Modulation of ankle muscle postural reflexes in stroke: influence of weight-bearing load
Modulation of ankle muscle postural reflexes in stroke: influence of weight-bearing load
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DOI：
10.1016/j.clinph.2004.07.002
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发表时间：
2004-12-01
影响因子：
4.7
通讯作者：
Inglis, JT
中科院分区：
文献类型：
--
作者：
Marigold, DS;Eng, JJ;Inglis, JT
目的：鉴于中风患者存在感觉运动障碍和负重姿势不对称，本研究的目的是确定中风是否影响不同负重负荷下站立姿势反射的调节。方法：10名慢性中风患者和10名健康老年人对照组在站立时接受意外的站立平台前后平移。施加了三种不同的姿势条件：增加负重负荷、减少负重负荷和自我选择姿势。记录双侧踝关节背屈肌(胫骨前肌)和伸肌(腓肠肌)的表面肌电信号，并测定背景肌活动(平台平移前)和姿势反射起始潜伏期及幅度(反射起始后75ms)。结果：对照组和卒中患者均存在踝伸肌群负荷调制。尽管对照组显示了脚踝背屈肌对不同负荷的调节，但中风患者没有表现出这种调节。此外，负荷并没有改变中风患者姿势反射的起始潜伏期。结论：瘫痪肌肉起始潜伏期的延迟和踝关节背屈肌姿势反射调节的受损可能是中风患者观察到的不稳定和频繁摔倒的原因。(C)2004年国际临床神经生理学联合会。爱思唯尔爱尔兰有限公司出版。版权所有。
Objective: Given the known sensorimotor deficits and asymmetric weight-bearing posture in stroke, the aim of this study was to determine whether stroke affects the modulation of standing postural reflexes with varying weight-bearing load.Methods: Ten individuals with chronic stroke and 10 healthy older adult controls were exposed to unexpected forward and backward platform translations while standing. Three different stance conditions were imposed: increased weight-bearing load, decreased weight-bearing load, and self-selected stance. Surface electromyography from bilateral ankle dorsiflexors (tibialis anterior) and extensors (gastrocnemius) were recorded and the magnitude of background muscle activity (prior to the platform translation) and postural reflex onset latency and magnitude (75 ms following reflex onset) were determined.Results: Load modulation of ankle extensors was found in controls and individuals with stroke. Although controls demonstrated modulation of ankle dorsiflexors to different loads, individuals with stroke did not show this modulation. Further, load did not change the onset latency of postural reflexes of the individuals with stroke.Conclusions: The delayed paretic muscle onset latencies in conjunction with impaired modulation of ankle dorsiflexor postural reflexes may contribute to the instability and frequent falls observed among individuals with stroke.Significance: The results provide some insight into standing postural reflexes following stroke. (C) 2004 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.