The Effect of Multi-channel FES Stimulation Gait Training based on Muscle Synergy Analysis on Gait Performance in Stroke Patients: A Case Study

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Purpose: Foot drop is a common symptom in disorders of the central nervous system (CNS : Central Nervous System), such as stroke. The combination of functional electrical stimulation (FES : Functional Electronical Stimulation) and gait rehabilitation is an effective intervention for stroke gait rehabilitation. Therefore, the aim of this study was to determine the effectiveness of FES training based on the muscle synergy pattern of stroke patients during gait. Methods: The intervention was tested on two chronic stroke patients. They underwent a 6-week intervention consisting of 30 min sessions of FES-supported gait three times per week. Muscle synergies were extracted from electromyography (EMG : electromyography) signals using a non-negative matrix factorization algorithm (NMF : Non-negative Matrix Factorization). Results: The optimal number of synergies has been defined as the minimum number needed to obtain variability accounted for (VAF) ⩾90%. Before treatment, both patients presented only three merged muscle synergies during gait, resembling two different gait abnormalities. After the 6-week intervention, the number of extracted synergies became four and they increased their gait speed with the physiological muscle synergies. The 10m walking test (10MWT : 10Meter Walking Test) used in the first and last days of intervention increased from 16.11 to 14.56 m/s, and from 19.76 to 15.37m/s for Subject 1 and Subject 2, respectively. Conclusion: Multi-channel FES walking intervention based on synergy analysis influenced the number of muscle synergies during the gait of stroke patients. This intervention has an effective effect on improving the gait performance of stroke patients.