Effects of stimulus predictability and interstimulus gap on saccades in Alzheimer's disease
Effects of stimulus predictability and interstimulus gap on saccades in Alzheimer's disease
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DOI：
10.1159/000057702
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发表时间：
2002-01-01
影响因子：
2.4
通讯作者：
Yee, RD
中科院分区：
文献类型：
--
作者：
Abel, LA;Unverzagt, F;Yee, RD
目的：阿尔茨海默病（AD）患者扫视眼动障碍的研究主要集中在简单的反射性眼动和反扫视任务上。操纵刺激时间的影响已经很少研究。研究方法：14例轻度至重度AD患者和11名年龄匹配的对照组进行了研究的antisaccade任务，而lavonon同时，间隙和可预测的任务记录从11例患者和11名对照组。痴呆的严重程度进行了评估与简易精神状态检查。结果：作为一个群体，患者的lavery显着更高，更可变的同时和间隙任务。可预测的任务表现是相似的平均值，但显着更多的变量。在可预测、同时和间隙任务中，患者的预期反应普遍。排除这些受试者的手段显示，AD患者，当目标驱动的扫视，表现出类似的幅度正常受试者的间隙效应。与对照组相比，患者做出的正确的反跳跃显著减少，而没有纠正反跳跃的反射性错误显著增加。结论：预期性扫视的频繁出现可能反映了注视机制的功能障碍，可能涉及从额叶到上级丘的投射。不太常见的，显着的潜伏期延长可能反映了后顶叶机制介导的反射性眼跳产生的变化。差距效应的存在表明了从外部控制的刺激脱离中受益的持续能力。患者对已知位置的目标进行适当定时扫视的能力特别受损，但目标序列本身至少是大致正确的学习。更大规模的研究可能能够识别临床上不同的AD患者群体。版权所有（C）2002 S，Karger AG，巴塞尔。
Objectives: Studies of saccadic eye movement impairment in Alzheimer's disease (AD) have largely focused on simple reflexive eye movements and the antisaccade task. The effects of manipulating stimulus timing have been lit-tie studied. Methods: Fourteen patients with mild to severe AD and 11 age-matched controls were studied on the antisaccade task, while latencies on simultaneous, gap and predictable tasks were recorded from 11 patients and 11 controls. Dementia severity was assessed with the Mini-Mental State Examination. Results: As a group, patients' latencies were significantly higher and more variable on the simultaneous and gap tasks. Predictable task performance was similar in mean but significantly more variable. Grossly anticipatory responses by patients were common on the predictable, simultaneous and gap tasks. Exclusion of these from subject means revealed that AD patients, when making target-driven saccades, demonstrated a gap effect of similar magnitude to normal subjects. Patients made significantly fewer correct antisaccades and significantly more reflexive errors not followed by a corrective antisaccade than did controls. Conclusions: The frequent presence of grossly anticipatory saccades may reflect dysfunction of fixation mechanisms possibly involving projections from frontal lobe to superior colliculus. The less frequently seen, marked prolongation of latency may reflect changes in posterior parietal mechanisms mediating reflexive saccade generation. The presence of the gap effect demonstrates a continued ability to benefit from externally controlled stimulus disengagement. Patients' ability to make appropriately timed saccades to targets of known locations was particularly impaired, but the target sequence itself was at least grossly correctly learned. Larger studies may be able to identify clinically distinct populations of AD patients. Copyright (C) 2002 S, Karger AG, Basel.