Objectives: The purpose of the current study is to expand on the existing research and further investigate the EF profiles in children with ASD using a parent-report measure, the Behavior Rating Inventory of Executive Function (BRIEF) in a large sample of school-aged children with ASD.
Methods: The sample included 99 children: 38 from a clinic-referred sample and 61 from a longitudinal study of ASD. Mean age was 9.1 years (s.d. 2.8; range 5-17). Level of cognitive functioning was assessed using the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) or the Differential Abilities Scale, Second Edition (DAS-II). For the children who received the WISC-IV, mean IQ score was 96.6 (s.d. 19.4; range 54-149). For the children who received the DAS-II, mean IQ score was 94.3 (s.d. 18.2; range 53-134). All children received the ADOS and were characterized by a team of experienced clinicians.
Results: Mean scores on the BRIEF indices were at or just below the clinically significant range overall; however, the group averages obscure the wide variability in the sample. For each of the 8 clinical scales on the BRIEF, 33 to 51% of the sample scored within the clinically significant range. Sixteen percent of the sample had no elevated scores, 13% had clinically significant elevations in only one domain, and 14% had clinically significant elevations on 7 or 8 domains. Hierarchical cluster analysis revealed two clusters, which were distinguished based on severity of EF impairment. There were no differences between the two cluster groups on cognitive ability or symptom severity, as measured using ADOS calibrated severity scores. However, there were significant differences in adaptive functioning, as measured using the Vineland Adaptive Behavior Scales, Second Edition (VABS-II), with the group with greater EF impairments having lower adaptive skills.
Conclusions: Behavioral impairments in regulatory and metacognitive functioning characterize many but not all children with ASD. There appears to be a subset of children for whom these challenges are present to a significant degree, independent of IQ and ASD symptom severity. This raises the question whether EF behaviors represent another dimension by which to characterize subgroups of ASD and whether there are implications for neurobiological mechanisms and the genetics of the disorder. From a clinical standpoint, the level of impairment in this group and the significant relationship to adaptive functioning suggest a need to focus on this domain of behaviors when assessing and treating children with ASD.