Continuous reaction time in brain damage.

Summary Brain-damaged patients have significantly slower visual RTs than control patients under simple and choice RT conditions on a continuous experimenter paced task with constant intervals between stimuli. The brain-damaged are more variable than control Ss, but this variability is not due to a skewing of slow responses; rather the whole distribution appears to be shifted in the slower direction. No performance decline is present in the Ss despite about 40 minutes of continual RT performance and they do not get more variable over trials. Both controls and braindamaged have significantly longer RTs under the choice conditions, but the added increment in RT is of similar magnitude in both groups. Thus the simple RT is as discriminating between groups as the choice RT task. Under these experimental conditions brain-damaged Ss manifest a deficit in RT performance which cannot be explained by lapses in attention or greater fatigue or “slowed”mental operations of a perceptual matching nature.