MISMATCH NEGATIVITY IN HYPERACTIVE-CHILDREN - EFFECTS OF METHYLPHENIDATE

This pilot study investigates electrophysiological correlates of methy lphenidate (MP) treatment among hyperkinetic children who are clinical responders to therapy. Event-related potentials were obtained from a small sample (6 hyperactive and 5 controls) during an auditory ''oddba ll'' task. In the ignore condition, oddball tones elicited a frontocen tral ''mismatch'' negativity (MMN) during the 100- to 200-msec latency range following stimulus presentation. In the attend condition, oddba ll target tones elicited a centroparietal P3 as well. MP significantly decreased hyperkinetic behaviors. Preliminary analyses of the electro physiological data indicated a decreased amplitude of the P3 wave-form among hyperkinetic children and a trend toward normalization on MP. W aveform abnormalities in the latency range of control MMN suggested ei ther a decrease in MMN amplitude or an increase in MMN latency in hype ractive subjects along with a trend toward normalization by MP. The pr eliminary data are suggestive of information-processing abnormalities among hyperactive children that may be sensitive to MP therapy.