Aerobic fitness is associated with inhibitory control in persons with multiple sclerosis

Cognitive impairment is highly prevalent, disabling, and poorly managed in persons with multiple sclerosis (MS). Aerobic fitness might be a target of exercise training interventions for improving cognition in this population. It is unknown if the well-established pattern of associations between higher aerobic fitness and better inhibitory control in the general population exists among persons with MS. The current cross-sectional study examined the effects of aerobic fitness (VO2peak) on inhibitory control, using a modified flanker task, in 28 persons with MS and 28 healthy controls matched by age, sex, and body mass index. This involved performing bivariate correlations and hierarchical linear regression analyses on measures of aerobic fitness and inhibitory control. Persons with MS demonstrated lower VO2peak (d = -0.45), slower (d = 0.62-0.84), and less accurate (d = -0.60 to 0.71) performance on the flanker task than controls. VO2peak was similarly associated with reaction time measures of inhibitory control in the MS and control samples (ρ = -0.40 to 0.54). VO2peak (p < .01), but not group (p ≥ .08) (MS vs. control), predicted reaction time on the flanker task, irrespective of age, sex, and education. This supports the development of aerobic exercise interventions for improving reaction time on tasks of inhibitory control in persons with MS, much like what has been successfully undertaken in the general population.