Effectiveness of Neuromuscular Electrical Stimulation in Post-Stroke Gait Training

Thesis Abstract

Neuromuscular Electrical Stimulation (NMES) is increasingly used to augment gait rehabilitation after stroke, yet evidence for its effectiveness on functional mobility and gait mechanics remains equivocal. This study addresses the gap by evaluating whether NMES applied to ankle plantarflexors and knee extensors during overground and treadmill walking improves gait speed, symmetry, endurance, and functional ambulation compared with conventional therapy. The aim is to determine the additive and sustained effects of NMES on post-stroke gait across acute, subacute, and chronic stages, and to identify moderator factors such as lesion side, severity, and baseline gait impairment that influence outcomes. A mixed-methods design was employed, integrating a multicenter randomized controlled trial with a nested qualitative exploration to capture patient-experienced barriers and facilitators. The quantitative strand enrolled 180 adults (120 males, 60 females) aged 40–85 years with first-ever ischemic or hemorrhagic stroke, within 6 months to 2 years post-event. Participants were randomized to NMES plus conventional physiotherapy (n=90) or conventional physiotherapy alone (n=90) for 8 weeks, with a 6-month follow-up. NMES was delivered using a dual-channel device delivering low-frequency pulsed stimulation (35–50 Hz) synchronized to the stance phase, applied during functional gait tasks for 45-minute sessions, three times per week. Outcome measures included gait speed (10-meter walk test), gait endurance (2-minute walk test), gait symmetry indices ( Unterstützung-Temporal Parameters from instrumented walkway), functional ambulation category, and daily activity levels (accelerometry). Secondary measures encompassed lower limb strength (handheld dynamometry), spatiotemporal gait parameters (GAITRite), and patient-reported outcomes (Stroke Impact Scale). Data collection occurred at baseline, post-intervention (8 weeks), and follow-up (6 months). The qualitative component selected a purposive sample of 30 participants (varying in stroke chronicity and NMES responsiveness) for semi-structured interviews to elucidate perceived usability, motivation, and integration of NMES into daily routines; interviews were analyzed using thematic analysis guided by the Theoretical Framework of Acceptability. Quantitative analysis used intention-to-treat principles. Primary analysis compared changes in gait speed and endurance between groups via repeated-measures ANOVA, with post hoc Bonferroni corrections. Multivariate linear regression examined predictors of response, including baseline impairment, time since stroke, paretic side, and lesion type. Mixed-effects models addressed repeated measures and intersite clustering. Mediation analyses explored whether improvements in ankle plantarflexor strength mediated gait velocity gains. The qualitative data were analyzed thematically, with coding conducted independently by two researchers and triangulated with quantitative findings to generate a comprehensive interpretation. Anticipated findings include superior improvements in gait speed (mean difference approximately 0.15–0.25 m/s) and 2-minute walk distance (increase ~50–75 meters) in the NMES group at post-intervention and sustained at 6 months, with enhanced gait symmetry and functional ambulation scores. Subgroup analyses may reveal greater benefits for individuals with subacute stroke and those with predominant plantarflexor weakness. The mediation analysis is expected to show that gains in ankle plantarflexor strength partly explain the observed gait improvements. Qualitative insights are projected to reveal high acceptability of NMES, with identified facilitators including intuitive device usability, task-specific training, and perceived functional relevance, whereas barriers may involve device setup time and fatigue. The study contributes to knowledge by providing robust, multicenter, randomized evidence on the efficacy of NMES in post-stroke gait rehabilitation, clarifying dose–response relationships, and identifying patient characteristics associated with favorable outcomes. It integrates functional, biomechanical, and patient-centered perspectives, thereby informing clinical guidelines on patient selection, NMES dosing, and integration with conventional therapy. The findings are expected to support more precise rehabilitation planning, potentially reducing long-term disability and improving community ambulation. Practical recommendations include standardized NMES protocols aligned with gait tasks, training for therapists on device setup, consideration of interim progress markers, and strategies to address adherence and fatigue. Limitations acknowledged include potential heterogeneity in lesion profiles and variations in conventional therapy intensity across settings, with sensitivity analyses planned to assess robustness.