Evaluation of Oxygen Uptake Kinetic Asymmetries in Patients with Multiple Sclerosis: A Pilot Study

Background of Study: Observations of limb to limb differences (bilateral asymmetry) in leg strength, power, peak oxygen uptake (VO2) and bone mineral density has been reported in individuals with Multiple Sclerosis (MS). Objetives: The purpose of this study was to quantify the magnitude of bilateral asymmetries in oxygen uptake (VO2) kinetics response to single leg cycling (SLC) in relapsing-remitting multiple sclerosis (MS) patients. Methods: Five MSpatients (2 men, 3 women; age 43±7 yrs) performed constant work rate SLC trials to determine VO2 kinetics in each leg. Asymmetry scores were used to quantify the magnitude of the bilateral asymmetries. Results: Significant asymmetries were seen in VO2 peak and parameters of VO2 kinetics. VO2peak asymmetry score was significantly different than 0% (p=0.015). Similarly,significant asymmetry for VO2 kinetic response to exercise as mean response time was observed (p=0.03). In addition the VO2 response to exercise resulted in a significant asymmetry in VO2 deficit between legs (p=0.03). No correlation between EDSS scores and any asymmetry scores existed. Conclusions: These findings provide insight into the potential differences in metabolic perturbation and limb specific symptomatic fatigue within the MS population