Development of a video-based technique for ambulatory monitoring of foot placement with an instrumented rollator.

Abstract

To develop a video-based system, mounted on a rollator to quantify the step width values of rollator users in the community. A total of 5 able-bodied young adults, age range 24-28 years. A digital video camera system was mounted on the rollator frame to capture the position of the participant's feet during overground walking. A method of estimating step width from the video data was developed and evaluated against the output from a concurrently recording Vicon MX motion capture system. Mean step widths of the rollator and motion capture systems were 14.40 cm (standard deviation (SD) 4.64) and 14.37 cm (SD 4.34), respectively, revealing a strong level of agreement; intra-class correlation coefficient 0.999 (95% confidence interval (95% CI) 0.987-1.000; and root-mean-square difference 0.70 cm. The video-based system mounted on a rollator to collect foot placement data enabled accurate measurement of step width during rollator use. The ability to record foot placement measurements outside the laboratory setting, characterizing foot placement patterns occurring in the community, will enable research into how these assistive devices influence mobility during everyday use.