Accuracy and responsiveness of the stepwatch activity monitor and ActivPAL in patients with COPD when walking with and without a rollator.
OBJECTIVE
To evaluate the measurement properties of the StepWatch(™) Activity Monitor (SAM) and ActivPAL in COPD.


METHODS
Whilst wearing both monitors, participants performed walking tasks at two self-selected speeds, with and without a rollator. Steps obtained using the monitors were compared with that measured by direct observation.


RESULTS
Twenty participants aged 73 ± 9 years (FEV(1) = 35 ± 13% pred; 8 males) completed the study. Average speeds for the slow and normal walking tasks were 34 ± 7 m·min(-1)and 46 ± 10 m·min(-1), respectively. Agreement between steps recorded by the SAM with steps counted was similar irrespective of speed or rollator use (p = 0.63) with a mean difference and limit of agreement (LOA) of 2 steps·min(-1) and 6 steps·min(-1), respectively. Agreement for the ActivPAL was worse at slow speeds (mean difference 7 steps·min(-1); LOA 10 steps·min(-1)) compared with normal speeds (mean difference 4 steps·min(-1); LOA 5 steps·min(-1)) (p = 0.03), but was unaffected by rollator use. The change in step rate between slow and normal walking via direct observation was 12 ± 7 steps·min(-1) which was similar to that detected by the SAM (12 ± 6 steps·min(-1)) and ActivPAL (14 ± 7 steps·min(-1)).


CONCLUSIONS
The SAM can be used to detect steps in people who walk very slowly including those who use a rollator. Both devices were sensitive to small changes.
School of Physiotherapy and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia.
Li Whye
LW
Cindy Ng
Sue
S
Jenkins
Kylie
K
Hill
D000054:Acceleration; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D016552:Ergometry / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D009043:Motor Activity; D010101:Oxygen Consumption; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000534:rehabilitation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013147:Spirometry; D014853:Walkers; D016138:Walking / Q000502:physiology*