This study aimed to investigate the immediate changes in muscle synergies in patients with stroke after a single session of HAL-assisted gait training.
Six patients after stroke were included in this study. Case A: male, 48 years old, pontine haemorrhage, Fugl–Meyer Assessment for Lower Extremity (FMA-LE)=27, functional ambulation category (FAC)=4; case B: female, 78 years old, thalamic haemorrhage, FMA-LE=24, FAC=5; case C: female, 82 years old, corona radiata infarction, FMA-LE=26, FAC=3; case D: male, 88 years old, corona radiata infarction, FMA-LE=13, FAC=2; case E: male, 84 years old, infarction of the posterior internal capsule, FMA-LE=24, FAC=2; case F: female, 86 years old, frontal lobe infarction, FMA-LE=22, FAC=2.
Each patient underwent a 30-minute HAL-assisted gait training session, and muscle synergy analysis was performed before and after the session to assess the immediate changes in muscle coordination during walking. Muscle activity was recorded using the TeleMyo G2 surface electromyography system (Noraxon). The activities of the eight muscles of the paralyzed lower limb during comfortable walking were recorded, and data for 10 walking cycles were collected. Non-negative matrix factorization was applied to the electromyogram data to extract muscle synergies, and the number of modules representing the muscle coordination patterns during walking, weighting of muscles, and muscle activation patterns were determined.
After the HAL-assisted gait training session, three patients (cases A-C) demonstrated an increase in the number of muscle synergy modules from two to three, indicating improved muscle coordination during walking. In case D, while the number of modules remained at two, there were changes in the activation patterns and muscle weightings. Two patients showed no changes: case E remained at two modules, and case F remained at one module.
The immediate increase in the number of muscle synergy modules observed in some patients (cases A–C) and the changes in activation patterns and muscle weightings in case D suggest that HAL-assisted gait training can enhance muscle coordination during walking in patients after stroke. These findings suggest that most patients experienced immediate enhancements in muscle synergy complexity or patterns following HAL training, potentially contributing to improved gait function in stroke rehabilitation, while a minority showed no change.
These results indicate that incorporating HAL-assisted gait training into rehabilitation programs may enhance muscle coordination and gait function in patients after stroke. Further research is needed to confirm these findings and to understand the mechanisms by which HAL training affects muscle synergy.
robot-assisted gait training
muscle synergy
