Repeated transspinal stimulation decreases soleus H-reflex excitability and restores spinal inhibition in human spinal cord injury
Repeated transspinal stimulation decreases soleus H-reflex excitability and restores spinal inhibition in human spinal cord injury
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DOI：
10.1371/journal.pone.0223135
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发表时间：
2019-09-26
期刊：
影响因子：
3.7
通讯作者：
Murray, Lynda M.
中科院分区：
文献类型：
--
作者：
Knikou, Maria;Murray, Lynda M.
经皮脊髓或经脊髓刺激胸腰椎扩大，运动神经元支配腿部肌肉的脊柱位置，调节参与运动控制的神经回路。慢性脊髓损伤（SCI）患者每日经脊髓刺激（如重复）对比目鱼h反射兴奋性的影响程度在很大程度上仍然未知。在这项研究中，我们建立了反复阴极经脊髓刺激对慢性脊髓损伤和非慢性脊髓损伤患者比目鱼h反射兴奋性和脊髓抑制的影响。10名脊髓损伤者和10名健康对照者分别接受1 ms持续时间、0.2 Hz的单相右比目鱼肌经脊髓诱发电位阈下和阈上强度刺激。脊髓损伤受试者平均接受16次刺激，而健康对照组平均接受10次刺激。在干预前和干预后1天或2天，我们使用比目鱼H反射来评估运动神经元募集的变化，在0.1、0.125、0.2、0.33和1.0 Hz的单次胫骨神经刺激后的同突触抑制，以及在刺激间隔为60、100、300和500 ms的配对胫骨神经刺激后的激活后抑制。运动不完全性和完全性脊髓损伤患者双下肢比目鱼h反射兴奋性降低，而健康对照组无此现象。运动不完全性和完全性脊髓损伤均存在比目鱼h反射同突触抑制和激活后抑制，但强度低于健康对照。反复的经脊髓刺激增加了所有脊髓损伤受试者的同突触抑制，而在健康对照中保持不变。激活后抑郁在所有受试者组中保持不变。最后，经脊髓刺激可降低痉挛和踝关节阵挛的严重程度。结果表明，经脊髓反复刺激后，人脊髓反射性亢进性降低，脊髓抑制控制恢复。经脊髓刺激是一种无创的神经调节方法，用于恢复脊髓损伤后脊髓介导的传入反射动作。
Transcutaneous spinal cord or transspinal stimulation over the thoracolumbar enlargement, the spinal location of motoneurons innervating leg muscles, modulates neural circuits engaged in the control of movement. The extent to which daily sessions (e.g. repeated) of transspinal stimulation affects soleus H-reflex excitability in individuals with chronic spinal cord injury (SCI) remains largely unknown. In this study, we established the effects of repeated cathodal transspinal stimulation on soleus H-reflex excitability and spinal inhibition in individuals with and without chronic SCI. Ten SCI and 10 healthy control subjects received monophasic transspinal stimuli of 1-ms duration at 0.2 Hz at subthreshold and suprathreshold intensities of the right soleus transspinal evoked potential (TEP). SCI subjects received an average of 16 stimulation sessions, while healthy control subjects received an average of 10 stimulation sessions. Before and one or two days post intervention, we used the soleus H reflex to assess changes in motoneuron recruitment, homosynaptic depression following single tibial nerve stimuli delivered at 0.1, 0.125, 0.2, 0.33 and 1.0 Hz, and postactivation depression following paired tibial nerve stimuli at the interstimulus intervals of 60, 100, 300, and 500 ms. Soleus H-reflex excitability was decreased in both legs in motor incomplete and complete SCI but not in healthy control subjects. Soleus H-reflex homosynaptic and postactivation depression was present in motor incomplete and complete SCI but was of lesser strength to that observed in healthy control subjects. Repeated transspinal stimulation increased homosynaptic depression in all SCI subjects and remained unaltered in healthy controls. Postactivation depression remained unaltered in all subject groups. Lastly, transspinal stimulation decreased the severity of spasms and ankle clonus. The results indicate decreased reflex hyperexcitability and recovery of spinal inhibitory control in the injured human spinal cord with repeated transspinal stimulation. Transspinal stimulation is a noninvasive neuromodulation method for restoring spinally-mediated afferent reflex actions after SCI in humans.