肌电生物反馈的非线性机制

目的探讨肌电生物反馈中肌电与脑电活动间的相关联系及其机制。方法动态同步采集肌电生物反馈中肌电和脑电信号后,在评价肌电幅值和频率的基础上,利用非线性动力学参数——近似熵(ApEn)和互近似熵(Cross-ApEn),分析肌电信号内部以及肌电-脑电信号间的非线性改变。结果随生物反馈次数的增加,对照组及生物反馈组实验前后肌电振幅的最大值、最小值和平均值都明显降低(F=3.85~25.59,P<0.05),生物反馈组实验前及实验后肌电频率明显上升(F=6.71、8.67,P<0.05);同时,肌电信号的ApEn明显降低(F=5.42、2.81,P<0.05),肌电与脑电信号间的互近似熵也明显升高(F=13.77~19.52,P<0.05)。最后2次反馈中上述指标均明显不同于对照组(P<0.05)。结论肌电生物反馈中肌电变化的机理,可能与生物反馈加强了大脑的有意识的调控作用而减弱了大脑对下运动神经元-肌肉系统的非线性易化有关。

A Pilot Study on Electromyographic Biofeedback Mechanism by Nonlinear Analysis

Objective: To study the mechanism of electromyographic (EMG) biofeedback. Methods: The EMG and electroencephalographic (EEG) signals were recorded dynamically during the course of EMG biofeedback. Changes of EMG amplitude and frequency during EMG biofeedback were assessed with linear analysis. We also applied the nonlinear analysis, approximate entropy (ApEn) of EMG signals and Cross Approximate entropy (Cross-ApEn) between EMG and EEG signals, to assess regularities in EMG and correlation between EMG and EEG. Results: With the processing of EMG biofeedback, the maximum, minimum and mean amplitude of EMG signals decreased significantly (F=3.85~25.59,P<0.05), inversely, the frequency of EMG signals increased significantly (F=6.71,8.67,P<0.05). At the same time, the ApEn value of EMG signals decreased remarkably (F=5.42,2.81,P<0.05), but the value of Cross-ApEn between EMG and EEG signals increased remarkably (F=13.77~19.52,P<0.05) after each EMG biofeedback. Remarkable difference also existed in ApEn and cross-ApEn between biofeedback group and control group after the last two EMG biofeedback (P<0.05). Conclusion: The EMG biofeedback may modulate EMG signals by strengthening the voluntary regulation and weakening the non-linear facilitation of brain to unit of lower motor neuron and muscle system.