Cognitive Functioning and Adaptive Behavior in Children with Autism

Background: Studies have consistently demonstrated deficits in adaptive functioning in children with autism spectrum disorders, particularly in the areas of communication and socialization. These deficits remain even when children with autism spectrum disorders are compared on measures of adaptive functioning after controlling for potential confounding effects related to intelligence. However, the nature of the relationship between intelligence as measured by standard tests and adaptive functioning in children with autism spectrum disorders remains uncertain.

Objectives: The purpose of this study was to compare the correlations between full-scale and sub-scale measures of IQ and socialization scores on the Vineland Adaptive Behavior Scale in children and adolescents with autism spectrum disorders.

Methods: Thirty-three children and adolescents with an autism spectrum disorder (2 females) and 37 children and adolescents with a non-autism spectrum psychiatric diagnosis (8 females) were assessed with the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) and the Vineland Adaptive Behavior Scales, Second Edition (Vineland-II). Correlations between the WISC-IV full-scale and subscale (verbal comprehension, perceptual reasoning, working memory, processing speed) standard scores and Vineland II Socialization scores (including the subscale scores for interpersonal relations, play and leisure, and coping skills) were calculated and compared between groups.

Results: The two groups did not differ significantly on any WISC-IV scores. However, patients with autism had a significantly lower correlation between their WISC-IV verbal comprehension and Vineland-II interpersonal skills scores (r=-0.05) than non-spectrum controls (r=0.05; p<0.05). At the same time, patients with autism had a significantly higher correlation between their WISC-IV perceptual reasoning and their Vineland-II socialization scores (r=0.4) than non-spectrum controls (r=0.2; p<0.05).

Conclusions: Unlike non-autism spectrum psychiatric controls, interpersonal skills in children and adolescents with autism spectrum disorders are best predicted by their perceptual (non-verbal) IQ scores. These findings suggest that examining interpersonal skills scores from the Vineland in the context of verbal and non-verbal intelligence scores may be of benefit in clarifying the diagnosis of autism spectrum disorders and may further our understanding of the social deficits in these disorders.