Abstract: BACKGROUND: Deep muscle stimulation has the effects of releasing muscle adhesion, relieving muscle spasm, improving and restoring muscle compliance and elasticity. Electromyographic biofeedback therapy can promote nerve recovery and improve lower limb motor function and gait. 
OBJECTIVE: To observe the effect of the effect of deep muscle stimulation combined with electromyographic biofeedback therapy on the spasm of the triceps surae and gait changes after stroke by using a digital muscle detector and three-dimensional gait analysis system.
METHODS: A total of 72 patients who met the inclusion criteria were selected from the Rehabilitation Department of the First Affiliated Hospital of Guangdong Pharmaceutical University from October 2020 to October 2023. And they were enrolled and randomly divided into two groups (n=36 per group): a control group and a combined group. The control group received routine rehabilitation therapies, electromyographic biofeedback and pseudo deep muscle stimulation, while the combined group received true deep muscle stimulation treatment on the basis of the control group, five times per week, for 4 consecutive weeks. The oscillation frequency and dynamic stiffness of the affected gastrocnemius muscle, active range of motion of the ankle dorsiflexion muscle, electromyographic signal of the tibialis anterior muscle, Fugl-Meyer assessment of the lower limbs, and three-dimensional gait analysis parameters were statistically analyzed before and after treatment in two groups.  
RESULTS AND CONCLUSION: After treatment, oscillation frequency and dynamic stiffness values of the inner and outer sides of the affected gastrocnemius muscle in both groups of patients were significantly reduced compared with before treatment (P < 0.05), and the combined group showed a more significant decrease compared with the control group (P < 0.05). The active range of motion of the ankle dorsiflexion muscle, electromyographic signal of the tibialis anterior muscle, and Fugl-Meyer scores after treatment were significantly increased or improved compared with before treatment (P < 0.05), while the combined group showed a more significant increase or improvement compared with the control group (P < 0.05). In terms of gait parameters, the walking speed, frequency, and stride in both groups of patients were significantly increased compared with before treatment (P < 0.05), while the combined group showed a more significant increase compared with the control group (P < 0.05). The percentage time of support phase on the healthy side was shortened compared with before treatment (P < 0.05), while the combined group showed a more significant decrease compared with the control group (P < 0.05). In addition, there was no significant difference between the two groups except for the percentage of healthy side support (P > 0.05). To conclude, the combination of deep muscle stimulation and electromyographic biofeedback can effectively alleviate triceps spasm in the short term after stroke, improve ankle dorsiflexion function, enhance lower limb motor function, and improve gait. The treatment effect is significant and worthy of clinical promotion and application.

Key words:  stroke, deep muscle stimulation, digital muscle detector, spasm, gait