Jiang Sheng-Long, Wang Zhongpeng, Yi Weibo, He Feng, Qi Hongzhi, Ming Dong
Biomedical Engineering Department, School of Precision Instrument & Opto-Electronics Engineering, Tianjin University, Tianjin, China.
Beijing Machine and Equipment Institute, Beijing, China.
Front Hum Neurosci. 2019 May 15;13:152. doi: 10.3389/fnhum.2019.00152. eCollection 2019.
Neuromuscular electrical stimulation (NMES) is frequently used in rehabilitation therapy to improve motor recovery. To optimize the stimulatory effect of NMES, the parameters of NMES, including stimulation mode, location, current intensity, and duration, among others have been investigated; however, these studies mainly focused on the effects of changing parameters in the current plateau stage of the NMES cycle, while the impacts on other stages, such as the current rising stage, have yet to be investigated. In this article, we studied the electroencephalograph (EEG) effects during NMES, with different rates of current change in the rising stage, and stable current intensity in the plateau stage. EEG signals (64-channel) were collected from 28 healthy subjects, who were administered with high, medium, or low current change rate (CCR) NMES through a right-hand wrist extensor. Time-frequency analysis and brain source analysis, using the LORETA method, were used to investigate neural activity in sensorimotor cortical areas. The strengths of cortical activity induced by different CCR conditions were compared. NMES with a high CCR activated the sensorimotor cortex, despite the NMES current intensity in the plateau stage lower than the motor threshold. Reduction of the Alpha 2 band (10-13 Hz) event related spectral power (ERSP) during NMES stimulation was significantly enhanced by increasing CCR ( < 0.05). LORETA-based source analysis demonstrated that, in addition to typical sensory areas, such as primary somatosensory cortex (S1), sensorimotor areas including primary motor cortex (M1), premotor cortex (PMC), and somatosensory association cortex (SAC) were all activated by within threshold NMES. Furthermore, compared with the low CCR condition, cortical activity was significantly enhanced in the S1, M1, and PMC areas under high CCR conditions. This study shows CCR in the NMES rising stage can affect EEG responses in the sensorimotor cortex and suggests that CCR is an important parameter applicable to the optimization of NMES treatment.
神经肌肉电刺激（NMES）常用于康复治疗以促进运动恢复。为优化NMES的刺激效果，人们对NMES的参数进行了研究，包括刺激模式、部位、电流强度和持续时间等；然而，这些研究主要集中在NMES周期中电流平稳阶段参数变化的影响，而对其他阶段，如电流上升阶段的影响尚未进行研究。在本文中，我们研究了NMES过程中，电流上升阶段具有不同变化速率且平稳阶段电流强度稳定时的脑电图（EEG）效应。从28名健康受试者采集了EEG信号（64通道），这些受试者通过右手腕伸肌接受高、中或低电流变化率（CCR）的NMES。采用时频分析和基于LORETA方法的脑源分析来研究感觉运动皮层区域的神经活动。比较了不同CCR条件下诱发的皮层活动强度。尽管平稳阶段的NMES电流强度低于运动阈值，但高CCR的NMES仍激活了感觉运动皮层。通过增加CCR（<0.05），NMES刺激期间Alpha 2频段（10 - 13Hz）事件相关谱功率（ERSP）的降低显著增强。基于LORETA的源分析表明，除了典型的感觉区域，如初级体感皮层（S1）外，包括初级运动皮层（M1）、运动前皮层（PMC）和体感联合皮层（SAC）在内的感觉运动区域均被阈下NMES激活。此外，与低CCR条件相比，高CCR条件下S1、M1和PMC区域的皮层活动显著增强。本研究表明，NMES上升阶段的CCR可影响感觉运动皮层的EEG反应，并提示CCR是适用于优化NMES治疗的一个重要参数。
