Assessing the concurrent validity of a gait analysis system integrated into a smart walker in older adults with gait impairments

Objective: To assess the concurrent validity of a smart walker-integrated gait analysis system with the GAITRite (R) system for measuring spatiotemporal gait parameters in potential users of the smart walker. Design: Criterion standard validation study. Setting: Research laboratory in a geriatric hospital. Participants: Twenty-five older adults (> 65 years) with gait impairments (habitual rollator use and/or gait speed <0.6 m/s) and no severe cognitive impairment (Mini-Mental State Examination > 17). Main measures: Stride, swing and stance time; stride length; and gait speed were simultaneously recorded using the smart walker-integrated gait analysis system and the GAITRite system while participants walked along a 7.8-m walkway with the smart walker. Concurrent criterion-related validity was assessed using the Bland-Altman method, percentage errors (acceptable if <30%), and intraclass correlation coefficients for consistency (ICC3,1) and absolute agreement (ICC2,1). Results: Bias for stride, swing and stance time ranged from -0.04 to 0.04 seconds, with acceptable percentage errors (8.7%-23.0%). Stride length and gait speed showed higher bias (mean(bias) (SD) = 0.20 (0.11) m; 0.19 (0.13) m/s) and not acceptable percentage errors (31.3%-42.3%). Limits of agreement were considerably narrower for temporal than for spatial-related gait parameters. All gait parameters showed good-to-excellent consistency (ICC3,1 = 0.72-0.97). Absolute agreement was good-to-excellent for temporal (ICC2,1 = 0.72-0.97) but only poor-to-fair for spatial-related gait parameters (ICC2,1 = 0.37-0.52). Conclusion: The smart walker-integrated gait analysis system has good concurrent validity with the GAITRite system for measuring temporal but not spatial-related gait parameters in potential end-users of the smart walker. Stride length and gait speed can be measured with good consistency, but with only limited absolute accuracy.