Authors:
Downs J, Leonard H, Jacoby P, Brisco L, Baikie G, Hill K.
Authors notes:
Disabil Rehabil. 2015;37(21):1992-6.
Keywords:
Outcome measure, Rett syndrome, physical activity, walking
Abstract:
Rett syndrome is a pervasive neurological disorder with impaired gait as one criterion.
This study investigated the capacity of three accelerometer-type devices to measure walking activity in Rett syndrome.
METHODS: Twenty-six participants (mean age 18 years) wore an Actigraph, ActivPAL and StepWatch Activity Monitor (SAM) during a video-taped session of activities.
Agreement was determined between step-counts derived from each accelerometer and observation.
Repeatability of SAM-derived step counts was determined using pairs of one-minute epochs during which the same participant was observed to walk with the same cadence.
RESULTS: The mean difference (limit of agreement) for the Actigraph, ActivPAL and SAM were -41 (SD 33),-16 (SD 21) and -1 (SD 16) steps/min, respectively.
Agreement was influenced by a device/cadence interaction with greater under-recording at higher cadences.
For SAM data, repeatability of step-count pairs was excellent.
The standard error of measurement was 6 steps/min and we would be 95% confident that a change ≥17 steps/min would be greater than within-subject measurement error.
CONCLUSION: The capacity of the SAM to measure physical activity in Rett syndrome allows focus on participation-based activities in clinical practice and clinical trials.