Accelerometry as a measure of walking behavior in multiple sclerosis

Objective Accelerometry has been identified as a possible ecologically valid and objective approach for measuring community ambulation in multiple sclerosis (MS). This study provides a validation of accelerometer output based on associations with Expanded Disability Status Scale (EDSS), Patient Determined Disease Steps (PDDS) Scale, and Multiple Sclerosis Walking Scale‐12 (MSWS‐12) scores, timed 25‐foot walk (T25FW) and 6‐min walk (6MW) performance, oxygen cost (O2 cost) of walking, and spatial and temporal parameters of gait. Materials and Methods 256 persons with MS completed the PDDS and MSWS‐12, underwent an examination for the generation of an EDSS score, undertook two T25FW tests and a 6MW while wearing a portable metabolic unit for measuring the O2 cost of walking, completed two trials of comfortable walking on a GAITRite electronic walkway for measuring spatial and temporal parameters of gait, and then wore an Actigraph accelerometer during the waking hours of a 7‐day period. Results The accelerometer output was significantly correlated with EDSS (ρ = −0.522), PDDS (ρ = −0.551), and MSWS‐12 (ρ = −0.617) scores, T25FW (ρ = −0.595) and 6MW (ρ = 0.630) performance, and O2 cost of walking (ρ = −0.457). Regarding gait parameters, the accelerometer output was significantly correlated with velocity (ρ = 0.420), cadence (ρ = 0.349), step time (ρ = −0.353), step length (ρ = 0.395), double support (ρ = −0.424), and single support (ρ = 0.400). Conclusion We provide comprehensive evidence from a large sample of persons with MS that further supports accelerometry as a measure of walking behavior.