Atypical frontal brain activation in ADHD: Preschool and elementary schoolboys and girls

Objective: To investigate patterns of frontal brain activation in unmedicat ed preschool and school boys and girls with attention-deficit/hyperactivity disorder (ADHD). Method: Baseline electroencephalographic activity of 117 children (66 aged 4 years, 51 aged 8 years) was subjected to power spectral analysis, and laterality scores were determined. Results: Boys with ADHD e xhibited a less right-lateralized frontal activation pattern than normal co ntrol boys. Girls with ADHD displayed a more right-lateralized frontal acti vation pattern than normal control girls. This finding applied to children at both 4 1/2 and 8 years of age. There was no difference between children with ADHD and children with ADHD plus oppositional defiant disorder. Conclu sions: This pattern of frontal brain activation is in line with magnetic re sonance imaging studies of ADHD. It could be demonstrated in children as yo ung as 4 1/2 years, as well as in school-age children. The opposite directi on of asymmetry in boys and girls stresses the importance of gender-specifi c analyses in ADHD.