Chen Jing, Ho Shu-Leong, Lee Tatia Mei-Chun, Chang Richard Shek-Kwan, Pang Shirley Yin-Yu, Li Li
Department of Psychology, The University of Hong Kong, Hong Kong, China.
Division of Neurology, University Department of Medicine, The University of Hong Kong, Hong Kong, China.
Neuropsychologia. 2016 Jan 8;80:102-114. doi: 10.1016/j.neuropsychologia.2015.10.036. Epub 2015 Oct 31.
Previous studies have suggested that the deteriorated visuomotor control in patients with PD (Parkinson's disease) is due to deficits in various aspects of the sensory-motor processing rather than motor control itself. In the current study, by taking a control-theoretic approach, we systematically examined how PD and antiparkinsonian medication affect visuomotor control and the underlying sensory-motor system. We tested 20 PD patients in both ON and OFF medication states and 20 demographically matched healthy controls with a commonly used manual control task. Specifically, in each 95-s trial, participants were instructed to use a joystick to control a randomly moving target to keep it centered on a computer display. We found that although antiparkinsonian medication improved visuomotor control in PD patients, they still showed significantly decreased control precision (measured by RMS error) and response amplitude (gain) as well as increased response delay (phase lag) compared with healthy controls. Our model-driven analysis revealed that PD impairs the responsiveness and the predicting ability of the sensory-motor system as well as the stability of the neuromuscular system. Taking antiparkinsonian medication improves the responsiveness of the sensory-motor system. More importantly, it improves the ability of the sensory-motor system to make sensory predictions of the current control actions (see Wolpert et al., 1995) to anticipate the input error signals and generate control responses ahead of time up to the level of healthy controls. However, taking antiparkinsonian medication does not improve the stability of the neuromuscular system. These results support the claim that the effect of antiparkinsonian medication on visuomotor control is mainly through improving visual-stimulus-dependent sensory-motor processing. The present study provides the first quantitative examination of the effects of PD and antiparkinsonian medication on the visual-stimulus-dependent sensory-motor and visual-stimulus-independent neuromuscular systems underlying visuomotor control. The findings have practical implications for developing sensitive assessment tools to evaluate the efficacy of different therapies for PD and preliminary screening and training tools for fitness-to-drive in PD patients.
先前的研究表明，帕金森病（PD）患者视觉运动控制能力的下降是由于感觉运动处理各个方面的缺陷，而非运动控制本身。在本研究中，我们采用控制理论方法，系统地研究了帕金森病及其抗帕金森药物如何影响视觉运动控制以及潜在的感觉运动系统。我们对20名处于服药和未服药状态的帕金森病患者以及20名在人口统计学上匹配的健康对照者进行了一项常用的手动控制任务测试。具体而言，在每次95秒的试验中，参与者被要求使用操纵杆控制一个随机移动的目标，使其在电脑显示屏上保持居中。我们发现，尽管抗帕金森药物改善了帕金森病患者的视觉运动控制，但与健康对照者相比，他们的控制精度（通过均方根误差衡量）、反应幅度（增益）仍显著降低，反应延迟（相位滞后）增加。我们基于模型的分析表明，帕金森病损害了感觉运动系统的反应性和预测能力以及神经肌肉系统的稳定性。服用抗帕金森药物可改善感觉运动系统的反应性。更重要的是，它提高了感觉运动系统对当前控制动作进行感觉预测的能力（见Wolpert等人，1995），以提前预测输入误差信号并生成控制反应，达到健康对照者的水平。然而，服用抗帕金森药物并不能改善神经肌肉系统的稳定性。这些结果支持了抗帕金森药物对视觉运动控制的影响主要是通过改善视觉刺激依赖的感觉运动处理这一观点。本研究首次对帕金森病及其抗帕金森药物对视觉运动控制基础的视觉刺激依赖的感觉运动和视觉刺激独立的神经肌肉系统的影响进行了定量研究。这些发现对于开发敏感的评估工具以评估帕金森病不同疗法的疗效以及帕金森病患者驾驶适宜性初步筛查和训练工具具有实际意义。
