Many children with autistic spectrum disorders (ASD) have significant symptoms of Attention Deficit Hyperactivity Disorder (ADHD), i.e., inattention, hyperactivity, and impulsivity. Given that deficits in cognitive task performance are associated with ADHD in the general pediatric population, children with ASD who have significant ADHD symptomatology may also be at high risk for cognitive task deficits. Using parent and teacher behavioral rating techniques, our group previously demonstrated that parent and teacher ratings of executive function (EF) deficits were related to ADHD--but not ASD--symptomatology in children with ASD. The purpose of this study was to determine if cognitive task performance deficits would also be related only to ADHD symptomatology—but not autistic symptomatology--in children with ASD.
The purpose of this study was to examine the relationships between 1) cognitive task performance and 2) behavioral ratings of autistic symptomatology and ADHD symptomatology in children with ASD.
Participants were 92 children (73 boys; mean age=9.4 yrs.; mean Stanford-Binet 5th Ed. Full Scale IQ=84) who met DSM-IV criteria for ASD on the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS). Relationships between the children's cognitive task performance and standardized parent and teacher behavioral ratings of autistic symptomatology (on the Social Communication Questionnaire; SCQ) and ADHD symptomatology (Swanson, Nolan and Pelham Rating Scale, 4th Edition; SNAP-IV) were examined using correlational methods. Cognitive tasks included the Continuous Performance Task (sustained attention and impulsivity), the Speeded Classification Task (selective attention), the Matching Familiar Figures Task (inhibition/impulsivity), and the Delayed Match to Sample Task (immediate memory).
Children with ASD who had more severe ADHD symptomatology were found to be at significantly higher risk for weaker cognitive task performance, relative to those with milder ADHD symptoms. In contrast, more severe levels of autistic symptoms were not associated with an increased risk of poor cognitive task performance. This relationship between cognitive task performance and behavioral ratings was similar for parent and teacher raters.
These results extend our previous findings by demonstrating that cognitive task deficits were also strongly related to ADHD severity—but not to ASD severity--in high functioning children with ASD. Thus, the results of this study provide additional support for the idea that ADHD is manifested in a similar way in children with ASD as it is in the general pediatric population—and that the cognitive task deficits are not associated with the core symptoms of ASD. Rather, these cognitive deficits are manifested in a subset of children with ASD who also have significant ADHD symptoms. Given that cognitive deficits associated with ADHD in the general pediatric population are often successfully treated with medication and/or by behavioral means, cognitive tasks tapping domains such as attention and inhibition may play a helpful role in monitoring ADHD treatment response in children with ASD.
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