基于非线性动力学的咀嚼肌表面肌电信号相空间重构

目的 通过非线性动力学的方法,对咬肌和颞肌前束表面肌电(surface electromyography,sEMG)信号进行相空间重构,探求sEMG轨迹变化规律.方法 选择口颌系统基本正常的个体,男女各10名,在牙尖交错位(intercuspal position,ICP)紧咬时采集左右咬肌和颞肌前柬sEMG信号,基于Matlab平台开发咀嚼肌sEMG非线性动力学分析程序,用C-C法计算时延和嵌入维,再用主成分分析法重构sEMG信号的相空间图.结果 咀嚼肌sEMG非线性动力学分析程序可对20名个体的双侧咬肌和颞肌前束sEMG信号进行处理分析,重构的sEMG信号相空间图显示,正常个体在ICP紧咬时咬肌和颞肌前束的sEMG信号呈现出典型的混沌吸引子的形态特征.结论 咬肌和颞肌在ICP紧咬时sEMG具有混沌特征,适合用非线性动力学方法进行分析.

Phase space reconstruction of mastication muscles surface electromyography signal based on nonlinear dynamics

Objective To calculate the delay times and embedding dimensions of surface electromyogragh(sEMG) signal of the masseter and temporal muscle during clenching at intercuspal position (ICP) , and to reconstruct the space phase of sEMG signal with method of nonlinear dynamics.Methods Ten male and 10 female young volunteers with normal masticatory system were included in the study, the signals of surface sEMG of bilateral masseter and temporal muscles in the position of ICP were collected, and the delay times and embedding dimensions of the sEMG signals were calculated using C-C method, the space phase of the sEMG signals was reconstructed.Results A program of nonlinear dynamic analysis of mastication muscles sEMG signals was developed base on the platform of Matlab.The signals of the sEMG of the masseters and temporals were analyzed with nonlinear dynamic methods, the delay times and embedding dimensions of each muscles sEMG signals were obtained, and the space phase of each sEMG signals were reconstructed.The graphs of the space phase indicated the typical characteristic of chaotic attractor.Conclusions The signals of the masseter and temporal muscles of surface sEMG during clenching at ICP of normal masticatory system show the typical characters of chaos, the methods of nonlinear dynamics are effective to analyze the sEMG signals of mastication system.