Brown R G, Marsden C D
MRC Movement Disorders Research Group, University Department of Neurology, London, England.
Mov Disord. 1988;3(2):152-61. doi: 10.1002/mds.870030207.
It has been suggested that patients with Parkinson's disease have a basic deficit in shifting "set." Previous authors have used this hypothesis as an explanation for deficits on a range of cognitive tasks. An experiment was conducted to investigate this phenomenon. A reaction time paradigm was used in which the subject had to make left-right decisions under two stimulus conditions. Both patients and controls showed a facilitation in performance with repetition within each block of trials, followed by a deterioration in performance when the stimulus type switched. Furthermore, the shapes of the reaction-time functions were equivalent in both groups, suggesting that the patients had no deficit in either switching or establishing set in this task. In contrast, they were impaired on the Wisconsin Card Sorting Test. This dissociation suggests that patients with Parkinson's disease do not have a generalized deficit in switching set. It is suggested that patients with Parkinson's disease are impaired on tasks where they have to rely upon internal control for the regulation of behaviour, but are relatively unimpaired on tasks where external cues are available.
有人提出帕金森病患者在转换“定势”方面存在基本缺陷。先前的作者曾用这一假说来解释一系列认知任务中的缺陷。为此进行了一项实验来研究这一现象。采用了一种反应时范式，在此范式中，受试者必须在两种刺激条件下做出左右决策。患者和对照组在每个试验块内的重复过程中表现均有所促进，而当刺激类型切换时表现则会变差。此外，两组的反应时函数形状相同，这表明患者在该任务中的转换或定势建立方面并无缺陷。相比之下，他们在威斯康星卡片分类测验中表现受损。这种分离表明帕金森病患者在转换定势方面并不存在普遍缺陷。有人认为，帕金森病患者在必须依靠内部控制来调节行为的任务中会受损，但在有外部线索可用的任务中相对未受损害。
