Differentiating between Children with and without ADHD Using the Delis-Kaplan Executive Function System and Conners' Continuous Performance Test-II

Abstract

The Delis-Kaplan Executive Function System (D-KEFS) is a relatively new measure of executive functioning (EF) that has not been fully evaluated for its potential of differentiating between children with and without ADHD. The Conners’ Continuous Peformance Test (CCPT) is a computerized task that has been studied extensively in ADHD populations and been found to have moderate success at predicting diagnostic status. The present study examined diagnostic group differences on the D-KEFS and CCPT between children with ADHD (n = 32) and a control group (n = 37). Results replicate previous findings in both the D-KEFS and general EF literature (Corbett et al., 2009; Frazier et al., 2004; Wodka et al., 2008a; Wilcutt et al., 2005). Specifically, ADHD group performance on several measures of planning, reconstitution, and inhibition was found to be below average or significantly lower than that of the control group. Additionally, performance on most D-KEFS variables, including some less executive tasks, was associated with diagnostic group status. Inattentive and Hyperactive/Impulsive symptoms, as rated by parents on the CPRS, were significantly related to almost all D-KEFS variables. However, higher magnitude correlations between Inattention and the Trailmaking and Color-Word Interference tests were noted. On the CCPT, between-group differences were found for Hit Reaction Time Standard Error, Detectability, and Omission errors. Intercorrelations between the CCPT and CPRS symptom scales revealed Reaction Time variables related to both symptom domains, Omissions related to Inattention, and Detectability and Response Style related to Hyperactivity/Impulsivity. Significant correlations between several CCPT and D-KEFS variables were found, with some planning/inhibition/switching and more basic skill D-KEFS measures being associated with CCPT scores. Moderate predictive utility of diagnostic group was found for both the D-KEFS and CCPT individually. Combined predictive utility of both measures resulted in non-significant models. Recommendations are provided regarding the use of the D-KEFS and CCPT in evaluating ADHD, as well as important future research directions.