Test-retest reliability of a single tri-axial accelerometer-based gait analysis in older adults with normal cognition and comparison with an walkway system

Abstract

Objectives: We investigated the test-retest reliability of spatio-temporal gait parameters measured with a single tri-axial accelerometer (TAA), determined the optimal number of steps required for obtaining acceptable levels of reliability, compared the reliability with the GAITRite® system, studied the level of agreement with parameters derived from GAITRite® system, and compared the reliability and level of agreement of the estimated gait parameters across the three reference axes of the TAA.

Methods: A total of 82 cognitively normal elderly participants walked around a 40-m long round walkway twice wearing a TAA at their center of body mass. Gait parameters such as cadence, gait velocity, step time, step length, step time variability, and step time asymmetry were estimated from the low pass-filtered signal of the TAA. Evaluation of the test-retest reliability and comparison with the GAITRite® system were carried out for the estimated gait parameters.

Results: Gait parameters using signals from the vertical axis showed excellent reliability for all gait parameters

the intraclass correlation coefficient (ICC) was 0.79-0.90. A minimum of 26 steps and 14 steps were needed to achieve excellent reliability in step time variability and step time asymmetry, respectively. A strong level of agreement was seen for the basic gait parameters between the TAA and GAITRiteⓇ (ICC=0.91-0.96).

Conclusion: The measurement of gait parameters of elderly individuals with normal cognition using a TAA placed on the bodys center of mass was reliable and showed superiority over the GAITRiteⓇ with regard to gait variability and asymmetry. Considering its wearability and low price, the TAA system may be a promising alternative to the pressure sensor walkway system for measuring gait parameters.