ERP differences in visual attention processing between attention-deficit hyperactivity disorder and control boys in the absence of performance differences

Event-related potentials (ERPs) were recorded during a visual two-choice re action time (RT) task in attention-deficit hyperactivity disorder (ADHD) an d control boys selected using strict inclusion and exclusion criteria. No g roup differences were found in mean RT and correct responses. Although earl y occipital ERPs were not affected in the ADHD group, the peak latency of e arly anterior ERPs (N1, P1, N2) was significantly delayed. ADHD showed a la rger effect of stimulus type on the frontal negativity (N530) and the poste rior late negativity (nSW) and a smaller effect of stimulus type on anterio r N2 and posterior P3b amplitude. The development of N530 and P450 amplitud e across blocks of five trials was analyzed using orthogonal polynomial tre nd analysis of variance software. In the control group, P450 amplitude to " frequent" stimuli reduced across blocks. In the ADHD group, N530 amplitude increased for "rare" stimuli across blocks. It is suggested that the ADHD g roup showed a lack of automatization of the categorization process with inc reasing time on task for which they compensated by controlled attentional p rocesses.