中风后下肢肌肉的站立神经生理学评估
Summary
该协议描述了在中风后使用TMS对站立位置的下肢肌肉，胫骨前部和比目鱼进行神经生理学评估的过程。该位置提供了引发卒中后TMS反应的更大概率，并允许在神经生理学评估期间使用降低的刺激器功率。
Abstract
经颅磁刺激（TMS）是一种常用工具，用于测量健康和神经受损人群中运动回路的行为。TMS广泛用于研究运动控制和对上肢神经康复的反应。然而，TMS在下肢姿势和行走特异性运动控制的研究中应用较少。下肢TMS评估的有限使用和额外的方法学挑战导致文献中下肢TMS程序缺乏一致性。受记录下肢TMS运动诱发电位（MEP）能力下降的启发，该方法报告详细介绍了在站立姿势下进行卒中后TMS评估的步骤。站立姿势允许激活神经肌肉系统，反映出更类似于姿势和步行任务期间系统状态的状态。使用双顶力板，我们指示参与者在他们的假肢和非假肢之间平均分配他们的重量。提供了参与者体重分布的视觉反馈。使用图像引导软件，我们通过双锥线圈将单个TMS脉冲传递到参与者的病变和非病变半球，并测量了假性和非假性胫骨前肌和比目鱼肌的皮质运动反应。在站立位置进行评估可提高TMS反应率，并允许使用与标准坐姿/休息姿势相比较低的刺激强度。当姿势和步态障碍的神经康复令人感兴趣时，使用该TMS方案可以提供一种通用方法来评估卒中后下肢皮质运动反应。
Introduction
经颅磁刺激（TMS）是一种用于测量神经回路行为的仪器。大多数TMS研究的重点是运动控制/表现的研究是在上肢进行的。上肢和下肢检查之间的不平衡部分是由于测量下肢皮质运动反应（CMR）的额外挑战。其中一些方法障碍包括运动皮层内下肢肌肉的较小皮质表征以及相对于头皮的更深位置1。在神经损伤人群中，还存在其他障碍。例如，大约一半的卒中后个体在下肢肌肉休息时对TMS没有反应2，3。当患者保持对肌肉的一些意志控制时，甚至可以看到对TMS缺乏反应，表明皮质脊髓束至少部分完整。
缺乏可测量的TMS反应和维持的运动功能导致我们对卒中后姿势和行走特异性运动控制以及神经康复的神经生理学影响的理解下降。然而，卒中后下肢神经生理学评估的一些挑战已被克服。例如，双锥线圈可用于可靠地激活位于半球间裂缝1深处的下肢运动神经元。双锥线圈产生更大，更强的磁场，比更常用的八字线圈4更深入地穿透大脑。可以实施的另一个方法学变化可以提高对TMS的响应性，即在轻微的自愿收缩期间测量CMR5。通常，这种收缩是在最大自愿关节扭矩或最大肌电图（EMG）肌肉活动的预定水平上进行的。周围神经刺激也可用于引发最大的肌肉反应，并且该反应的记录肌电图可用于设置肌肉的目标自愿激活。
在活动性肌肉收缩期间进行中风后TMS评估在上肢相当普遍，其中等距任务可以模仿功能活动，例如，抓取/握住物体。相反，步行是通过皮质，皮质下和脊髓结构双侧激活多个肌肉群来完成的，并且需要姿势肌激活以抵抗重力的影响。在测量产生等距收缩的孤立肌肉时，这种激活状态可能不会反映出来。以前几项旨在了解姿势和步行特定运动控制的研究在参与者行走6，7，8和站立9，10，11，12，13，14，15时提供TMS脉冲.在直立位置测量CMR允许激活姿势肌肉和姿势和步态运动控制网络的皮质下成分。迄今为止，尚无任何关于卒中后个体进行长期TMS评估的报告。
本研究提出了一种标准化的方法，建立在现有的文献文献的基础上，即站立TMS方法6，7，8，9，10，11，12，13，14，15，用于中风后CMR的站立TMS评估。该方法可由研究但不限于姿势缺陷和卒中后行走特异性运动控制的研究小组使用，并建立TMS程序的更大一致性。该方法学调查的目的是确定站立式TMS评估在中风后中度步态障碍患者中是否可行。我们假设在站立位置进行评估将1）增加引发可测量反应（运动诱发电位，MEP）的可能性，以及2）用于进行站立TMS评估的刺激器功率/强度将低于通常进行的坐姿/休息评估。我们相信，该协议的成功完成和广泛使用可能会导致对中风后姿势和行走特异性运动控制的神经生理学方面以及神经康复的影响有更深入的了解。
Protocol
Representative Results
Discussion
实验方案被大多数参与者很好地耐受。一名患者由于先前存在的继发于糖尿病并发症的褥疮溃疡和涉及先前存在的膝关节疼痛的骨科问题而无法完成站立性TMS评估。从腿部装载/卸载体重的量是最小的。然而，平均而言，在应用TMS脉冲期间测量的下向力略大。这可能是由于线圈的重量和调查人员施加的向下压力，以确保头皮/头部和TMS线圈之间有足够的接触。与静态试验相比，TMS程序中捕获的体重?…
Divulgations
The authors have nothing to disclose.
Acknowledgements
作者要感谢Brian Cence先生和Alyssa Chestnut夫人对参与者招募和数据收集的贡献。
该项目的资金部分由NIH国家神经调节康复中心（NM4R）（HD086844）的技术发展奖以及退伍军人事务康复研究与发展职业发展奖1（RX003126）和优异奖（RX002665）提供。
本报告的内容不代表美国退伍军人事务部、美国国立卫生研究院或美国政府的观点。
Materials
| Data Acquisition Software | MathWorks | MatLab | The custom data collection program was written in Matlab. However, other software/hardware providers can be used (e.g. National Instruments, AD Instruments, CED Spike2 or Signal) |
| Double-cone coil | Magstim | D110 | Double-cone coil for TMS pulse delivery |
| Dual force plate | Advanced Mechanical Technology Inc (AMTI) | Dual-top Accusway | Force plate used to measure force/weight distrobution under each leg independently. |
| Dual-pulse TMS | Magstim | Bistim 200 | Connects two Magstim 200 units together for dual-pulse applications |
| EMG pre-amplifiers | Motion Labs Inc | MA-422 | Preamplifiers for disposable surface EMG electrodes |
| EMG system | Motion Labs Inc | MA400 | EMG system for data collection |
| Neuronavigation System | Rogue Research | Brainsight | Software and hardware used to ensure consistent placement/delivery of magnetic stimulations. Marking the stimulation location on a participant's head or on a place showercap can also be used in the absence of neuronavigational software. |
| Recruitment Database | N/A | N/A | Electronic database including names of possible individuals who are eligble for your studies. |
| TMS unit (x2) | Magstim | Magstim 200 | Delivers TMS pulses |
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