Synergy-based Functional Electrical Stimulation for gait rehabilitation in chronic stroke: a pilot study.

Abstract

Introduction: Chronic stroke gait disorders involve impaired motor coordination. While high-intensity gait training (HIGT) is supported by current clinical practice guidelines, and Functional Electrical Stimulation (FES) to tibialis anterior addresses foot drop, extending FES to multiple muscles may improve functional outcomes.

Methods: Using a FES neural sleeve capable of recording muscle activity and joint angles, we tested preliminary efficacy and feasibility of a personalized multichannel FES (MFES) intervention based on the individual's motor coordination impairment paired with HIGT. Fourteen individuals with chronic stroke were randomly assigned to either HIGT or MFES + HIGT for six weeks. Gait speed, endurance, gait biomechanics, and muscle synergies were assessed at baseline, midpoint, post-training, and one-month follow-up.

Results: Despite the small sample, only the MFES + HIGT group demonstrated significant endurance gains from baseline to post-training and follow-up, while both groups improved walking speed, impaired limb step length, and muscle synergy similarity to normative data. Feasibility was evaluated by measuring setup time (therapist putting device on participant and setting stimulation parameters) and collecting feedback from participants and four therapists. System setup time plateaued at 4.53 min by the ninth session. Both participants and therapists rated the intervention highly feasible, acceptable, and usable. Adherence was high in both groups, with only one dropout in the HIGT group due to preexisting medical conditions.

Discussion: This pilot study demonstrates the preliminary effectiveness of synergy-based MFES in improving walking endurance and confirms its feasibility for integration into chronic stroke gait rehabilitation, supporting the need for larger-scale trials to validate clinical efficacy and identify responders.

Clinical trial registration: https://clinicaltrials.gov/study/NCT06099444, identifier NCT0609944.