An investigation into the accuracy and test-retest reliability of the Microsoft Kinect compared to the perometer for measuring lower limb volume in a healthy adult population.

Abstract

Question: Is the Kinect an accurate and reliable method of measuring lower limb volume compared to the perometer when testing a healthy adult population? Design: A study of accuracy and test-retest reliability of the Kinect compared to the perometer. Two measurement methods were analysed and each participant was randomly allocated to each measurement method. Participants: The sample population consisted of 15 healthy adults (7 male and 8 female) between the ages of 18 and 34. Intervention: Each participant had the volume of their dominant lower limb measured using the perometer and the Kinect three times. Outcome measures: The accuracy and test-retest reliability of the lower limb volumes recorded by the Kinect in comparison with the perometer. Results: High intraclass correlation coefficient (ICC) values were found for the perometer (0.994) and for the Kinect (0.956). The perometer had the lowest standard error of measurement (SEM) (145.8) compared to the Kinect (911.9). The Kinect had the propensity to overestimate limb volume compared to the perometer. The mean difference observed between the Kinect and the perometer was 625.7 (±633.1). The limits of agreement (LOA) were calculated as 1867.7 for the upper LOA and -615.2 for the lower LOA. Conclusion: The Kinect is an unreliable and inaccurate method of measuring lower limb volume. Therefore, it cannot be used interchangeably with the perometer. Further investigation is required in a healthy population prior to using the Kinect in a population with lymphoedema. In order to do this, a standardised protocol is required for the Kinect.