Do individuals with high functioning autism have the IQ profile associated with nonverbal learning disability?

Abstract

Previously researchers have noted a high level of occurrence of the IQ profile associated with nonverbal learning disability (NLD) in Asperger syndrome (ASP) but not in high functioning autism (HFA). We examined the IQ profile scores of a large sample of children ( n = 69) and adults ( n = 77) with HFA, stringently diagnosed according to ADOS, ADI-R, and DSM-IV criteria, and a corresponding sample of typical child ( n = 72) and adult controls ( n = 107). At least one of the three primary components of the Wechsler pattern seen in NLD were found in 17–26% of the children and 20–32% of the adults with HFA. All three components occurred in slightly more than 5% of the children and adults with autism. Overall, the VIQ > PIQ profile seen in NLD occurred in 18% of the sample of individuals stringently diagnosed with HFA. Therefore, obtaining this IQ profile is not a valid clinical discriminator between NLD and HFA.