Adaptive and intellectual functioning in autistic and nonautistic retarded children.

This study examined the relationship between adaptive functioning on the Vineland Adaptive Behaviour Scale (VABS) and intellectual functioning on the Stanford-Binet Intelligence Scale, 4th edition (SB-IV) in autistic children and nonautistic retarded children of comparable CA and SB-IV composite score (IQ). The autistic group had lower scores than the retarded group in VABS adaptive composite, Socialization domain, and Communication domain, and SB-IV Verbal Reasoning area. VABS domain scores yielded higher classification rates than the SB-IV area scores in discriminating the two groups. Correlations between the two measures were much higher for the autistic group than for the retarded group. Results support the conclusion that the cognitive impairment in autism is reflected in greater impairment in adaptive behaviors than in mental retardation without autism.