Altered Motor Unit Discharge Coherence in Paretic Muscles of Stroke Survivors.
Altered Motor Unit Discharge Coherence in Paretic Muscles of Stroke Survivors.
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DOI：
10.3389/fneur.2017.00202
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发表时间：
2017
影响因子：
3.4
通讯作者：
Hu X
中科院分区：
文献类型：
--
作者：
Dai C;Suresh NL;Suresh AK;Rymer WZ;Hu X
脑中风后，脊髓上和脊髓神经系统的一系列变化可以改变肌肉激活的控制，导致持续的运动障碍。然而，这些不同水平的神经系统对肌肉激活受损的相对影响尚不清楚。运动单元（MU）尖峰序列的一致性被认为部分反映了更高级别控制的活动，不同的频带代表不同级别的控制。因此，本研究的目的是量化改变肌肉激活的不同来源。我们检查了 14 名半球中风幸存者的麻痹侧和对侧第一背侧骨间肌的表面肌电图 (sEMG) 分解的 MU 尖峰序列的一致性。 sEMG 是在最大自主收缩的 40%、50% 和 60% 的一系列力收缩水平上获得的。我们的结果表明，与对侧相比，受影响侧的 δ（1-4Hz）、α（8-12Hz）和 β（15-30Hz）频段的 MU 相干性显着增加，但在 γ（30-60Hz）频段保持在相同水平。此外，在中高力水平（40-60%）中没有观察到显着的变化。这些结果表明，运动神经元的共同突触输入在瘫痪侧增加，并且共同输入的增加可能源于多个水平的变化，包括中风后的脊髓和脊髓上水平。所有这些变化都会导致中风幸存者受影响肌肉的激活受损。我们的研究结果还提供了有关中风后肌肉激活受损的不同起源的证据。
After a cerebral stroke, a series of changes at the supraspinal and spinal nervous system can alter the control of muscle activation, leading to persistent motor impairment. However, the relative contribution of these different levels of the nervous system to impaired muscle activation is not well understood. The coherence of motor unit (MU) spike trains is considered to partly reflect activities of higher level control, with different frequency band representing different levels of control. Accordingly, the objective of this study was to quantify the different sources of contribution to altered muscle activation. We examined the coherence of MU spike trains decomposed from surface electromyogram (sEMG) of the first dorsal interosseous muscle on both paretic and contralateral sides of 14 hemispheric stroke survivors. sEMG was obtained over a range of force contraction levels at 40, 50, and 60% of maximum voluntary contraction. Our results showed that MU coherence increased significantly in delta (1–4 Hz), alpha (8–12 Hz), and beta (15–30 Hz) bands on the affected side compared with the contralateral side, but was maintained at the same level in the gamma (30–60 Hz) band. In addition, no significant alteration was observed across medium–high force levels (40–60%). These results indicated that the common synaptic input to motor neurons increased on the paretic side, and the increased common input can originate from changes at multiple levels, including spinal and supraspinal levels following a stroke. All these changes can contribute to impaired activation of affected muscles in stroke survivors. Our findings also provide evidence regarding the different origins of impaired muscle activation poststroke.