Interlimb interactions during bilateral voluntary elbow flexion tasks in chronic hemiparetic stroke.
Interlimb interactions during bilateral voluntary elbow flexion tasks in chronic hemiparetic stroke.
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DOI：
10.1002/phy2.10
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发表时间：
2013-06
影响因子：
2.5
通讯作者：
Li, Sheng
中科院分区：
文献类型：
--
作者：
Chang, Shuo-Hsiu;Durand-Sanchez, Ana;Ditommaso, Craig;Li, Sheng
目的是系统地研究慢性偏瘫中风的肢体间相互作用。 14 名中风后偏瘫受试者（> 1 岁）在没有视觉反馈的情况下用一肢（单侧）和两肢同时（双侧）执行最大自主收缩（MVC）肘部弯曲任务。在次最大水平下，受试者对视觉目标产生的力反映了单侧任务中相应 MVC 的 20%、40%、60% 和 80%，以及双边任务中单侧 MVC 的总和。双侧测量肘部屈曲力和二头肌表面肌电图（EMG）。在未受损肢体的单侧任务中观察到对侧肢体的肌电图活动成比例增加（运动溢出），但在受损肢体的单侧任务中却没有观察到。在次最大水平的双侧任务期间，与基于单侧 MVC 的预期力相比，受损肢体产生的力较小（即力不足 [FD]）。受损肢体上的力不足通过未受损肢体上产生更大的力来补偿，从而达到视觉目标。然而，当次最大收缩水平增加时，力对总力的贡献从未受损侧逐渐减少。在双侧 MVC 任务中，受损肢体上没有 FD，但在未受损肢体上观察到 FD。观察到双边小幅赤字与肌电图平行变化的最终结果。这些关于激活水平依赖性相互作用和不对称对侧运动溢出的新发现提供了新的见解，即除了不平衡的半球间抑制之外，来自未病变半球的同侧皮质脊髓投射在慢性中风的肢体间相互作用中发挥着重要作用。
The purpose was to systematically investigate interlimb interactions in chronic hemiparetic stroke. Fourteen poststroke hemiparetic subjects (>1 year) performed maximum voluntary contraction (MVC) elbow flexion tasks without visual feedback with one (unilateral) and two limbs simultaneously (bilateral). At submaximal levels, subjects produced force to a visual target reflecting 20%, 40%, 60%, and 80% of corresponding MVC in unilateral tasks, and of summated unilateral MVCs in bilateral tasks. Elbow flexion force and biceps surface electromyogram (EMG) were measured bilaterally. Proportionally increased EMG activity on the contralateral limb (motor overflow) was observed during unilateral tasks of the nonimpaired limb but not of the impaired limb. During bilateral tasks at submaximal levels, the impaired limb produced less force (i.e., force deficit [FD]) as compared to expected forces based upon its unilateral MVC. Force deficit on the impaired limb was compensated by greater force production on the nonimpaired limb such that the visual target was reached. However, force contribution to the total force progressively decreased from the nonimpaired side, when the level of submaximal contractions increased. During bilateral MVC tasks, there was no FD on the impaired limb, but FD was observed on the nonimpaired limb. A net result of a small bilateral deficit in force with parallel changes in EMG was observed. These novel findings of activation level–dependent interactions and asymmetrical contralateral motor overflow provide new insights that, among other compensatory mechanisms, ipsilateral corticospinal projections from the nonlesioned hemisphere play an important role in interlimb interactions in chronic stroke, in addition to unbalanced interhemispheric inhibition.