In this study, we investigated the frequency characteristics of independent components (ICs) of event-related potentials (ERPs) recorded in persons with attention deficit/hyperactivity disorder (ADHD) and normal adults under conditions of continuous performance test (CPT). A group of 50 participants (10 ADHD subjects and 40 ones with no attention disorders) was examined. Independent component analysis was applied to the recorded signals. For ERP extraction, averages for each group of ICs, which were time-locked to the onset of stimuli, were calculated. Several frequency characteristics (704 items) were extracted from different ERPs in each IC. Eight features of the brain signals had a significant (P