Validity and reliability of inertial measurement units for gait assessment within a post stroke population

The ability to objectively measure spatiotemporal metrics within individuals post-stroke is integral to plan appropriate intervention, track recovery, and ultimately improve efficacy of rehabilitation programs. Inertial measurement units (IMUs) provide a means to systematically collect gait-specific metrics that could not otherwise be obtained from clinical outcomes. However, the use of IMUs to measure spatiotemporal parameters in stroke survivors has yet to be validated. The purpose of this study is to determine the validity and reliability of IMU-recorded spatiotemporal gait metrics as compared to a motion capture camera system (MCCS) in individuals post-stroke.

Participants (n = 23, M/F = 12/11, mean (SD) age = 50.2(11.1) spatiotemporal data were collected simultaneously from a MCCS and APDM Opal IMUs during a five-minute treadmill walking task at a self-selected speed. Criterion validity and test-retest reliability were assessed using Lin's concordance correlation coefficients (CCCs) and intraclass correlation coefficients (ICCs), respectively. Spatiotemporal values from MCCS and IMU were used to calculate gait asymmetry, and a t-test was used to assess the difference between asymmetry values.

There were fair-to-excellent agreement between IMU and MCCS of temporal parameters (CCC 0.56-0.98), excellent agreement of spatial parameters (CCC >0.90), and excellent test-retest reliability for all parameters (ICC >0.90).

Compared to motion capture, the APDM Opal IMUs produced accurate and reliable measures of spatiotemporal parameters. Findings support the use of IMUs to assess spatiotemporal parameters in individual's post-stroke.