Exploring the concurrent validity of the ActiGraph™ wGT3X-BT activity monitor, waist vs. wrist, in measuring physical activity levels in pwPD: a 7-day study of free-living.
(2016) Exploring the concurrent validity of the ActiGraph™ wGT3X-BT activity monitor, waist vs. wrist, in measuring physical activity levels in pwPD: a 7-day study of free-living., no. 29.
Question: Does the ActiGraph™ wGT3X-BT demonstrate concurrent validity when worn on the waist and wrist across 7 days of free living in pwPD? Design: A concurrent validation study conducted in a free-living environment across 7 days. Participants: 9 participants with a mean age of 68 years who had a medical diagnosis of Parkinson's Disease. Intervention: The intervention involved wearing both ActiGraph™ monitors on the waist and wrist concurrently during all waking hours in the home environment over a 7-day period. Participants were instructed to wear both monitors whilst undertaking usual activities, except during swimming or showering. Participants also maintained a diary log, documenting when the monitors were taken on and off. Results: All participants completed the study and were included in analysis. Following 7-day surveillance, the results demonstrated a weak correlation between the monitors (rs =0.496, n=63, p<0.001) per day and (rs =0.483, n=9, p<0.187) for the weekly average. Bland and Altman plots revealed poor agreement between the monitors when measuring time spent physically active at all intensities. Wide limits (95% confidence interval) per day (-49, -377), per week (4, -385) and for MVPA (47, -155). With no criterion standard and small sample size, a consensus regarding how well this population are meeting the physical activity guidelines remains inconclusive. Further research with a larger sample size is required to truly establish the validity of the ActiGraph™ in measuring physical activity in pwPD. Conclusion: The ActiGraph™ wGT3X-BT is not currently considered a valid method for measuring physical activity levels in pwPD.