Innovative Journal of Medical and Health Science 3 : 6 November
December (2013) 268 - 273. Contents lists available at
www.innovativejournal.in INNOVATIVE JOURNAL OF MEDICAL AND HEALTH
SCIENCE Journal homepage:
http://www.innovativejournal.in/index.php/ijmhs 268 DYSPHONIA
SEVERITY INDEX IN CHILDREN WITH VELOPHARYNGEAL DYSFUNCTION: A
PRE-POST OPERATIVE COMPARISON. 1K.Gnanavel, 2H.V. Satish, ,1M.
Pushpavathi1 Department of Speech Language Pathology, All India
Institute of Speech and Hearing, Mysore, India; 2 Vikram Jeev
Hospital, Mysore, India. ARTICLE INFO ABSTRACT Corresponding
Author: Gnanavel KuppusamyJunior Research Fellow (JRF) Dept.of SLP
All India Institute of Speech and Hearing (AIISH) Manasagangothiri,
Mysore-570006. India Key words: Dysphonia severity Index;
Velopharyngeal Dysfunction; Voice Quality
Background&Objective:Voiceisanimportanttoolfor
communicationthroughwhichweexpressourthoughtsinformorsounds
producedbymovementofvocalfolds.Thevoicequalityisaffectedin
childrenwithcleftlipandpalateduetovelopharyngealdysfunction(VPD)
which is associated with abnormalities of velum leading to hyper
adduction ofvocalfolds.DysphoniaSeverityIndex(DSI)isanobjective
multiparametricapproachtoevaluatevoicequality.Thepresentstudy
aimedtocomparetheDysphoniaseverityindex(DSI)inchildrenwith
velopharyngeal dysfunction before and after velopharyngeal
surgery.Method:Twelvechildren(6malesand6females)withVelopharyngeal
dysfuctionintheagerangeof7-12yrswereconsideredforthepresent
study.Individualsdiagnosedtohavevelopharyngealdysfunctionby
craniofacialteamusingcineradiographywereconsideredforthestudy.
Maximumphonationtime(MPT),frequencyandintensity,jitter
measurementsweremadeusingLingwavesvoiceclinicsuiteprosoftware
Version 2.5 (Wevosys, Germany).Results and conclusion: There was
significant difference between children
withvelopharyngealdysfunctionandagematchedtypicallydeveloping
childrenonDysphoniaSeverityIndexvalues.Therewasasignificant
difference for I-low (p=0.03) and Dysphonia Severity Index (p=0.01)
for pre
andpost-operativeconditions.Therewassignificantdifferencebetween
genderonFo highandfemales(3.11)hadbetterDSIvaluescomparedto males
(2.37). These results of the present study suggest the need for
gender
specificvoicetherapygoalsinrehabilitationofvoiceproblemsinchildren
with VPD. 2013, IJMHS, All Right Reserved
INTRODUCTIONSpeechisavocalizedformofhuman
communicationthatisdependentontheorganicintegrity
ofthecentralnervoussystem,structuresandfunctionof
theorgansthatcomprisingthespeechproduction
mechanismofthehumanbody.Thespeechproduction process can be divided
into three parts namely respiration,
phonationandarticulation.Respirationprovidesthe
exhalatoryairsupplyneededtoproducethespeech
sounds.Phonationisconcernedwiththevibratory
mechanismthatisneededtochangetheairsupplyinto
voicedspeechsounds.Articulationisconcernedwith shaping sounds into
specific phonemes of a language.
Velopharyngealdysfuction(VPD)isaninabilityto completely close the
velopharyngeal part ofthe oral cavity during speech. This result in
the escape of air into the nasal
cavityduringspeechcausinghypernasalvocalresonance
andnasalemission.ThecausesofVPDmayresultfrom
congenitalshortpalate,deeppharynxandmalinsertionof
thelevatormuscles[15].Individualswithimproper
functioningoftheirvelopharyngealmechanismcanshow
disordersofresonance,articulationandvoice.Voice
problemsrefertodisorderedphonationatthelevelofthe
larynxandcanincludehoarseness,breathiness,low
volume,and/orabnormalpith[15].Thoughthelarynxis the primary
structure for voice production, this system also
requirestheintegrationoftherespiratorysystemandthe
oralandnasalcavitiesofthevocaltract.Duetothe
integratednatureofthespeechsystem,problemsatthe level of the velum
may affect the functioning of the larynx.High prevalence of voice
problems in children with
velopharyngealdysfunction(VPD)werereportedin
literature[2,3,14,19].Theauthorshypothesizedthat
individualswithvelopharyngealdisordersusegrateror
hyperadductionofvocalfoldstocompensatethe
inadequatelyfunctioningvelopharyngealclosure.Voice
qualityreferstothosevoicecharacteristicsthatrecognize
anindividualandtodifferentiatethatindividualfromthe
others.TheabnormalvoicequalityinchildrenwithVPD
mayresultfromforceduseofvocalfoldsinorderto Gnanavel
et.al/Dysphonia Severity Index In Children With Velopharyngeal
Dysfunction: A Pre-Post Operative Comparison. 269
compensatetheinappropriateloudnessproducedby inadequate closure of
velopharyngeal closure.The measurement of voice quality is
important for groupingordescribingtheproblemandplanfor
management.Theperceptualandinstrumentalmethods
wereusedtoevaluatevoicequalityinindividualswith
velopharyngealdysfunction.Theperceptualevaluation methods were
widely used for documentation of severity in voice quality and the
major drawback is that it is subjective
andhasaverylowreliability.Theobjectivemeasuresof
voicequalityassessvariousacousticparametersofvoice.
Thepreviousstudiesreportedthatnotalltheacoustic parameters of voice
correlate well with the perceived voice
quality[7,8,16].Amultiparametricapproachwas
developedwhichusesacombinationofseveralacoustic
andaerodynamicparameterstobettercorrelatewiththe perceived voice
quality.Dysphoniaseverityindex(DSI),oneofthe
multiparametricapproachesforobjectivemeasurementof
voicequalitywasdevelopedbyWuytsetal.[23].The
authorconsideredseveralacousticandaerodynamic
parameterssuchasJitter(%),Shimmer(%),Noiseto
HarmonicRatio(NHR),Highestfrequency(F0-High)(Hz),
F0-Low(Hz),F0-Range(Hz),Semitone-range,Lowest Intensity (I-Low)
(dB), I-High (dB), I-Range (dB), maximum
phonationtime(MPT,s),VitalCapacity(VC)(cc)and
PhonationQuotient(PQ)(cc/s)tocalculatetheweightage of each
parameter on perceived voice quality. On analyzing
theseentirevariablesonnormalanddisordered
population,theauthorderivedtheindexconsistedof
weighedparameterssuchashighestfundamental
frequency(F0-high),lowestintensity(I-low),maximum
phonationtime(MPT)andjitter(%).TheDSIis
constructedasDSI=0.133*MPT+(0.00533*F0-High)- (0.263* I-Low) -
(1.183* Jitter %) + 12.4. TheresultingDSIvaluesvarybetween>+5(No
dysphonia) and < 5 (severe dysphonia). Since the range of
possiblescoresontheseparateparametersiswide,scores
+5(goodvoicequality)or+5(poorvoicequality)are
possibleaswell(Wuytsetal.,2000).DSIisnotlimitedto
theinterval+5,5.Inclinicalpracticevaluesof6and
morearealsoreported.Thisisgenerallycausedbyhigh jitter values. The
DSI can be obtained easily and quickly by speech pathologist in a
clinical setup. The DSI is very useful in evaluation of individuals
with voice problems. Van Lierde et al. [19] examined the vocal
quality and effectofvocalqualityongenderinchildrenwithcleftlip
andpalate.Twentyeightchildrenwithunilateralor bilateral cleft
lipand palate were considered for the study.
Thevoicequalitywasmeasuredusingtheusing
videolaryngostroboscopicandperceptualevaluations, aerodynamic,
voice range, acoustic, and dysphonia severity
index(DSI)measurements.Theresultsshowedgender related vocal quality
differences, the male children showed
overallvocalqualityof+0.62withslighterdegreeof
hoarsenessandfemalechildrenshowed+2.4reflectinga perceptually
normal voice. The results of the present study
providedvaluableinsightsintothevocalquality characteristics
children with cleft palate.
VanLierdeetal.[22]studiedspeechoutcomeon
voicecharacteristicsinsevensubjectsintheagerange
from4.7to9.1yearswithameanageof6.9years
postoperativelyfollowingpharyngealflapsurgery.
DysphoniaseverityIndex(DSI)wascalculatedinsubjects postoperatively
after one year. The stroboscopic evaluation
forvocaloutcomeshowednormalvocalfolds.Theresults showed that
overall vocal quality of the DSI was 1.7 (range
04.8)reflecting,asveryslightlyimpairedvocalquality.
Theseresultsmaybehypothesizedduetothestronger
adductoryforceonthevocalfoldstominimize hypernasality and to reach
specified voice intensity. ThesestudiesbyVanLierdeetal.[19,22]in
literaturehighlightstheincidenceofvoiceproblemsin
childrenwithcleftlipandpalateusingDSI.Theauthors
usedvariousmethodologiesbuttherearenostudiesin
literaturecomparingthepre-operativeDSIparameters with
post-operative DSI in individuals with velopharyngeal
dysfunction.Hencethepresentstudyisaimedtocompare
thepre-operativeDSIscoreswithpost-operativescores after surgery for
velopharyngeal closure. The present study
isalsohypothesizedtostudytheeffectofgenderonvocal quality in
individuals with velopharyngeal dysfunction.METHOD
ParticipantsTwelve children (6 males and 6 females) with cleft
lipandpalateintheagerangeof7to12yrswhohave
undergoneprimarypalatalrepair(cleftofhardpalateand
softpalate,cleftofthesoftpalate)fortheclosureofthe
cleftwillbeidentifiedafterconsultationwithplastic
surgeonwereconsideredforthepresentstudy.Allthe participants were
evaluated by the craniofacial team at unit
forstructuraloro-facialanomalies(U-SOFA),AIISH.
Individualsdiagnosedtohavevelopharyngealdysfunction
bycraniofacialteamusingdirectvisualizationprocedures
suchascineradiography/nasoendoscopywiththehelpof
plasticsurgeonandradiologistwereconsideredforthe
study.Allthesubjectsunderwentsecondaryspeech
surgeryunderthesamesurgeonandthedetailswere
representedintable1.Noneofthemhadcleftassociated
withsyndromes,cognitivedeficits,neuromotor
dysfunction,andahearingthresholdabove20dBinboth ears.Table 1.
Demographic details of children with VPD S.NoSubjectAge/GenderType
of Surgery 1A9yrs/MFurlows Z plasty 2B9yrs/MFurlows Palatoplasty
3C7yrs.MFurlows Double opposing Z plasty 4D12yrs/MFurlows Z plasty
5E7yrs/MFurlows Palatoplasty 6F7yrs/MFurlows Palatoplasty
7G9yrs/FFurlows Z plasty 8H12yrs/FHynes Pharyngoplasty
9I7yrs/FHynes Pharyngoplasty 10J8yrs/FFurlows Z plasty
11K11yrs/FFurlows Z plasty 12L7yrs/FFurlows Z plasty Mean age :
8.75 yearsAll the subjects were followed up after surgery and
evaluationsweredoneaftersixmonths.Awrittenconsent was obtained from
the parents of the participants and they were explained about the
method and the procedure of the study. Procedure and
Instrumentation The individuals considered for present study were
evaluatedforvoicequalityusingLingwavesvoiceclinic
suiteprosoftwareVersion2.5(Wevosys,Germany).The
Lingwavessoftwareisacomputerbasedstandardized measurement system
for voice and speech diagnostics. The
parametersusedforDSImeasurementsarethehighest fundamental frequency
(F0-high in Hz), lowest intensity (I-low in dB sound pressure level
(SPL), maximum phonation time (MPT in sec), and jitter (%). The
testing was done in a Gnanavel et.al/Dysphonia Severity Index In
Children With Velopharyngeal Dysfunction: A Pre-Post Operative
Comparison. 270 veryquietenvironmentwithahelpofSPLmeterandthe
soundpressurelevelduringthesilencedidnotexceed more than 45 dB (A).
The distance between SPL meter and
individualsmouthwasabout30cmandthesubjectwas
instructedtokeepthepositionsamethroughoutthe procedure. The same
procedure was carried out six months
postoperativelyforeachsubject.Thedifferentparameters of DSI
includes a)Maximum Phonation Time (MPT/sec)
MaximumPhonationTime(MPT)wasmeasured on the basis of three trials
with the vowel /a/, sustained at
theindividualshabitualpitchandloudnessinfreefield.
Thelengthofthesustainedvowelwasmeasuredusing
Adobeauditionsoftware(version3).Thebestandlongest
sustainedvowel/a/ofthethreetrailswasmeasuredis seconds (s) and
considered for analysis. b)HighestFrequency(F0-High/Hz)andlowest
Intensity (I low/dB) ThehighestfrequencyandlowestintensityofDSIwas
measured using Voice diagnostic centre (VDC) of lingwaves
software.Thevoicediagnosticcentrerepresentsa
combinedvoicerangeprofileanalysisandvoicequality
analysis.Thesubjectswereinstructedtomaintaina
distanceof30cmfromthesoundlevelmeter.Theywere
askedtophonatevowel/a/assoftlyaspossibleattheir
habitualpitchandlatertheywereaskedtophonatethe
vowel/a/goinguptothehighestpitchandcomingdown to the lowest pitch.
The subjects performed three trials and
thebetteronewasconsideredforanalysis.ThehighestFo
andlowestintensitywerecalculatedfromphonetogram VDC display.
c)Jitter (%) Jitter(%)isaperiodtoperiodvariationin
fundamentalfrequencyanditwascalculatedusing Vospector DSIin
Lingwaves software. Withthe lingwaves
Vospectorwecantakethemeasurementsofvoice
parameterswereextractedforcalculationofDSI.The subjects were asked
to phonate a vowel /a/ at comfortable
pitchandsustainitfor2to3seconds.Themiddleportion
oftherecordedphonationmorethanonesecondwas selected for calculation
of jitter (%). TheDSIisconstructedasDSI=0.133*MPT+
(0.00533*F0-High)-(0.263*I-Low)-(1.183*Jitter%)+
12.4.TheLingwaveDSIclassificationisadifferent compared to Wuyts et
al.23 because the authors used an old jitter algorithm form Kay
Elemetrics system. The lingwaves
usesanewerevaluatedclinicaljitteralgorithmwithon average higher
values ( 4.4 No dysphonia). STATISTICAL ANALYSIS
AcommerciallyavailableIBMSPSS20wasused
forstatisticalanalysisofobtainedvoicedata.Wilcoxon
signedranktestwasdonetofindsignificantdifference
betweenthepre-operativeandpost-operativevaluesof
Dysphoniaseverityindex(DSI).Multivariateanalysisof
variance(MANOVA)wasdonetofindouttheeffectof
genderontheparametersofDSI.Tofindthetestretest reliability 10% of
the data were reanalysed using the same
softwareandtheresultsshowedgreaterthan90%
reliability.RESULTSTheresultsofthepresentstudyareexplainedinthe
following subsectionsa)Comparison of DSI parameters in individuals
with VPDacrossgenderforpreandpost-operative
conditions.ThemeanandstandarddeviationofDSIparameters
acrossgenderforbothconditionswerecompared.
Thedatawasfurthercomparedwithnormativedata for parameters of DSI in
typically developing children [9] and the values were represented
in Table 2.
Table 2. Mean and S.D for DSI parameters in Individuals with VPD
for pre and post operative conditions across gender.
ParameterPreoperativePostoperativeNormative Heylen et al. (1998)
MalesFemalesMalesFemalesMalesFemales MPT(Sec)10.16 (0.75)10.33
(2.73)10.16(1.83)10.33(2.87)14.23(0.27)13.36(0.22)
F0-High(Hz)632.81 (23.53)740.35(22.10)636.56
(12.81)740.80(12.22)861(35)901(31) I-low(dB)53.72(3.76)56.16
(2.63)52.80 (2.57)53.58(2.87)48.3(0.5)47.8 (0.4) Jitter (%)1.48
(0.77)0.47 (0.48)0.83(0.67)0.51(0.25)0.55(0.01)0.61(0.01)
DSI1.28(1.50)2.51 (0.61)2.37 (1.36)3.11(0.84)5.76 The results of
preoperative conditions showed that
maleshadhighervaluesinmaximumphonationtimeand
jitterthanfemalesubjects.Butfemaleshadgratervalues
forFo-high,lowestintensity,DSIthanmalesubjects.In
postoperativeconditions(after6months)themale
participantsshowedgratervaluesforMPT,lowest
intensity,Jitterthanfemalesubjects.Andfemalesubjects showed grater
values for Fo-high and DSI values.
WhencomparingthemeansscoresofDysphonia
severityindex(DSI)formalesandfemalesacrosspreand
postoperativeconditionsboththegendershadincreased
DSIvaluescomparetotheirpreoperativescores.The preoperative quality
of voice was found to be more affected
inmales(DSI=1.28)representingamoderatedegreeof
dysphoniabutinfemales(DSI=2.51)itwasfoundtobe better than males but
still had a slight to moderate level of
dysphonia.ThepostpostoperativeDSIwasfoundtobe
betterinfemales(3.11)representingslightorminimal
degreeofdysphoniaandmales(DSI=2.37)hadslightto
moderatedysphonia.Bothfemalesandmaleshad
improvedvoicequalitycomparedtopreoperative measurements.
Theobtainedmeanscoresforpreandpost-operativeDSIanditsparameterswerecomparedtothe
normativedatabyHeylenetal.[9]usingMannWhitneyU
test.Theresultsshowedthattherewasasignificant
differencebetweennormalsandchildrenwithVPDon
MPT,Fo-high,I-lowandDSIforbothpreandpost-operativeconditions.Therewasnosignificantdifference
wasnotseenacrossgenderbetweenpreandpost-operative conditions.
Gnanavel et.al/Dysphonia Severity Index In Children With
Velopharyngeal Dysfunction: A Pre-Post Operative Comparison. 271
b)Effect of gender on DSI parameters across DSI values for
preoperative condition. Fig.1. Scatterplot showing effect of gender
on DSI parameters A. MPT B.Fo-high C.I-low D. Jitter for
preoperative condition. Thefigure1showstherelationshipbetweenthe
parameters such as MPT, Fo-high, I-low and jitter for males
andfemalesacrosspreoperativeDSIvalues.MANOVAwas
donetofindoutifthereisanysignificantdifference
betweenthegenderandDSIparameters.Theresults
showedasignificantdifferencebetweenthegenderonF0-highvalues[F(1,16)=66.54,p
