Brown R G, Marsden C D
Medical Research Council Human Movement and Balance Unit, London, UK.
Brain. 1991 Feb;114 ( Pt 1A):215-31.
In recent years, there has been a growing consensus among investigators that the presence or absence of external cues guiding behaviour and attention is an important factor in determining whether or not deficits are found in patients with Parkinson's disease (PD). In an earlier study, the authors suggested that the pattern of impaired and intact performance could be explained in terms of differential resource demands of the tasks, combined with depleted levels of central processing resources in PD patients. Two experiments are reported, both employing dual-task paradigms. The first assessed, in normal subjects, the relative processing demands of a cued and an uncued version of the Stroop task. The results supported the proposal that the noncued task made greater demands on the subject's limited processing resources. Further, performing a resource demanding secondary task concurrently with the Stroop test produced, in normal subjects, the same pattern of impaired performance as that reported previously in PD patients. In the second experiment the same dual-task paradigm was employed with a group of PD patients and normal aged-matched controls. Only the patients showed an increase in reaction time on the Stroop task when performing a resource demanding secondary task. The patients also showed an interfering effect with concurrent foot tapping but not with an articulatory suppression task. The results were taken to support the hypothesis that PD patients have depleted central processing resources. In considering the present data, alternative explanations for the results are considered, in particular the possibility that they represent a deficit in switching processing resources between two tasks as the combined demands outweigh available resources.
近年来，研究人员越来越达成共识，即引导行为和注意力的外部线索的存在与否是决定帕金森病（PD）患者是否存在缺陷的一个重要因素。在早期的一项研究中，作者认为，受损和完好表现的模式可以用任务的不同资源需求来解释，再加上PD患者中枢处理资源水平的耗尽。本文报告了两个实验，均采用双任务范式。第一个实验评估了正常受试者中，线索化和非线索化版本的斯特鲁普任务的相对处理需求。结果支持了这样的提议，即非线索化任务对受试者有限的处理资源提出了更高的要求。此外，在正常受试者中，与斯特鲁普测试同时执行一项需要资源的次要任务，产生了与先前在PD患者中报告的相同的表现受损模式。在第二个实验中，对一组PD患者和年龄匹配的正常对照组采用了相同的双任务范式。只有患者在执行一项需要资源的次要任务时，斯特鲁普任务的反应时间增加。患者还表现出对同时进行的足部敲击有干扰作用，但对发音抑制任务没有干扰作用。这些结果被认为支持了PD患者中枢处理资源耗尽的假设。在考虑当前数据时，对结果的其他解释也被考虑在内，特别是它们可能代表在两项任务之间切换处理资源时的缺陷，因为综合需求超过了可用资源。
