Differentiating Attention Deficit Hyperactivity Disorder and Reading Disability with the Delis-Kaplan Executive Function System

The present study assessed the sensitivity of the Delis-Kaplan Executive Function System (D-KEFS) for evaluating executive functions (EF’s) in children with Attention Deficit Hyperactivity Disorder (ADHD), Reading Disability (RD), and both ADHD and RD. Participants comprised 50 children (35 ADHD only, 5 RD only, and 10 ADHD/RD). Using categorical and dimensional analyses, performance was compared on three subtests of the D-KEFS; Trail Making, Verbal Fluency, and Tower. Word reading abilities were associated with lower scores on Letter Sequencing and higher scores on Number Letter Switching when controlling for Letter Sequencing on Trail Making. On Verbal Fluency, attention difficulties were associated with lower scores on Category Switching Accuracy, while reading difficulties were related to lower scores on Letter Fluency. On the Tower, children with attention difficulties as well as children with combined reading and attention difficulties exhibited a higher number of rule violations and lower scaled scores on the move accuracy ratio, when compared to children with reading difficulties. The comorbid group generally showed deficits on tasks associated with both attention and reading difficulties, and generally had lower performance than both single groups. The D-KEFS is differentially sensitive to difficulties associated with attention difficulties and reading difficulties.