Study On The Method For Synergy And Coupling Characteristics Analysis Of Emg Signals In Rehabilitation Movement

The central nervous system(CNS)controls the human movement by modulating multiple skeletal muscles with synergistic modules and neural oscillations between the activated muscles.In this process,the interrelationship between electromyography(EMG)signals can be used to reflect the different control processes of the CNS,including the synergy mechanism among multichannel EMG signals during movement and coupling relationship between the two-channel EMG signals.Therefore,it is of great significance to introduce EMG signals into quantitative analysis of motor function and study the analysis methods about synergy and coupling feature between EMG signals for acquiring the modular control mechanism of muscles,the regulation mechanism of neural oscillations and evaluation of motor function in stroke patients.Firstly,the main research ideas of time-frequency synergy and time-frequency synergy-coupling are proposed based on the research status of muscle synergy and intermuscular coupling analysis methods and the limitations of current EMG signal synergy mechanism and coupling relationship analysis method.Secondly,to describe the frequency characteristics of muscle synergy,a method based on wavelet packet transform(WPT)-nonnegative matrix factorization(NMF)was proposed.To quantitatively analyze the levels of muscle activation during movement,the time scale signal was transformed into time-frequency scale component by using WPT method,and then the muscle synergy model were extracted based on NMF.The experimental results show that the method can effectively describe the modular control mechanism of muscles at different time-frequency scale.Thirdly,in order to characterize the multi-scale correlation of two-channel EMG signals,this paper build a NMF-time-frequency coherence analysis model for the study of the synergy-coupling relationship in the upper limb movement process.Firstly,the NMF method was used to extract the synergistic muscle pair,and then the time-frequency coupling characteristics of the muscle pair were analyzed based on the short-time Fourier time-frequency coherence analysis method.The results show that the method can quantitatively analyze the synergy-coupling characteristics during each frequency band of the two-channel EMG signal in each time period.Finally,the method proposed in this paper was applied to the analysis about the synergy and coupling characteristics of upper limb EMG signals in stroke patients.And then the time-frequency synergy and synergy-coupling characteristics of the EMG signals were analyzed and compared with the results of healthy patients.The results show that there is certain degree of abnormalities of the patient's synergy and coupling characteristics at some time-frequency scales.The results reflect the different activation levels of the patient's muscles,verify the effectiveness of WPT-NMF and NMF-TFC methods in describing the synergy and coupling characteristics,and provide a theoretical reference for the formulation of rehabilitation strategy in the patient's motor function.