Farley Becky G, Sherman Scott, Koshland Gail F
Department of Physiology, University of Arizona, Tucson, AZ 85724, USA.
Exp Brain Res. 2004 Jan;154(2):160-75. doi: 10.1007/s00221-003-1654-7. Epub 2003 Oct 15.
Bradykinesia is one of the primary symptoms of Parkinson disease and leads to significant functional limitations for patients. Single joint movement studies, that have investigated the mechanism of bradykinesia, suggest that several features of muscle activity are disrupted, including modulation of burst amplitude and duration, and the number of bursts. It has been proposed that it is the blending of these different burst deficits that collectively defines bradykinesia. This study adds two new approaches to the study of bradykinesia. First, we examined the features of shoulder muscle activities during multijoint arm movement in bradykinetic and control subjects, such that previously reported single joint hypotheses could be tested for generalized arm movement. Second, we directly manipulated speed while keeping distance constant for a large range of speeds. In this manner, we could compare individual trials of muscle activity between controls and subjects with Parkinson's disease (PD) for movements matched for both speed and movement duration. Our results showed that while a multiple burst pattern of shoulder muscles was a common strategy for all subjects (young, elderly controls and PD), subjects with PD showed several burst abnormalities, including deficits in initial agonist burst amplitude and duration at both fast and slow speeds. Subjects with PD also (1) failed to produce a one-burst pattern at fast speeds and, instead, produced a predominance of multiple burst patterns and (2) showed a relationship between the number of burst deficits and the severity of disease. These results extend the findings of single joint studies to multi-joint and similarly indicate that a combination of burst modulation abnormalities correlate with bradykinesia and disease severity.
运动迟缓是帕金森病的主要症状之一，会给患者带来严重的功能限制。针对运动迟缓机制进行研究的单关节运动研究表明，肌肉活动的几个特征受到了破坏，包括爆发幅度和持续时间的调节以及爆发次数。有人提出，正是这些不同的爆发缺陷共同导致了运动迟缓。本研究为运动迟缓的研究增加了两种新方法。首先，我们检查了运动迟缓患者和对照组在多关节手臂运动过程中肩部肌肉活动的特征，以便对先前报道的单关节假说进行全身性手臂运动测试。其次，我们在保持距离不变的情况下，在很大的速度范围内直接控制速度。通过这种方式，我们可以比较对照组和帕金森病（PD）患者在速度和运动持续时间匹配的运动中肌肉活动的个体试验。我们的结果表明，虽然肩部肌肉的多爆发模式是所有受试者（年轻、老年对照组和PD患者）的常见策略，但PD患者表现出一些爆发异常，包括在快速和慢速时初始主动肌爆发幅度和持续时间的缺陷。PD患者还（1）在快速时未能产生单爆发模式，而是产生了多种爆发模式的优势，并且（2）显示爆发缺陷数量与疾病严重程度之间存在关联。这些结果将单关节研究的结果扩展到多关节，同样表明爆发调节异常的组合与运动迟缓和疾病严重程度相关。
