Gauntlett-Gilbert J, Roberts R C, Brown V J
School of Psychology, University of St. Andrews, Fife, UK.
Neuropsychologia. 1999 May;37(5):605-16. doi: 10.1016/s0028-3932(98)00049-9.
Patients with Parkinson's disease (PD) show impairments on tasks that require them to switch attention between two perceptual dimensions (extradimensional (ED) shifting). It has been suggested that ED shifting deficits can be caused by two separate mechanisms, 'learned irrelevance' and 'perseveration'. This study set out to test the hypothesis that enhanced learned irrelevance is present in medicated patients with PD. An enhancement of learned irrelevance in PD patients should result in increased errors on a 'deficit' shift relative to controls and decreased errors on an 'improvement' shift. A similar pair of deficit and improvement shifts were used to detect possible enhanced perseveration in patients. Instead of showing the predicted patterns of deficit and improvement, patients displayed a consistent deficit on those shifts that required that they switch their attention to a different dimension (ED shifts). In contrast, patients were not impaired on shifts that required no such shift of attention (intradimensional shifts). Although there was an increase in errors at the learned irrelevance deficit shift, a similar increase at the learned irrelevance improvement shift shows that enhanced learned irrelevance is not responsible for either of these results. Patients were no more distractible than controls, but displayed increased 'loss of set' as measured by errors generated after a rule was learned. These results point to the existence of exaggerated, rigid selective attention in patients with PD rather than a breakdown in the ability to selectively attend. There was no evidence for the existence of enhanced learned irrelevance in the patients.
帕金森病（PD）患者在需要他们在两个感知维度之间转换注意力的任务（维度外（ED）转换）上表现出障碍。有人提出，ED转换缺陷可能由两种不同的机制引起，即“习得性无关”和“持续性”。本研究旨在检验以下假设：在接受药物治疗的PD患者中存在增强的习得性无关。相对于对照组，PD患者习得性无关的增强应导致在“缺陷”转换上的错误增加，而在“改善”转换上的错误减少。使用类似的一对缺陷和改善转换来检测患者中可能增强的持续性。患者并未表现出预测的缺陷和改善模式，而是在那些需要他们将注意力转换到不同维度的转换（ED转换）上表现出一致的缺陷。相比之下，患者在不需要这种注意力转换的转换（维度内转换）上没有受损。虽然在习得性无关缺陷转换上错误增加，但在习得性无关改善转换上也有类似增加，这表明增强的习得性无关并非导致这些结果的原因。患者并不比对照组更容易分心，但按照学习规则后产生的错误来衡量，他们表现出增加的“定势丧失”。这些结果表明PD患者存在过度、僵化的选择性注意力，而非选择性注意能力的崩溃。没有证据表明患者中存在增强的习得性无关。
