title: Behavioural assessment of autism spectrum disorders in people with multiple disabilities.
abstract: BACKGROUND
  It is difficult to diagnose autism spectrum disorder (ASD) in people with a combination of intellectual and sensory disabilities because of overlap in behaviour. The ASD typical behaviours of people with combined intellectual and sensory disabilities are often caused by their disabilities and not by ASD. Current diagnostic tools are inadequate to differentiate between people with and without ASD when they have these combined disabilities, because tools lack norms for this population or are subjective, indirect or unable to adapt to the variety of disabilities that these people may have. Because giving a correct diagnosis is necessary for treatment and support, a new observational tool was developed to diagnose ASD in people with multiple disabilities, observation of autism in people with sensory and intellectual disabilities (OASID).
  
  
  METHODS
  Observation of autism in people with sensory and intellectual disabilities was tested on 18 participants with moderate to profound intellectual disabilities, one or dual sensory impairment, with and without ASD. Two independent experts diagnosed these participants as well in order to test the psychometric properties and differentiating abilities of OASID.
  
  
  RESULTS
  Observation of autism in people with sensory and intellectual disabilities showed high inter-rater reliability, internal consistency of scales and content and construct validity. OASID could differentiate people with and without ASD without overlap.
  
  
  CONCLUSIONS
  Observation of autism in people with sensory and intellectual disabilities could differentiate people with intellectual disabilities combined with sensory impairments, who clearly had or did not have signs of ASD. People with unclear signs of ADS scored in between those two groups with regard to their OASID scores. Psychometric properties of OASID are promising.
authors.affiliation: Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: de Vaan
authors.affiliation: Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Vervloed
authors.affiliation: Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.|Driestroom, Elst, The Netherlands.
authors.forename: N C
authors.initials: NC
authors.lastname: Peters-Scheffer
authors.affiliation: Royal Dutch Kentalis, Sint-Michielsgestel, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: van Gent
authors.affiliation: Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.|Royal Dutch Kentalis, Sint-Michielsgestel, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Knoors
authors.affiliation: Behavioural Science Institute, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Verhoeven
mesh_terms: D000293:Adolescent; D000328:Adult; D000067877:Autism Spectrum Disorder / Q000175:diagnosis* / Q000453:epidemiology; D001766:Blindness / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D015897:Comorbidity; D003638:Deafness / Q000175:diagnosis* / Q000453:epidemiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011594:Psychometrics / Q000295:instrumentation*; D055815:Young Adult
keywords: Autism; assessment; diagnosis; intellectual disability; multiple disabilities; sensory impairments