This proposal aims: 1) to develop a psychophysiological test battery to predict responses of children with minimal brain dysfunction (MBD) to stimulants, and 2) to clarify the neurophysiological effects of stimulants on MBD children. To develop a psychophysiological test battery, we will first retrospectively study MBD children previously identified as either (a) responding positively to treatment with stimulants or (b) as not responding positively to treatment with stimulants. Next, children awaiting a clinical trial of stimulants will be studied prospectively to determine the predictive utility of the psychophysiological battery. Physiological measurements will be made using skin resistance, electroencephalograms, visual evoked potentials and auditory evoked potentials. Evaluation of clinical response will be by means of WISC, Porteus Maze, and ratings by parent, teacher, and treating physician. Finally, additional studies will be designed specifically to examine the effects of stimulants that appear to be different in the two groups of MBD children.