Agreement in Measures of Truncal Deviation Between a Wearable Wireless Motion Analysis System and a Standard 3D Gait Analysis System

We evaluated the agreement between a wearable wireless motion analysis system and a 3D gait-lab system in healthy adults, healthy elderly, and Parkinson’s disease (PD) patients. A cross-sectional study included 35 participants from three groups. Participants walked a 6-meter line while both systems recorded truncal deviations (lateral, vertical) and gait speed (antero-posterior). Agreement was assessed using Bland-Altman plots and intraclass correlation coefficients (ICCs). Mean differences between systems were: healthy adults (lateral: 0.55 cm, vertical: 0.11 cm, speed: −0.02 m/s), healthy elderly (lateral: 0.47 cm, vertical: 0.43 cm, speed: −0.02 m/s), and PD (lateral: 0.13 cm, vertical: 0.17 cm, speed: −0.02 m/s). Good agreement was observed for truncal deviations, but systematic errors were noted in gait speed. ICCs ranged from 0.764 to 0.953. The wearable system demonstrated moderate to good agreement and reliability in healthy adults and healthy elderly, and good to excellent agreement in PD patients.