The external validity of Asperger disorder: Lack of evidence from the domain of neuropsychology.

Abstract

The present study compared individuals with high-functioning autism (HFA) and Asperger disorder (AD) in intellectual, motor, visuospatial, and executive function domains. Participants with AD demonstrated significantly higher Verbal and Full Scale IQ scores, significantly larger Verbal-Performance IQ discrepancies, and significantly better visual-perceptual skills than those with HFA. Once the superior intellectual abilities of the AD group were controlled (both statistically through analysis of covariance and by examining IQ-matched subgroups of HFA and AD participants), no significant group differences in motor, visuospatial, or executive functions were evident, save a marginally significant trend toward poorer fine motor performance in the AD group. This suggests that AD may simply be "high-IQ autism" and that separate names for the disorders may not be warranted. The relation of these findings to theories of autism and AD are discussed.

Brief Report: The Level and Nature of Autistic Intelligence Revisited

“…Here, the exclusive use of Raven IQs could lead to a systematic underestimation of true intellectual abilities. Numerous previous studies have shown relatively better Wechsler verbal IQ for individuals with Asperger syndrome and relatively better Wechsler performance IQ in individuals with autism (e.g., Miller and Ozonoff 2000;Mottron 2004;Ehlers et al 1997;Hayashi et al 2008). Those patterns have been equated with higher fluid intelligence in autism and higher crystallized intelligence in Asperger syndrome (Ehlers et al 1997), which would indeed predict underestimation of IQ in Asperger syndrome by tests of fluid intelligence such as the Raven.…”

When Prototypes Are Not Best: Judgments Made by Children with Autism

“…The children in the autism group had been diagnosed by clinicians as having either Asperger syndrome (13) or autism (5) according to established criteria such as those specified by the DSM-IV (American Psychiatric Association, 1994). Following Miller and Ozonoff's (2000) view of Asperger syndrome as high IQ-autism, children with both diagnoses were included within a single HFA group. They were recruited from special education facilities and ranged in age from 9 years and 5 months to 15 years and 8 months.…”

Asperger syndrome: an update

“…12 Although the advent of the DSM-IV definition was intended to create a consensual diagnostic starting point for research, it has been consistently criticized as overly narrow, 20,21 rendering the diagnostic assignment of AS improbable or even "virtually impossible". 22,23 The introduction of AS in DSM-IV and ICD-10 13 was prompted by the recognition that autism is a clinically heterogeneous disorder and that the characterization of subtypes of PDD might help behavioral and biological research by allowing the identification of clinically more homogeneous groups. [24][25][26] While this effort has been successful for some PDD conditions (e.g., Rett syndrome), 27 it has not been the case in AS.…”