脊髓损伤肌肉电生理特性评估及康复机器人干预后的功能重建研究

Individuals with cervical spinal cord injury (SCI) experience significant function impairment of their upper extremities, with subsequent challenges in activities of daily living. SCI predisposes survivors to muscle atrophy, contracture, and increased fat infiltration which might be one of the causes of limited physical activity. However, quantitative evaluation of muscle function after SCI is still limited. In this current study, electrical impedance myography (EIM) will be used to assess the muscle changes after SCI with a localized multi-frequency technology. EIM could quantify muscle inherent electrical properties such as in cell membrane permittivity, loss of muscle fibers, fat infiltration as well as anisotropy characteristics. Our preliminary results in SCI showed the EIM parameters such as resistance, reactance and phase angle changed after the injury. However, the mechanism behind the changes are still not clear. In this study, surface electromyography (sEMG) combine with joint torque will also be applied to evaluate the muscle activation and strength after SCI and correlated with EIM parameters. At last, a six-weeks upper limb rehabilitation robot intervention will be conducted on incomplete cSCI and EIM, EMG combined muscle strength will be used to compare the training effects. Since EIM requires no patient effort and is quick and convenient to conduct, it may provide a useful tool for examination of paralyzed muscle changes after SCI. Assessing muscle structural and physiological modifications after SCI will facilitate the understanding of the mechanism of muscle weakness and/or spasticity after injury and to profound insights to method and evidence for rehabilitation intervention and develop training regimes.

脊髓损伤(Spinal Cord Injury, SCI)后常出现肢体肌肉萎缩、屈曲性痉挛、习得性废用等问题从而严重影响肌肉发力和其他基本功能，但定量化评估损伤导致肌肉本身特性变化的方法仍缺乏。本项目引入肌肉电阻抗图技术(EIM)，其参数主要反映肌纤维和肌内细胞在弱电流下的通透性、排列特性、肌内外脂肪比例以及各向异性等指标。前期已发现SCI患者的EIM电阻、电抗、相位有变化，然而其影响肌肉功能的机制未明。课题将结合表面肌电信号(EMG)和关节力矩等其他神经肌肉电生理信息，比较SCI和正常对照在肌肉放松和不同发力强度下的变化以及疲劳性测试，关联EIM深入了解损伤后肌肉电生理特性的动态变化。 最后设计针对不完全性颈部脊髓损伤患者的上肢康复机器人训练方案, 利用EIM、EMG和力矩进行干预效果的评估，阐明康复训练在肌肉层次上的电生理机制，为跟踪SCI肌肉进展和制定干预手段提供理论依据和技术基础。

中枢神经损伤后肌肉本身特性改变是导致运动功能障碍的原因之一，但临床上缺乏定量化评估肌肉特性的有效手段。本研究通过肌肉电阻抗图、表面肌电图、B型超声、肌肉弹性、肌力测试等技术定量化评估中枢神经损伤后肌肉的生理特性。肌肉特性参数与临床量表进行相关性分析，揭示了中枢神经损伤后肌肉参数变化导致肌肉力量与功能异常的机制， 也有助于定量化评估临床康复训练效果。本项目主要开展了三个方面的研究工作：1）结合EIM技术和肌肉弹性、表面肌电图技术，验证EIM评估脊髓损伤肌肉变化的可行性，探讨脊髓损伤导致的运动功能障碍的神经肌肉机制。电阻抗结果显示SCI受试者的电阻及电抗减小,提示肌肉组织对微电流的频谱响应的阻抗与正常对照有所不同；肌肉弹性结果显示SCI受试者的震荡频率和动态硬度减小，对数衰减值和机械应力松弛时间增加。电阻抗及肌肉弹性参数与临床量表之间具有密切的相关性；表面肌电图结果显示SCI 受试者最大收缩力明显减小，且不同发力强度下肌纤维动作电位传导速度明显减慢。以上研究结果提示脊髓损伤后由于肌肉萎缩和肌张力增高，肌肉变硬，弹性应变能力变差，同时伴有肌力下降。2）结合EIM和B型超声技术，验证了EIM评估脑卒中肌肉变化的可行性,并与超声测量的肌肉形态参数进行相关性分析，探讨脑卒中损伤导致的运动功能障碍的神经肌肉机制。研究结果发现EIM测到的肌肉组成成分参数与超声下的肌肉形态结构参数相互关联，且随关节角度而变化，并与临床量表相关。3）将电阻抗图技术应用于临床的康复效果干预评估，我们发现对脑卒中患者进行功能性电刺激结合踩单车训练后，下肢肌群的电阻抗参数发生不同程度的改变，并与临床量表密切相关。本项目的研究结果提示肌肉电阻抗图技术作为一项无创电生理检测技术可以与超声、表面肌电图技术结合用于科学评估中枢神经损伤后肌肉特性并探讨损伤导致的运动功能障碍的肌肉电生理机制，为开展临床康复提供理论依据和技术支持。