ALTERED MUSCLE ACTIVITY DURING LOCOMOTION POST-STROKE

描述(申请人提供)：中风幸存者生活质量的一个主要障碍是行走能力受损，恢复运动能力是一个重要目标。本研究的目的是确定中风后步行能力受损的机制。运动的特征通常是腿部肌肉活动的严格计时模式。然而，在中风后偏瘫患者中，肌肉活动的时间不正常，这导致了缓慢和不安全的运动。运动肌肉计时异常的原因人们知之甚少；然而，一个占主导地位的理论是，异常的肌肉计时是由于过度活跃的伸展反射所致。另一种可能性是，运动肌肉的激活模式从根本上得到了重组。本研究旨在确定拉伸反射升高和运动模式重组在卒中后肌肉计时异常中的作用。有或没有中风后偏瘫的受试者都将参加。使用踏板任务，运动的方向将被操纵，腿部肌肉的皮肤反射将被激发。肌肉活动和皮肤反射幅度将在踏板过程中进行量化。它假设，如果异常的运动肌肉计时是由于伸展反射的升高引起的，那么无论踏板的方向如何，在肌肉延长的过程中都会出现异常的肌肉活动。如果中风后运动模式重新组织，将观察到与踏板生物力学组件序列相关的肌肉计时的方向依赖变化，皮肤反射调制将重新组织。

DESCRIPTION (provided by applicant): A major obstacle to quality of life for stroke survivors is impaired walking ability, and restoration of locomotion is an important goal. The objective of this research is to identify mechanisms contributing to impaired walking ability post-stroke. Locomotion is normally characterized by critically-timed patterns of muscle activity in the legs. However, in persons with post-stroke hemiparesis, muscle activity is abnormally timed, which contributes to slow and unsafe locomotion. The causes of abnormal locomotor muscle timing are poorly understood; however, a dominant theory is that abnormal muscle timing is due to hyperactive stretch reflexes. Another possibility is that locomotor muscle activation patterns are fundamentally reorganized. This study aims to identify the contributions of elevated stretch reflexes and reorganization of the locomotor pattern to abnormal muscle timing post-stroke. Subjects with and without post-stroke hemiparesis will participate. Using a pedaling task, the direction of locomotion will be manipulated, and cutaneous reflexes will be elicited in leg muscles. Muscle activity and cutaneous reflex amplitude will be quantified during pedaling. It is hypothesized that, if abnormal locomotor muscle timing arises from elevated stretch reflexes, abnormal muscle activity will be present during muscle lengthening, regardless of pedaling direction. If the locomotor pattern is reorganized post-stroke, direction-dependent changes in muscle timing that are related to the sequence of the biomechanical components of pedaling will be observed, and cutaneous reflex modulation will be reorganized.