Impact of Functional Electrical Stimulation Cycling on Performance Measures in People with Secondary Progressive Multiple Sclerosis

Background: Individuals with secondary progressive multiple sclerosis (SPMS) experience worsening ambulation over time. Exercise can help motor/ambulatory dysfunction in MS, but challenges exist implementing an exercise regimen for individuals with higher levels of disability. Functional electrical stimulation (FES) cycling is an intervention allowing for assisted exercise in individuals with moderate-to-severe disability.

Objectives: To evaluate whether performance measures in SPMS improve with active FES cycling.

Methods: Participants with SPMS were recruited at the Johns Hopkins MS center from 2012-2019 with main inclusion criteria of age 18-70 years, Expanded Disability Status Scale (EDSS) score 5.0-7.0, and stable symptomatic treatments within one month of screening. Participants were randomized to receive either active FES or passive cycling on an RT-300 ergometer for one hour, three times weekly during a 12-week period. The FES-assisted cycling arm participants were instructed to actively pedal while assisted by FES (electrodes attached to quadriceps, hamstrings and glutei muscles) and the cycle motor. The passive cycling arm participants were instructed to relax their legs to allow the cycle motor to move their legs. The primary outcome was change in timed 25 foot walk (T25FW). Secondary outcomes included Timed Up and Go (TUG) test, 2-Minute Walk Test, quantitative leg strength-dynamometry, and RAND 36-Item Health Survey 1.0 (RAND-36).

Results: Sixteen participants were enrolled and 14 completed the study. There were 8 participants in the FES-assisted cycling group and 8 in the passive cycling group; 2 passive cyclists did not complete the study. Mean age was 57.4 years in the FES-assisted cycling group and 52.8 years in the passive cycling group. There were no significant differences in demographics between groups. One active cycling participant had an unrelated injury during the study and was not included in analyses of longitudinal walking measures. Mean change (±standard deviation) in T25FW was -0.9±1.0 seconds in the FES-assisted cycling group and +0.1±1.2 seconds in the passive cycling group (p=0.11). Mean difference in TUG was -2.0±2.7 seconds with FES-assisted cycling and -0.9±0.5 seconds with passive cycling (p=0.31). Difference in 2-Minute Walk Test distance averaged +11.0±16.7 meters and +4.4±10.4 meters for FES-assisted and passive cycling groups, respectively (p=0.42). No significant differences were seen with other measures except the social functioning domain of RAND-36; passive cycling group had positive changes compared to the active cycling group (p=0.03).

Conclusions: There were modest improvements in some walking measures with either intervention. Integrating passive or active cycling into clinical practice will require additional studies, but remains a promising form of exercise for individuals with SPMS and more severe disability.