This study attempted to identify cognitive and behavioral deficits which might be unique to hyperactive children. Fifty children between the ages of 5 and 12 were subjects of the investigation. Four experimental groups were formed: Hyperactive (HA), Behavior Problem Children (BP), Severely Asthmatic Children (AC), and Normal Control Children (NC). Several commonly used paper and pencil tests measuring variables related to impulsiveness, attention and motor inhibition were administered individually. Reaction time measures were taken while the subject was seated on a stablimetric cushion which automatically recorded gross motor activity. Results suggest that hyperactive children are more inattentive, more impulsive, and more easily frustrated than normal children. They also appeared more active than the controls. The BP group was similar to the HA group on all but 3 measures. BP children shared deficits in impulse control but not the HA group's attentional problems. The AC group performed as poorly as the HA group on several measures. Asthmatic children shared deficits in impulse control and motor inhibition with HA children, but did not share their problems with attentional processes. The only deficit unique to the HA group was that of attention. (Author/RH)