Comparison of a new inertial sensor based system with an optoelectronic motion capture system for motion analysis of healthy human wrist joints

Abstract

This study aims to compare a new inertial measurement unit based system with the highly accurate but complex laboratory gold standard, an optoelectronic motion capture system. Inertial measurement units are sensors based on accelerometers, gyroscopes, and/or magnetometers. Ten healthy subjects were recorded while performing flexion-extension and radial-ulnar deviation movements of their right wrist using inertial sensors and skin markers. Maximum range of motion during these trials and mean absolute difference between the systems were calculated. A difference of 10◦ ± 5◦ for flexion-extension and 2◦ ± 1◦ for radial-ulnar deviation was found between the two systems with absolute range of motion values of 126◦ and 50◦ in the respective axes. A Wilcoxon rank sum test resulted in a no statistical differences between the systems with p-values of 0.24 and 0.62. The observed results are even more precise than reports from previous studies, where differences between 14◦ and 27◦ for flexion-extension and differences between 6◦ and 17◦ for radial-ulnar deviation were found. Effortless and fast applicability, good precision, and low inter-observer variability make inertial measurement unit based systems applicable to clinical settings.