Deacon D, Campbell K B
University of Ottawa, Canada.
Electroencephalogr Clin Neurophysiol. 1991 Feb;78(2):133-41. doi: 10.1016/0013-4694(91)90113-i.
In an earlier study, we have demonstrated that the choice reaction times (RTs) of closed head-injured patients may be reduced significantly by instructions which emphasize speed, thus indicating that this portion of the RT delay was not due to a motor deficit. Despite the reduction in patient RTs, however, they remained significantly longer than those of controls. Furthermore, the RTs of patients were 56 msec longer than their P300 latencies, whereas those of controls occurred at about the same time as P300. The delay which remained in patient RTs was thus not entirely due to longer stimulus evaluation times. The goal of the present study was to further reduce patient RTs using feedback (FB) on response speed and time windows within which subjects were required to respond. When FB on speed and a 'narrow' time window were used, patient RTs occurred at about the same time as P300 latency (as was also the case with controls) indicating that the longer RTs of these patients in our earlier study, and in the other conditions of the present study, could not have been exaggerated beyond P300 latency due to a motor deficit. It was suggested that CHI patients may not be able to internally monitor their responses to the same degree as controls. The provision of external cues may have compensated for this deficit.
在早期的一项研究中，我们已经证明，对于闭合性颅脑损伤患者，强调速度的指令可显著缩短其选择反应时（RT），这表明反应时延迟的这一部分并非由于运动功能缺陷所致。然而，尽管患者的反应时有所缩短，但仍显著长于对照组。此外，患者的反应时比其P300潜伏期长56毫秒，而对照组的反应时与P300潜伏期大致相同。因此，患者反应时中仍存在的延迟并非完全是由于更长的刺激评估时间。本研究的目的是利用关于反应速度和要求受试者做出反应的时间窗口的反馈（FB），进一步缩短患者的反应时。当使用关于速度的反馈和“狭窄”的时间窗口时，患者的反应时与P300潜伏期大致相同（对照组也是如此），这表明在我们早期研究以及本研究的其他条件下，这些患者较长的反应时不可能因运动功能缺陷而被夸大超过P300潜伏期。有人提出，闭合性颅脑损伤患者可能无法像对照组那样在相同程度上进行内部反应监测。提供外部线索可能弥补了这一缺陷。
