to evaluate the effect of pharyn-gealsurgeryonswallowing.ItwasapprovedbytheEthics Committeeofthisinstitution (protocol003.0.388.000-10), registeredinClinicalTrials(NCT01335594),andallpatients signedaninformedconsent.

The diagnosis of OSA was based on the presence of characteristic symptoms and findings from a supervised overnight polysomnography evaluation carried out in the sleeplaboratory.Thepatientgroupconsistedof17menand fivewomen, withamean age of 48.4years (range27---62 years),bodymassindex(BMI)of29.0kg/m2_(ranging _from 25to35.1kg/m2_),_and_mean_neck_{circumference}_of_41.5_cm (range36---48cm). Six patients(27.3%) had systemic arte-rialhypertensionandthreeweresmokers(13.6%).Regarding thepharyngealanatomy,19hadgradeIorIIpalatinetonsils (8.4%)andthreehadgradeIIIorIVtonsils(13.6%).20

Themeanapnea---hypopneaindex(AHI)was40.7(range 7.2---89.4), with 16 patients (72.7%) with severe AHI (AHI >30),three(13.6%)withmoderateAHI(AHI≤15≤30),and

three(13.6%)withmildAHI(5≤AHI<15).Themean

mini-mumoxyhemoglobinsaturationwas77.6%(range51---88%). TheEpworthsleepinessscale(ESS)showedameanscoreof 15inthisseries,rangingfrom4to19,withninecases(40.9%) showingexcessivesleepiness(Epworth>10).

The patients weredivided intotwogroups, those with dysphagiaandthosewithoutdysphagia,basedonthe assess-mentoftheswallowingquestionnaireandvideoendoscopy ofswallowing(VES).Patientswereconsideredasdysphagic whentheyshowedalterationsin thequestionnaireand/or VES.Incontrast,patientswithnormalVESandquestionnaire comprisedthegroupwithoutdysphagia.

Questionnaire

All patients answered a questionnaire13 ₍_Table ₁₎ _that included six questions about symptoms of dysphagia perceived by the patient in the previous month. The responseswerescoredusingascaleof0---3,where0meant ‘‘never’’,1‘‘rarely’’,2‘‘often’’,and3‘‘always’’.Ascore of2or3inatleastoneofthequestionswasconsideredas indicativeofthepresenceofdysphagia.

Fiberopticendoscopicevaluationofswallowing (FEES)

VESwasperformed21_in_all_patients,_using_a_3.2-mm_flexible endoscope(Pentax---Japan),introducedthroughthewider nasalcavity withouttheuseoftopicalanestheticinorder not to alter the upper airway mucosa sensitivity. The patient remained in a comfortable sitting position, with mild ventroflexion simulating a meal position, while the pharynxandlarynxwereassessed.

At the basal evaluation, the upper aerodigestive tract anatomy was assessed, as well as the presence of sali-varystasis, laryngeal sensitivity(test of glottaladduction

toendoscopetouch),mobility,andappearanceofthevocal foldsandvelopharyngealclosureduringphonationand swal-lowingofsaliva.

Under direct visualization through the endoscope, the dynamic assessment was performed for each patient dur-ingtheswallowingoffoodscoloredwithbluefoodcoloring, at room temperature, administered separately at three different consistencies (liquid,semi-solid,and solid).The completeswallowingofeachconsistencywasassessedthree times, totaling nine swallowing analyses. The liquid con-sistency comprised 5mL, 10mL, and 15mL of artificially flavoredstrawberrydrink(Clightbrandpowderedsoftdrink, strawberry flavor; Kraft Foods Brazil SA --- Curitiba, PR, Brazil)ateachtime.

The semi-solid food consisted of artificially flavored strawberry mixed with a thickening agent (BioSen NutriSenior®_, _Taboão _da _Serra, _SP, _Brazil), adminis-teredthreetimesusingatablespoon.Forsolidfood,three 2.5cm×2.5cmcrackersweregiventopatients.

TheexaminationswererecordedonDVDfor reanalysis. The authorsclassifiedthefollowingparametersaspresent orabsent:(a)prematureleakage:thefoodbolusleavesthe oralcavityandreachesthepharynxbeforetheswallowing reflexistriggered;(b)velopharyngealdysfunction:thesoft palatedoesnotfullyoccludethenasopharynxduring swal-lowing,allowingfoodleakage;(c)laryngealpenetration:the foodentersthelarynx,butdoesnotcrosstheglottis;(d) tra-chealaspiration:thefoodentersthelarynxandgoesthrough theglottis;(e)food residueafterswallowing:presence of somefoodinthepharynxafterthreecompleteswallowing movements.Thepresenceofprematureleakagewas consid-eredwhenitoccurredinatleasttwoofthenineswallowing analyses;asfortotheotheralterations,theiroccurrencein oneserieswassufficienttobeclassifiedaspresent.

Additionally,weevaluatedwhetherthecoughreflexwas associated with the penetration and/or aspiration events andwhetheritwaseffectiveineliminatingthepenetrated and/or aspirated content, aswell asthenumber of spon-taneousorrequestedswallowingmovementsnecessaryfor completeclearingofthefoodbolus(whichwasconsidered abnormalwhenthereweremorethanthree).

The presence of any alterationin the dynamic assess-mentplacedthepatientinthedysphagiagroup.Dysphagia severitywasnotassessed.

Pharyngoesophagealmanometry

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Table1 Swallowingassessmentquestionnaire.Score:0=never,1=rarely,2=often,3=always.Thepresenceofscores2or3 atanyquestionsignifiesclinicallypresentdysphagia.

Questions Score

1.Doyouchokeonliquidsduringmeals? 0 1 2 3

2.Doyouchokeonsemi-solidfoodduringmeals? 0 1 2 3

3.Doyouchokeonsolidfoodduringmeals? 0 1 2 3

4.Doyoufeelthefoodwentdownthewrongplace? 0 1 2 3

5.Doyoufeelthefoodstuckinyourthroat? 0 1 2 3

6.Doyoufeelthefoodiscomingbackthroughyournose? 0 1 2 3

The catheterwasintroduced throughthenose intothe stomach,whichwaslocatedbyassessingthepressure mea-suredbythedevice.Then,theLESwasassessedusingthe slow withdrawal technique, i.e., pullingout the catheter 1cm ata timewiththenostril asthe pointof reference. The zero reference of the examination is the intragas-tricpressure, whichis thegastric baseline.The pressures increase in theLES and decreaseagain in the esophageal body(esophagealbaseline),increasingagainintheUES.The pressuresintheLESarehigherduringinspirationandlower duringexpiration.

The LES pressure, obtained in the region with higher pressures overthreetofivestablerespiratorycycles,was calculatedasthedifferencebetweentheintragastric pres-sureandthemaximumLESpressureduringexpiration,and considered by thesimple arithmeticmean of pressuresin eachofthefourchannelsonthecathetertip,yieldingthe maximalexpiratorypressure(MEP).ThemeanLESpressure betweenexpirationandinspirationcorrespondstothemean respiratory pressure (MRP).Values below the normal MEP and/or MRPvaluesindicateLES hypotonia. Therelaxation oftheLESwasassessedduringwetswallowing.22,23

For the study of UES, the authors also used the four more distal catheter radial openings and the same slow withdrawal technique. The resting pressure of the UES wasanalyzed,andrepresentedthedifferencebetweenthe esophagealbaselineandthemanometrictracing.Thiswas measuredatthepointofthehighestandmoststable pres-sure.TherelaxationoftheUESwasevaluatedatthepointof highestpressure,withthreeswallowingmovementsof5mL ofwater.24

The pharynxwasevaluatedwiththe radialchannelsin threedifferentpoints,located2cm,4cm,and6cmabove theupperborderoftheUES.Theamplitudeofpharyngeal contractionwasdetermined,whichrepresentedtothe dif-ferencebetweenthepharyngealbaselineandthemaximum wavepeakstudied.Forthatpurpose, swallowingpressure measurementswereconductedthreetimesat eachpoint, withtheintakeof5mLofwater,andconsideringthemean value of the three swallowing movements at each point (meanpharyngealpressure---MPP).

Statisticalanalysis

Spearman’s correlation was usedto study the association between quantitative variables. Regarding thequalitative variables,Fisher’sexacttestwasusedtoverifyassociations. Wilcoxon’srank-sumtestwasusedtostudytheassociation

Table 2 Alterations found in the Fiberoptic endoscopic evaluationofswallowing(FEES)inthe22 patientsstudied (totalof15caseswithalterations).

FindingsatVESS Numberofpatients(%)

Prematurebolusleakage 15(68.2) Bolusresidueinthe

pharynx

5(22.7)

Laryngealpenetration 3(13.6) Changesinanatomy

(Reinke’sedema)

1(4.5)

between qualitative and quantitative variables. The 95% confidenceintervalforproportionswascalculatedfor quali-tativevariables.Thesignificancelevelusedinthetestswas 5%,alwaysconsideringatwo-tailedalternativehypothesis.

Results

Of the 22 patients assessed, 17 (77.3%) had dysphagia; two(9.1%) due to alterations detected only in the swal-lowingquestionnaire, 10(45.5%)due toalterations inthe VES,andfive(22.7%)withalterationsinboth theVESand thequestionnaire.Thedysphagiagrouphadameanageof 48.6years,with12men(70.6%),ameanAHIof 41.7/h,a meanBMI of28.6kg/m2_, _and_a _mean_neck _{circumference} of 40.9cm. The non-dysphagia group (five cases; 22.7%) had a mean age of 47.6 years (p=0.70), with five men (100%) (p=0.29), a mean AHI of 37/h (p=1.00), a mean BMI=30.4kg/m2₍_p₌_0.32),_and_a_mean_neck_{circumference} of43.5cm(p=0.10).

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Table3 Comparisonbetweengroupswithandwithout dys-phagia regarding manometric measurements inthe lower esophageal sphincter (LES), upper esophageal sphincter (UES),andthepharynxatthelevelsof2cm;4cm,and6cm abovetheUES.

Parameter Mean(SD) p

Nodysphagia Withdysphagia

LES-MRP 13.9(7.2) 18.1(7.6) 0.49 LES-MEP 6.5(4.1) 10.7(6.0) 0.16 P-UES 69.9(53.5) 62.1(32.5) 1.00 MPP2cm 77.6(14.1) 80.6(42.5) 0.82 MPP4cm 82.5(5.2) 85.3(38.9) 0.82 MPP6cm 120.7(39.0) 109.5(24.2) 0.70

LES,loweresophagealsphincter;MRP,meanrespiratory pres-sure;MEP,maximalexpiratorypressure;P,pressure;UES,upper esophageal sphincter; MPP, mean pharyngeal pressure; SD, standarddeviation.

pharyngoesophageal manometry measurements (Table 3). Thedysphagia grouphad eightcases(47.1%)of LES hypo-tonia,twocases(11.8%) of UES hypertonia,andone case (5.9%) of UES hypotonia, but with normal UES relaxation and coordinated with the pharynx in all cases. In the non-dysphagia group, there were four cases (80%) of LES hypotonia(p=0.32) andonecase (20%)of UEShypertonia (p=1.00),alsowithnormalUESrelaxationandcoordinated withthepharynxinallcases.

The correlation between the variablesUES, LES, mean pharyngeal pressure, questionnaire results, and VES find-ings, aswell asbetween them and the variablesage and AHIwereassessed.Theonlystatisticallysignificantfinding wasthecorrelationbetweenlaryngealpenetrationandage. Patientswithlaryngeal penetrationwereolder (meanage 60 years, SD=0.00) compared to those without laryngeal penetration(meanage46.5years,SD=9.7;p=0.01).

Discussion

In this series of consecutive cases, a high frequency of dysphagia in the group of adult patients with OSA that weresnorers wasobserved, with31.8%of patients repor-tingsymptomsofdysphagiaand45.5%showingalteredVES without clinicalsymptoms. All68.2% ofcases with abnor-malVEShadprematureleakageofthefoodbolusbetween theoralcavityandthepharynx.Thismaysuggestan impair-mentintheafferentsensoryfunctionoftheoropharyngeal mucosaororalphasedysfunction,attheapproximationof theposteriorpartofthetonguewiththesoftpalate.

Whenprematureleakageoccurs,masticationand breath-ingarenotinhibited,andthus, thereis arisk oftracheal penetrationoraspiration.25_The_pharyngeal_and_esophageal manometryshowednodifferencesbetweenthegroupswith andwithoutdysphagia,aswellasthedemographic, anthro-pometric,andpolysomnographicdata.Thesefindingsseem tofavortheroleofneurogenicalterationsasthecauseof oropharyngealdysphagiainOSA,tothedetrimentoftherole ofpharyngealmusclealterations.1,2_To_the_authors’ knowl-edge,thisis thefirststudy thatmeasured thepharyngeal pressureofswallowinginpatientswithOSA.

Although nodifferences were found regarding the age of patients with and without alterations in VES, those withlaryngeal penetrationwere older thanthosewithout it. Swallowing assessment through videofluoroscopy with barium showed that among snoring patients with OSA, dysphagia appeared in older patients, regardless of OSA severity.10 _Studies _in _healthy _individuals _have _shown _that aging is associated with a higher frequency of penetra-tionandaspirationcomparedtoyoungadults,butwithout excludingpatientswithsnoringandapnea.26,27_One hypoth-esis that could be raised is that older patients have had a longer exposure tovibration trauma caused by snoring, resultinginmoresevereswallowingalterations.

Although the present study favorsthe hypothesis of a peripheralcausefor dysphagiainOSA,thissubjectis con-troversialintheliterature.Teramotoetal.showedthatthe latencyofthepharyngealswallowingreflexwasincreased, which required alargervolume offood inthe pharynxto triggerthereflexinpatientswithOSA.7_Jobin_et_al._found_a significantreductionintheswallowingreflexlatencyinOSA, suggesting theimpairmentoftheinhibitorymodulation of thereflexandcentralcontrolofswallowing.8

Snorers without9,10 _and _with _OSA9,10,14 _show subclini-calswallowingalterations between52% and64%of cases, comparabletothe45.5%foundinthepresentstudy. Appar-ently,theriskofdysphagiainsnorersdoesnotcorrelatewith the presence or severity of OSA,10 _indicating _the _harmful roleoftissuevibrationcausedbysnoring,leadingtonerve damage in the upper airways, which would contribute to dysphagia.28_There_was_no_correlation_between_the_severity ofOSAandthepresenceofdysphagiainthepresentstudy.

Itwasobserved that,ingeneral,the complaintof dys-phagiawasnotspontaneously mentionedby patientswith OSA,butwhenperceived,italertedpatientstoother poten-tial impacts of OSA on their quality of life, acting asan additionalmotivatorforseekingandadheringtotreatment. This aspect is often ignored in the management of OSA; specific treatments for swallowing, such as the teaching ofmaneuvers,posturaladjustments,facilitationtherapies, and changes in diet consistency can also have a positive impactonqualityoflifeofthesepatients,similartowhat occursinpatientswithdysphagiasecondary toParkinson’s disease.29,30

Amongthe 31.8%cases withdysphagia complaints, the majority(27.3%)reportedhavingthesensationoffoodstuck in thethroat. Inclinical practice,this symptomis usually attributed to pharyngolaryngeal reflux. However, pharyn-geal dysphagia is often a slowly progressive disorder, in which the individual develops compensatory mechanisms suchasdietchangesormasticationvelocity.Thus,the symp-tomsmayappearonlywhenthecompensatorystrategiesno longerovercometheintensityofthedisorder.Priortothat, anactivemedicalinterventioncanalreadydetectimpaired swallowing.31 _Thus, _the _early _and _adequate _treatment _of snoringandOSAcanpreventthedevelopmentofpharyngeal dysphagia.Theliteraturehasareportoftwocasesofsevere OSAthatshowedimprovementofdysphagiaafteroneyear oftreatmentwithcontinuousnasalpositiveairwaypressure (CPAP)andweightloss.32

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completion of the swallowing movement and resumption ofbreathing,possiblyindicatingalterationsinperistalsisor pharynxelevation,astheUESrelaxationwasnotdifferent between the groups. To the best of the authors’ knowl-edge, the normal values for pharyngeal pressure in this populationareunknown,althoughthereareinitialstudies withtheJapanesepopulation.33_As_much_of_the_pharyngeal swallowing pressure is exerted by the tongue, whose electromyographicactivityisincreasedduringwakefulness inpatientswithOSA,34_it_is_considered_unlikely_that pharyn-geal manometry willshow alterations infuture studiesof OSA cases,unlike previous studieswith myastheniagravis andHuntington’sdisease,whicharecharacterizedbymajor alterationsinmusclestrength.35,36

Esophagealpressuremeasuresdidnotdifferbetweenthe groupswithandwithoutdysphagia.ThefindingofLES hypo-tonia,whichcanbeassociatedwithgastroesophagealreflux disease(GERD),37_was_present_in_both_groups_(p₌_0.32),_but sinceitwasanexclusioncriteria,ourpatientshadno symp-toms suggestive of the disease. The association between GERDandOSAhasbeendescribedintheliterature,38,39_but wasnotevaluatedinthisstudy.

We recognize that this study has some limitations. A largerpatientgroupwithoutdysphagiaperhapscouldhave revealedsomestatisticaldifferencesthatwerenot demon-stratedinthisanalysis.Additionally,theinclusionofagroup ofprimarysnorersandacontrolgroupneithersnored snor-ersnorhadOSApatientswouldhelptoclarifytherolesof OSAandsnoringinthedysphagiathesepatientsexhibited, perhaps demonstratingdifferencesinpharyngeal swallow-ingpressures between thegroups. The use of avalidated questionnaire would be more appropriate, but the study was based on a simpler questionnaire used in a similar studysincethesepatientsdidnothavemanycomplaintsof dysphagia.Anotherlimitationwasthefactthatsolid-state esophageal manometry which is superior when assessing rapid high-pressure events that occur in the pharynx was notavailable.15,33_However,_the_perfusion_method_was per-formedbyanexperiencedgastroenterologistwhopersonally conductedtheexaminationinallpatients.

Conclusion

ThisstudyfoundthatamongpatientswithOSA,therewasno significantdifferenceinswallowingpressuresofthepharynx and esophagus between subjects with and without orop-haryngealdysphagia.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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