Dissociating Executive Function and ADHD Influences on Reading Ability in Children with Dyslexia

Dissociating Executive Function and ADHD Influences on Reading Ability in Children with Dyslexia

First Author: Noor Al Dahhan -- Massachusetts Institute of Technology
Additional authors/chairs: 
Kelly Halverson; Carrie Peek; Dayna Wilmot; Rachel Romeo; Andrea Imhof; Karolina Wade; Anila D’Mello; Anissa Sridha; John D. E. Gabrieli; Joanna A. Christodoulou
Keywords: Executive Functions, Reading, Reading Ability, ADHD, Dyslexia
Abstract / Summary: 

Purpose
Dyslexia and attention-deficit/hyperactivity disorder (ADHD) are two of the most common neurodevelopmental disorders among school-age children. These disorders frequently co-occur with one another, impacting an estimated 5-10% of school-age children. Despite distinct diagnostic criteria for dyslexia and ADHD, executive functions (EF) and reading skills vary across children with dyslexia with or without comorbid ADHD. The goal of the current study was to investigate whether the high co-occurrence of dyslexia and ADHD specifically reflects the frequent occurrence of impaired EF in ADHD, or reflects other aspects of ADHD.

Methods
We examined reading abilities and EF abilities in eighty-eight children (6-13 years old) with typical reading ability, with dyslexia only, or with comorbid dyslexia and ADHD. Participants completed measures sampling EF, ADHD characteristics, reading, language, and related skills.

Results
Results indicate that stronger EF skills are associated with better reading performance and a lower risk for ADHD symptomatology. Results also showed that children with EF deficits are more impaired on reading tasks compared to children with unimpaired EF, regardless of the presence of an ADHD diagnosis. This indicates that once EF abilities are controlled for, ADHD diagnosis does not play a large role in predicting reading performance.

Conclusion
These findings support the potential importance of EF dysfunction in dyslexia, and indicate that other facets of ADHD are unrelated to dyslexia once EF dysfunction is taken into account. Implications include careful examination of neurocognitive skill sets rather than reliance on diagnostic status for understanding skill sets.