Asperger's and executive functioning

I ran across an interesting small-sample (but well controlled with subject matching) study in the recent issue of Neuropsychologia re: possible impairments in executive processes/function (EF) in adults with Asperger's Syndrome. The article presents a nice summary (in table form) of prior matched-control studies that have examined the performance of individuals with Asperger's on many classic executive function measures (e.g., Wisconsin Cart Sort Test; Delis-Kaplan).

The most important finding from this study is the possibility that specific EF deficits (viz., response initiation and intentionality, in particular the ability to engage and disengage actions in the service of overarching goals),may be associated with Asperger's, but this may not have emerged in prior research that has used traditional EF measures. IN particular, the authors identify two less frequently used EF measures (Behavioral Assessment of Dysexecutive Syndrome, BADS; Hayling Test) as being potentially important for clinicians to evaluate for possible diagnostic use.

• Hill, E. Bird, C. (2006) Executive processes in Asperger syndrome: Patterns of performance in a multiple case series Neuropsychologia,44, 2822–2835 (click here to view)
  

Abstract

• Mixed evidence exists for executive dysfunction in autism spectrum disorders (ASD). This may be because of the nature of the tasks used, the heterogeneity of participants, and difficulties with recruiting appropriate control groups. A comprehensive battery of ‘executive’ tests was administered to 22 individuals with Asperger syndrome and 22 well-matched controls. Performance was analysed both between groups and on an individual basis to identify outliers in both the ASD and control groups. There were no differences between the groups on all ‘classical’ tests of executive function. However, differences were found on newer tests of executive function. Specifically, deficits in planning, abstract problem solving and especially multitasking. On the tests that discriminated the groups, all of the ASD individuals except one were identified as significantly impaired (i.e. below the 5th percentile of the control mean) on at least one executive measure. This study provides evidence for significant executive dysfunction in Asperger syndrome. Greatest dysfunction appeared in response initiation and intentionality at the highest level—the ability to engage and disengage actions in the service of overarching goals. These deficits are best observed through using more recent, ecologically valid tests of executive dysfunction. Moreover, performance on these measures correlated with autistic symptomatology.

Technorati Tags: psychology, educational psychology, school psychology, neuropsychology, neuroscience, Aspergers, autism, intelligence, IQ, executive system, executive function, Wisconsin Card Sort Test, WCST, Delis-Kaplan, BADS, Hayling test

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