Executive Dysfunction Is More Predictive of Adaptive Functioning in a Sample of High-Functioning Autism

Background: Individuals with ASD display a varied profile of executive functioning across domains, although these deficits do not appear to be universal. While individuals with high-functioning ASD (HFA; IQ >70) often exhibit adequate performance on behavioral tasks of executive functioning when compared to controls, parent and caregivers often report significant difficulties with behavior regulation in real-life.  The discrepancy between performance on behavioral tasks and ratings of real-world behavior is striking and necessitates further investigation to elucidate these differences.

Objectives: To examine the relationship between parent-report of executive function abilities and adaptive behaviors in a cohort of individuals diagnosed with autism, with and without intellectual disability (ID), as well as an ID sample without ASD. 

Methods: A cohort of 37 individuals was drawn from a larger sample of an ongoing, longitudinal study. A wealth of diagnostic, phenotypic and descriptive data is available both for this current time point (T3), as well as from earlier assessments. The focus of the current study is drawing from parent report measures of executive function (BRIEF) and adaptive functioning (Vineland).  Additional measures may be included as predictive variables if warranted.

Results: Comparison of ASD (IQ >70) to DD (IQ < 70) shows a significant group difference on the BRIEF Metacognition Composite (p = .020); Global Executive Composite (p = .021) and a trend for Behavior Regulation Index (p = .058). Interestingly, the group differences were not in the hypothesized direction, finding that individuals with ASD performed worse on ratings of executive measures than those in the DD group. There were no significant group differences in overall adaptive behavior (Vineland Adaptive Behavior Composite, p =  .297)

Conclusions: These data indicate that measures of executive function may be more predictive of adaptive functioning than IQ in a high-functioning ASD sample. Additionally, the lack of a group difference on overall adaptive functioning necessitates further understanding of what factors (e.g. IQ vs. impaired EF) impacts these impairments for each particular group. Delineating particular areas of weakness (e.g. initiation) is relevant for understanding more basic cognitive processes, as well as for developing targeted interventions.