Adolescents with Asperger's Syndrome Impaired in Several Domains of Executive Function as Measured by the Behavior Rating Inventory of Executive Function

Background:

There are inconsistent results in the literature about executive dysfunctions in individuals with higher functioning forms of autism, specifically in planning, set-shifting, and working memory (Ozonoff, South, & Miller, 2000; Goldberg, Mostofsky, Cutting, Denckla, & Landa, 2005; Ozonoff & Strayer, 2001). Gioia et al. (2002) examined executive functions in children with higher functioning forms of autism; Asperger’s Syndrome, PDD NOS, and higher functioning autism (HFA). They used the Behavior Rating Inventory of Executive Function (BRIEF), a parent report measure of executive function. The study found that these children were significantly elevated across all scales relative to controls. These data suggest that the children with higher functioning ASD are impaired in planning/organization, shifting, working memory, emotional control, initiation, monitoring and organization of materials. Further, these results indicate that parent reports of executive function, as measured by the BRIEF, may be an important tool for illuminating our understanding of the executive dysfunctions present in higher functioning forms of autism. Currently, there is a lack of BRIEF data on adolescents with higher functioning forms of autism. Yet, executive functions greatly develop during adolescence in the typically developing population and so studying this developmental stage is critically important for characterizing atypical development of executive functions in individuals with higher functioning forms of autism.

Objectives:

The objective of the current study was to examine whether adolescents with Asperger’s Syndrome compared to matched typically developing controls are reported to have impairments in executive functions across the 8 scales of the BRIEF.

Methods:

The current study examined executive functioning in 17 adolescents with Asperger’s Syndrome (8 Female; 9 Male) and 17 typically developing adolescents matched for gender and age and less closely matched for IQ. One parent, typically mothers, of each of the thirty-four children, filled out the BRIEF.

Results:

Parents reported that adolescents with Asperger’s Syndrome had significantly poorer executive function abilities than typically developing controls across all of the scales of the BRIEF (see Table 1), except for the Organization of Materials scale which was approaching significance.

Table 1.

Paired Samples T Tests for BRIEF Scales

Subscale                      t-test (df =16)                        p value

_____________________________________________________________

Inhibit                                       -4.43                              **

Shift                                          -7.58                              **                              

Emotional Control                    -4.83                              **                               

Initiate                                       -7.45                              **                                

Working Memory                      -9.11                              **                             

Plan/Organize                          -10.78                              **                             

Monitor                                      -4.43                              **                            

Organization of Materials         -1.72                             0.11

_____________________________________________________________

** = p < .001

Conclusions:

The current study suggests that adolescents with Asperger’s Syndrome have impairments in several domains of executive function, specifically in planning/organization, shifting, working memory, emotional control, initiation, and monitoring. Furthermore, the results suggest that the BRIEF may be used in the future as an important instrument to help reveal the nature of executive dysfunctions in adolescents with higher functioning forms of autism.