EEG correlates of methylphenidate response among children with ADHD: a preliminary report.

BACKGROUND: Recent electrophysiologic studies have found fairly consistent differences between children with attention-deficit/hyperactivity disorder (ADHD) and age-matched control subjects. The present study examined electroencephalogram (EEG) changes associated with a double blind, placebo-controlled administration of methylphenidate among children with ADHD. METHODS: Subjects were 10 children, ages 8 to 13, with a primary diagnosis of ADHD. Brain electrical activity was recorded with 7 electrodes in the frontal, central, and midline areas during baseline and cognitive activation conditions. RESULTS: Repeated-measures ANOVAs indicate that children exhibiting a positive medication response had reductions of theta and alpha as well as increased beta in the frontal regions, while nonresponders showed the opposite pattern (p < .05). Significant correlations between improvement on a vigilance task and changes in beta activity in the frontal electrodes emerged as well. CONCLUSIONS: These preliminary findings indicate that there are different electrophysiologic correlates to methylphenidate among ADHD children who are medication responders and nonresponders.