Fylstra Bretta L, Dai Chenyun, Hu Xiaogang, Huang He Helen
Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:5974-5977. doi: 10.1109/EMBC.2018.8513661.
As research is progressing towards EMG control of lower limb prostheses, it is vital to understand the neurophysiology of the residual muscles in the amputated limb, which has been largely ignored. Therefore, the goal of this study was to characterize the activation patterns (muscle recruitment and motor unit discharge patterns) of the residual muscles of lower limb amputees. One transtibial amputee subject was recruited for this pilot study. The participant wore three high-density EMG electrode pads (8x8 grid with 64 channels) on each limb (a total of six pads) - one on the tibialis anterior (TA), medial gastrocnemius (MG), and lateral gastrocnemius (LG), respectively. The participant was asked to follow a ramping procedure plateauing at 50% of maximum voluntary contraction (MVC) for both the TA and Gastrocnemius muscles. The EMG signals were then decomposed offline; the firing rate and spatial activation patterns of the muscle were analyzed. Results showed slower and more variable firing rate in motor units of residual muscles than those of intact side. In addition, the spatial pattern of muscle activation differed between residual and intact muscles. These results indicate that surface EMG signals recorded from residual muscles present modified signal features from intact shank muscles, which should be considered when implementing myoelectric control schemes.
随着研究朝着下肢假肢的肌电图控制方向发展，了解截肢肢体中残留肌肉的神经生理学至关重要，但这一点在很大程度上被忽视了。因此，本研究的目的是描述下肢截肢者残留肌肉的激活模式（肌肉募集和运动单位放电模式）。招募了一名经胫截肢受试者进行这项初步研究。参与者在每条肢体上佩戴三个高密度肌电图电极垫（8×8网格，64通道）（总共六个垫子），分别置于胫骨前肌（TA）、腓肠肌内侧头（MG）和腓肠肌外侧头（LG）上。要求参与者对TA肌和腓肠肌均采用斜坡程序，在最大自主收缩（MVC）的50%处达到平稳状态。然后对肌电图信号进行离线分解，分析肌肉的放电频率和空间激活模式。结果显示，残留肌肉运动单位的放电频率比健侧更慢且变化更大。此外，残留肌肉和健侧肌肉的肌肉激活空间模式也有所不同。这些结果表明，从残留肌肉记录的表面肌电图信号呈现出与完整小腿肌肉不同的信号特征，在实施肌电控制方案时应予以考虑。
