The influences of methylphenidate on heart rate and behavioral measures of attention in hyperactive children.
Reaction-time performance and heart-rate responses associated with attention were used to assess the hyperactive child's attentional deficit and his response to methylphenidate. Attentional deficits shown by long response latencies were reflected in heart-rate responses theoretically incompatible with sustained attention. Subjects exhibiting the greatest attentional deficit displayed the most favorable response to methylphenidate in both reaction-time performance and physiological measures. However, subjects who showed the greatest improvement in social behavior were those who showed the least improvement in reaction-time performance.