Rivaud-Péchoux S, Vidailhet M, Brandel J P, Gaymard B
Institut National de la Santé et de la Recherche Médicale, Boulevard de l'Hôpital, Paris, France.
Brain. 2007 Jan;130(Pt 1):256-64. doi: 10.1093/brain/awl315. Epub 2006 Nov 22.
Prosaccades and antisaccades were investigated in three groups of patients with parkinsonian syndromes, Parkinson's disease, corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), and in a control group. Saccade tasks were performed in single-task blocks (i.e. either blocks of prosaccades or blocks of antisaccades) and in mixed-task blocks (i.e. in blocks of randomly interleaved pro- and antisaccades). Saccade latencies and directional errors (misdirected saccades) were analysed in each subject, and we concentrated more specifically on the comparison of error rates in single tasks and in repeated trials of mixed tasks (i.e. mixing costs). The performance of each group in single tasks was largely consistent with previous studies, with normal antisaccade error rates in Parkinson's disease and CBD patients and increased antisaccade error rates in PSP patients. In contrast, a double dissociation was observed in mixed tasks. Parkinson's disease and CBD patients showed a marked increase in prosaccade and antisaccade error rates in repeated trials of mixed tasks, illustrated by increased mixing costs, whereas PSP patients showed similar error rates in single and repeated trials of mixed tasks, i.e. normal mixing costs. These results demonstrate that: (i) antisaccade performances may be differentially affected in mixed tasks and single tasks; (ii) the region of the dorsolateral prefrontal cortex which is crucial for reflexive saccade inhibition does not seem to be involved in the additional processes required in mixed-task conditions; (iii) the study of interleaved pro- and antisaccades may increase the accuracy of the differential diagnosis between these parkinsonian syndromes.
我们对三组帕金森综合征患者（帕金森病、皮质基底节变性（CBD）和进行性核上性麻痹（PSP））以及一组对照组进行了顺向眼跳和反向眼跳研究。眼跳任务在单任务块（即顺向眼跳块或反向眼跳块）和混合任务块（即随机交替的顺向和反向眼跳块）中进行。分析了每个受试者的眼跳潜伏期和方向误差（错误导向的眼跳），我们更具体地关注了单任务和混合任务重复试验中的错误率比较（即混合成本）。每组在单任务中的表现与先前的研究基本一致，帕金森病和CBD患者的反向眼跳错误率正常，而PSP患者的反向眼跳错误率增加。相比之下，在混合任务中观察到了双重分离。帕金森病和CBD患者在混合任务的重复试验中，顺向眼跳和反向眼跳错误率显著增加，表现为混合成本增加，而PSP患者在混合任务的单试验和重复试验中表现出相似的错误率，即正常的混合成本。这些结果表明：（i）在混合任务和单任务中，反向眼跳表现可能受到不同影响；（ii）对反射性眼跳抑制至关重要的背外侧前额叶皮质区域似乎不参与混合任务条件下所需的额外过程；（iii）交错的顺向和反向眼跳研究可能会提高这些帕金森综合征鉴别诊断的准确性。
