Related Experiment Video
Updated: May 3, 2026
Home-Based Monitor for Gait and Activity Analysis
Published on: August 8, 2019
Validation of a body-worn accelerometer to measure activity patterns in octogenarians
Lynne M Taylor1, Jochen Klenk2, Alistair J Maney3
1National Institute for Health Innovation, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
Objective:
To determine the validity of a triaxial body-worn accelerometer for detection of gait and postures in people aged >80 years.
Design:
Participants performed a range of activities (sitting, lying, walking, standing) in both a controlled and a home setting while wearing the accelerometer. Activities in the controlled setting were performed in a scripted sequence. Activities in the home setting were performed in an unscripted manner. Analyzed accelerometer data were compared against video observation as the reference measure.
Setting:
Independent-living and long-term-care retirement village.
Participants:
Older people (N=22; mean age ± SD, 88.1±5y) residing in long-term-care and independent-living retirement facilities.
Interventions:
Not applicable.
Main Outcome Measures:
The level of agreement between video observation and the accelerometer for the total duration of each activity, and second-by-second correspondence between video observation and the accelerometer for each activity.
Results:
The median absolute percentage errors between video observation and the accelerometer were <1% for locomotion and lying. The absolute percentage errors were higher for sitting (median, -22.3%; interquartile range [IQR], -62.8% to 10.7%) and standing (median, 24.7%; IQR, -7.3% to 39.6%). A second-by-second analysis between video observation and the accelerometer found an overall agreement of ≥85% for all activities except standing (median, 56.1%; IQR, 34.8%-81.2%).
Conclusions:
This single-device accelerometer provides a valid measure of lying and locomotion in people aged >80 years. There is an error of approximately 25% when discriminating sitting from standing postures, which needs to be taken into account when monitoring longer-term habitual activity in this age group.
