Concurrent validity and reliability of the Microsoft kinect™ device in cervical spine range of motion assessment

This study assessed the cervical spine range of motion in asymptomatic individuals using the universal goniometer and the Microsoft KinectTM device, respectively and also determined the validity and test-retest reliability of the Microsoft KinectTM device with a view to establishing the accuracy and reproducibility of an alternative but a valid tool for the assessment of cervical spine range of motion. This cross-sectional study involved 420 apparently healthy undergraduates from the Colleges of Health Sciences, Obafemi Awolowo University Ile–Ife and Ladoke Akintola University of Technology, Osogbo Campus, who were recruited consecutively after obtaining ethical clearance from the Health Research and Ethics Committee, Institute of Public Health, Obafemi Awolowo University, Ile-Ife, Nigeria. Cervical motions were evaluated using the universal goniometer and the KinectTM device. The Microsoft Software Development Kit (SDK), version 1.8 and the Markus Bader Software solution were used to calculate the cervical motion based on Kinect skeleton tracking data. Anthropometric characteristics (age, height and weight) were recorded and body mass index was calculated. Every measurement was made twice and the average value used for statistical analysis. The intraclass correlation coefficient was used to investigate correlation and reliability between measurements obtained from the two techniques. An alpha level was set at p<0.05. The cervical spine range of motion for flexion, extension, right and left lateral rotation and right and left lateral flexion for the goniometer were 36.71 ± 6.340, 43.11 ± 5.540, 49.15 ± 5.880, 47.69 ± 5.110, 23.22 ± 3.950 and 22.67 ± 3.830 while for the Microsoft KinectTM were 48.80 ± 6.760, 15.34 ± 2.940, 15.73 ± 3.040, 15.09 ± 3.090, 23.49 ± 4.590 and 24.49 ± 4.720 , respectively. There was no significant correlation in all of the cervical spine range of motion measurements obtained using the Microsoft Kinect (extension r = 0.09, p = 0.571; right lateral rotation r = 0.01, p = 0.614; left lateral rotation r = 0.008, p = 0.437; right lateral flexion r = 0.09, p = 0.571; left lateral flexion r = 0.01 p = 0.591) with the exception of cervical flexion (r = 0.198, p = 0.001). The intra-rater reliability of both the Microsoft KinectTM and goniometer in the assessment of cervical spine range of motion was excellent (r > 0.75). The intra-rater reliability values for flexion, extension, right and left lateral rotation and right and left lateral flexion for the Microsoft KinectTM were 0.98, 0.93, 0.95, 0.96, 0.97, and 0.98 while for the goniometer were 0.98, 0.98, 0.98, 0.98, 0.96, and 0.96, respectively. The Microsoft KinectTM was found to be a reliable tool yet showing weak concurrent validity when compared with the universal goniometer in the cervical spine range of motion assessment, except for cervical flexion, among apparently healthy undergraduates.