Harrison J, Henderson L, Kennard C
Academic Unit of Neuroscience, Charing Cross and Westminster Medical School, London, UK.
J Neurol Neurosurg Psychiatry. 1995 Nov;59(5):499-506. doi: 10.1136/jnnp.59.5.499.
Two pairwise matched groups of patients with mild to moderate Parkinson's disease and a group of normal age matched controls were used to investigate the effects on simple and choice reaction time (RT) of brief withdrawal of levodopa therapy. Comparisons within and across these groups disclosed a selective effect of levodopa withdrawal. After about 12 hours of levodopa deprivation, patients exhibited an exaggeration of normal refractoriness, the well established tendency for RT to increase progressively as the delay between a response and the next imperative signal is reduced below 0.5 s. Increased refractoriness was at least as great for simple as choice RT. Choice RT on trials involving repetition (as opposed to alternation) of the previous response, however, showed no tendency towards greater impairment by brevity of the recovery period or by withdrawal of medication, eliminating an effector based account. With longer recovery periods, RT was unaffected by medication; indeed, unmedicated patients were as fast as normal subjects under these conditions. Even at the briefest delays, fully medicated patients did not differ from normal controls. The paper concludes with a critical review of chronometric studies of medication effects in Parkinson's disease.
选取两组轻度至中度帕金森病患者进行配对，同时选取一组年龄匹配的正常对照组，以研究左旋多巴治疗短暂停药对简单反应时间和选择反应时间（RT）的影响。对这些组内和组间的比较揭示了左旋多巴停药的选择性效应。在左旋多巴剥夺约12小时后，患者表现出正常不应期的夸张现象，即随着反应与下一个强制信号之间的延迟减少到0.5秒以下，反应时间（RT）逐渐增加的既定趋势。简单反应时间和选择反应时间的不应期增加至少一样大。然而，在涉及重复（与交替相反）先前反应的试验中，选择反应时间并未显示出因恢复期短暂或停药而有更大受损的趋势，排除了基于效应器的解释。恢复时间较长时，反应时间不受药物影响；实际上，在这些条件下，未用药的患者与正常受试者一样快。即使在最短的延迟情况下，完全用药的患者与正常对照组也没有差异。本文最后对帕金森病药物作用的计时研究进行了批判性综述。
