Kapelner Tamás, Jiang Ning, Holobar Aleš, Vujaklija Ivan, Roche Aidan D, Farina Dario, Aszmann Oskar C
Institute for Neurorehabilitation Systems, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University, Göttingen, Germany.
Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada.
PLoS One. 2016 Feb 22;11(2):e0149772. doi: 10.1371/journal.pone.0149772. eCollection 2016.
Targeted muscle reinnervation (TMR) is a surgical procedure used to redirect nerves originally controlling muscles of the amputated limb into remaining muscles above the amputation, to treat phantom limb pain and facilitate prosthetic control. While this procedure effectively establishes robust prosthetic control, there is little knowledge on the behavior and characteristics of the reinnervated motor units. In this study we compared the m. pectoralis of five TMR patients to nine able-bodied controls with respect to motor unit action potential (MUAP) characteristics. We recorded and decomposed high-density surface EMG signals into individual spike trains of motor unit action potentials. In the TMR patients the MUAP surface area normalized to the electrode grid surface (0.25 ± 0.17 and 0.81 ± 0.46, p < 0.001) and the MUAP duration (10.92 ± 3.89 ms and 14.03 ± 3.91 ms, p < 0.01) were smaller for the TMR group than for the controls. The mean MUAP amplitude (0.19 ± 0.11 mV and 0.14 ± 0.06 mV, p = 0.07) was not significantly different between the two groups. Finally, we observed that MUAP surface representation in TMR generally overlapped, and the surface occupied by motor units corresponding to only one motor task was on average smaller than 12% of the electrode surface. These results suggest that smaller MUAP surface areas in TMR patients do not necessarily facilitate prosthetic control due to a high degree of overlap between these areas, and a neural information-based control could lead to improved performance. Based on the results we also infer that the size of the motor units after reinnervation is influenced by the size of the innervating motor neuron.
靶向肌肉再支配（TMR）是一种外科手术，用于将原本控制截肢肢体肌肉的神经重新导向截肢上方的残留肌肉，以治疗幻肢痛并促进假肢控制。虽然该手术有效地建立了强大的假肢控制能力，但对于再支配运动单位的行为和特征却知之甚少。在本研究中，我们比较了5名TMR患者的胸肌与9名健全对照者的运动单位动作电位（MUAP）特征。我们记录了高密度表面肌电信号，并将其分解为运动单位动作电位的单个尖峰序列。在TMR患者中，TMR组的MUAP表面积相对于电极网格表面积归一化后（分别为0.25±0.17和0.81±0.46，p<0.001）以及MUAP持续时间（分别为10.92±3.89毫秒和14.03±3.91毫秒，p<0.01）均小于对照组。两组之间的平均MUAP幅度（分别为0.19±0.11毫伏和0.14±0.06毫伏，p = 0.07）无显著差异。最后，我们观察到TMR中MUAP的表面表示通常重叠，并且仅对应于一项运动任务的运动单位所占据表面平均小于电极表面的12%。这些结果表明，TMR患者较小的MUAP表面积不一定有助于假肢控制，因为这些区域之间存在高度重叠，基于神经信息的控制可能会提高性能。基于这些结果，我们还推断再支配后运动单位的大小受支配运动神经元大小的影响。
