Pilot Study: Evaluation of the Effect of Functional Electrical Stimulation Cycling on Muscle Metabolism in Nonambulatory People With Multiple Sclerosis

Abstract Objective To investigate the changes in muscle oxygen consumption (m V ˙ O2 ) using near-infrared spectroscopy (NIRS) after 4 weeks of training with functional electrical stimulation (FES) cycling in nonambulatory people with multiple sclerosis (MS). Design Four-week before-after trial to assess changes in m V ˙ O2 after an FES cycling intervention. Setting Rehabilitation hospital. Participants People (N=8; 7 men, 1 women) from a volunteer/referred sample with moderate to severe MS (Expanded Disability Status Scale score>6.0). Intervention Participants cycled 30 minutes per session, 3d/wk for 4 weeks or a total of 12 sessions. Main Outcome Measures m V ˙ O2 of the right vastus lateralis muscle was measured with NIRS before and within 1 week after the intervention. Six bouts of 15-second electrical stimulation increasing from 2 to 7Hz were used to activate the muscle. m V ˙ O2 was assessed by analyzing the slope of the NIRS oxygen signal during a 10-second arterial occlusion after each electrical stimulation bout. Results Significant FES training by electrical stimulation frequency level interaction was observed ( P =.031), with an average increase in m V ˙ O2 of 47% across frequencies with a main effect of training ( P =.047). Conclusions FES cycling for 4 weeks improved m V ˙ O2 , suggesting that FES cycling is a potential therapy for improving muscle health in people with MS who are nonambulatory.