Guangdong Work Injury Rehabilitation Center, Guangzhou 510970, China.
Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Biosensors (Basel). 2021 Sep 27;11(10):356. doi: 10.3390/bios11100356.
Surface electromyography (EMG) recorded by a linear or 2-dimensional electrode array can be used to estimate the location of muscle innervation zones (IZ). There are various neurophysiological factors that may influence surface EMG and thus potentially compromise muscle IZ estimation. The objective of this study was to evaluate how surface-EMG-based IZ estimation might be affected by different factors, including varying degrees of motor unit (MU) synchronization in the case of single or double IZs. The study was performed by implementing a model simulating surface EMG activity. Three different MU synchronization conditions were simulated, namely no synchronization, medium level synchronization, and complete synchronization analog to M wave. Surface EMG signals recorded by a 2-dimensional electrode array were simulated from a muscle with single and double IZs, respectively. For each situation, the IZ was estimated from surface EMG and compared with the one used in the model for performance evaluation. For the muscle with only one IZ, the estimated IZ location from surface EMG was consistent with the one used in the model for all the three MU synchronization conditions. For the muscle with double IZs, at least one IZ was appropriately estimated from interference surface EMG when there was no MU synchronization. However, the estimated IZ was different from either of the two IZ locations used in the model for the other two MU synchronization conditions. For muscles with a single IZ, MU synchronization has little effect on IZ estimation from electrode array surface EMG. However, caution is required for multiple IZ muscles since MU synchronization might lead to false IZ estimation.
线性或二维电极阵列记录的表面肌电图（EMG）可用于估计肌肉神经支配区（IZ）的位置。有各种神经生理因素可能会影响表面 EMG，并可能影响肌肉 IZ 估计。本研究的目的是评估基于表面 EMG 的 IZ 估计可能会受到哪些因素的影响，包括单或双 IZ 情况下运动单位（MU）同步程度的不同。该研究通过实施模拟表面 EMG 活动的模型来进行。模拟了三种不同的 MU 同步条件，即无同步、中度同步和完全同步模拟 M 波。分别从具有单 IZ 和双 IZ 的肌肉模拟记录二维电极阵列的表面 EMG 信号。对于每种情况，从表面 EMG 估计 IZ，并与模型中用于性能评估的 IZ 进行比较。对于只有一个 IZ 的肌肉，在所有三种 MU 同步条件下，从表面 EMG 估计的 IZ 位置与模型中使用的位置一致。对于具有双 IZ 的肌肉，在没有 MU 同步的情况下，从干扰表面 EMG 可以适当估计至少一个 IZ。然而，对于其他两种 MU 同步条件，从表面 EMG 估计的 IZ 与模型中使用的两个 IZ 位置中的任何一个都不同。对于具有单个 IZ 的肌肉，MU 同步对从电极阵列表面 EMG 进行 IZ 估计的影响很小。但是，对于具有多个 IZ 的肌肉，需要谨慎，因为 MU 同步可能导致错误的 IZ 估计。
