Characteristics of adults with autism sp (2)

Characteristics

of

adults

with

autism

spectrum

disorder

who

use

adult

developmental

disability

services:

Results

from

25

US

states

Amy

S.

Hewitt

a,

*

,

Roger

J.

Stancliffe

b

,

Annie

Johnson

Sirek

a

,

Jennifer

Hall-Lande

a

,

Sarah

Taub

c

,

Joshua

Engler

c

,

Julie

Bershadsky

c

,

Jon

Fortune

c

,

Charles

R.

Moseley

d

a

ResearchandTrainingCenteronCommunityLiving,UniversityofMinnesota,102PatteeHall,150PillsburyDriveSE,Minneapolis,MN55455,USA b_{UniversityofSydney,FacultyofHealthSciences,Rm119,JBlock,75EastStreet,POBox170,Lidcombe,NSW1825Australia}

c

HumanServicesResearchInstitute,2336MassachusettsAvenue,Cambridge,MA02140,USA d

NationalAssociationofStateDirectorsofDevelopmentalDisabilitiesServices,113OronocoStreet,Alexandria,VA22314,USA

1. Introduction

1.1. Background

Theterm‘‘autismspectrumdisorders’’encompassesarangeofbehaviorallydefinedconditionsthatinclude:autistic disorder(autism),Aspergerdisorder,andpervasivedevelopmentaldisorder—nototherwisespecified(PDD-NOS).Autism spectrumdisorder(ASD)ischaracterizedbyqualitativeimpairmentsincommunicationandsocialinteraction,aswellas restricted,repetitiveandstereotypedpatternsofbehavior(AmericanPsychiatricAssociation(APA),2000).

Many individualswithASDalso experienceotherdevelopmentaldisabilities,includingintellectualdisabilities (ID). Recentestimatesofthepresenceofco-occurringIDamongchildrenwithASDrangefrom19.2%(Boulet,Boyle,&Schieve, 2009)to41%(CentersforDiseaseControlandPrevention(CDC),2009).Inthepast,whenASDwasthoughtofsolelyinterms ofautisticdisorder(excludingotherASDs),co-occurringIDwasidentifiedintwo-thirdsormoreofchildrenwithASD(Rutter, 2005).Inotherwords,evenwithouteligibilityforservicesarisingspecificallyfromtheirASD,thoseindividualswithASDand

IDlikelywereeligibleforintellectualanddevelopmentaldisabilities(IDD)servicesonthebasisoftheirIDalone.Thuswith

ARTICLE INFO

Articlehistory:

Received17June2011

Receivedinrevisedform19October2011

Accepted19October2011

Keywords:

Intellectualdisabilities

Autismspectrumdisorder

ABSTRACT

Thereisasignificantincreaseintheprevalenceofautismandautismspectrumdisorders (ASD)inchildrenwithestimatesnowreaching1in110childrenintheUnitedStates. Familiesreportdifficultiesinfindingservicesfortheiryoungandadultchildren.Many adults with ASD receive services and supports through state intellectual and developmentaldisabilities(IDD)adultservicesystems.Thisstudypresentsdescriptive dataonarandomsampleof12,382individualusersofadultIDDservicesfrom25states thatincluded1002individualswithanautismdiagnosis(8.1%).Dataareprovidedon demographic characteristics,diagnoses, communication andrelationship status for adultswithautism/ASDandacomparisonofthesefindingsforIDDserviceuserswho haveotherdiagnoses.

ß _{2011ElsevierLtd.Allrightsreserved.}

Abbreviations:HCBS,HomeandCommunityBasedServices;ICF/MR,IntermediateCareFacilitiesfortheMentallyRetarded;NCI,NationalCore

Indicators.

* Correspondingauthor.Tel.:+16126251098;fax:+16126256619.

E-mailaddresses:hewit005@umn.edu(A.S.Hewitt),roger.stancliffe@sydney.edu.au(R.J.Stancliffe),joh02055@umn.edu(A.JohnsonSirek),

hall0440@umn.edu(J.Hall-Lande),staub@hsri.org(S.Taub),jenger@hsri.org(J.Engler),jbershadsky@hsri.org(J.Bershadsky),jfortune@hsri.org(J.Fortune),

cmoseley@nasddds.org(C.R.Moseley).

ContentslistsavailableatSciVerseScienceDirect

Research

in

Autism

Spectrum

Disorders

J ou rna l hom e pa ge : h tt p: / / e e s . e l se v i e r . com / R AS D / de f a ul t . a s p

1750-9467/$–seefrontmatterß_{2011ElsevierLtd.Allrightsreserved.}

therisingprevalenceofASDandtheintroductionofpolicyinitiativesinanumberofstatesintendedtoprovideaccesstoIDD servicesonthebasisofASDdiagnosisalone,thereislikelyanincreasingnumberofIDDserviceuserswithASD.

QualityoflifeamongadultswithASDisrelatedtoreceiptofformalsupportsthatareindividualizedandcomprehensive (Renty&Roeyers,2006).MostindividualswithASDexperiencepooradultoutcomes(Billstedt,Gillberg,&Gillberg,2005; Howlin,Goode,Hutton,&Rutter,2004)withongoingchallengesofcommunication,socialrelationships,socialinteractions, employment,andindependence(Howlin,Mawhood,&Rutter,2000;Lawer,Brusilovskiy,Salzer,&Mandell,2009).

Thus,theresearchandservicecontextforadultswithASDincludesindicatorsofloweredqualityoflifeandissuesof accesstoadequateserviceandsupportsystems.StateIDDadultservicesystemsrepresentonemajorsourceofservicesand support,butlittleisknownaboutthenumberofadults(age18yearsorolder)withASDwhousetheseservices,thetypesof servicestheyuse,andthecharacteristicsofadultIDDserviceuserswithASDascomparedtootherIDDserviceuserswhoare notsodiagnosed.Thecurrentstudydrawsona25-statecross-sectionalsampleofadultsfromtheNationalCoreIndicators (NCI)programtoprovidedescriptiveinformationabouttheseissues.

1.2. PrevalenceofASDandaccesstoadultIDDservices

Diagnosticcriteriathatincorporatedaspectrumofautisticsymptomswereimplementedintheearly1990s.Ratesof ASDdiagnoseshavebeenincreasingsteadilysince1990(Newschaffer,Falb,&Gurney,2005).Forexample,a57%increasein prevalencewasobservedamongeight-year-oldsfrom2002to2006(CDC,2009),andonein110childrenintheUnited StatesarecurrentlydiagnosedwithASD(CDC,2010).Thesestatisticspointtoavastandrapidlyincreasingdemandfor effectivesystemsthatsupport individualswithASDthroughout thelifespan. However,with thetrendtowardearly diagnosisofASD,itislikelythat10–15yearswillelapsebeforetheserecentlydocumentedincreasesinASDprevalencewill inturnaffectserviceusernumbersintheadultIDDsystemtoasimilardegree.Inrecentyearspolicyinitiativeswithin severalstateIDDservicesystemshaveexpandedaccesstopersons withASDdiagnosesbyamendingcurrentservice eligibilitycriteriatoinclude‘‘related conditions’’clausesthatallowaccessby personswithASDdiagnosesorbythe developmentofseparateautism-specificHomeandCommunityBasedServices(HCBS)Section1915(c)Medicaidwaiver programs.

TherehasbeenlimitedandconflictingevidenceregardingtheprevalenceofadultsdiagnosedwithASD(Hall-Lande, Hewitt,&Moseley,2011).Suchinformationhasbeendifficulttomeasurereliablybecause,(a)lackofaccesstosupport servicesoftenleavesadultswithASDunderrepresentedintheliteratureandunderservedintheircommunities,and(b) manyolderadultscurrentlyservedintheIDDsystemhaveaprimarydiagnosisofdevelopmentaldisabilities(DD)andmay notnecessarilyhaveanautismdiagnosiseventhoughtheypresentwiththesymptoms.Itisalsolikelythatthereisalsoavast cohortofadultswithASDwhoarenotreceivingneededservices(Graetz,2010).Inaddition,manyindividualsaredeemed ineligibleforIDDservicesbecausetheirIQscoresexceedthemaximumallowableforIDdiagnosisorduetofailureto demonstratefunctionallimitationsinthreeormorelifeskills(Hall-Landeetal.,2011).

1.3. DemographiccharacteristicsofpeoplewithASD

BoysarenearlyfourtofivetimesmorelikelytobediagnosedwithASDthangirls(Croen,Grether,&Selvin,2002;Giarelli etal.,2010;Koganetal.,2009;Yeargin-Allsoppetal.,2003).CentersforDiseaseControlandPrevention(2009)reportedthat, whenASDdiagnosticestimatesarestratifiedbygender,approximatelyonein70boysisdiagnosedwithASD,whileonlyone in315girlsisdiagnosedwithASD.TheInteractiveAutismNetwork(IAN)(2009)proposedthatthewidelyacceptedmale: femaleratioof‘‘fourorfivetoone’’appliesonlytochildrenwithASDandnoID.Male:femaleratiosofchildrenwithASDand

IDmaybeclosertotwotoone.WhilefewerfemalesarediagnosedwithASD,theseveritywithwhichfemalesexperienceASD andco-occurringdisordersissubstantial.FemaleswithASDaremorelikelythanmalestoalsobediagnosedwithcognitive impairment,seizures,andepilepsy(IAN,2009).

Inconsistencyexistsin theresults ofstudiesthatmeasure variablesofrace andtheincidence ofASDdiagnoses.

Yeargin-Allsoppetal.(2003)foundcomparableASDprevalenceratesbyrace,whereasKoganetal.(2009)reportedthat blackandmultiracialchildrenmayhaveloweroddsofbeingdiagnosedwithASDthannon-Hispanicwhitechildren.Other studieshavereportedhigherrisksofASDdiagnosesamongchildrenborntoblackmothers(Croenetal.,2002;Keen,Reid, &Arone,2010).

AdultswithASDhavebeendescribedashavingpoorsocialrelationshipsandfewclosefriends(Howlinetal.,2004).From asampleof42adultswithhigh-functioningautismorAspergerdisorder,itwasreportedthatnoneweremarriedorhad children,andonlya fewhadsomekindofpartner(Engstrom,Ekstrom, &Emilsson, 2003). Onlyasmallproportionof individualswithASDdevelopintimaterelationshipsinadolescenceandadulthood(LeBlanc,Riley,&Goldsmith,2008).

1.4. CommunicationissuesforpeoplewithASD

1.5. Serviceandsupportuse

ResearchonadultswithASDservedwithintheIDDsystemhasshownthattheygenerallyreceivedthesametypesof servicesasthosereceivedbypersonswithoutASD(HumanServicesResearchInstitute(HSRI),2008).Themajorityofstates intheU.S.operateHCBSSection1915(c)Medicaidwaiverprogramswithrelatedconditionsorrelateddisabilityclauses (Hall-Landeetal.,2011).ThesepoliciesallowindividualswithASDtobeeligibleforHCBSthatareavailabletopeoplewith DDorID.Atthetimeofthestudy11stateshaddesignedandimplementedasubsetofwaiverprogramsspecificallygeared forchildrenwithASD(CO,IN,KS,MD,MA,MO,MT,NE,NY,SC,andWI)(Hall-Landeetal.,2011).Yet,atthetimeofthestudy onlytwostateshaveimplementedspecificwaiverprogramsforadultswithASD(INandPA).Fundinglimitationsandlong waitlistsperpetuatebarriersinaccessingrelateddisabilityservices.

1.6. Studypurpose

Thisstudyprovidesanoverviewofthecharacteristicsofindividualswithanautism/ASDdiagnosisincludedwithina randomsampleofIDDservicerecipientswithin25states.Theprimaryresearchquestionis:Whatarethecharacteristicsof adultswithASDwhoreceiveHCBSandIntermediateCareFacilitiesfortheMentallyRetarded(ICF/MR)servicesintheUnited States?HowarethesecharacteristicssimilarordifferentfromservicerecipientswithoutanASDdiagnosis?

2. Method

2.1. Sample

2.1.1. Stateselection

Datacamefrom25ofthe26statesthatparticipatedintheNCIprogramin2006–2007and2007–2008.Theexception, Maine(N=436),didnotprovidedataaboutautism/ASDdiagnosis.The25statesthattookpartinthisstudyconsistedof23 statesparticipatinginthe2007–2008NationalCoreIndicators(NCI)program,andtwoadditionalstatesthatparticipatedin 2006–2007,butnot2007–2008.Thetwostatesthatprovided2006–2007surveydatawereCA(OrangeCountyonly)and WA;whereas2007–2008datawereusedforthefollowing23states:AL,AR,AZ,CT,DE,GA,HI,IN,KY,LA,MO,NC,NJ,NM,NY, OK,PA,RI,SC,TX,VT,WV,andWY.

TheNCIsurveyisacomponentofa nationalprojectonqualityassurance/enhancementcoordinatedbytheHuman ServicesResearchInstituteandtheNationalAssociationofStateDirectorsofDevelopmentalDisabilitiesServices.TheNCI surveyisadministeredonlyinstatesthatopttoparticipateintheNCIprogram.Theparticipatingstatesincludedinthisstudy arethosethatcollectedNCIConsumerSurveydata(describedsubsequently)in2006–2008.

2.1.2. Withinstatesampleselection

Statesampleswererandomlyselectedwithineachstate’spopulationofadults(age18yearsorolder)withIDDreceiving institutional, communityorhome-basedservices,or somesubsetof these(e.g.,somestatesrestrictedtheir sampleto recipientsofHCBS).Overallsamplesizesinparticipatingstatesrangedfrom137to1594andaveraged507.Thisvariationin samplesizeisattributedpartlytothesizeofthepopulationandtheservicesystemswithineachofthesestates.

2.1.3. Participants

ThetotalNCIparticipantsampleconsistedof13,169individualusersofadultIDDservicesfrom25states,but787(6.0%) hadmissingdataonthepresenceofanautism/ASDdiagnosis.Theoverallsampleof12,382wasmadeupof6862(55.6%) menand5485(44.4%)women(gendermissingfor35participants),withanaverageageof42.65years(range18–100).More detailedinformationaboutage,gender,race,diagnoses,levelofID,maritalstatus,andcommunicationtrendsarepresented intheresultssection.

2.2. Instrument

DatawerecollectedusingtheNCIConsumerSurvey2006–2007version(2states)and2007–2008version(24states).This paperdrawsonlyondatafromtheNCI‘‘Backgroundsection’’whichwasidenticalforbothNCIversions.TheNCIBackground sectionrequestsdataontheserviceuser’spersonalcharacteristics,functioning,diagnoses,health,problembehavior,living arrangements,andservices.Thesedataareobtainedfromindividualrecords,settingadministratorsorcasemanagers,direct supportproviders,andoccasionallythefamilymembersorindividualsthemselves.Thepresenceorabsenceofanautism/ ASDdiagnosiswasdeterminedbyareviewoftheindividuals’recordsorstatecomputerdatabaseandcompletedduringthe pre-surveyprocess.Theinformationrelatedtodiagnosesisprovidedbytheservicecoordinator/casemanagerandverified bytheindividualorfamilymember.Theperson(s)completingthediagnosticassessmentandtheinstrumentsusedbythese cliniciansarenotknown.However,tobeeligiblefordevelopmentaldisabilityservicesinallstatesamedicaldiagnosisis required.

diagnosesfoundin reviewofindividuals’records,interviewersaskedrespondentsaboutdisabilitiesotherthan Mental Retardationthatwerenotedinanindividual’srecords,and‘‘autism’’waslistedasaresponseoption.Thisoptionwasupdated to‘‘AutismSpectrumDisorder(e.g.,Autism,AspergerSyndrome,PervasiveDevelopmentalDisorder)’’inthe2008–2009 Consumersurveyinstrument.

2.2.1. Interviewertraining

Toensurethatallinterviewersreceivedconsistenttraining,theNCIConsumerSurveyprotocolissupportedbyatraining programforinterviewers,includingtrainingmanuals,presentationslides,trainingvideos,scriptsforschedulinginterviews, listsoffrequentlyaskedquestions,pictureresponseformatsandareviewofthesurveytool.

2.2.2. Reliability

Multipletestsyieldedinter-rateragreementof92–93%,andasingleexaminationoftest-retestreliabilityresultedin80% agreement(Smith&Ashbaugh,2001).

3. Results

3.1. Percentageofserviceuserswithautism/ASD

Thesampleof12,382participantsincluded1002individualswithanautism/ASDdiagnosis(8.1%,99%CI=7.5–8.7%). Withintheindividualstatesamples,thepercentageofsamplememberswithautism/ASDrangedfrom3.7%(99%CI=1.3– 6.2%)to27.4%(99%CI=20.6–34.3%).Thelargevariabilitybetweenstatesledustoexaminetheeligibilityrequirementsfor IDD services in the participating states to document whether these requirements were associated with systematic differencesinthepercentageofserviceuserswithautism/ASD.Nineteenofthe25statescoveredinthisstudyinclude ‘‘relatedconditions’’intheireligibilitycriteriaforpubliclyfundedservices(Hall-Landeetal.,2011).Arelatedcondition clausemeansthat peoplewithautism/ASDaswellasotherspecifiedconditionsarespecificallyidentifiedbydisability categoryaseligibleforthestate’sdevelopmentaldisabilityservicesprovidedtheymeetfunctionalskillandIQlimitations. Fiveofthestates(IN,MO,NY,PAandSC)inthisstudyalsohaveautism-specificHCBSwhichmeansthatinordertobeeligible fortheseservicesthepersonhastohaveadiagnosisofautism/ASDandhavefunctionalskilllimitations(Hall-Landeetal., 2011).Additionally,6states(AL,CT,HI,KY,OKandTX)hadneitherarelatedconditionsclausenoranautism-specificwaiver (Hall-Landeetal.,2011).

Ananalysisofthedifferencesinprevalencebetweenstatesgroupedaccordingtothepresenceorabsenceofthesepolicies wasconducted.ThisanalysisshowedthatsixstateswithneitherrelatedconditionseligibilitynortargetedHCBSwaiver programshadthelowestpercentageofindividualswithautism/ASD(6.6%)amongtheiraggregatedsamplesofadultservice users,whereasthefivestateswithbotharelatedconditionsclauseandanautism-specificwaiverhadthehighestpercentage ofserviceuserswithautism/ASD(9.3%).Overallthesedifferencesweresignificant,

x

2=17.39,df=2,n=12,382,p<.001.

3.2. Analysesandsignificancelevel

Markeddifferenceswerefoundbetweenparticipantswithandwithoutautism/ASDintermsofage,genderandlevelof intellectualdisability.Thesefactorscanbestronglyrelatedtoothercharacteristics(e.g.,ageandlevelofIDarerelatedtothe prevalenceofotherdisabilities),andthereforeitwasimportanttocontrolforthesefactorswhencomparingparticipants withandwithoutautism/ASD.Asaresult,weconductedanexaminationoftherelationshipbetweenautism/ASDanda number of other characteristics both as raw (univariate) comparisons and by using multivariate analysis (logistic regression),controllingforage,genderandlevelofintellectualdisability.Finally,giventhelargesamplesizeandthenumber ofcomparisons,analphawassetasp<.001forunivariateanalysesandp<.01formultivariateanalyses.

3.3. Demographiccharacteristics

3.3.1. Age

Samplememberswithadiagnosisofautism/ASD(M=34.11years,SD=12.05)weresignificantlyyoungerthanother samplemembers(M=43.40years,SD=14.29),t(1257.2)=22.97,p<.001(two-tailed).Asthisdifferencewassubstantial

(9.3years),weconductedacloserinvestigationoftheagedistributionofthegroupwithautism/ASD.Thesedataareshown inFig.1.Oneimportantreasonforthedifferenceinmeanagebetweenthegroupswithandwithoutanautism/ASDdiagnosis wasthattherewasastrongoverrepresentationofpeoplewithautism/ASDintheyoungestagegroup(18–29years)anda notablyfewerintheolderagegroups,

x

2(4)=404.79,N=12,343,p<.001.ItisalsonotableinFig.1thatamuchlarger

percentageofpeoplewithautism/ASDage18–29yearsdonothaveID(2.53%ofallparticipantsinthisagegroupor15.32%of individualswithautism/ASDage18–29years).

3.3.2. Gender

Therewasasubstantialoverrepresentationofmaleswithanautism/ASDdiagnosis,

x

2(1)=182.58,N=12,347,p<.001.

(4.0%).Giventhehigherproportionofmalesinthesampleasawhole(55.6%),theabsolutenumbersofmaleswithanautism/ ASDdiagnosis(n=758)versusfemales(n=240)yieldedanaveragegenderratioof3.16:1.

Takingthisanalysisfurtherandlookingatbothagegroupandsexyieldsthefollowingstrongassociationbetweenageand autism/ASDdiagnosisformales,

x

2(4)=291.72,N=6843,p<.001,andforfemales,

x

2(6)=98.24,N=5468,p<.001(see

Fig.2).Fig.2showsthemaleparticipantswithautism/ASDasapercentageofallmaleswithineachagegroup,andthese samepercentagesforfemales.

Table1showsthenumbersofmalesandfemalesbyagegroup.BothFig.2andTable1revealaverystrongageeffect, whichismuchmorepronouncedinmalesthanfemales.Themale:femalegenderratiosforparticipantswithautism/ASDfor eachagegrouprangedfrom3.38to2.63to1,whereasamongthosewithoutanautism/ASDdiagnosisthegenderratiowas muchlowerandrangedfrom1.21to1.14.

3.3.3. Race

Atotalof242samplememberswithadiagnosisofautism/ASDwerenon-white(3responded‘‘don’tknow’’).Therewas nosignificantdifferenceintheprevalenceofautism/ASDbyrace,

x

2(7)=10.38,N=12,248,p=.17(seeTable2).

3.3.4. Hispanic/Latinostatus

Withinthegroupofsamplemembersdiagnosedwithautism/ASD,62wereidentifiedasSpanish,HispanicorLatinoand 10selected‘‘don’tknow.’’Therewasnosignificantdifferenceintheprevalenceofautism/ASDbyethnicity(Latinostatus),

x

2

(2)=5.46,N=12,120,p=.065.

3.3.5. Levelofintellectualdisability

Ofthesamplememberslabeledwithadiagnosisofautism/ASD,97hadnointellectualdisability(ID)label,190hadmild ID,255ModerateID,213SevereIDand198profoundID.Therewasaninterestingbi-modaldistributionofautism/ASD diagnosisbylevelofintellectualdisabilitywithhigherproportionsforpeoplewithnoIDdiagnosisorsevere/profoundID.

Fig.1.Percentageofallparticipantsineachagegroupwithanautism/ASDdiagnosisbypresenceofintellectualdisability(ID)diagnosis.

21.6%

11.7%

8.2%

6.2%

2.5% 9.3%

4.3% _3.7%

2.3%

1.1%

0% 5% 10% 15% 20% 25%

18-29 30-39 40-49 50-59 60+ Age Group

Percentage of Participants

Male Female

SamplememberswithmildIDhadthelowestprevalenceofautism/ASD.Thesedifferencesweresignificant,

x

2(4)=214.9,

N=11,949,p<.001. Amongsamplememberswithautism/ASD,thedifferencesingenderratiobylevelofIDwerenot

significant,

x

2(4)=3.02,N=950,p>.05.

3.4. Primarymeansofexpression

Samplememberswithautism/ASDhadvariedprimarymeansofcommunication.Fivehundredandthirty-threesample membersusedspokenlanguageasaprimarymeansofcommunication,399gestures/bodylanguage,15signlanguage,21 communicationaidordeviceand10responded‘‘don’tknow.’’Therewasavastdifferenceinprimarymeansofexpression betweenthosewithandwithoutandautism/ASDdiagnosis,

x

2(5)=269.5,N=12,290,p<.001,withalowerpercentage

usingspeech(5.8%)thanwouldbeexpectedsimplyfromtheirrepresentationinthesample(8.1%)andanespeciallyhigh percentageofthoseusingcommunicationaidsordevices(22.3%).

3.5. Otherdisabilitydiagnoses

Findingson otherdisability diagnoses arereported both as raw(univariate)comparisons (alpha=.001),and using multivariateanalysis(logisticregression,alpha=.01)toevaluatetheeffectofautism/ASD,controllingforage,genderand

Table1

Numberandpercentageofparticipantsbyautism/ASDdiagnosis,genderandagegroup.

Agegroup Male Female Genderratio

Autism Autism Autism

No Yes Total No Yes Total No Yes

18–29

n 1265 349 1614 1040 107 1147 1.21 3.26

% 78.4 21.6 100.0 90.7 9.3 100.0

30–39

n 1281 169 1450 1103 50 1153 1.16 3.38

% 88.3 11.7 100.0 95.7 4.3 100.0

40–49

n 1507 134 1641 1275 49 1324 1.18 2.73

% 91.8 8.2 100.0 96.3 3.7 100.0

50–59

n 1218 81 1299 1091 26 1117 1.12 3.11

% 93.8 6.2 100.0 97.7 2.3 100.0

60+

n 818 21 839 719 8 727 1.14 2.63

% 97.5 2.5 100.0 98.9 1.1 100.0

Total

n 6089 754 6843 5228 240 5468 1.16 3.16

% 89.0 11.0 100.0 95.6 4.4 100.0

Table2

Numberandpercentageofparticipantswithandwithoutanautism/ASDdiagnosisbyrace.

Race Autismdiagnosis

No Yes Total

AmericanIndianorAlaskanative 147 7 154

1.3% 0.7% 1.3%

Asian 283 25 308

2.5% 2.5% 2.5%

BlackorAfricanAmerican 1764 138 1902

15.7% 13.9% 15.5%

PacificIslander 68 8 76

0.6% 0.8% 0.6%

White 8047 749 8796

71.5% 75.4% 71.8%

Otherracenotlisted 795 55 850

7.1% 5.5% 6.9%

Twoormoreraces 103 9 112

0.9% 0.9% 0.9%

Don’tknow 47 3 50

0.4% 0.3% 0.4%

Total 11,254 994 12,248

levelofintellectualdisability.Intheregressionanalysesallfourindependentvariableswereenteredsimultaneouslyand indicatorcontrastswereusedforcategoricalindependentvariables,withmaleandnothavingautism/ASDservingasthe referencecategories.

3.5.1. Psychiatricdiagnosis

Overall,therewasasignificantlysmallerpercentageofparticipantswithautism/ASD(26.1%)withapsychiatricdiagnosis thanthosewithoutautism/ASD(31.6%)(seeTable3).However,multivariateanalysis(logisticregression)revealedthatonce age,level ofintellectual disabilityand genderweretaken intoaccountstatistically, therewasno longer a significant associationbetweenautism/ASDandhavingapsychiatricdiagnosis(Table4).Itwasnotablethatolderparticipantsand thosewithmilderIDweresignificantlymorelikelytohaveapsychiatricdiagnosis.Asnoted,samplememberswithautism/ ASDweremuchyoungerandhadmoreseveredisability,whichhelpsexplainwhytherawcomparisonsweremisleadingin showingthatasmallerproportionofpeoplewithautism/ASDalsohadapsychiatricdiagnosis.Genderhadnosignificant multivariaterelationshipwiththepresenceofapsychiatricdiagnosis.

3.5.2. Seizuredisorder/neurologicalproblem

Therewasnosignificantunivariateormultivariateassociationbetweenautism/ASDandseizuredisorderorneurological problem(Tables3and4).YoungerindividualsandthosewithmoresevereIDweresignificantlymorelikelytohaveaseizure disorderorneurologicalproblem.

Table3

Numberandpercentageofparticipantswithandwithoutanautism/ASDdiagnosisbypresenceofothercharacteristics.

Characteristic Characteristic

present

Autismdiagnosis

No Yes Total Chi-square

Otherdisability

Mentalillness/psychiatricdiagnosis No 7780 735 8515 x2(1)=13.25,N=12,374,p<.001

91.4% 8.6% 100.0%

Yes 3600 259 3859

93.3% 6.7% 100.0%

Seizuredisorder/neurologicalproblem No 8362 721 9083 x2(1)=0.42N=12,373p=.52

73.5% 72.5% 73.4%

Yes 3017 273 3290

26.5% 27.5% 26.6%

Visionimpairment No 9516 900 10,416 x2(1)=33.63,N=12,371,p<.001

91.4% 8.6% 100.0%

Yes 1862 93 1955

95.2% 4.8% 100.0%

Hearingimpairment No 10,533 936 11,469 x2(1)=3.81,N=12,370,p<.05

91.8% 8.2% 100.0%

Yes 844 57 901

93.7% 6.3% 100.0%

Physicaldisability No 9902 934 10,836 x2(1)=40.45,N=12,372,p<.001

91.4% 8.6% 100.0%

Yes 1476 60 1536

96.1% 3.9% 100.0%

Communicationdisorder No 10,215 838 11,053 x2(1)=29.65,N=12,373,p<.001

92.4% 7.6% 100.0%

Yes 1163 157 1320

88.1% 11.9% 100.0%

Downsyndrome No 10,215 967 11,182 x2(1)=60.77,N=12371,p<.001

91.4% 8.6% 100.0%

Yes 1163 26 1189

97.8% 2.2% 100.0%

Prader–Willisyndrome No 11,326 988 12,314 x2(1)=0.06,N=12,370,p=.80

92.0% 8.0% 100.0%

Yes 51 5 56

91.1% 8.9% 100.0%

Relationships

Evermarried Nevermarried 10,728 988 11,716 x2(3)=28.71,N=12,273,p<.001

95.2% 98.8% 95.5%

Married 209 4 213

1.9% .4% 1.7%

Single(married

previously)

278 5 283

2.5% .5% 2.3%

3.5.3. Visionimpairment

A significantly smaller percentage of participants with autism/ASD (9.4%) had a vision impairment compared to participantswithoutautism/ASD (16.4%)(Table3),and thisassociationcontinuedtobesignificantundermultivariate analysis(Table4). IndividualswhowereolderandhadmoresevereIDweresignificantlymorelikely tohavea vision impairment(Table4).

3.5.4. Hearingimpairment

Basedonourchosensignificancelevelof.001forunivariateanalyses,therewasnosignificantunivariatedifferenceby autism/ASDdiagnosisinthepercentageofparticipantswithahearingimpairment(Table3).Likewise,autism/ASDwasnot significantlyrelatedtohearingimpairmentundermultivariateanalysis,althougholderparticipantsandthosewithmore severeIDweresignificantlymorelikelytohaveahearingimpairment(Table4).

3.5.5. Physicaldisability

Asignificantlysmallerproportionofpeoplewithautism/ASD(6.0%)hadaphysicaldisabilitythanthosewithoutautism/ ASD(13.0%), afinding thatwasalso confirmedbymultivariate analysis(Table4). Havingmore severeIDwasalso a significantmultivariatepredictorofphysicaldisability.

3.5.6. Communicationdisorder

Asignificantlylargerpercentageofparticipantswithautism/ASD(15.8%)hadacommunicationdisorder,relativetothose withoutautism/ASD(10.2%)(Table3).Logisticregressionshowedthat,inadditiontoautism/ASD,youngerageandmore severeIDwerealsosignificantpredictorsofacommunicationdisorder.

3.5.7. Downsyndrome

Asignificantlysmallerpercentageofparticipantswithautism/ASD(2.6%)hadDownsyndromecomparedtoindividuals withoutautism/ASD(10.2%)(Table3).ThiscompareswithaprevalenceofDownsyndromeof9.7%(99%CI=9.0–10.4%)

Table4

Resultsoflogisticregressionofage,levelofintellectualdisability,autism/ASDandgenderontootherdisabilitydiagnoses.

Dependentvariable Independentvariables B Wald Oddsratio Sig. Nagelkerke

Rsquare

Otherdisability

Mentalillness/psychiatricdiagnosis Age .015 113.926 1.015 .000

MilderID .194 117.958 1.214 .000

Autism .080 1.022 .923 .312 .03

Female .052 1.648 1.053 .199

Seizuredisorder/neurologicalproblem Age .011 54.205 .989 .000

MilderID .469 632.896 .626 .000

Autism .178 4.897 .837 .027 .08

Female .020 .215 .980 .643

Visionimpairment Age .010 29.861 1.010 .000

MilderID .227 110.101 .797 .000

Autism .599 26.278 .549 .000 .03

Female .038 .559 1.039 .455

Hearingimpairment Age .019 61.730 1.019 .000

MilderID .140 21.296 .869 .000

Autism .124 .701 .883 .402 .02

Female .024 .109 .977 .741

Physicaldisability Age .004 3.132 1.004 .077

MilderID .471 373.086 .624 .000

Autism .936 42.839 .392 .000 .07

Female .060 1.111 1.062 .292

Communicationdisorder Age .008 13.475 .992 .000

MilderID .714 674.678 .490 .000

Autism .305 9.150 1.356 .002 .13

Female .064 1.045 .938 .307

Downsyndrome Age .017 54.427 .983 .000

MilderID .148 30.320 .862 .000

Autism 1.628 61.898 .196 .000 .03

Female .011 .033 .989 .855

Relationships

Evermarrieda

Age .031 90.188 1.031 .000

MilderID 1.062 272.060 2.892 .000

Autism 1.193 10.689 .303 .001 .16

Female .833 70.428 2.300 .000

Note:Oddsratios>1.0denotethatthepresenceofthedependentvariable(e.g.,otherdisability)wasmorelikelyforparticipantsrespectivelywhowere

older,hadmilderdisability,hadautism/ASDandwerefemale.a=.01formultivariateanalyses.

amongUSadultIDDserviceusersreportedbyStancliffeetal.(inpress).MultivariateanalysisshowedthatDownsyndrome wassignificantlyassociatedwithyoungerage,moresevereIDandnothavinganautism/ASDdiagnosis(Table4).

3.6. Relationships

3.6.1. Maritalstatus

Veryfewpeopleincludedinthesamplewerecurrentlymarriedorhadbeenmarriedinthepast.Evenso,therewasa significantdifferenceintheprevalenceofautism/ASDbymaritalstatus,

x

2(3)=28.71,N=12,273,p<.001,withfewer

peoplewithautism/ASDevermarried(Table3).Logisticregressionanalysisrequiresabinarydependentvariable.Sincethe overwhelmingmajoritynevermarried,maritalstatus datawererecodedintoabinaryevermarrieddependentvariable (yes=marriednoworinthepast;no=nevermarried).Participantsweresignificantlymorelikelytobemarriednoworinthe pastiftheywereolder,hadmilderintellectualdisability,hadnoautism/ASDdiagnosisandwerefemale.

4. Discussion

4.1. Limitations

Thisstudyhasseverallimitations.TheNCIprogramrequiresastandardizedapproachtosurveyingthatdoesnotallowfor moreindepth,individualizedexplorationoftheissuesaskedaboutinthesurveyandthedecision-makingprocessusedby respondentsincompletingtheirresponses.Thepresenceofadiagnosisofautism/ASDonthesurveyinstrumentisgenerally identifiedbywhetherornottherespondentfindsarecordofsuchdiagnosisintheperson’sfile.Theassessmentinstruments andprocessesusedtodetermineadiagnosisarenotrecordedintheNCI,whichcouldresultininconsistencyinhowthe determinationofautism/ASDisyielded.Itisalsopossiblethatsomepeople(particularlyoldersamplemembers)mayhave characteristicsofASDandyetneverbeengivenanASDdiagnosisduetochangesindiagnosticprocesses,greaterawareness andanincreasedidentificationofco-occurringdisabilitiesinthepastdecade.

4.2. Demographiccharacteristics

Thepercentageofsamplemembersinthisstudywithadiagnosisofautism/ASDaveraged8.1%witharangeof3.2–27.4% dependinguponthestate.Thisfindingrepresentsawidevariationthatmaybeexplained,inpart,bystatepolicy.Thelowest percentageofindividualswithautism/ASDexistedinstateswithoutautism-specificwaiversorrelatedconditionseligibility policies(6.6%),andthefivestateswithbothofthesepoliceshadthehighestpercentageofserviceuserswithautism/ASD (9.3%).ThissuggeststhatiftheprogramandrelatedpoliciesaretailoredtotheneedsofpeoplewithASD,oriftheeligibility criteriaincludeASDasatargeteddisabilitycategory,theprogramismorelikelytoservepeoplewithASD.Intheabsenceof thesestate-drivenpoliciesitmaybemoredifficultforpeoplewithASDtoreceiveneededsupportsandservicesthatare commonlyofferedbyHCBS.ThisisparticularlytrueforpeoplewhohaveanASDdiagnosisbutdonothaveID.Intheabsence ofspecificeligibilitycriteriathatdonotrequireadiagnosisofID,itisunlikelythatpeoplewithAspergerdisorderorhigh functioningautismwillbeservedinthedevelopmentaldisabilitiessystem.Itisimportanttonotethatirrespectiveofthese twoeligibilitypolicies,eachstateincludedinthissampledidservepeoplewithASDintheirHCBSwaiverand/orICF/MR programs.Thisindicatesthatatleastacertainpercentageofpeoplewithautism/ASDarebeingservedinthecurrentadult servicessystemdesignedforpeoplewithintellectualanddevelopmentaldisabilities.

Thisstudyfoundthatmalesamplememberswereoverthreetimesmorelikelytohaveanautism/ASDdiagnosisthan females.Themale:femaleratiowasonly1.16forsamplememberswithoutautism/ASDbutwas3.16forthosewithan autism/ASDdiagnosis.However,at3.16:1thisratiowassomewhatlowerthanthecommonlyacceptedASDgenderratioof between4:1and5:1(CDC,2009).Interestingly,amongparticipantswithautism/ASDandnoIDlabel,thegenderratiowas higher(4.10:1)thanforthosewithID(butthesedifferenceswerenotsignificant),consistentwiththepropositionthatthe moremarkedgenderdifferencesapplytoindividualswithautism/ASDbutwithoutID,whereasgenderratiosforthosewith ASDandIDmaybesmaller(IAN,2009). Thepropositionthatthegenderratioamongpeople withautism/ASDdiffers accordingtothepresenceandseverityofIDwarrantsfurtherinvestigation.

Withinthissampletherewerenosignificantdifferencesinprevalenceofautism/ASDbasedonraceandethnicity.This findingisinconsistentwithpreviousstudiesthathaveshownanunderrepresentationandunder-diagnosis(CDC,2006; Mandelletal.,2009)oranoverrepresentationandover-diagnosisofASDinchildrenfromracialandethnicminoritygroups (Barnevik-Olsson,Gillberg,&Fernell,2008;MinnesotaDepartmentofHealth,2009).

betteroption.ItisalsoimportanttoconsiderwhetherpeoplewithASDarebeingservedinIDDservicesystemsbecauseother optionsarenotavailable.

4.3. Co-occurringdisabilities

Inthisstudy,samplememberswithadiagnosisofautism/ASDweremorelikelytoalsohaveadiagnosisofnointellectual disabilityorsevere/profoundID.Thisfindingisconsistentwithpreviousresearchontheexistenceofco-occurringnon-ASD developmentaldiagnosesamongchildrenwithASDthatshowthisexistencein41%(CDC,2009)to83%(Levyetal.,2010)of thispopulation.Yet,thereislittleexistingresearchtoexplaintheincreasedlikelihoodforsamplemembersnottohaveanID diagnosis.ThisfindingisperhapsexplainedbytheoverallincreaseintheprevalenceofpeoplewithASDingeneral(CDC, 2010)andtheemergenceofviewingthisdisorderonaspectrumwithmorepeoplebeingdiagnosedwithAspergerdisorder whodonothaveID.AdditionallythisfindingmaybeexplainedbystatepoliciesthatallowforpeoplewithASDtobeserved eveniftheydonothaveID.

Interestinglythisstudyalsofoundthathavingadiagnosisofautism/ASDwasnotpredictiveofanincreasedco-occurring hearing,epilepsyorDownsyndromediagnosis.Otherstudieshavefoundthatfoundthat10%ofchildrenwithASDhadan identifiablegenetic,neurologicormetabolicdisorder,suchasfragileX orDownsyndrome(Cohen,Pichard,Tordjman, Baumann,&Burglen,2005).

4.4. Primarymeansofexpression

Asignificantly higherpercentageof participantswithautism/ASD(15.8%)werereported tohavea communication disorderthan participantswithoutautism/ASD (10.2%).Thiswasexpectedbased onthecharacteristicsofpeople with autism/ASD.Informationabouteachperson’sprimarymeansofexpressionrevealedthatsignificantlyfewerindividualswith autism/ASD used natural speech (53.4% of participants with autism/ASD; 68.7% without autism/ASD), and a higher percentageusedgesturesand bodylanguageora communicationaidordevice.Despite thesubstantial percentageof participantswhodidnotusenaturalspeech,thenumberwhousedacommunicationaidordevicewasverylow(0.8%ofthe totalsample;2.1%ofthosewithautism/ASD).Itisofconcernthatuptakeofcommunicationaidsordevicesissolow,because allindividualshavearighttoeffectivecommunication.

5. Implications

ThereisadearthofresearchonadultswithASDwhoreceivedevelopmentaldisabilityservicessuchasHCBSandICF/MR. Thisstudyprovidesasnapshotofthecharacteristicsofadultswhoreceivesuchservicesin25statesandsetsoutimportant descriptiveinformation.Thefindingsareinmanywaysconsistentwithpreviousstudiesonthecharacteristicsofchildren andyouthwithASD.Yet,theyalsopointtoimportanttrendswithinservicedelivery,suchasthedisproportionatenumberof youngerpeople(age18–29years)withanASDdiagnosis.Thisfinding,alongwiththegrowingprevalenceofASDinthe UnitedStates(CDC,2010)likelyindicatesthattherewillcontinuetobegrowthofpeoplewithASDreceivingadultservicesin allagegroups.Theservicesystemwillneedtodevelopandimplementeffectivestrategiestobestservetheseindividuals whohaveuniqueneedsintheareasofcommunication,socialskillsandbehavior.

Additionally,thereareimportantfindingsinthisstudyrelatedtostatepolicyandaccessandutilizationofservicesfor peoplewithASD.ClearlyinstatesinwhichtherearespecificautismHCBSprogramsandinstatesthathaverelatedclausesin theireligibilitycriteriaforHCBSprograms,ahigherpercentageofpeoplewithautism/ASDareservedthaninthosewithout suchdesignatedprograms.ThisisparticularlyimportantforpeoplewithASDwhodonothaveanintellectualdisabilitybut dohavefunctionallimitationsforwhichtheyneedservicesandsupport.

Declarationofinterest

TheHuman Services ResearchInstitute (HSRI) employsseveral oftheauthors. HSRIcoordinates theNationalCore Indicatorsprojectandreceivesafeefromparticipatingstates.Theauthorsaloneareresponsibleforthecontentandwriting ofthepaper.

Acknowledgements

Preparation of this paper was supported by Grant #H133G080029 from the National Institute on Disability and RehabilitationResearch,U.S.DepartmentofEducation(Federalfundsforthisthreeyearprojecttotal$599,998(99.5%ofthe totalprogramcosts,with0%fundedbynon-governmentalsources)).

References

Barnevik-Olsson,M.,Gillberg,C.,&Fernell,E.(2008).PrevalenceofautisminchildrenborntoSomaliparentslivinginSweden:Abriefreport.Developmental MedicineandChildNeurology,50,598–601.

Billstedt,E.,Gillberg,C.,&Gillberg,C.(2005).Autismafteradolescencepopulation-based13-to22-yearfollow-upstudyof120individualswithautismdiagnosed

inchildhood.JournalofAutismandDevelopmentalDisorders,35(3),351–360.

Boulet,S.L.,Boyle,C.A.,&Schieve,L.A.(2009).HealthcareuseandhealthandfunctionalimpactofdevelopmentaldisabilitiesamongUSchildren,1997–2005.

ArchivesofPediatricandAdolescentMedicine,163(1),19–26.

CentersforDiseaseControlandPrevention(CDC).(2006).MMWR:Parentalreportofdiagnosedautisminchildrenaged4–17years,UnitedStates,2003–2004.Fact

sheet.Retrievedfrom<http://www.cdc.gov/media/transcripts/ASDMMWRfactSheet.pdf>.

CentersforDiseaseControlandPrevention(CDC).(2010).Autismspectrumdisorders:Data&statistics.Retrievedfrom<http://www.cdc.gov/ncbddd/autism/

data.html>.

CentersforDiseaseControlandPrevention(CDC),&AutismandDevelopmentalDisabilitiesMonitoringNetworkSurveillanceYear2006PrincipalInvestigators,

(2009).Prevalenceofautismspectrumdisorders:Autismanddevelopmentaldisabilitiesmonitoringnetwork,UnitedStates,2006.MMWRSurveillance

Summaries,58(10),1–20.

Cohen,D.,Pichard,N.,Tordjman,S.,Baumann,C.,Burglen,L.,Excoffier,E.,etal.(2005).Specificgeneticdisordersandautism:Clinicalcontributiontowardstheir

identification.JournalofAutismandDevelopmentalDisorders,35(1),103–116.

Croen,L.A.,Grether,J.K.,&Selvin,S.(2002).DescriptiveepidemiologyofautisminaCaliforniapopulation:Whoisatrisk?JournalofAutismandDevelopmental

Disorders,32(3),217–224.

Engstrom,I.,Ekstrom,L.,&Emilsson,B.(2003).PsychosocialfunctioninginagroupofSwedishadultswithAspergersyndromeorhighfunctioningautism.Autism,

7(1),99–110.

Giarelli,E.,Wiggins,L.D.,Rice,C.E.,Levy,S.E.,Kirby,R.S., Pinto-Martin,J.,etal.(2010).Sexdifferencesintheevaluationanddiagnosisofautismspectrum

disordersamongchildren.DisabilityandHealthJournal,3(2),107.

Graetz,J.(2010).Autismgrowsup:Opportunitiesforadultswithautism.Disability&Society,25(1),33–47.

Hall-Lande,J.,Hewitt,A.,&Moseley,C.R.(2011).PolicyResearchBrief:HomeandCommunity-BasedServices(HCBS)forindividualswithautismspectrumdisorders.

ManuscriptinPreparation.

Howlin,P.,Goode,S.,Hutton,J.,&Rutter,M.(2004).Adultoutcomeforchildrenwithautism.JournalofChildPsychologyandPsychiatry,45(2),212–229.

Howlin,P.,Mawhood,L.,&Rutter,M.(2000).Autismanddevelopmentalreceptivelanguagedisorder—Afollow-upcomparisoninearlyadultlifeII:Social,

behavioural,andpsychiatricoutcomes.JournalofChildPsychology&Psychiatry&AlliedDisciplines,41(5),561–578.

HumanServiceResearchInstitute.(2008).NCIdatabrief:WhatdoesNCItellusaboutpeoplewithautism?NationalAssociationofStateDirectorsofDevelopmental

DisabilitiesServices,6(2),1–7.

InteractiveAutismNetwork(IAN).(2009).IANresearchreport#12–December2009:GirlswithASD.KennedyKriegerInstitute.Retrievedfrom

http://www.ian-community.org/cs/ian_research_reports/ian_research_report_dec_2009.

Keen,D.V.,Reid,F.D.,&Arone,D.(2010).Autism,ethnicityandmaternalimmigration.TheBritishJournalofPsychiatry,196,274–281.

Kogan,M.D.,Blunberg,S.J.,Schieve,L.A.,Boyle,C.A.,Perrin,J.M, Ghandour,R.M.,etal.(2009).Prevalenceofparent-reporteddiagnosisofautismspectrum

disorderamongchildrenintheUS,2007.Pediatrics,124(5),1395–1403.

Lawer,L.,Brusilovskiy,E.,Salzer,M.,&Mandell,D.(2009).Useofvocationalrehabilitativeservicesamongadultswithautism.JournalofAutism&Developmental

Disorders,39(3),487–494.

LeBlanc,L.A.,Riley,A.R.,&Goldsmith,T.R.(2008).Autismspectrumdisorders:Alifespanperspective.InJ.Matson(Ed.),Clinicalassessmentandinterventionfor

autismspectrumdisorders(pp.65–84).Burlington,MA:Elsevier.

Levy,S.E.,Giarelli,E.,Lee,L.C.,Schieve,L.A.,Kirby,R.S.,Cunniff,C.,etal.(2010).Autismspectrumdisorderandco-occurringdevelopmental,psychiatric,and

medicalconditionsamongchildreninmultiplepopulationsoftheUnitedStates.JournalofDevelopmentalandBehavioralPediatrics,31(4),267–275.

Mandell,D.,Wiggins,L.D.,Carpenter,L.A.,Daniels,J.,DiGuiseppi,C., Durkin,M.S.,etal.(2009).Racial/ethnicdisparitiesintheidentificationofchildrenwith

autismspectrumdisorders.AmericanJournalofPublicHealth,99(3),493–498.

MinnesotaDepartmentofHealth.(2009).AutismspectrumdisordersamongpreschoolchildrenparticipatingintheMinneapolisPublicSchoolsEarlyChildhoodSpecial

EducationPrograms.St.Paul,MN:author.

Newschaffer,C.J.,Falb,M.D.,&Gurney,J.G.(2005).NationalautismprevalencetrendsfromtheUnitedStateseducationdata.Pediatrics,115(3),e277–e282.

Renty,J.,&Roeyers,H.(2006).Qualityoflifeinhigh-functioningadultswithautismspectrumdisorder:Thepredictivevalueofdisabilityandsupport

characteristics.Autism,10(5),511–524.

Rutter,M.(2005).Incidenceofautismspectrumdisorders:Changesovertimeandtheirmeaning.ActaPaediatrica,94,2–15.

Smith,G.,&Ashbaugh,J.(2001).Nationalcoreindicatorsproject:PhaseIIconsumersurveytechnicalreport.http://www.hsri.org.

Stancliffe,R.J.,Lakin,K.C.,Larson,S.A.,Engler,J.,Taub,S.,Fortune,J.,&Bershadsky,J.(inpress).Demographiccharacteristics,healthconditionsandresidential

serviceuseinadultswithDownsyndromeintwenty-fiveUSstates.IntellectualandDevelopmentalDisabilities.

Wilkins,J.,&Matson,J.L.(2009).AcomparisonofsocialskillsprofilesinintellectuallydisabledadultswithandwithoutASD.BehaviorModification,33(2),

143–155.