Effect of treatment with stimulant medication on nonverbal executive function and visuomotor speed in children with attention deficit/hyperactivity disorder (ADHD).

This study used a novel hidden maze learning test to examine the nature and magnitude of impairment on separable aspects of executive function in 36 children with ADHD. A within-subject analysis of children with ADHD was also conducted to assess cognitive effects of open-label stimulant treatment. Compared to 31 age-matched controls, unmedicated children with ADHD were slower and made significantly more errors that were indicative of relative impairment in prepotent response inhibition and ability to "maintain set" while using simple rules to complete the task. Open-label administration of stimulant medication led to faster and more efficient performance, with children with ADHD making fewer perseverative and rule-break errors than when off medication. This instrument might be useful in monitoring treatment response in specific aspects of executive function and in assisting with dose-titration decisions.