Is executive dysfunction a potential contributor to the comorbidity between basic reading disability and attention-deficit/hyperactivity disorder?

ABSTRACT

Our study is one of the few to analyze executive functioning (EF) in a comprehensive, multi-modal fashion as a potential contributor to the comorbidity between attention-deficit/hyperactivity disorder (ADHD) and basic reading disability (RD). We included multiple, traditional, neuropsychological measures of EF, along with the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire, to assess inhibit, shift, working memory (WM), planning, generation fluency, and problem-solving. Participants included 263 children, ages 8–12 years, with RD, ADHD, RD/ADHD, and typically developing controls. When using the traditional measures in a 2 × 2 MANCOVA, we found both RD and ADHD had poor cognitive EF in most areas at the group level, with phonological loop deficits being more specific to RD and behavioral regulation deficits being more specific to ADHD. Children with RD/ADHD performed comparably to those with RD and ADHD alone. Results were similar on the BRIEF. In contrast, only WM predicted both basic reading and inattention when the data were assessed in a continuous fashion. It also explained the correlations between basic reading and inattention, being worthy of longitudinal research to determine if it is a shared contributor to RD/ADHD. When comparing hypotheses as to the nature of RD/ADHD, we found the multiple deficit hypothesis was better supported by our EF data than the phenocopy hypothesis or the cognitive subtype hypothesis.

KEYWORDS:

• ADHD
• reading disorder
• reading disability
• executive functioning
• comorbidity

Acknowledgments

We would like to thank the parents and children who participated in this project and the teachers who completed the questionnaires.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The measures included in this study are part of a larger dataset. The larger dataset is being used as part of other ongoing projects, and, hence, it is not deposited in a repository. This data is available for data checking upon request to the corresponding author.

Additional information

Funding

Data collection was supported in part by the National Institutes of Health/National Institute of Child Health and Human Development under Grants [R03 HD048752 and R15 HD065627]. The content of this article may not reflect the views of NIH or NICHD.