MOTOR CONTROL AND MUSCLE ACTIVITY IN ELDERLY SUBJECTS

该项目的长期目标是：(1)进一步了解动态老年人运动控制变化的生物力学和功能指标之间的相关性；(2)建立可用于改善老年人运动控制的干预计划的科学基础，从而减少老年人跌倒的发生率。我们之前的研究表明，老年人的姿势摇摆和步态开始有明显的异常，这可能使这些人容易跌倒。事实上，在一项初步研究中，我们发现有跌倒风险的老年人在姿势摇摆方面的损伤更严重。我们也有初步证据表明，姿势摇摆和步态开始的异常都与下肢肌肉活动增加有关。然而，现在已经知道这些异常是否会导致平衡障碍和跌倒等功能性后果。此外，目前尚不清楚通过肌电生物反馈减少下肢肌肉活动是否会改善或恶化老年人的平衡功能和步态启动。因此，本研究的具体目的是：(1)确定可走动老年人下肢肌肉活动与(a)姿势摇摆动力学和平衡功能以及(b)步态启动动力学和活动功能之间的关系；(2)横断面确定老年人体位摇摆动力学和步态起始的变化是否与跌倒有关；(3)确定通过肌电生物反馈减少下肢肌肉活动是否会改善或恶化老年人的平衡功能和步态启动。我们计划研究两个健康的流动老年人样本：一个样本是100名不明原因的跌倒者，另一个样本是100名非跌倒者。将对每个受试者进行静站立和步态启动测试（有和没有肌电生物反馈）。这项工作可以显著减少跌倒的频率、发病率和成本，并帮助老年人在日常生活和行动活动中实现最大的独立性。

The long-term goal of this project are: (1) to gain an increased understanding of the correlations between biomechanical and functional measures of motor control changes in a population of ambulatory elderly, and (2) to establish the scientific foundation fir abn intervention program that could be used to improve motor control in older adults and thereby serve to reduce the incidence of falls in the elderly. Our previous studies suggest that there are significant abnormalities in postural sway and gait initiation in elderly people, that may predispose these individuals to fall. In fact, in one pilot study, we found that elders at risk of falling had exaggerated impairments in postural sway. We also have preliminary evidence indicating that the abnormalities in postural sway and gait initiation are both associated with increased lower-limb muscle activity. It is now known, however, whether these abnormalities have functional consequences such as balance impairment and falls. In addition, it is not known whether reducing lower-limb muscle activity via EMG biofeedback improves or worsens balance function and gait initiation in elderly people. Therefore, the specific aims of this study are: (1) to determine the relationships between lower-limb muscle activity and (a) postural sway dynamics and balance function, and (b) gait-initiation dynamics and mobility function, in ambulatory elderly people; (2) to determine cross-sectionally whether variations in postural sway dynamics and gait initiation in elderly people are associated with falls; and (3) to determine whether reducing lower-limb muscle activity via EMG biofeedback improves or worsens balance function and gait initiation in elderly people. We plan to study two samples of healthy ambulatory elders: one sample of 100 fallers with unexplained falls and one sample of 100 non-fallers. Quiet-standing and gait- initiation tests (with and without EMG biofeedback) will be conducted on each subject. This work could serve to reduce significantly the frequency, morbidity and cost of falling and assist aged individuals in achieving maximal independence in activities of daily living and mobility.