EFFECTS OF METHYLPHENIDATE IN CHILDREN WITH ATTENTION-DEFICIT HYPERACTIVITY DISORDER - A COMPARISON OF EVENT-RELATED POTENTIALS BETWEEN MEDICATION RESPONDERS AND NONRESPONDERS

Event-related potentials (ERPs) were compared among three groups, each with 13 subjects: (1) ADHD non-responders to methylphenidate treatmen t; (2) ADHD responders to methylphenidate treatment; and (3) normal co ntrol children. Response to methylphenidate was determined through ext ensive psychoeducational and cognitive assessments during a 4-week dou ble-blind medication assessment. ERPs were recorded each week from 13 active electrodes during a visual feature detection task and a semanti c classification task Significant group effects were found for N2 and P3b latencies due to longer latencies for the ADHD children. Off medic ation, there were no differences between responders and non-responders . However, on methylphenidate non-responders had significantly longer P3b latencies than responders. Cognitive testing also revealed differe ntial performance on medication between non-responders and responders on the paired-associate learning (PAL) task Thus, both cognitive and E RP measures were found to differentiate ADHD non-responders and respon ders to methylphenidate treatment. (C) 1997 Elsevier Science B.V.