Accuracy and precision of wrist-worn actigraphy for measuring steps taken during over-ground and treadmill walking in adults with Parkinson's disease

• Published in: Parkinsonism & related disorders 2021-07, Vol.88, p.102-107
• Main Authors: Cederberg, Katie L.J., Jeng, Brenda, Sasaki, Jeffer E., Lai, Byron, Bamman, Marcas, Motl, Robert W.
• Format: Article
• Language: English
• Subjects: Accelerometry; Accuracy; Actigraphy - instrumentation; Actigraphy - standards; Aged; Female; Humans; Male; Middle Aged; Parkinson Disease - diagnosis; Parkinson's disease; Precision; Step counts; Walking - physiology; Wearable Electronic Devices - standards; Wrist
• ISSN: 1353-8020; 1873-5126
• DOI: 10.1016/j.parkreldis.2021.06.009

Step counts represent a straight-forward method of measuring physical activity in adults with Parkinson's disease (PD). The present study examined the absolute and relative accuracy and precision of a wrist-worn research-grade accelerometer (i.e., ActiGraph GT3X+) for measuring step counts during over-ground and treadmill walking in adults with PD and controls without PD. Participants (PD: n = 29; controls: n = 31) wore two ActiGraph GT3X + accelerometers, one on each wrist, and completed an over-ground walking bout followed by a treadmill walking bout at the same speed. Step counts were measured manually using a hand-held tally counter. Accuracy and precision were based on absolute and relative metrics. The ActiGraph GT3X + underestimated step counts in both participants with PD (4.7–11% error) and controls without PD (8.8–17% error), with a greater discrepancy in controls. The ActiGraph GT3X + provided more accurate and precise estimates of step counts when placed on the more affected wrist and non-dominant wrist for participants with PD and controls, respectively, and was more accurate and precise during over-ground walking compared with treadmill walking for both groups. Our results suggest that placement of the device (i.e., dominant vs. non-dominant), type of activity (i.e., over-ground vs. treadmill walking), and presence of clinical conditions may impact the accuracy and precision of data when using the research-grade ActiGraph GT3X + accelerometer for measuring step counts. •ActiGraph GT3X + underestimated step counts in participants with PD and controls.•ActiGraph GT3X+ was more accurate and precise on the more affected wrist in PD.•ActiGraph GT3X+ was more accurate and precise on the non-dominant wrist in controls.•ActiGraph GT3X+ was more accurate and precise during over-ground walking.