Accelerometry as a measure of walking behavior in multiple sclerosis
R. W. Motl, Department of Kinesiology and Community Health, University of Illinois, 233 Freer Hall, Urbana, IL 61801, USA
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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.
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).
We provide comprehensive evidence from a large sample of persons with MS that further supports accelerometry as a measure of walking behavior.