title: Reliability of RT3 accelerometer for measuring mobility in people with multiple sclerosis: pilot study.
abstract: This pilot study investigated the test-retest reliability of an RT3 accelerometer (RT3) for measuring motion in people with multiple sclerosis (MS). Ten people with MS (mean age 49 yr; Extended Disability Status Scale mean +/- standard deviation = 3.4 +/- 1.3) and ten nondisabled people (mean age 40 yr) wore the RT3 while they performed three discrete mobility tasks on two occasions separated by 1 week. The intraclass correlation coefficients (ICCs) calculated from the RT3 motion data for the group with MS were 0.64 for the 5-minute walk test (p = 0.01), 0.50 for the timed up and go test (p = 0.05), and 0.76 for the stair-climbing task (p = 0.002). For the control group, these values were 0.65 (p = 0.01), -0.04 (p = 0.54), and 0.39 (p = 0.11), respectively. We found that the RT3 can potentially provide stable data when measuring walking, but a more robust, yet participant-friendly, method of attaching the RT3 is required. Both participant groups demonstrated inconsistencies in motor-task performance, highlighting a potential source of measurement error that would need to be addressed when future studies are designed. Based on the results of the 5-minute walk test in this study, a sample of 53 participants would be required to obtain an ICC value with a 95% confidence interval of width 0.2 using two repeat measurements.
authors.affiliation: Centre for Physiotherapy Research, University of Otago, Dunedin, New Zealand. leigh.hale@otago.ac.nz
authors.forename: Leigh
authors.initials: L
authors.lastname: Hale
authors.forename: Kimberly
authors.initials: K
authors.lastname: Williams
authors.forename: Craig
authors.initials: C
authors.lastname: Ashton
authors.forename: Tim
authors.initials: T
authors.lastname: Connole
authors.forename: Hayley
authors.initials: H
authors.lastname: McDowell
authors.forename: Colleen
authors.initials: C
authors.lastname: Taylor
mesh_terms: D000328:Adult; D016001:Confidence Intervals; D004867:Equipment Design; D005080:Exercise Test / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009043:Motor Activity / Q000502:physiology*; D009103:Multiple Sclerosis / Q000503:physiopathology* / Q000534:rehabilitation; D010865:Pilot Projects; D015203:Reproducibility of Results; D013997:Time Factors; D016138:Walking / Q000502:physiology*