Wearable Bioimpedance Sensing for Quantifying Knee Health in Juvenile Idiopathic Arthritis

Juvenile Idiopathic Arthritis (JIA) is chronic arthritis that impacts children under the age of 16. Improved technologies for assessing joint health in patients with JIA can enable personalized titration of care and lead to improved outcomes. In this work, we studied, for the first time, wearable bioimpedance measurements as a technique for quantifying joint health in JIA. Knee bioimpedance data were collected from 23 children with JIA and 8 healthy controls with custom wearable sensing hardware. Bioimpedance data were collected at 5 kHz and 100 kHz in knee flexion and extension positions. The calculated
$\boldsymbol{H}_{alpha}$
compares the changes in 5 kHz and 100 kHz resistance from flexion and extension position.
$\boldsymbol{H}_{alpha}$
showed statistically significant results (p<0.05) for discriminating between healthy controls and subjects with JIA. Additionally, EBI data were collected from multiple subjects (n=4) serially throughout treatment. With treatment,
$\boldsymbol{H}_{alpha}$
decreases over time implying decreased disease activity. The results of this study show the potential for using wearable EBI to determine JIA status and treatment effectiveness.