Pilot Study of Enhancing Cardiorespiratory Exercise Response in People With Advanced Multiple Sclerosis With Hybrid Functional Electrical Stimulation.

OBJECTIVE:To investigate through a pilot study the acute cardiorespiratory responses during functional electrical stimulation (FES) cycling, arm crank ergometry (ACE), and a combination of ACE and FES cycling (hybrid FES cycling) in people with advanced multiple sclerosis (MS) to provide preliminary guidance for effective aerobic exercise prescription. DESIGN:Acute repeated measures. SETTING:Laboratory setting. PARTICIPANTS:Inclusion criteria was a diagnosis of MS, with Expanded Disability Status Scale (EDSS) 6.0-8.5. Included were 9 participants (N=9; 7 female, age 54.7±8.8y, EDSS 7.2±0.7). INTERVENTIONS:Participants were assessed on 3 different exercise modalities (FES cycling, ACE, hybrid FES cycling) at 40%, 60%, 80%, and 100% of mode-specific peak workload. MAIN OUTCOME MEASURES:Oxygen consumption and heart rate were measured at each workload. RESULTS:Hybrid FES cycling evoked a significantly higher oxygen consumption relative to body weight (V̇o2relative) (mL/kg/min) and heart rate (beats per minute [BPM]) at most workloads compared with ACE or FES cycling. At the 100% workload, heart rate for hybrid FES cycling was 125 BPM (range, 113-148 BPM) and was significantly higher than ACE at 99 BPM (range, 95-119 BPM) (P=.008) and FES cycling at 94 BPM (range, 79-100 BPM) (P=.008). Similarly, at the 100% workload, V̇o2relative for hybrid FES cycling was 11.8 mL/kg/min (range, 7.6-17.6 mL/kg/min) and was significantly higher than ACE at 8.9 mL/kg/min (range, 5.3-12.5 mL/kg/min) (P=.012) and FES cycling at 6.8 mL/kg/min (range, 4.1-9.2 mL/kg/min) (P=.012). CONCLUSIONS:This pilot study showed that hybrid FES cycling can elicit a greater cardiorespiratory response than ACE or FES cycling in people with advanced MS. Thus, hybrid FES cycling might provide a potent enough stimulus to induce clinically relevant changes in cardiorespiratory fitness. Training studies are warranted to document the magnitude and sustainability of aerobic capacity adaptations to hybrid FES cycling and associated health outcomes in advanced MS.