Evidence for Increased Activation of Persistent Inward Currents in Individuals With Chronic Hemiparetic Stroke
Evidence for Increased Activation of Persistent Inward Currents in Individuals With Chronic Hemiparetic Stroke
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DOI：
10.1152/jn.90563.2008
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发表时间：
2008-12-01
影响因子：
2.5
通讯作者：
Dewald, Julius P. A.
中科院分区：
文献类型：
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作者：
McPherson, Jacob G.;Ellis, Michael D.;Dewald, Julius P. A.
尽管在慢性轻偏瘫中风患者的轻瘫肢体中普遍存在牵张反射过度活跃，但对其表达的基本病理生理机制仍知之甚少。本研究测试是否表现为过度活跃的牵张反射中风后的持续性内向电流（PIC）的发展，导致过度兴奋的运动神经元支配的麻痹肢体。由于1a传入反馈的重复齐射可诱发PIC，本研究通过诱发10名清醒的慢性偏瘫患者的肱二头肌强直振动反射（TVR）并测量上肢的关节扭矩和肌电图（EMG）反应来评估运动神经元的兴奋性。肘关节扭矩和二头肌，肱桡肌，肱三头肌的长头和侧头的肌电图活动记录在8秒的112-Hz的二头肌振动（唤起TVR）和5秒后停止刺激。重复测量方差分析显示，
Despite the prevalence of hyperactive stretch reflexes in the paretic limbs of individuals with chronic hemiparetic stroke, the fundamental pathophysiological mechanisms responsible for their expression remain poorly understood. This study tests whether the manifestation of hyperactive stretch reflexes following stroke is related to the development of persistent inward currents (PICs) leading to hyperexcitability of motoneurons innervating the paretic limbs. Because repetitive volleys of 1a afferent feedback can elicit PICs, this investigation assessed motoneuronal excitability by evoking the tonic vibration reflex (TVR) of the biceps muscle in 10 awake individuals with chronic hemiparetic stroke and measuring the joint torque and electromyographic (EMG) responses of the upper limbs. Elbow joint torque and the EMG activity of biceps, brachioradialis, and the long and lateral heads of triceps brachii were recorded during 8 s of 112-Hz biceps vibration (evoking the TVR) and for 5 s after cessation of stimulation. Repeated-measures ANOVA tests revealed significantly (P