The
Diagnostic
Behavioral
Assessment
for
autism
spectrum
disorder—Revised:
A
screening
instrument
for
adults
with
intellectual
disability
suspected
of
autism
spectrum
disorders
Tanja
Sappok
a,1,*
,
Isabell
Gaul
a,1,
Thomas
Bergmann
a,
Isabel
Dziobek
b,
Sven
Bo¨lte
c,
Albert
Diefenbacher
a,
Manuel
Heinrich
aaEvangelischesKrankenhausKo¨niginElisabethHerzberge,Abteilungfu¨rPsychiatrie,PsychotherapieundPsychosomatik,Herzbergstr.79,
10365Berlin,Germany
bClusterofExcellenceLanguagesofEmotion,FreieUniversita¨tBerlin,HabelschwerterAllee45,14195Berlin,Germany
cDepartmentofWomen’sandChildren’sHealth,CenterofNeurodevelopmentalDisorders,KarolinskaInstitutet,SE-17177Stockholm,
Sweden
1. Introduction
Individualswithintellectualdisability (ID) exhibitan increasedrisk for autism spectrumdisorder (ASD),which is associatedwithhighratesofcomorbidmentalhealthproblemsandchallengingbehaviors(Matson&Shoemaker,2009; McCarthyetal.,2010;Sappok,Bergmann,Kaiser,&Diefenbacher,2010;Sappok,Budczies,Dziobek,etal.,2013).ASDisa neurodevelopmentaldisordercharacterizedbyimpairmentsinsocialcommunicationandrepetitive,stereotypedbehaviors
ARTICLE INFO
Articlehistory:
Received1November2013
Receivedinrevisedform16December2013 Accepted26December2013
Keywords:
Autismspectrumdisorder Intellectualdisability Diagnostics
Psychometricproperties Adults
ABSTRACT
Giventhestrongassociationbetweenintellectual disability(ID)andautismspectrum disorder(ASD),standardizedinstrumentsfortheassessmentofASDinadultswithIDare desirable.TheDiagnosticBehavioralAssessmentforASD–Revised(DiBAS-R)isa DSM-5/ICD-10basedcaregiver-reportscreeningtoolthatconsistsof19Likert-scaleditems.Thisstudy evaluatedtheitem-validities,item-difficulties,item-variances,part-wholecorrecteditem total-correlations,reliability,andthefactorial,diagnostic,andconvergent/discriminant validitiesoftheDiBAS-Rinaclinical,adultIDsample(N=219).Factoranalysisyieldedtwo consistent dimensions; i.e., social interaction/communicationand stereotypy/rigidity/ sensoryabnormalities.Thediagnosticvaliditywasadequate,asreflectedbyanareaunder thecurveof0.89andbalancedsensitivityandspecificityvaluesof81%.TheDiBAS-Rtotal scoresweresignificantlycorrelatedwiththeSocialCommunicationQuestionnaire(r=0.52), theScaleforPervasiveDevelopmentalDisordersinMentallyRetardedPersons(r=0.50),and theAutism-Checklist(r=0.59),whilenosignificantcorrelationwiththeModifiedOvert AggressionScalewasobserved.Theinterraterreliabilitywasexcellent(ICC=0.88).These findingsindicatethattheDiBAS-Risapromisingandpsychometricallysoundinstrument forASDscreeningofadultswithID.
ß2014ElsevierLtd.Allrightsreserved.
*Correspondingauthor.Tel.:+493054724950;fax:+493054722943.
E-mailaddresses:t.sappok@keh-berlin.de,tanja.sappok@t-online.de(T.Sappok).
1 Theseauthorssharedfirstauthorship.
ContentslistsavailableatScienceDirect
Research
in
Autism
Spectrum
Disorders
J our na l ho me pa ge : ht t p: / / e e s. e l s e v i e r. c om/ R A S D / de f a ul t . a sp
1750-9467/$–seefrontmatterß2014ElsevierLtd.Allrightsreserved.
andinterests(DSM-5;AmericanPsychiatricAssociation,2013).Approximately25%ofpeoplewithIDexhibitcomorbidASD (Fombonne,2009;Kim,2011;Sappoketal.,2010).WhileASDonsetoccursinearlychildhood,manyASDpatientswith comorbidIDremainundiagnosedanduntreateduntiladulthood(Malfa,Lassi,Bertelli,Salvini,&Placidi,2004;Sappok, Diefenbacher,Budczies,etal.,2013).
Diagnosing mental disorders or ASD in patients with ID remains challenging for a number of reasons. Firstly, individuals with ID are less able to report their inner experiences due to diminished speech comprehension and expressive abilities(Balboni,Coscarelli,Giunti,&Schalock,2013).Secondly,duetodiagnosticovershadowing(Reiss& Szyszko, 1983),problem behaviorsor mental disordersmay beattributed totheID itselfrather thananadditional comorbid diagnostic entity. Thirdly, diagnostic substitution, i.e., diagnosing ASD rather thanID may occur (King & Bearman, 2009; Shattuck, 2006; Weintraub, 2011). Fourthly, neurological disorders, such as sensory or motor impairmentsandepilepsy,mayfurtherhamperdiagnosticclarification(Matson&Shoemaker,2009).Finally,currently, manyadultswithIDhavebeenraisedin long-termmental institutionsand/orhavelost contactwiththeirrelatives (Haberfellner,Grausgruber,Grausgruber-Berner,Ortmair,&Scho¨ny,2004);thus,theirmedicalhistoriesarefragmented, whichproducesdifficultiesintheproperdiagnosticclassificationofASD.OnthebackgroundofDSM-5’semphasisona lifetime perspective for diagnosing ASD, a thorough medical history with detailed and reliable early childhood informationgetevenmoreimportant.
Forthisreason,ASDdiagnosticsfor thisgroup aremainlybasedonassessmentsof currentbehavior.Individuals withID,especiallythosewithcomorbidASD,maybehavedifferentlywheninteractingwithunfamiliarpeopleorwhen inanunfamiliarenvironment,suchasaclinicalsetting(Gerberetal.,2011;Kumin,1994).Therefore,itismandatory thatinformationfromtheprivate livingenvironment,includinginformationfromclose caregivers,besoughtin the diagnosticprocess.DiagnosticclarificationallowsformoreappropriatetreatmentoptionsinIDandcomorbidASDthat include non-drug strategies and lead to improved mental health and quality of life (Gordon et al., 2011; van Bourgondien, Reichle, & Schopler, 2003). Standardized, evidence-based instruments can support clinicians and researchersinthisdiagnosticprocess;e.g.,theAutismDiagnosticObservationSchedule(ADOS;Lordetal.,1989),the PervasiveDevelopmentalDisorderinMentalRetardationScale(PDD-MRS;Kraijer,2006;Kraijer&Melchers,2003),the Social Communication Questionnaire (SCQ; Berument,Rutter, Lord, Pickles, & Bailey, 1999; Rutter, Bailey, & Lord, 2001), the Autism Spectrum Disorder-Diagnostic Scale for Adults (ASD-DA; Matson, Boisjoli, Gonza´lez, Smith, & Wilkins, 2007; Matson, Wilkins, Boisjoli, & Smith, 2008), and the Autism-Checklist (ACL; Sappok, Heinrich, & Diefenbacher,2013).
The ADOSisa semi-structuredobservationalinstrument thatassessessocial communicativeabilities(Lordetal., 1989),whiletheADI-Risasemi-structuredparentalinterviewthatevaluatessocialinteraction,communication,and restrictive,repetitivebehaviorsandinterestsfromchildhoodtoadulthood(Lord,Rutter,&LeCouteur,1994).Thesetwo instrumentsarefrequentlyusedincombinationfordiagnosingautisminchildrenandtheyhaverecentlybeenvalidated foradultswithID(Sappok,Diefenbacher,Budczies,etal.,2013).However,bothmeasuresaretime-consumingandcan onlybeappliedtoalimitednumberofadultswithID(Sappok,Diefenbacher,Budczies,etal.,2013).Withincreasing severityofIDandcomorbidityofASD,thefeasibilityoftheADOSwasreducedto68%,whiletheapplicabilityoftheADI-R wasevenreducedto37%,presumablyduetolossofcontacttocloserelatives.TheSCQisascreeninginstrumentthat consistsof40binaryitemsthatareratedbyparentsorclosecaregivers(Berumentetal.,1999;Rutteretal.,2001).There arelifetimeandcurrentversionsoftheSCQ.TheSCQ-lifetimehasbeenfoundtohaveparticularlypoorspecificityvalues incasesofmoderateandsevereID(Sappok,Diefenbacher,Gaul,&Bo¨lte,inpress).Raisingthecut-offvalueofthe SCQ-currentimprovesdiagnosticvalidityforthisspecialgroupofpatients,butthespecificityremainsratherlow.TheASD-DA isanotherdiagnosticinstrumentthatconsistsof31itemsinwhichtheraterendorsesas0fornoimpairment/notdifferent,
or1forsomeimpairment/different.Theratersareinstructedtocomparethetargetpersontoanindividualwithasimilar
age living in the community. A three-factor modelwas computed forthe scale,which showed good psychometric properties(Matsonetal.,2007;Matsonetal.,2008).ThePDD-MRS assessesbehaviorsduringdailyroutinesandwas conceptualized for individualswithID betweenthe agesof2 to70years(Kraijer, 2006;Kraijer &Melchers, 2003). Althoughthistestisconsideredascreeninginstrument,itscompletiontakesapproximatelyhalfanhour,andthetest mustbeadministeredbyaspecialist;e.g.,apsychologistorpsychiatrist.TheAutism-Checklist(ACL)isanICD-10-based screening instrument for physicians. This test evaluates characteristic social interaction, communication, and stereotypies.The completion of thistestrequires approximately 10min. Asthesensitivity andspecificity valuesof thistestare 91and68%, respectively,theACLis asuitable measureforadultswith IDandsuspected ASD(Sappok, Heinrich,etal.,2013).Inconclusion,thereisaneedforanASDscreeninginstrumentthatcanbeeasilyadministeredby close caregivers without specific knowledge of ASD. For this purpose, we developed a 20-item questionnaire, the DiagnosticBehavioralAssessmentforASD(DiBAS)thatisderivedfromtheICD-10andDSM-5criteriaforASD.Inapilot study,theDiBASwasappliedto91patientswithIDandsuspectedASD(Sappok,Gaul,etal.,2014).Itemvalidityanalysis revealed8itemsthatdidnotdifferentiatesufficientlybetweenindividualswithandwithoutcomorbidASD,anddespite theappropriatesensitivityof83%,thespecificitywaslow(64%).Thus,anitem-revisionoftheDiBASwasrecommendedto furtherimproveitsdiagnosticvalidity.Theinvaliditemswerereplacedbyanother8ICD-10/DSM-5-basedquestionsto replenishtheDiBAS-Revised(DiBAS-R).
2. Materialandmethods
2.1. Settinganddesign
ThestudywasconductedatadepartmentofpsychiatryspecializedinmentalhealthcareforadultswithIDinBerlin, Germany.Thisserviceconsistsofanin-andoutpatientunitandoffersassessmentandtreatmentforadultswithIDand mentaldisordersand/orseverechallengingbehaviors.Giventhissetting,allparticipantsofthisstudyhavehadanadditional mentalorbehavioralproblemonadmission.ASDassessmentincludingtheDiBAS-Rwasappliedafterremissionoftheacute mentalillnessinthein-oroutpatientservice.DiagnosticclassificationincludingASDandseverityofIDwasconductedin accordancewiththediagnosticresearchcriteriaformentaldisordersproposedbyICD-10.TheDiBAS-Rwascompletedbya closecaregiver,i.e.,aparentorastaffmemberofaresidentialhomeinoutpatientsandapsychiatricnurseorspecialneeds caregiverininpatients.Inarandomfashion,theDiBAS-Rwashandedouttwicetoassessinterraterreliabilitybytworatings fromdifferentratersonthesameindividual.
ASDdiagnoses wereassigned byamultidisciplinaryteam consensusconferenceaccordingtotheICD-10diagnostic researchcriteriaforautismoratypicalautism[F84.0/F84.1].Ifnoinformationaboutthedevelopmentalhistorycouldbe obtained,atypicalautismwasdiagnosed.Asdifferentiationbetween autism(F84.0)andatypicalautism(F84.1)almost alwaysdepended ontheavailabilityofearlychildhoodinformation(F84.10),we subsumedthesediagnoses underthe broadertermofASD;however,participantsclinicallyappearedtohavesevereformsofclassicalautism.
Themultidisciplinaryteamconsistedofatleasttwo psychiatrists,a clinicalpsychologist,a specialneeds caregiver, therapists,andnursingstaffthatwasexperiencedinthefieldsofIDandASD.Thediagnoseswerebasedonallavailable information,includingmedicalhistories,psychiatricandphysicalexaminations,structuredvideo-basedbehavioranalyses acrossavarietyofcontexts,andvariousstandardizedmeasuressuchastheACL(Sappok,Heinrich,etal.,2013),the SCQ-current(Bo¨lte&Poustka,2006;Rutteretal.,2001),thePDD-MRS(Kraijer,2006;Kraijer&Melchers,2003),and,incasesof diagnosticuncertainty,theADOS(Lord,Rutter,DiLavore,&Risi,2001),theADI-R(Rutter,LeCouteur,&Lord,2003),the SchemeofAppraisalofEmotionalDevelopment(SAED;Dosen,2005a,2005b;Sappok,Budczies,Bo¨lte,etal.,2013),andthe Music-basedScaleforAutismDiagnostics(MUSAD;Bergmann,Sappok,Diefenbacher,&Dziobek,2012).Convergentvalidity wasassessedbycorrelationanalysiswiththeSCQ,theACL,andthePDD-MRS,whiledivergentvaliditywasassessedby correlationanalysiswithanon-ASDmeasure,theModifiedOvertAggressionScale(MOAS).TheACLwascompletedbythe primarypsychiatrist,theSCQ-currentwascompletedbyaninformantfromthepatient’sprivatelivingenvironment,andthe PDD-MRS,theADOS,andtheADI-Rwerecompletedbyapsychologist(H.K.)whowasnotinvolvedinthestudy.Existingdata fromdiagnosticprocedureswereused,andtheseprocedureswereperformedwiththeinformedconsentofthepatientsasa partofroutinepatientcare(Landeskrankenhausgesetz§25.1,version18.09.2011).Thestudywasadditionallyapprovedby thelocal ethicscommittee (06.10.2009)and wasconducted accordingto therecommendationsof theDeclaration of Helsinki.
2.2. Sample
Thesampleconsistedof219adultswithIDwhowereadmittedtothein-oroutpatientspecializedpsychiatricservice describedabovebetween1/2012and7/2013.Themeanageoftheparticipantswas35.0years(SD=12.0).Overall,77(35%) participantswerediagnosedwithadditionalASD.Morethanhalfofallparticipants(n=125;57%)weremales.Therateof comorbiditybetweenIDandASDwashigherinthemalesthaninthefemales,
x
2(1,N=219)=6.70,p=0.01,and68.8%ofthe individualsdiagnosedwithASDweremale.Thus,thefrequencyofmaleadultswithASDwashigherthantheexpected frequency(standardizedPearsonresidual=2.6).Thebaselinecharacteristicsofthestudypopulationaredescribedindetail inTable1.LevelofIDwasassessed withtheDisabilityAssessmentSchedule (DAS,Meins &Su¨ßmann,1993)or standardized intelligencetests,e.g.,theColoredProgressiveMatrices,theKaufmann-Assessment-BatteriesforChildren,the Snijders-Omen-NonverbalIntelligenceTest,andtheWechsler-IntelligenceTestforAdults.TheDAShasdemonstratedconvergent validitywithestablishedmeasuresofnonverbalIQ,suchastheColoredProgressiveMatrices(r=0.75)andtheColumbia MentalMaturityScale(r=0.77;Holmes,Shah,&Wing,1982;MeinsandSu¨ßmann,1993).IncasesinwhichstandardizedID assessments were not available, intellectual functioning was categorized based on the daily living skills and social-communicationmaturityusingjudgmentofaclinicalpsychiatristwhowasexperiencedinthefieldofID.Sixty-eight(31%) individualswereclassifiedwithmildID,83(38%)withmoderateIDand68(31%)withseveretoprofoundID.Combined,the individualswithID/ASDexhibitedgreaterdegreesofID,
x
2(2,N=219)=17.92,p<0.001.Thefrequencyofindividualswithsevere-to-profoundIDwashigherthantheexpectedfrequencyintheASDgroup(standardizedPearsonresidual=4.0).The proportionsofparticipantswithmildIDwerelowerthanexpectedintheASDgroup(standardizedPearsonresidual= 2.6) andhigherintheID-onlygroup(standardizedPearsonresidual=2.6).However,thefrequencyofmoderateIDintheASD groupdidnotdiffermeaningfullyfromtheexpectedfrequency(standardizedPearsonresidual= 0.9).
Mooddisorders(F3:n=93,43%),schizophrenia(F2:n=56,26%)andneurotic,stress-relatedandsomatoformdisorders (F4:n=37,17%)werethemostcommonpsychiatricconditionsinthissample.Non-ASDindividualsweremorelikelytohave personality disorders compared to individuals with ASD,
x
2 (1, N=219)=9.99, p<0.01. No individual with ASDEpilepsywasthemostcommonneurologicaldisorderinthissample(n=56,26%);20(9%)participantssufferedfroma disablingvisualdisorder,8(4%)hadaseverehearingdisorder,and19(9%)sufferedfromarelevantmovementdisorder.One hundredthirty-one(60%)weretakinghigh-potencyantipsychoticssuchasolanzapine,risperidone,oraripiprazole,67(31%) were taking low-potency antipsychotics such as promethazine, melperone, or pipamperone, 69 (32%) were taking antidepressants,78(36%)weretakinganticonvulsants,and29(13%)weretakingbenzodiazepines.Nosignificantgroup differenceswereobservedbetweentheASDandnon-ASDgroupswithrespecttoneurologicalcomorbiditiesormedication. ThesamplecharacteristicsoftheadultsIDaloneandthosewithcombinedIDandASDaresummarizedinTable1.
2.3. Measures
2.3.1. DiagnosticBehavioralAssessmentforASD–revised(DiBAS-R)
TheDiBAS-Risa20itemscreeningscalethatwasdevelopedtoassessautisticfeaturesinadultswithIDandiscompleted byprofessionalcaregiversorrelatives.Eachquestioniswordedinplainlanguagetoallowratingbypersonswithoutany specificknowledgeofASD.ThequestionnairewaswrittenandadministeredinGerman;theitemsweretranslatedforan English-speakingaudience(c.f.Table2).Thescaleiseasytoadministerandself-explanatoryandthusdoesnotrequireany preparatorytraining.
TheitemsoftheDiBAS-Raretheresultofanitemselectionprocedurethatwasconductedinaclinicalsampleofadults withID(N=91),which hasbeendescribed indetail elsewhere(Sappok,Gaul, etal.,2014). Briefly,20 questionswere formulatedaccordingtothediagnosticcriteriaforASDlistedintheICD-10andDSM-5.Informationfromareviewofthe literaturefocusingonsymptomsthatdifferentiateASDformID-only,anitemanalysisonotherdiagnosticmeasuresforASD, e.g.,theADOS,theDiBAS,andtheACL,andexperiencesfromclinicalexpertsinthefieldofIDandASDendorsedtheitem deductionprocess.Theseitemswereevaluatedintermsofdiagnosticvalidityusingthefinaldiagnosticclassificationofthe multidisciplinarycaseconferenceasanexternalcriterion(Sappok,Gaul,etal.,2014).Theresulting12discriminativeitems werecomplementedby8additionalitemsthatassesstypicalASDbehaviorsinadultswithID.Theitemsarescoredonthe following4-pointordinalLikertscale:certainlytrue(3points),oftentrue(2points),sometimestrue(1point),andnevertrue(0 points).Thefinalscoresrangefrom0to60,andhigherscoresindicategreaterASDsymptomloads.
2.3.2. SocialCommunicationQuestionnaire(SCQ)
The SCQ is an ASD screening scale that assesses autistic features in communication, interaction,and stereotyped behaviorsusing40binaryitemsthatwerederivedfromtheADI–R(Berumentetal.,1999;Lordetal.,1994).Themaximum Table1
Samplecharacteristics.
Samplecharacteristics(N=219) ASD/IDcombined ID-only pa
Generalcharacteristics
N 77 142
Age 35.2(12.0) 34.9(12.1) 0.88b
Gender(male) 53(68.8%) 72(50.7%) 0.01*
SeverityofID
MildID 14(18.2%) 54(38.0%) <0.001***
ModerateID 26(33.8%) 57(40.1%)
Severe–profoundID 37(48.1%) 31(21.8%)
Psychiatriccomorbidities
Mentaldisordersduetopsychoactivesubstanceuse(F1x.x) 2(2.6%) 6(4.2%) 0.72c
Schizophrenia(F2x.x) 24(31.2%) 32(22.5%) 0.16
Mooddisorders(F3x.x) 30(39.0%) 63(44.4%) 0.44
Neurotic,stress-relatedandsomatoformdisorders(F4x.x) 13(16.9%) 24(16.9%) 0.99
Personalitydisorders(F6x.x) 0(0%) 17(12.0%) <0.01**
Neurologicalcomorbidities
Hearingdisorder 3(3.9%) 5(3.5%) 0.99c
Visualdisorder 7(9.1%) 13(9.2%) 0.99
Movementdisorder 3(3.9%) 16(11.3%) 0.06
Epilepsy 19(24.7%) 37(26.1%) 0.82
Medication
Highpotencyantipsychotic 49(63.6%) 82(57.7%) 0.40
Lowpotencyantipsychotic 28(36.4%) 39(27.5%) 0.17
Antidepressant 19(24.7%) 50(35.2%) 0.11
Anticonvulsant 22(28.6%) 56(39.4%) 0.11
Benzodiazepine 12(15.6%) 17(12.0%) 0.45
a p-valueasresultofx2-testifnotindicatedotherwise.
b t-Testforindependentsamples. cFisher’exacttest.
scoresare39forverbaland33fornonverbalindividualsbecauseoneitemclassifiesgeneralverbalabilitiesandcanleadto theexclusion ofitems thatask forindividual characteristicsin theuseoflanguage.To fulfillthediagnosticpurpose, individualsshouldbeatleast4yearsoldandshouldnecessarilyhaveachievedadevelopmentalageof2yearsormore (Rutteretal.,2001).Inthisstudy,theGermanversionoftheSCQ-currentwasapplied(Bo¨lte&Poustka,2006).Thediagnostic validityoftheSCQhasbeenassessedintoddlers,youngchildrenandadolescents(e.g.,Allen,Silove,Williams,&Hutchins, 2007; Berument et al., 1999; Bo¨lte, Crecelius,& Poustka, 2000; Bo¨lte, Holtmann, & Poustka, 2008, Bo¨lte, Poustka,& Constantino,2008;Oosterlingetal.,2009).ArecentstudyofthediagnosticvalidityofthisscaleinadultswithIDrevealeda highsensitivitybutalowspecificityinthispopulation(Sappok,Diefenbacher,Gaul,etal.,inpress).
2.3.3. PervasiveDevelopmentalDisorderinMentalRetardationScale(PDD-MRS)
ThePDD-MRSisaninterview-basedscreeningquestionnairethatwasspecificallydesignedtoassessASDinindividuals withIDusing12binary,partlyweighteditems.TotalPDD-MRSscorescanrangefrom0to19,andscores>9resultinASD
classification(Kraijer&Bildt, 2005). A comprehensive studythat wasconductedtonorm this instrumentresulted in promisingoverallsensitivityandspecificity(both92%;Kraijer&Bildt,2005).Additionally,thePDD-MRShasproducedgood resultsintermsofitsdiagnosticvalueoverthecompleterangesofIDandagecoveredinthepresentstudy(Kraijer&Bildt, 2005).
2.3.4. Autism-Checklist(ACL)
TheACLisanexpert-ratedscreenerforASDinadultswithIDandwasderivedfromtheICD-10researchcriteriaforautism (F84.0)andatypicalautism(F84.1).Eachdomain(socialcommunication,interaction,andstereotypedbehaviors)consistsof 4ordinalitemsthatinclude0(noASD),0.5(suspectedforASD)and1(ASD).TheACLhasshowngoodpsychometricproperties andaninternalconsistency(i.e.,Cronbach’salpha)of
a
=0.81,adiagnosticvalidity(i.e.,areaunderthecurve)of0.86,an overallpredictivevalueof80.5%,aCohen’skappaof0.60,andsensitivityandspecificityvaluesof91%and68%,respectively. TheACLsumscorewashighlycorrelatedwithestablishedscreeningmeasuressuchastheSCQ(Spearman’srho(rs)=0.62) andthePDD-MRS(rs=0.49).Theinterraterreliabilityassessedinasampleof53individualswasgood(Cohen’skappa=0.70; rs=0.55;Sappok,Heinrich,etal.,2013).Table2
Itemcharacteristicsandfactorloadings.
Subscale Patternmatrix
(N=219)
Itemcharacteristics (N=196)
Ma
SCI factor
SRS factor
Item difficulty
Item variance
rit ID/
ASD ID-only
Socialcommunicationandinteraction
1. Doeshesmilebackwhensmiledat? 0.71 0.22 0.43 1.18 0.72 1.9 1.0
2. Canyoutellhowhefeelsbyhisfacialexpression? 0.75 0.02 0.40 0.78 0.63 1.6 1.0
3. Doeshehavefriendshipswithpeers? 0.81 0.15 0.70 1.21 0.75 2.8 1.7
5. Doesheshowyouthingshelikesorisinterestedintoshare enjoymentwithyou?
0.88 0.04 0.53 1.21 0.77 2.2 1.3
7. Doeshecomfortothersiftheyaresad? 0.83 0.15 0.79 0.80 0.72 2.8 2.1
8. Doesheinvolveyouinactivitiesthatresultintakingturns andsharedexperiences?
0.87 0.05 0.66 1.03 0.74 2.5 1.7
9. Doeshespontaneouslyjoingroupactivities? 0.79 0.00 0.64 1.17 0.65 2.4 1.6
11. Doesherespondinapositivewaywhensomebodyelse approacheshim?
0.74 0.04 0.47 0.78 0.69 1.9 1.2
12. Doesherefertohimselfinthefirstperson,e.g.,‘‘I‘‘,and‘‘me‘‘? 0.61 0.27 0.52 1.91 0.64 2.5 1.1
14. Doeshelookupandpayattentiontoyouwhenyoutalktohim withoutcallinghisname?
0.63 0.17 0.32 1.01 0.59 1.5 0.7
16. Doeshenodtomean‘yes’? 0.60 0.06 0.59 1.62 0.52 2.3 1.5
18. Doeshetalktoyoujusttobefriendly? 0.62 0.08 0.71 1.22 0.53 2.5 1.9
Stereotypy,rigidity,andsensoryabnormalities
4. Arethereparticularritualsthatareimportantforhim? –0.17 0.78 0.52 1.42 0.61 2.4 1.1
6. Doesherepeatcertainwordsinexactlythesameway? 0.13 0.61 0.31 1.19 0.47 1.3 0.7
10. Doeshehaveunusualhobbiesorinterests;e.g.,flippingthroughbooks, timetables,orelectricalappliances?
0.06 0.68 0.31 1.42 0.55 1.6 0.6
13. Doesheliketosmellortapatobjects/walls? 0.23 0.67 0.18 0.93 0.56 1.2 0.2
15. Doesheshowchallengingbehaviorwhenunpredictablechangesoccur? 0.15 0.72 0.51 1.12 0.66 2.3 1.2
17. Doesheshowoddmovementsofhisbody,suchasrocking,fingerflapping, walkingontiptoes,orspinningaroundhisbody’saxis?
0.24 0.81 0.38 1.56 0.76 2.1 0.6
19. Doesheshowself-injuriesbehavior? 0.16 0.57 0.36 1.35 0.54 1.7 0.7
Note.Factorloadingsprintedinboldfaceare>0.40(Geominrotation).SCI=SocialCommunicationandInteraction;SRS=Stereotypy,Rigidity,andSensory
Abnormalities;M=meanvaluesforindividualswithIDandASDandID-only;rit=part-wholecorrecteditemtotalcorrelationcalculatedforeachsubscale
separately.
2.3.5. ModifiedOvertAggressionScale(MOAS)
TheMOASisaratingscalethatassessestheintensityofaggression(verbal,towardobjects,towardtheself,andtoward others;Knoedler,1989;Yudofsky,Silver,Jackson,Endicott,&Williams,1986).Oliver,Crawford,Rao,ReeceandTyrer(2007) assessedtheinterraterreliabilityofthisinstrumentinasmallsampleofadultswithID.Theanalysisresultedinpromising estimationforMOASoverallscore(ICC=0.93).
2.4. Dataanalysis
DifferencesindemographicandclinicalcharacteristicsbetweentheparticipantswithcombinedIDandASDandthose withIDalonewereassessedusinga
x
2-tests(orFisher’exacttestswhenappropriate)forcategoricalvariablesort-testsfor independentsamplesincaseofcontinuousvariables(i.e.,age).StandardizedPearsonresidualswereadditionallycalculated whenthex
2-testsweresignificanttogetanimpressionofthesizeandthedirectionofthedifferenceofobservedand expectedfrequenciesinsinglecellsofacontingencytable(Agresti,2002).Inthiscasetheterm‘expected’ referstothe frequenciesestimatedonthebasisofobservedfrequenciesundertheassumptionthatthetwocategoricalvariablesarenot associatedwitheachother(Eid,Gollwitzer,&Schmitt,2011).AstandardizedPearsonresidual(absolutevalue)greaterthan2 indicatesarelevantdiscrepancy(Agresti,2002).Anexploratoryfactoranalysis(EFA)wasappliedtotheitemsoftheDiBAS-R.Inthisnewlydevelopedscale,thefactor structurewasnotpredetermined.Sincetheitemshavenotbeenfactoranalyzedbefore,anexploratoryprocedurewasused. Anobliquerotationmethod(Geomin)thatallowedforfactorcorrelationswasutilized(Fabrigar,Wegener,MacCallum,& Strahan,1999).Singleitemsweretreatedasordered-categoricalvariables;thus,arobustweightedleastsquare-meanand varianceadjusted(WLSMV)-estimatorwasused(Muthe´n,DuToit,&Spisic,1997).Asrecommended,morethanonecriterion wasconsideredwhendeterminingthenumberofthefactors(Costello&Osborne,2005).Inthisstudy,eigenvaluecriteria (i.e.,factorswitheigenvaluesgreaterthan1 wereconsideredtolikely bemeaningful),scree plotevaluations,andthe interpretabilityoftheextractedfactors(whichwastakenasthemostimportantcriterion)wereutilized.Additionally,root meansquareerrorsofapproximation(RMSEAs),standardizedrootmeansquareresiduals(SRMRs),comparativefitindices (CFIs)andchi-squaredstatisticsarereportedforevaluationsofmodelfit.RMSEAs0.06,SRMRs0.08andCFIs0.95were usedascutoffsforgoodmodelfit(Hu&Bentler,1999;Muthe´n,1998–2004).Thechi-squaredstatisticswererequiredtobe non-significanttoindicategoodmodelfits.Theentiresample(N=219)wasincludedintheEFA,whichwasperformedwith MPlus6.1(Muthe´n&Muthe´n,1998–2010).Theresultsofthefactoranalysiswereusedtogrouptheitemsintosubscales.The reliabilitiesofthesubscalesandthereliabilityoftheentirescalewerecalculatedintermsofinternalconsistenciesusing Cronbach’salpha.
Caseswithoneormoremissingvaluesonanyoftheitemswereexcludedfromfurtheranalyses.Theitemanalyses consisted of calculatingtheitem-validities,item-difficulties, item-variances, and thepart-wholecorrected item total-correlations(separatelyforeachsubscale;Kelava&Moosbrugger,2012).Allthesemeasuresareofhighlydescriptivevalue. ItemvaliditymeasuresthediscriminantpowerofeachsingleitemfordifferentiationofASDandnon-ASDbehaviors. Consideringthelikert-typescale,itemvaliditywasassessedbyMann–WhitneyUtests.
Item-difficultieswerecalculatedbysummingallobservedscoresofasingleitemanddividingthissumthroughthescore which wouldresultifallindividualsreach themostsymptomatic categorywhich iscertainlytrue (3points;Kelava& Moosbrugger,2012).Ahighervalueofitemdifficultyindicatesthatmoreindividualsdisplayacertainbehaviorassessed withthis item.Eachitem shouldshowa varianceabovezerotobeabletodepictdifferencesbetweenindividuals.The associationofeachitemwiththewholescalewasevaluatedwithpartwholecorrecteditem-totalcorrelations.Ingenerala highcorrelationbetweensingleitemscoresandthesumscoreoftherestoftheitemsaredesirable(Kelava&Moosbrugger, 2012). This indicates that differences in singleitem scores arereflected in differences in totalsumscores (Kelava & Moosbrugger,2012).
Toassessdiagnosticvalidity,Mann–WhitneyUtestswereusedtoassessthestatisticalsignificanceofdifferencesin DiBAS-Rsum-scoresanditemscoresbetweenparticipantswithandwithoutASD.Mann–WhitneyUtestsisarankbased procedure which is moreappropriate withordinaldata (Gravetter &Wallnau, 2009). Receiveroperatorcharacteristic analyses(ROCs)wereusedtocalculatethesensitivitiesandspecificitiesoftheobservedscoresthatwereextractedfromthe DiBAS-Rsubscalesandtotalscoreusingthediagnosticdecisionsofthemulti-professionalcaseconferenceastherelevant diagnosticcriterion.AROCcurvewasplottedtovisualizetherelationofsensitivityandspecificityovertheentirerangeof observedscores.Theareaunderthecurve(AUC),whichindicatesthegeneraldifferentiatingvalueofatest,wasdetermined (Goldhammer&Hartig,2012).
Atwo-stepexploratoryprocedurewasusedtodeterminetheoptimalcut-off.Inthefirststep,separatepotentialcut-offs foreachsubscaleandthetotalscoreweredeterminedusingROCanalyses.Inthesecondstep,severalcombinationsof cut-offswereevaluatedintermsofdiagnosticvalues.Thecombinationofcut-offsthatachievedthemostbalancedsensitivity and specificitywasused.Allfurtheranalyseswerebasedonthis cut-off.Cohen’kappawascalculated toevaluatethe agreementbetweenthediagnosticdecisionsoftheDiBAS-Randthoseoftheconsensusconference.
betweentheDiBAS-RandMOAStotalscores.Ashintfordivergentvaliditythecorrelationshouldbenon-significantand closetozero.
InterraterreliabilitywasestimatedbycalculatingtheICCsbetweentheoverallDiBAS-Rtotalandsubscalescores.ICCisa commonproceduretoquantifythedegreetowhichscoresofagiveninstrumentresembleindifferentratings.
Thescale’sfeasibilitywasassessedusingtheproportionofcompletedratingsonscaleanditemlevel.
Alltestsexcepttheassessment of convergentand divergentvalidity wereperformedtwo-tailed,and p<0.05was
consideredstatisticallysignificant.Alldataanalyses,withtheexceptionofthefactoranalysis,wereperformedwithSPSS 15.0.ROCcurveswerevisualizedusingR(RCoreTeam,2013).
3. Results
3.1. Factoranalysis
Inthefirststep,all20itemswereusedinthefactoranalysis.Threeeigenvaluesgreaterthan1indicatedathree-factor solution(eigenvalues:9.41,2.71,1.13,and0.93),andexplorationofthescreeplotindicateda2-factorsolution.Examination ofthepatternmatrixoftheGeomin-rotated2-and3-factorsolutionsidentifiedthe2-factorsolutionasthemostappropriate in terms of interpretability and the DSM-5 diagnostic criteria. Only one item (‘‘Does he useyour hand as a tool to communicatehisneeds?’’)showedcomparableloadingsonbothfactorswithaloadingdifferencebelow0.15.Thisitemwas thereforeremoved,andthefactoranalysiswasrerunwith19items.Forthissolution,theRMSEA=0.058,90%CI[0.045, 0.070],theCFI=0.98,andtheSRMR=0.052indicatingatleastadequatemodelfit.However,achi-squaredtestofmodelfit wassignificantwitha
x
2(134)=233.3,p<0.001.Theitemsassociatedwithsocialcommunicationandinteractionloadedonthefirstfactor,whiletheitemsassociatedwithrestrictive,repetitivebehaviorsandsensoryaspectsloadedonthesecond factor.Thetwofactorswerecorrelated(r=0.50).ThefactorloadingsoftheGeomin-rotated2-factorsolutionarepresentedin Table2.
Items with loadings >0.40 on one factor were grouped into subscales. The first subscale was termed Social
CommunicationandInteraction(SCI)andthesecondsubscalewastermedStereotypy,Rigidity,andSensoryAbnormalities (SRS).
TheSocialCommunicationandInteractionsubscaleconsistedof12items.Allitemsexhibitedstrongfactorloadingsthat rangedfrom0.60(DiBAS-R:16–‘‘Doeshenodtomean‘yes’?’’)to0.88(DiBAS-R:5–‘‘Doesheshowyouthingshelikesoris interestedintoshareenjoymentwithyou?’’).TheStereotypy,Rigidity,andSensoryAbnormalitiessubscaleconsistsof7 items.Allitemsshowedstrongloadingsonthesecondfactor(0.57).Theinternalconsistencieswere
a
=0.91anda
=0.84 fortheSocialCommunicationandInteractionandStereotypy,Rigidity,andSensoryAbnormalitiessubscales,respectively. Theinternalconsistencyoftheentirescalewasa
=0.91.3.2. Item-analysis
Theitem-validities,-difficulties,-variances,andtheitem-totalcorrelationsaresummarizedinTable2.Meanitemvalues forindividualswithIDonlywerelowerthanthoseofthecombinedIDandASDindividuals(Table2).AscalculatedbyMann– WhitneyUtests,all19itemsexhibitedsignificantdifferencesbetweentheID/ASDandID-onlygroups(allps<0.001).The
part-wholecorrecteditem-totalcorrelationsfortheSocialCommunicationandInteractionsubscalerangedfromrit=0.77
(DiBAS-R:5‘‘Doesheshowyouthingshelikesorisinterestedintoshareenjoymentwithyou?’’)torit=0.52(DiBAS-R:16
‘‘Doeshenodtomean‘yes’?’’).Themedianwasrit=0.67.Theitemdifficultiesofthissubscalerangedfrom0.32(DiBAS-R:14
‘‘Doeshelookupandpayattentiontoyouwhenyoutalktohimwithoutcallinghisname?’’)to0.79(DiBAS-R:7‘‘Doeshe comfortothersiftheyaresad?’’).Themedianitemdifficultyofthissubscalewas0.56.Theitem-variancesrangedfrom0.78 (DiBAS-R:2‘‘Canyoutellhowhefeelsbyhisfacialexpression?’’;DiBAS-R:11‘‘Doesherespondinapositivewaywhen somebodyelseapproacheshim?’’)to1.91(DiBAS-R:12‘‘Doesherefertohimselfinthefirstperson,e.g.,‘I’and‘me’?),andthe medianwas1.18.
Thepart-wholecorrecteditem-totalcorrelationsoftheStereotypy,Rigidity,andSensoryAbnormalitiessubscalevaried betweenrit=0.47(DiBAS-R:6‘‘Doesherepeatcertainwordsinexactlythesameway?’’)andrit=0.76(DiBAS-R:17‘‘Doeshe
showoddmovementsofhisbody,suchasrocking,fingerflapping,walkingontiptoes,orspinningaroundhisbody’saxis?’’). Themedianwasrit=56.Theitemdifficultiesrangedfrom0.18(DiBAS-R13:‘‘Doesheliketosmellortapatobjects/walls?’’)
to0.52(DiBAS-R:4‘‘Arethereparticularritualsthatareimportantforhim?’’),andthemedianwas0.36.Item17(‘‘Doeshe showoddmovementsofhisbody,suchasrocking,fingerflapping,walkingontiptoes,orspinningaroundhisbody’saxis?’’) exhibitedthehighestitem-variance(1.56),anditem13(‘‘Doesheliketosmellortapatobjects/walls?’’)exhibitedthelowest itemvariance(0.93).Themedianoftheitem-variancesoftheStereotypy,Rigidity,andSensoryAbnormalitiessubscaleitems was1.35.
3.3. Diagnosticvalidity
U=943.50,Z= 8.97,p<0.001,theSocialCommunicationandInteractionsubscalescore,U=1598.50,Z= 7.23,p<0.001,
andtheStereotypy,Rigidity,andSensoryAbnormalitiessubscalescore,U=1151.50,Z= 8.43,p<0.001.Allmeansand
mediansofthetotalandsubscalescoresweresignificantlygreaterinthesubsamplewithASDcomparedtothesubsample withoutASD.
ROCanalysisoftheDiBAS-RtotalscoresresultedinanAUCof0.89,95%CI[0.85,0.94],p<0.001.TheAUCfortheSocial
CommunicationandInteractionsubscalewas0.82,95%CI[0.76,0.87],p<0.001,andtheAUCfortheStereotypy,Rigidity,
andSensoryAbnormalitiessubscalewas0.87,95%CI[0.82,0.92],p<0.001.Allestimationsindicatedgooddiscriminative
ability.TheROCcurvesarepresentedinFig.1.
ThesensitivityandspecificityvaluesandCohen’skappasforthreepossiblecut-offvaluesforeachsubscalearepresented inTable4.
Severalcombinationsofcut-offswereevaluatedintermsofsensitivitiesandspecificities.Acombinationofcut-off scoresof 29pointsonthetotalscale,21pointsontheSocialCommunicationandInteractionsubscale, and5points Table3
MeansandmediansfortheDiBAS-RsumscoresdifferentiatedforadultswithandwithoutASD.
Scale Sumscores pa
Total(n=196) ASD/ID(n=67) ID-only(n=129)
DiBAS-R-total M(SD) 27.9(12.9) 39.4(8.3) 22.0(10.8) <0.001
Mdn 28.0 40.0 20.0
SCI M(SD) 20.2(9.3) 26.8(5.6) 16.9(9.0) <0.001
Mdn 21.0 27.0 16.0
SRS M(SD) 7.7(5.7) 12.6(5.0) 5.2(4.1) <0.001
Mdn 6.0 13.0 4.0
Note.SCI=DiBAS-RSocialCommunicationandInteractionsubscale;SRS=DiBAS-RStereotypy,Rigidity,andSensoryAbnormalitiessubscale;M=mean;
SD=standarddeviation;Mdn=median.
a AsresultofMann–WhitneyUTest.
Table4
PsychometricpropertiesoftheDiBAS-Rfordifferentcutpoints.
DiBAS-Rtotal SCI SRS Combinedcutpoint
Cut-off 28 29 30 20 21 22 4 5 6 (29–21–5)
Sensitivity% 89.6 88.1 85.1 89.6 86.6 83.6 95.5 94.0 91.0 80.6
Specificity% 69.8 72.1 74.4 60.5 65.1 69.0 43.4 54.3 63.6 80.6
Kappa 0.53 0.55 0.55 0.43 0.46 0.48 0.31 0.40 0.48 0.59
Note.SCI=DiBAS-RSocialCommunicationandInteractionsubscale;SRS=DiBAS-RStereotypy,Rigidity,andSensoryAbnormalitiessubscale.
fortheStereotypy,Rigidity,andSensoryAbnormalitiessubscaleresultedinthemostbalancedsensitivityandspecificity values. Using these combined cut-off values, 80.6% of patients with ASD and 80.6% of the patients without ASD werecorrectly recognized by theDiBAS-R. The positive predictive valuewas 68.4%. The DiBAS-R classificationand the diagnostic decision agreed in 80.6% of all individuals of the current sample (n=158). The Cohen’s kappa was 0.59.
3.4. Convergentanddiscriminantvalidity
TheresultsofthecorrelationanalysesassessingconvergentvalidityaresummarizedinTable5.
TheDiBAS-Rtotalscorewassignificantlycorrelatedwiththesumscoresofalloftheestablisheddiagnosticinstruments that were available for the participants (r0.5, p<0.001, one-tailed). The overall sumscores exhibited the highest
correlationwiththeACLsumscore,r(89)=0.59,p<0.001,one-tailed.ThecorrelationsoftheDiBAS-Rsubscalescoreswith
the other established measures ranged between r(75)=0.35, p<0.01, one-tailed (PDD-MRS and DiBAS-R Social
CommunicationandInteractionsubscalescore)andr(89)=0.53,p<0.001,one-tailed(ACLsumscoreandDiBAS-RSocial
Communicationand Interactionsubscale score).Analyses of divergentvalidities revealednon-significant correlations betweentheMOASandtheDiBAS-Rtotalscorer(79)= 0.08,p=0.23,one-tailed,ns,theDiBAS-RSocialCommunicationand Interactionsubscaletotalscorer(79)= 0.11, p=0.17,one-tailed,ns,andtheDiBAS-RStereotypy,Rigidity,andSensory Abnormalitiessubscaletotalscorer(79)= 0.01,p=0.46,one-tailed,ns.
3.5. Interraterreliability
TheICCcoefficientsforestimationofinterraterreliability(n=36)were0.88,95%CI[0.78,0.94],p<0.001fortheDiBAS-R
totalscore,0.72,95%CI[0.51,0.85],p<0.001fortheSocialCommunicationandInteractionsubscalescoreand0.78,95%CI
[0.60,0.88],p<0.001fortheStereotypy,Rigidity,andSensoryAbnormalitiessubscalescore.
3.6. Feasibility
Thescale’sfeasibilitywas100%,and196/219oftheparticipantscompletedtheentirequestionnaire.
4. Discussion
IDandASDco-occurathighrates.TheDIBAS-RwasdesignedtoenablequickscreeningforASDinthehighlyvulnerableID population.Factoranalysisindicatedtwosubscales,theDiBAS-RSocialCommunicationandInteractionandtheDiBAS-R Stereotypy,Rigidity,andSensoryAbnormalitiessubscales.DiagnosticvalidityanalysisproducedanAUCof0.89,andthe balancedsensitivityandspecificityvaluesof81%indicatedthescale’spotentialforscreeningforASDinadultswithID.This potentialwasfurthersupportedbytheconvergentvaliditieswithestablishedASDdiagnosticscales.Theinterraterreliability wasexcellent(ICC=0.88).Overall,theDiBAS-RprovedtobeavalidandreliableinstrumentforthescreeningofASDinadults withID.
TheapplicationoftheDiBAS-Rhasseveraladvantages.Thescaleiseasytoadministerinanytypeofsetting;e.g.,hospitals, outpatientclinics,residentialhomesettings,etc.Nospecialknowledgeisneededtocompletethequestionnaire,andno preparatory training is necessary to compute the final score. Thus, the scale can be used by general practitioners, psychiatrists,orpsychologiststoscreenforASDinthehighlyunder-diagnosedIDpopulation(LaMalfaetal.,2004).Thescale exhibitedahighfeasibility(100%),andrequirednomorethan5minforscoringandcomputing.Moreover,administrationis notdependentonthecollaborationoftheexaminedindividual.Thevalidityandreliabilityresultssuggestthatthisscale representsanefficientapproachtoinitialASDscreeningofadultswithID.
Thefactoranalysisidentifiedaninterpretabletwo-factorsolutionthatused19ofthe20items.Twelveoftheitemsloaded onafactorthatwascomprisedofsocialcommunicationandinteractionaspects,andtheremaining7itemsloadedonafactor that wasspecific tostereotypic and rigidbehaviors and sensoryabnormalities. This factor structure reflectsthe two behavioraldomainsoftheASDcriteriaofthecurrentdiagnosticmanual,theDSM-5.TheRMSEAof0.058andSRMRof0.052 reflectedafitthatwasatleastadequateconsideringtheconfidenceintervaloftheRMSEA.
Table5
ConvergentvalidityoftheDiBAS-RwiththeSCQ-current,thePDD-MRS,andtheACL.
DiBAS-RSRS
n=196
DiBAS-Rtotal
n=196
SCQcurrent
n=87
PDD-MRS
n=77
ACL
n=91
DiBAS-RSCI 0.47*** 0.92*** 0.47*** 0.35** 0.53***
DiBAS-RSRS 1 0.77*** 0.39*** 0.45*** 0.45***
DiBAS-Rtotal – 1 0.52*** 0.50*** 0.59***
Note.SCI=DiBAS-RSocialCommunicationandInteractionsubscale;SRS=DiBAS-RStereotypy,Rigidity,andSensoryAbnormalitiessubscale.
AlloftheitemsthatwereultimatelyincludedintheDiBAS-RsignificantlydiscriminatedbetweentheID-onlyandID/ASD combinedgroups.Thus,thediscriminativevaluesoftheDiBAS-R itemswereanimprovementoverthoseoftheDiBAS (Sappok,Gaul,etal.,2014)becauseonly12ofthe20DiBASitemsdifferentiatedbetweenadultswithandwithoutASD.These 12DiBASitemswereretainedintheDiBAS-Rquestionnaireandcomplementedbyanadditional8items.Theitemdifficulty variedfrom0.18to0.78,whichmatchesthepreferredrangesuggestedbyBortzandDo¨ring(2006).Theitemvariances rangedfrom0.78to1.62.Noitemexhibitedvariancethatwasclosetozero;thus,noitemneededtoremoveduetolackof variance.Theitem-totalcorrelationsvariedfromr=0.45tor=0.77,whichindicatesfairtogoodcorrelationsbetweeneach itemanditsrespectivesubscale(Cicchettietal.,2011).Overall,theDiBAS-Rconsistsofitemsthatarediscriminativeand applicablefordetectingASDinadultswithID.
BasedontheAUCof0.89,thekappaof0.59,andthesensitivityandspecificityof81%and81%,respectively,theDIBAS-R well-suitedfordistinguishingASDandnon-ASDindividualswithID.ThediagnosticvalidityoftheDIBAS-Rwasimproved comparedtothatoftheoriginalDiBAS,whichexhibitedanAUCof0.81,asensitivityof83%,aspecificityof64%,andakappa of0.47(Sappok,Gaul,etal.,2014).ASDscreens,suchastheSCQ(sensitivityandspecificityof98and47%,respectively;AUC 0.85;kappa0.47),theACL(sensitivityandspecificityof91and68%,respectivelyAUC0.86;kappa0.60),andtheASD-DA (sensitivityandspecificityof86and62%,respectivelyAUC0.74)haveshowncomparableresults,butmaybelessappropriate foradultswithID(SCQ),requireexperts(ACL),orarenotavailableinGerman(ASD-DA;Matsonetal.,2007;Matsonetal., 2008;Sappok,Diefenbacher,Gaul,etal.,inpress;Sappok,Heinrich,etal.,2013).ThePDD-MRSisanother,moreelaborate ASDmeasureforindividualswithIDthatwasdesignedforIDadults.ThePDD-MRShasshownsensitivityandspecificity valuesof92%thataresuperiortothoseoftheDiBAS-R,andthisdifferencemaybeduetodifferencesinstudydesigns,the populationsstudied,andadministrationtechniques(Kraijer&Bildt,2005).Manynon-institutionalresidentsorindividuals attendingdaycarecenterswereincludedintheaforementionedstudy,whileallparticipantsinthepresentstudywere referred topsychiatrists due toa severemental or behavioral problem. Thegreater differentialdiagnostic challenges encounteredinthisstudymayhaveconfoundedtheresults.Moreover,thespecificASDknowledgeofthepsychologistsor psychiatristswhoadministerthePDD-MRSmayfurtherimprovethescalesabilitytodetectASDcomparedtotheDiBAS-R, whichcanbecompletedbylaypersons.Therefore,theDiBAS-Rmaybeappliedearlierinthediagnosticprocessinsettingsin whichthePDD-MRScannotbeappliedtofacilitatetransferstocentersthatoffertheentirerangeofASDdiagnosticmeasures. Thisapproachmaysaveresourcesandhelpfine-tuneaccesstomoretime-andpersonal-intensivemeasuressuchasthe PDD-MRS,theADOS,andtheADI-R.
TheDiBAS-RmeanscoresweresignificantlycorrelatedwiththemeansofotherASDmeasuressuchastheACL,theSCQ, andthePDD-MRS.ThisfindingfurthersupportsthediagnosticvalidityoftheDiBAS-Rbecauseallofitsscalesaimtodetect current behaviorsthat arecharacteristicof ASD.Nosignificantcorrelationwasobserved withtheMOAS,a scalethat measuresaggressionandisnotprimarilyassociatedwithASD.
GiventheCronbach’salphaof0.9,theinternalconsistencyoftheDiBAS-Rwasgood.Moreover,thevaluesofthetwo subscaleswereabove0.8,whichsupportsthestrongcorrelationsofeachitemwithallotheritemsintherespectivefactor. Theinterraterreliabilitywas0.88.AccordingtoCicchettietal.(2011),thisvalueindicatesan‘excellent’agreementbetween thescaleresultsacrossdifferentraters.However, theconfidenceintervalswerebroad;thus,theabsolutevalueofthe estimationofreliabilityshouldbeinterpretedwithcaution.TheinterraterreliabilitywassimilartothoseofotherASD observationscalessuchastheSocialResponsivenessScale(Bo¨lte,Holtmann,etal.,2008,Bo¨lte,Poustka,etal.,2008)andthe
Children’sSocialBehaviorQuestionnaire(Bildtetal.,2009).
Severalissuesshouldbeconsideredwheninterpretingtheseresults.First,thelevelofIDdifferedbetweengroups;theID/ ASDsubgroupexhibitedhigherlevelsofIDthandidtheID-onlysubgroup.Thisfindingreflectstheincreasedprevalenceof ASDin individualswithlowerintellectualfunctioning (Cooper, Smiley,Morrison,Williamson, &Allan, 2007; deBildt, Sytema,Kraijer,&Minderaa,2005;Sappoketal.,2010)andisacommonphenomenoninstudiesassessingASDinindividuals withID(Sappok,Diefenbacher,Budczies,etal.,2013;Sappok,Heinrich,etal.,2013).Second,allpatientshadcomorbid psychiatricdisordersorseriousbehavioralproblemsuponadmission.However,theASDassessmentswereperformedafter remissionofacutementalorbehavioraldisorders.Furthermore, theDiBAS-Rwasprimarilydesignedforuseinclinical settings;therefore,thepresentstudyreflectstherealitiesthatcliniciansfaceintheirdailyroutines.Third,manypatients weretreatedwithvariouspsychotropicdrugs,whichmayhaveaffectedthebehaviorsthatareassessedbytheDiBAS-R.In contrast,individualswithIDand/orASDareamongthemostmedicatedgroupsofsociety(Esbensen,Greenberg,Seltzer,& Aman,2009;Tsakanikos,Costello,Holt,Sturmey,&Bouras,2007;Witwer&Lecavalier,2005),andtheconditionsofthis studymirrorthehealthsituationsofthepeopleforwhichthisscalewasdesigned.Finally,wewouldliketoemphasizethat the DiBAS-R is a screening instrument and should be used as such. Proper diagnostic classificationsshould include comprehensiveassessmentsofvariouspresentandpastaspectsthatshouldbesupportedbymoreelaboratemeasuressuch asthePDD-MRS,theADOS,andtheADI-R.TheDiBAS-RcanbeappliedtoscreenforASDinadultIDsamples,inpsychiatricor somaticservicesforadultswithID,inout-andinpatientclinicstreatingIndividualswithIDandothers,ortoguidereferrals toservicesthatspecializeinASDassessment.
instruments specifically designed for identification of ASD in adults, in particular in those with comorbid ID (cf. introduction).TheDiBAS-Rdesignedandvalidatedinthisstudymayfillthisgapandaidguidingthetimeandcostintensive diagnosticprocessinthispopulation.TheavailabilityofaquickASDscreenermaysupportcliniciansintheirdiagnostic work-upandresultinmorecorrectlyidentifiedindividualswithIDandASD.Consideringthelackofspecificmedicationsfor ASDsymptomatologyand thehighratesofpsychopharmacologyespeciallyin individualswithIDandASD,diagnostic clarification may reduce the prescription of sedative medication and increase the application of more effective psychobiosocialinterventions(Bo¨lte,2011;Broadstock,Doughty,&Eggleston,2007;Elvins&Green,2010).Knowledgeof theunderlyingcauseofacertainmaladaptivebehaviormayalsoreducethecaregivers’stressandunnecessaryeconomic costs(Knapp,Romeo,&Beecham,2009;Totsika,Hastings,Emerson,Lancaster,&Berridge,2011).Finally,itmayraisethe awarenessofASDsymptomatology,especiallyinindividualswithmultipledisabilitiesandthusreducethephenomenonof diagnosticovershadowing(Reiss&Szyszko,1983).
Inconclusion, individualswithIDcomposea population that isat highriskfor comorbidASD, which maynotbe recognizeduntiladulthood(LaMalfaetal.,2004;Sappok,Diefenbacher,Budczies,etal.,2013).Consideringthehighratesof challengingbehaviorsandtheassociatedhospitalreferralsoftheseindividuals,diagnosticclarificationoftheunderlying causesisessentialforprovidingtailoredtreatmentoptions.TheDiBAS-R,whichwasspecificallydesignedtoscreenforASD inthispopulation,provedtobeameasurewithhighfeasibilityandgoodpsychometricproperties.TheuseoftheDiBAS-R mayrepresentaneconomicmeansof guidingmorecomprehensiveASDassessmentsand therebyaddstotheexisting diagnosticwork-upandmentalhealthofindividualswithID.
Acknowledgments
Appendix
Name
des Patienten:________________________
_
Geburtsdatum:________
___________
_
Ausgefüllt
von:_____________________________
_
am:_________________
_ __________
_
* ImFragebogenwurdezurVereinfachungdiemännlicheFormbenutzt.GemeintistimmerauchdieweiblicheForm,also„sie“bei„er“bzw. „ihr“ bei „ihm“
© Ev.KrankenhausKöniginElisabethHerzberge
in derFassung von Sappok,T., Gaul, I., Bergmann, T., Dziobek, I., Bölte, S., Diefenbacher, A.& Heinrich,M. (2013)
DiBAS-R
BittebeurteilenSie,wieoftsichfolgendeVerhaltensweisenbeidem Patientenbeobachtenlassen.BeziehenSie sichinIhrerBeurteilungaufdieletzten3Monate.BitteachtenSiedarauf,dass alleFragenbeantwortetwerden. WennSiesichunsichersind, wählenSiedieKategorievonderSiemeinen, dasssiedasVerhaltendesPatienten am besten widergibt.
Trifft! zu
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2 KönnenSieanseinemGesichtsausdruckerkennen,wie er
sichfühlt? O O O O
3 HaterfreundschaftlicheBeziehungenzuGleichrangigen? O O O O 4 GibtesbesondereRituale,diefürihnwichtigsind? O O O O
5 ZeigterIhnen,was ihmgefälltoder ihn interessiert,umdiese
FreudegemeinsammitIhnenzuteilen? O O O O
6 WiederholterbestimmteWorteingenaudemselbenWortlaut? O O O O
7 Trösteterandere,wennsietraurigsind? O O O O
8 BeziehterSiebeieinerBeschäftigungsomitein,dassein
AustauschodereingemeinsamesErlebnis entsteht? O O O O 9 SchließtersichspontanGruppenaktivitätenan? O O O O
10 HaterungewöhnlicheHobbysundInteressen,z.B.ineinem
Buchblättern,anFahrplänenoderelektrischenGeräten? O O O O 11 Reagierterpositiv,wennsichihmeinAnderer nähert? O O O O
12 SprichtervonsichselbstindererstenPerson(also„ich“,
„mein“)? O O O O
13 BeriechtoderbeklopftergerneGegenstände/Wände? O O O O
14 SchauteraufundschenktIhnenAufmerksamkeit,wennSie
ihnansprechenauchohneseinenNamenzusagen? O O O O
15 ZeigterVerhaltensauffälligkeitenbeiunvorhersehbaren
Veränderungen? O O O O
16 Nickter,wennerjasagenwill? O O O O
17
ZeigterauffälligeBewegungsmuster,z.B.
Schaukelbewegungen,Fingerschlagen,Zehenspitzengang oderDrehbewegungenumdieKörperachse?
O O O O
18 Sprichter auch nur ausFreundlichkeitmitIhnen? O O O O
19 ZeigterselbstverletzendesVerhalten? O O O O
FolgendeFeldersind vomTestauswerterauszufüllen:
Domäne Punktewerte
(Grenzwert)
Grenzwert überschritten
Sindalle3Grenzwerteüberschritten, ergibt derDiBAS-RHinweisedarauf, dassdie Störung mit hoher Wahrscheinlichdemautistischen Spektrumzugeordnetwerdenkann: SozialeKommunikation/Interaktion
! ..
(21) ja /neinStereotypien/Rigidität/Sensorik
! ..
(5) ja /neinGesamtwert
! ..
(29) ja /nein ja neinAnmerkungen
... ...
.
... ...
...
.
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