ABSTRACT
The mechanism of the latent reaction time in task completion in elderly men was investigated by comparing the reaction time (RT), EMG-RT and motor time (MT) in young and elderly men. The motor performance was recorded as task completion through as a WS-RS, simple reaction or a choice reaction for each movement using a handgrip and switch.<BR>In this study, we found that the RT and EMG-RT of elderly men in all movements of WS-RS and choice reaction tasks were significantly longer than those of young men, especially in the choice reaction tasks were striking. Moreover, the MT of elderly men in all tasks was significantly longer than those of young men.<BR>These findings suggest that the latent RT and EMG-RT in a choice reaction task may be due to relayed information processing through as the discrimination and cognition functions in the brain, and that it may be also influenced by the mechanism of the latent reaction time of task completion in elderly men.
ABSTRACT
The reaction time(RT) has been known to reflect attention that controls the flow of information processing. Extensive research has demonstrated cognitive impairment in schizophrenia subjects using RT tasks. However, little work has been done examining the relative contribution of DT(decision time) and MT(motor time) to slowed RT in schizophrenics. Also, recent investigators have observed that schizophrenic patients exhibit larger intra-individual variability in RT than do normal comparison subjects. The purpose of this study, using multi-stimulus convergent RT task, was to explore the speed of RT, relative contribution of decision time(DT) and motor time(MT) to slowed RT, overall sequential profile in 25 repeated-time measurements in 10 schizophrenic out-patients and 10 normal control subjects. Overall reaction time and decision time were slower in schizophrenic subjects than in normal controls. The motor time was not shown to be significantly different between the two groups with 0.05 significance level, although there was some trend indicating schizophrenic subjects were slower consistently in repreated measurements over time. These results suggested that the slower reaction time in schizophrenic subjects was mostly determined by cognitive component, decision time rather than motor time. Sequential profile of repeated measurements showed greater intraindividual and interindividual variations in schizophrenics than in normal controls. These results indicate that high variabilities are not merely measurement errors but characteristic of schizophrenic psychopathology.