The Efficacy of Functional Electrical Stimulation (FES) Cycling for Improving Physiological Function in People with MS with Severe Mobility Impairment

Background: Exercise training has been shown to be beneficial in persons with multiple sclerosis (MS). However, these benefits have primarily been established in individuals with mild-to-moderate disability (Expanded Disability Status Scale [EDSS] scores 1.0-5.0), excluding those with severe mobility impairment. Adapted exercise modalities should be used to accommodate those with severe mobility impairment. Functional electrical stimulation (FES) cycling is one such adapted exercise training modality that has more recently been used among those with MS with severe mobility impairment.

Objectives: Examine the efficacy of FES cycling for improving walking ability and physical fitness in people with MS with severe mobility impairment.

Methods: 11 participants (age 38 to 64) with MS with severe mobility impairment (EDSS=5.5-6.5) were randomized to a FES leg cycling program (n=6) or a passive leg cycling (PLC) program (n=5) for 6 months. Both conditions consisted of 3 weekly exercise training sessions conducted on an RT300 FES cycle. Primary outcomes included walking ability and physical fitness (muscular strength and aerobic capacity). Walking ability was measured with the timed 25-Foot Walk Test (T25FW), 2 Minute Walk Test (2MW), and the Timed Up and Go Test (TUG). Muscular strength was measured using a computerized dynamometer and cardiorespiratory fitness was assessed with a symptom-limited incremental exercise test and expressed as the peak amount of oxygen consumed (VO_2peak) and peak work rate (WR_peak). Outcomes were assessed at baseline, midpoint (3 months) and post intervention (6 months).

Results: Eight participants completed the intervention (FES n=4, PLC n=4) all with a compliance of ≥80%. Three (FES n=2, PLC n=1) participants withdrew due to the time commitment associated with the study. After the FES cycling intervention there was a large positive effect of FES cycling on walking ability including the T25FW (η_ρ²=.44, p=.10), 2MW (η_ρ²=.68, p=.02), and TUG (η_ρ²=.57, p=.05) compared to PLC. There was a small-to-moderate positive effect of FES cycling on strength of the knee extensors (η_ρ²=.03, p=.70), VO_2peak (η_ρ²=.01, p=.80), and WR_peak (η_ρ²=.06, p=.57) compared to PLC. The intervention did not improve knee flexor strength (η_ρ²=.001, p=.94) compared to PLC.

Conclusions:  We provide preliminary evidence that FES cycling can improve walking ability, muscle strength and aerobic fitness in people with MS with severe mobility impairment.