Accelerometry and its association with objective markers of walking limitations in ambulatory adults with multiple sclerosis

Objective To validate accelerometry based on its correlations with 6-minute walk distance (6MWD) and oxygen cost of walking as objective markers of walking limitations in multiple sclerosis (MS). Design Cross-sectional. Setting Laboratory and general community. Participants Ambulatory participants with MS (N=26) who resided in the local community. Interventions Not applicable. Main Outcome Measures Patient Determined Disease Steps (PDDS) scale and Multiple Sclerosis Walking Scale-12 (MSWS-12); 6-minute walk test while wearing a portable metabolic unit for measuring the 6MWD and oxygen cost of walking; accelerometer during the waking hours of a 7-day period. Results The average of total daily movement counts from the accelerometer correlated significantly and strongly with MSWS-12 scores (ρ=.681, P=.001), PDDS scores (ρ=.609, P=.001), 6MWD (ρ=.519, P=.003), and oxygen cost of walking (ρ=.541, P=.002). Conclusions We provide evidence that further supports the validity of accelerometry as a measure of walking limitations in ambulatory persons with MS.