Benchmarking between two wearable inertial systems for gait analysis based on a different sensor placement using several statistical approaches

Despite the growing use of different wearable inertial systems for gait analysis in clinical setting, also based on a different sensor placement, there is still a lack of knowledge about the agreement between them and their repeatability. The purpose of this study is to investigate the agreement between two commercial wearable inertial systems for gait analysis: Opal and G-Walk Systems, and their repeatability. Fifty-three subjects, healthy and pathological, underwent a gait analysis session instrumented by both systems, seven spatiotemporal parameters were recorded. The study of agreement was carried out through Bland-Altman Analysis, Passing-Bablok regression and Paired t-test, the study of repeatability through the intra class correlation coefficient ICC(3,1). Study results showed a not perfect agreement between the two systems although they both showed good repeatability. This work underlines the importance to perform a study of agreement before using devices interchangeably or even as a replacement in order to have reliable measurements.