Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Neurosci Lett. 2010 Sep 20;482(1):1-6. doi: 10.1016/j.neulet.2010.06.054. Epub 2010 Jun 25.
Performance of repetitive finger movements is an important clinical measure of disease severity in patients with Parkinson's disease (PD) and is associated with a dramatic deterioration in performance at movement rates near 2 Hz and above. The mechanisms contributing to this rate-dependent movement impairment are poorly understood. Since clinical and experimental testing of these movements involve prolonged repetition of movement, a loss of force-generating capacity due to peripheral fatigue may contribute to performance deterioration. This study examined the contribution of peripheral fatigue to the performance of unconstrained index finger flexion movements by measuring maximum voluntary contractions (MVC) immediately before and after repetitive finger movements in patients with PD (both off- and on-medication) and matched control subjects. Movement performance was quantified using finger kinematics, maximum force production, and electromyography (EMG). The principal finding was that peak force and EMG activity during the MVC did not significantly change from the pre- to post-movement task in patients with PD despite the marked deterioration in movement performance of repetitive finger movements. These findings show that the rate-dependent deterioration of repetitive finger movements in PD cannot be explained by a loss of force-generating capacity due to peripheral fatigue, and further suggest that mechanisms contributing to impaired isometric force production in PD are different from those that mediate impaired performance of high-rate repetitive movements.
重复性手指运动的表现是帕金森病（PD）患者疾病严重程度的重要临床指标，与运动频率接近 2Hz 及以上时运动表现的急剧恶化有关。导致这种与频率相关的运动障碍的机制尚不清楚。由于这些运动的临床和实验测试涉及长时间的重复运动，由于外周疲劳导致的产生力量的能力的丧失可能导致运动表现恶化。本研究通过测量 PD 患者（无论是否接受药物治疗）和匹配的对照受试者在重复性手指运动前后的最大自主收缩（MVC），检查了外周疲劳对无约束索引手指弯曲运动表现的贡献。运动表现通过手指运动学、最大力量产生和肌电图（EMG）进行量化。主要发现是，尽管 PD 患者重复性手指运动的运动表现明显恶化，但 MVC 期间的峰值力和 EMG 活动与运动前任务相比并没有显著变化。这些发现表明，PD 中重复性手指运动的与频率相关的恶化不能用由于外周疲劳导致的产生力量的能力的丧失来解释，并且进一步表明，导致 PD 中等长力量产生受损的机制与介导高频率重复运动表现受损的机制不同。
