Sun Life Financial Movement Disorders Research and Rehabilitation Centre, Wilfrid Laurier University, 75 University Avenue West, Waterloo, Ontario, Canada N2L 3C5.
Neuropsychologia. 2013 Jul;51(8):1426-34. doi: 10.1016/j.neuropsychologia.2013.04.015. Epub 2013 May 1.
Recent research has found that perceptual deficits exist in Parkinson's disease (PD), yet the link between perception and movement impairments is not well understood. Inaccurate estimation of distance has the potential to be an underlying cause of movement impairments. Alternatively, those with PD may not be able to perceive their own movements accurately. The main objectives of these studies were to evaluate (1) whether distance estimation is influenced by static perception compared to perception during movement in PD, (2) how visual motion processing contributes to distance estimation during movement, and (3) how dopaminergic medication contributes to these distance estimation deficits. Thirty-seven participants (19 individuals with PD, 18 age-matched healthy control (HC) participants) estimated distance to a remembered target in a total of 48 trials, in 4 randomized blocks. Estimation conditions included: (i) static perception (laser): participants pointed with a laser, (ii) active dynamic perception (walk): participants walked to the estimated position, (iii) passive dynamic perception (wheelchair): participants were pushed in a wheelchair while they gave their estimate. PD patients completed this protocol twice; once OFF and once ON dopaminergic medication. Participants with PD and HC did not differ in judgment accuracy during the static perception (laser) condition. However, those with PD had greater amounts of error compared to HC participants while estimating distance during active dynamic perception (walk). Interestingly, those with PD significantly underestimated the target position compared to healthy control participants across all conditions. Individuals with PD also demonstrated greater variability in their judgments overall. There was no significant influence of dopaminergic medication in any of the conditions. Individuals with PD demonstrated distance estimation deficits only when required to actively move through their environment. In contrast to estimations made with movement, neither static perception (laser) nor passive dynamic perceptions (wheelchair) revealed significant differences in the magnitude of error between the two groups. Thus perceptual estimation deficits appear to be amplified during movement, which may be suggestive of an underlying sensory processing deficit which leads to a problem integrating vision and self-motion information.
最近的研究发现，帕金森病（PD）存在知觉缺陷，但知觉和运动障碍之间的联系尚不清楚。距离估计不准确有可能成为运动障碍的根本原因。或者，PD 患者可能无法准确感知自己的运动。这些研究的主要目的是评估：（1）与运动时的感知相比，PD 患者的距离估计是否受到静态感知的影响；（2）视觉运动处理如何有助于运动时的距离估计；（3）多巴胺能药物如何影响这些距离估计缺陷。37 名参与者（19 名 PD 患者，18 名年龄匹配的健康对照（HC）参与者）在总共 48 次试验中，在 4 个随机块中估计到记忆中目标的距离。估计条件包括：（i）静态感知（激光）：参与者用激光指示；（ii）主动动态感知（行走）：参与者走到估计的位置；（iii）被动动态感知（轮椅）：参与者坐在轮椅上时给出估计。PD 患者两次完成此方案；一次停用和一次使用多巴胺能药物。在静态感知（激光）条件下，PD 患者和 HC 参与者的判断准确性没有差异。然而，与 HC 参与者相比，PD 患者在主动动态感知（行走）期间估计距离时误差更大。有趣的是，与健康对照组参与者相比，PD 患者在所有条件下都显著低估了目标位置。PD 患者的判断也总体上表现出更大的变异性。在任何条件下，多巴胺能药物都没有显著影响。PD 患者只有在需要主动穿越环境时才会出现距离估计缺陷。与运动时的估计不同，两组之间的静态感知（激光）或被动动态感知（轮椅）的误差幅度都没有显著差异。因此，知觉估计缺陷似乎在运动中放大，这可能表明存在潜在的感觉处理缺陷，导致视觉和自身运动信息整合出现问题。
