Kinematic Validation of a Multi-Kinect v2 Instrumented 10-Meter Walkway for Quantitative Gait Assessments

Abstract

Walking ability is frequently assessed with the 10-meter walking test (10MWT), which may be instrumented with multiple Kinect v2 sensors to complement the typical stopwatch-based time to walk 10 meters with quantitative gait information derived from Kinect’s 3D body point’s time series. The current study aimed to evaluate a multi-Kinect v2 set-up for quantitative gait assessments during the 10MWT against a gold-standard motion-registration system by determining between-systems agreement for body point’s time series, spatiotemporal gait parameters and the time to walk 10 meters. To this end, the 10MWT was conducted at comfortable and maximum walking speed, while 3D full-body kinematics was concurrently recorded with the multi-Kinect v2 set-up and the Optotrak motion-registration system (i.e., the gold standard). Between-systems agreement for body point’s time series was assessed with the intraclass correlation coefficient (ICC). Between-systems agreement was similarly determined for the gait parameters’ walking speed, cadence, step length, stride length, step width, step time, stride time (all obtained for the intermediate 6 meters) and the time to walk 10 meters, complemented by Bland-Altman’s bias and limits of agreement. Body point’s time series agreed well between the motion-registration systems, particularly so for body points in motion. For both comfortable and maximum walking speeds, the between-systems agreement for the time to walk 10 meters and all gait parameters except step width was high (ICC ≥ 0.888), with negligible biases and narrow limits of agreement. Hence, body point’s time series and gait parameters obtained with a multi-Kinect v2 set-up match well with those derived with a gold standard in 3D measurement accuracy. Future studies are recommended to test the clinical utility of the multi-Kinect v2 set-up to automate 10MWT assessments, thereby complementing the time to walk 10 meters with reliable spatiotemporal gait parameters obtained objectively in a quick, unobtrusive and patient-friendly manner.

Accuracy and Reliability of the Kinect Version 2 for Clinical Measurement of Motor Function

“…Kinect V1 and V2 have been proposed for the quantification of motor symptoms, for example in posturography [3, 4], gait analysis [5–7] and quantification of hypokinesia in Parkinson’s disease [2]. Gait analysis with multi-camera [8] or single-camera setup [5, 6] in healthy subjects suggested high accuracy for gait speed, stride length, stride time but lower accuracy for other parameters like stride width or speed variability. The accuracy of functional movement parameters of standing balance seemed to depend on observed movement amplitude [3, 4].…”

“…However, analysis was confined to trunk landmarks in these studies. Comprehensive studies on Kinect V2 landmark movement accuracy [8, 9] pointed to differences in signal accuracy with landmark location and the direction of movements performed. Importantly, retest reliability was not generally lower with Kinect compared to other motion tracking systems.…”

Interference measurement of kinect for xbox one

“…Although multiple Kinect V2 setups has already been used in different research (e.g. [Geerse et al 2015]), it seems they ignore the possibility of interference between multiple sensors. Altough a detailed study of working principle of Kinect V2 suggests otherwise.…”

Investigating the impact of a motion capture system on Microsoft Kinect v2 recordings: A caution for using the technologies together

“…Previously, several studies found an apparent interference between two Kinect sensors in the same generation; none of them evaluated or discussed interference between Kinect sensors and golden standard motion capture systems [9,19,23–30]. …”