Asperger syndrome, autism and attention disorders: a comparative study of the cognitive profiles of 120 children.

The Wechsler Intelligence Scale for Children-Revised (WISC-R) was applied (in a Swedish version) in 120 children with Asperger syndrome, autistic disorder, and attention disorders. Using stepwise logistic regression analysis, the WISC's discriminating ability was investigated. The overall rate of correct diagnostic classification was 63%. Further, WISC profiles were analysed within each group. The group with autistic disorder was characterised by a peak on Block Design. The Asperger syndrome group had good verbal ability and troughs on Object Assembly and Coding. The group with attention disorders had troughs on Coding and Arithmetic. The results suggest that Kaufman's Verbal Comprehension, Perceptual Organisation and Freedom from Distractibility factors rather than verbal IQ and performance IQ account for the variance on the WISC. Furthermore, the Asperger syndrome and autistic disorder groups differed in respect of "fluid" and "crystallised" cognitive ability.