Article

OBJECTIVE: To estimate the criterion validity of accelerometer-based devices as
measures of steps and energy expenditure in healthy controls and people with
multiple sclerosis (MS) with varying disability levels during everyday
activities. DESIGN: Cross-sectional study. SETTING: University research room.
PARTICIPANTS: People with MS who used at most a stick to walk outdoors (MS-A;
n=19), people with MS who used bilateral support for gait (MS-B; n=11), and
healthy controls (n=15). INTERVENTIONS: Participants completed 85 minutes of 9
scripted everyday activities. MAIN OUTCOME MEASURES: Estimates of metabolic
equivalent thresholds (METs) and kilocalories from a portable metabolic system,
and steps counted from video of the activities. Step and MET estimates from an
integrative accelerometer and from a uniaxial accelerometer, and kilocalorie
estimates from the integrative accelerometer. RESULTS: The uniaxial accelerometer
had >30% error for steps for all groups. MET estimates had an intraclass
correlation coefficient (ICC) <0.2 for all groups. For the integrative
accelerometer, step estimates for controls had an ICC of .69 and <1% error. The
step estimates for MS-A and MS-B groups had >20% error. The MET estimates had an
ICC of .50 to .65 and 6% to 15% error. Kilocalorie estimates had 2.9% error for
controls, 8.16% for MS-A, and 2.56% for MS-B groups. ICCs were all >.67, and mean
differences from criterion were <20kcal. CONCLUSIONS: The agreement between steps
and MET estimates from both devices and the criterion was poor, particularly for
people with MS. Only the step and MET estimates for the control group for the
integrative accelerometer were not significantly different from the criterion.
Kilocalorie estimates from the integrative accelerometer using the proprietary
algorithms of the device provide the most valid estimate of physical activity
during activities of daily living for people with a range of walking disabilities
resulting from MS.
CI - Copyright (c) 2012 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS