Predictors and correlates of adaptive functioning in children with developmental disorders.

Autism is a developmental disorder marked by impairments in socialization, communication, and perseverative behavior and is associated with cognitive impairment and deficits in adaptive functioning. Research has consistently demonstrated that children with autism have deficits in adaptive functioning more severe than their cognitive deficits. This study investigates the correlates and predictors of adaptive functioning as measured by the Vineland Adaptive Behavior Scales in high- and low-functioning children with autism and their age and nonverbal IQ matched controls. Thirty-five 9-year-old children with high-functioning autism (HAD) were compared with 31 age-matched children with developmental language disorder (DLD), and 40 9-year-old children with low-functioning autism (LAD) were compared with 17 age-matched children with low IQ on adaptive functioning, IQ, autistic symptomology, and tests of language and verbal memory. Results indicate that both groups with autism were significantly impaired compared to their matched controls on Socialization and Daily Living, but not Communication and that these impairments were more pronounced in the HAD group than in the LAD group. Adaptive behavior was strongly correlated with autistic symptomology only in the HAD group. Regression analyses indicated that IQ was strongly predictive of adaptive behavior in both low-functioning groups, but tests of language and verbal memory predicted adaptive behavior in the higher functioning groups. Results suggest that IQ may act as a limiting factor for lower functioning children but higher functioning children are impaired by specific deficits, including autistic symptomology and impaired language and verbal memory.