Working memory, response inhibition, and within-subject variability in children with attention-deficit/hyperactivity disorder or reading disorder.

This study compared children with ADHD (n = 19), reading disorder (RD; n = 17), ADHD+RD (n = 21), and control children (n = 19) on linguistic and executive function measures. We found no evidence of response inhibition problems in ADHD or RD when a baseline measure of functioning was taken into account. General working memory problems were only found in children with RD or ADHD+RD. Both children with ADHD and RD showed a highly inaccurate (more commission errors) and variable (higher within-subject standard deviation of reaction time) response style. The comorbid group made most errors, suggesting that different factors underlie the high error rate in both disorders.