Study On Neuromuscular Cross-frequency Coupling Characteristics For Motor Function Evaluation After Stroke

How to scientifically and objectively evaluate the motor rehabilitation function after stroke to promote early rehabilitation of stroke patients is a key issue in the field of stroke rehabilitation.Studies have shown that the neuromuscular coupling phenomenon in rehabilitation exercise can reflect the information interaction between the brain and the corresponding muscles in the neuromuscular system,and can be used as a quantitative indicator for the evaluation of motor function.The cross-frequency coupling(CFC)in neuromuscular system can further reflect the neurodynamic characteristics of the brain and muscles on the time and space scales,which is important for understanding the pathological mechanism of motor dysfunction in stroke patients in the process of motor control.It also provides a new characteristic index for stroke rehabilitation assessment.In this thesis,aiming at the cross-frequency coupling phenomenon that might exist in the neuromuscular system after stroke,Pearson correlation analysis and phase-locked value methods were introduced to compare and analyze the differences in cross-frequency amplitude-amplitude coupling(AAC)and phase-phase coupling(PPC)in the neuromuscular system of stroke patients and healthy subjects.The correlation analysis between the cross-frequency coupling characteristics and the grades of the clinical rating scale can provide a theoretical basis for the clinical rehabilitation evaluation of stroke patients.The main research work of this thesis included:Firstly,aiming at the amplitude-amplitude coupling(AAC)characteristics of neuromuscular cross frequency,Pearson correlation analysis was introduced to calculate the instantaneous amplitude correlation between the two signals.Multiple sub-signals were obtained by wavelet package transfer(WPT),and then the Pearson correlation coefficients between different frequency band of EEG and EMG were calculated respectively to obtain the cross-frequency AAC eigenvalue between brain and muscle.This quantitatively described the information interaction of EEG signals in different frequency bands and explored the study of cross-frequency AAC characteristics of neuromuscular signals.Secondly,according to the characteristics of phase-phase coupling,the wavelet packet transfer and phase-locked value method were combined to calculate the eigenvalues of neuromuscular cross-frequency PPC.The phase-locked value was used to predict the stability of phase difference and then predict the phase accuracy.The PPC intensity differences across different frequency bands were analyzed,and the information interaction between EEG and EMG signals across different frequency bands was explored,and then the cross-frequency PPC characteristics between neuromuscles were studied.Thirdly,to explore the correlation between the cross-frequency coupling indexes of AAC and PPC between EEG and EMG after stroke,the FP Growth algorithm was used to calculate the association rules between significant differences in cross frequency coupling indexes.And the consistency between the coupling indexes in the association rules calculated by the Spearman correlation analysis method and the Shang Tian Min Rating Scale(STM).To explore the correlation between the coupling indexes at different cross-frequency bands and the clinical consistency of cross-frequency coupling indexes in the process of movement,so as to verify the effectiveness of the indexes.