Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)



Committee Chair(s)

Maryellen Brunson McClain


Maryellen Brunson McClain


Sarah Schwartz


JoAnn Tschanz


Kerry Jordan


Thomas Higbee


Children with autism and other NDDs experience some level of executive dysfunction including challenges with problem-solving, judgement, working memory, and flexibility. Considering autism and other NDDs including ADHD and ID have overlapping symptoms, it can be difficult to differentially diagnose the disorders. This dissertation sought to explore how co-occurring ADHD and ID impact the EF of autistic children. The first study systematically reviewed the current research examining EF of autistic children with co-occurring ADHD and ID. Findings suggest that co-occurring ADHD and ID result in increased executive dysfunction as compared to children with autism only. The systematic review also revealed inconsistencies in the current literature as well as supported previous research suggesting that different ways of measuring EF (i.e., performance-based vs. indirect) are measuring different constructs of EF. This led to the second study which investigated whether intellectual functioning, autism symptomology, and ADHD symptomology predict EF in autistic children using an indirect measure of EF and (due to its ecological validity) and a model of EF (due to the overlapping nature of areas of EF). Results suggest that social communication difficulties and hyperactivity/impulsivity negatively impact EF whereas restricted/repetitive behaviors, inattention, and intellectual functioning do not significantly predict EF. Additionally, the student identified emotion regulation as a relative EF weakness as compared to behavior and cognitive regulation. Overall, this multi-part dissertation adds to the current literature by suggesting a co-occurring ADHD or ID worsens EF; suggested significant predictors of EF with autistic children (i.e., social communication challenges and hyperactivity/impulsivity); and, identified emotion regulation as a possible relative EF weakness. These results provide clinical application for differential diagnostic strategies and targeted interventions.



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