利用非对称高频载波脉冲簇电刺激的肌疲劳缓解技术研究

Research on Muscle Fatigue Reduction Using Asymmetric High-Frequency Carrier Pulse Cluster Electrical Stimulation

为了缓解神经肌肉电刺激导致的肌肉疲劳,并减轻高频载波脉冲簇电刺激带来的不适感,提出了非对称高频载波脉冲簇电刺激的肌疲劳缓解技术,利用健康受试者,比较了所提技术和传统对称双相矩形脉冲电刺激的抗疲劳性能。在正中神经、尺神经束近端,分别施加载波频率为10 kHz的窄脉冲簇(高频模式)和传统的对称双相矩形脉冲(低频模式)并引起相同的收缩水平,持续刺激5 min以诱发肌疲劳并记录手指收缩力和指屈肌高密度肌电信号。研究结果显示,与低频刺激相比,高频刺激下肌肉疲劳速率显著降低,具体表现为力衰减变慢,绝对力衰减较小(3.8688±1.1368)N,平台力更大(7.296±1.3424)N,最终获得更大的力输出为(2282.8±341.48)N·s,同时高频刺激下更高的力-肌电幅值比说明诱发了更高的肌肉激活效率,这可能是高频模式缓解肌疲劳的潜在机制。与传统对称低频刺激相比,非对称高频载波脉冲簇电刺激可能通过诱发更高效率的肌肉激活,从而显著缓解电刺激下肌疲劳问题,这对电刺激技术在脑卒中等患者运动功能康复中的推广应用具有重要意义。

To alleviate muscle fatigue caused by neuromuscular electrical stimulation(NMES)and reduce the discomfort associated with high-frequency carrier pulse cluster electrical stimulation,this paper compares the anti-fatigue properties of the proposed asymmetric high-frequency carrier pulse cluster electrical stimulation with the conventional symmetric biphasic rectangular pulse electrical stimulation technique in healthy subjects.Specifically,the clustered narrow pulses with a carrier frequency of 10 kHz(high-frequency mode,HF)and the conventional symmetrical biphasic rectangular pulses(low-frequency mode,LF)are delivered to the proximal segment of the median/ulnar nerve bundles,eliciting the same level of contraction.Stimulation is continued for 5 minutes to induce muscle fatigue,and finger flexion forces and high-density electromyography(EMG)signals of the finger flexors are recorded.The results show that the rate of muscle fatigue is significantly reduced under the HF stimulation compared with the LF stimulation.This is manifested by a slower force decay rate,smaller absolute force decay(3.8688±1.1368)N,and a larger force plateau(7.296±1.3424)N,resulting in greater force output(2282.8±341.48)N·s.The higher force-to-EMG amplitude ratio under the HF stimulation indicated a higher efficiency of muscle activation,which may be a potential mechanism for alleviating muscle fatigue by the HF modes.The present study suggests that the asymmetric pulse clusters at a kilohertz carrier frequency may significantly alleviate muscle fatigue by inducing a higher efficiency of muscle activation compared to the conventional symmetric LF stimulation,which can potentially promote the application of the NMES-based motor neurorehabilitation technique in stroke patients.