Physical and Cognitive Functions, Physical Activity, and Sedentary Behavior in Older Adults With Multiple Sclerosis

Background and Purpose: Older adults with multiple sclerosis (MS) experience age-related declines in physical and cognitive functions that may be compounded by the disease and its progression and worsened by physical inactivity and sedentary behavior. However, the extent to which impairments in physical and cognitive functions are manifestations of MS and disease progression, reflective of the general aging process, or perhaps 2 detrimental processes exacerbating the synergistic effects of the other is relatively unknown. This study compared physical and cognitive functions, sedentary behavior, and physical activity between 40 older adults with MS (ie, 60 years of age and older) and 40 age- and sex-matched healthy older adults. We further examined whether physical activity and/or sedentary behavior explained differences between groups in physical and cognitive functions. Methods: Participants initially underwent the cognitive assessments, followed by the physical function assessments. The order of tests was standardized and participants were provided seated-rest between the administrations of the physical function assessments. Participants were then instructed to wear an accelerometer and document wear time in a log book for a 7-day period after the testing session. Results: Multivariate analyses of variance indicated that older adults with MS (n = 40) performed worse on all measures of physical function, and 1 measure of cognitive function (ie, information-processing speed), compared with healthy controls (n = 40). Older adults with MS engaged in less moderate-to-vigorous physical activity, more sedentary behavior, and longer duration of long sedentary bouts than healthy controls. Pearson correlations demonstrated that levels and patterns of physical activity were significantly associated with a majority of physical function variables but not cognitive function variables in both older adults with MS and healthy controls but to a greater extent in older adults with MS. Partial Pearson correlations further demonstrated that levels and patterns of sedentary behavior were significantly associated with a majority of physical function variables but not cognitive function variables primarily in older adults with MS. Linear regression analyses indicated that levels and patterns of physical activity and sedentary behavior partially accounted for differences in physical and cognitive function variables between older adults with MS and healthy controls. Conclusion: There is evidence of reduced function in older adults with MS, and this might be partially managed by behavioral interventions that target physical activity and sedentary behavior for the promotion of healthy aging in older adults with MS.