Lewis Simon J G, Slabosz Aleksandra, Robbins Trevor W, Barker Roger A, Owen Adrian M
Cambridge Centre for Brain Repair, Forvie Site, Addenbrooke's Hospital, Cambridge CB2 2PY, UK.
Neuropsychologia. 2005;43(6):823-32. doi: 10.1016/j.neuropsychologia.2004.10.001. Epub 2004 Dec 21.
Although Parkinson's disease is a common neurodegenerative disorder characterised by its motoric symptoms, there is an increasing recognition of accompanying impairments in cognition that have a profound impact on the quality of life of these patients. These deficits predominantly affect executive function and impairments of working memory have been frequently reported. However, the underlying neurochemical and pathological basis for these deficits are not well understood. In this study, 20 patients were tested 'on' and 'off' levodopa (L-dopa) medication on a task that allowed different aspects of working memory function such as maintenance, retrieval and manipulation to be tested within the same general paradigm as well as on an unrelated test of attentional set-shifting, which is known to be sensitive to deficits in early Parkinson's disease. Compared to healthy volunteers, PD patients were impaired at manipulation more than maintenance or retrieval of information within working memory. The patients were also impaired at the attentional set-shifting task. However, whereas L-dopa ameliorated the working memory deficit in manipulation (improving both accuracy and cognitive response time), it had no effect on the attentional set-shifting impairment. These results confirm that working memory deficits in PD are both psychologically specific and related to dopamine depletion. It is anticipated that greater understanding of these mechanisms will lead to future therapeutic improvements.
尽管帕金森病是一种常见的神经退行性疾病，以运动症状为特征，但人们越来越认识到其伴随的认知障碍对这些患者的生活质量有深远影响。这些缺陷主要影响执行功能，工作记忆受损的情况也经常被报道。然而，这些缺陷的潜在神经化学和病理基础尚未得到很好的理解。在本研究中，20名患者在服用左旋多巴（L-多巴）药物“开”和“关”的状态下，接受了一项任务测试，该任务允许在同一通用范式内测试工作记忆功能的不同方面，如维持、检索和操作，同时还接受了一项与注意力转换无关的测试，已知该测试对早期帕金森病的缺陷敏感。与健康志愿者相比，帕金森病患者在工作记忆中对信息的操作受损程度大于维持或检索。患者在注意力转换任务中也受损。然而，虽然左旋多巴改善了操作方面的工作记忆缺陷（提高了准确性和认知反应时间），但对注意力转换障碍没有影响。这些结果证实，帕金森病中的工作记忆缺陷在心理上是特定的，并且与多巴胺耗竭有关。预计对这些机制的更深入理解将带来未来治疗方法的改进。
