Pasluosta C, Lauck T B, Krauskopf T, Klein L, Mueller M, Herget G W, Stieglitz T
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:3815-3818. doi: 10.1109/EMBC44109.2020.9176850.
The dynamics of the adjustment of center of pressure (CoP) has been utilized to understand motor control in human pathologies characterized by impairments in postural balance. The control mechanisms that maintain balance can be investigated via the analysis of muscle recruitment using electromyography (EMG) signals. In this work, we combined these two techniques to investigate balance control during upright standing in transfemoral unilateral amputees wearing a prosthesis. The dynamics of the CoP adjustments and EMG-EMG coherence between four muscles of the trunk and lower limb of 5 unilateral transfemoral amputees and 5 age-matched able-bodied participants were quantified during 30 s of quiet standing using the entropic half-life (EnHL) method. Two visual conditions, eyes open and eyes closed, were tested. Overall, the group of amputees presented lower EnHL values (higher dynamics) in their CoP adjustments than controls, especially in their intact limb. The EnHL values of the EMG-EMG coherence time series in the amputee group were lower than the control group for almost all muscle pairs under both visual conditions. Different correlations between the EnHL values of the CoP data and the EMG-EMG coherence data were observed in the amputee and control groups. These preliminary results suggest the onset of distinct neuromuscular adaptations following a unilateral amputation.Clinical Relevance - Understanding neuromuscular adaptation mechanisms after an amputation may serve to design better rehabilitation treatments and novel prosthetic devices with sensory feedback.
压力中心（CoP）调整的动态变化已被用于理解以姿势平衡受损为特征的人类病理学中的运动控制。维持平衡的控制机制可以通过使用肌电图（EMG）信号分析肌肉募集来进行研究。在这项工作中，我们结合这两种技术来研究佩戴假肢的单侧经股骨截肢者直立站立时的平衡控制。使用熵半衰期（EnHL）方法，在5名单侧经股骨截肢者和5名年龄匹配的健全参与者安静站立30秒期间，对其躯干和下肢四块肌肉之间的CoP调整动态变化以及EMG-EMG相干性进行了量化。测试了两种视觉条件，即睁眼和闭眼。总体而言，截肢者组在CoP调整中的EnHL值（动态变化更大）低于对照组，尤其是在其健全肢体中。在两种视觉条件下，截肢者组中几乎所有肌肉对的EMG-EMG相干性时间序列的EnHL值均低于对照组。在截肢者组和对照组中观察到CoP数据的EnHL值与EMG-EMG相干性数据之间存在不同的相关性。这些初步结果表明单侧截肢后出现了明显的神经肌肉适应性变化。临床相关性——了解截肢后的神经肌肉适应机制可能有助于设计更好的康复治疗方法和具有感觉反馈的新型假肢装置。
