Shan Mianjia, Li Chenhao, Sun Jiayi, Xie Haixia, Qi Yan, Niu Wenxin, Zhang Ming
Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai, 201619, China.
Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
J Neuroeng Rehabil. 2025 Jan 8;22(1):4. doi: 10.1186/s12984-024-01522-7.
Motion complexity is necessary for adapting to external changes, but little is known about trunk motion complexity during seated perturbation in individuals with spinal cord injury (SCI). We aimed to investigate changes following SCI in trunk segmental motion complexity across different perturbation directions and how they affect postural control ability in individuals with SCI.
A total of 17 individuals with SCI and 18 healthy controls participated in challenging sagittal-seated perturbations with hand protection. Upper arm activation was measured using surface electromyography for trial consistency. Motion complexity parameters, quantified across three degrees of freedom, was assessed using relative angular acceleration from six trunk segments obtained through motion capturing system. Motion performance parameters were assessed using center of pressure (CoP) measurements from a force plate, including settling time, maximum CoP displacement (MD) variability, and steady-state error. Statistical analyses examined group and direction differences, while complexity-performance relationships were evaluated using multiple response least partial squares regression.
Compared to healthy controls, individuals with SCI showed significantly lower motion complexity in the lumbar and upper thoracic segments (approximately10% - 20%), with identical settling time and higher MD variability. Backward perturbations, as opposed to forward perturbations, resulted in reduced complexity in the aforementioned segments and increased steady-state error. Lower lumbar rotation complexity negatively correlated with MD variability (β = -0.240) and steady-state error (β = -0.485) in individuals with SCI, while showing a minor positive correlation with settling time (β = 0.152) during backward perturbation.
Simplified motion control in individuals with SCI may arise from uncoordinated lumbar and overactive thoracic neuromuscular control, compromising stability despite maintaining speed. Increasing lumbar motion complexity could enhance postural stability and accuracy during backward perturbation, representing a potential target for developing seated balance rehabilitation strategies and promoting more adaptive trunk control.
运动复杂性对于适应外部变化是必要的，但对于脊髓损伤（SCI）个体在坐位扰动期间的躯干运动复杂性知之甚少。我们旨在研究SCI后不同扰动方向上躯干节段运动复杂性的变化，以及它们如何影响SCI个体的姿势控制能力。
共有17名SCI个体和18名健康对照者参与了带有手部保护的具有挑战性的矢状位坐位扰动。使用表面肌电图测量上臂激活情况以确保试验的一致性。通过运动捕捉系统从六个躯干节段获得相对角加速度，以此评估在三个自由度上量化的运动复杂性参数。使用测力板测量压力中心（CoP）来评估运动性能参数，包括稳定时间、最大CoP位移（MD）变异性和稳态误差。统计分析检验了组间和方向差异，同时使用多元响应最小偏二乘回归评估复杂性与性能的关系。
与健康对照者相比，SCI个体在腰椎和上胸段的运动复杂性显著降低（约10% - 20%），稳定时间相同，但MD变异性更高。与向前扰动相反，向后扰动导致上述节段的复杂性降低以及稳态误差增加。在SCI个体中，下腰椎旋转复杂性与MD变异性（β = -0.240）和稳态误差（β = -0.485）呈负相关，而在向后扰动期间与稳定时间呈轻微正相关（β = 0.152）。
SCI个体运动控制的简化可能源于腰椎不协调和胸段神经肌肉控制过度活跃，尽管保持了速度，但损害了稳定性。增加腰椎运动复杂性可以增强向后扰动期间的姿势稳定性和准确性，这代表了开发坐位平衡康复策略和促进更适应性躯干控制的潜在目标。
