A review of psychophysiological research with hyperkinetic children.

A number of studies have appeared which focus on the issue of whether hyperactive children are psychophysiologically different from normal children and what impact the stimulant drugs may have on psychophysiological characteristics of these children. The present paper reviews these studies under the type of measures that were employed. In general, the results suggest that hyperactive children are probably not under- or overaroused in their resting levels of autonomic functions, although some children may display resting cortical underarousal. However, the findings of studies on the impact of stimulation on autonomic or central functions intimate that some hyperactive children are probably underreactive to environmental stimulation, or are "underarousable." Indeed, where differences between hyperactive and normal children are found in such evoked-response studies, they are consistently in this direction of "underarousability." Results for the effects of stimulant drugs suggest that these drugs energize or increase the "arousal" of these children and enhance the impact of stimulation on the nervous system. The implications of these results for current theories of hyperactivity and for future research are discussed.