Design and Validation of a Wearable System for Enhanced Monitoring of Lower Limb Lymphedema

Abstract

Lymphedema, characterized by limb swelling, is typically treated with Complex Decongestive Therapy (CDT), which includes physical exercise. This study seeks to design and validate a wearable device aimed at enhancing CDT by monitoring patient adherence to prescribed exercises and tracking changes in the range of motion of the affected limbs. A wearable device, constituted by two boards with 2 IMUs, connected by a flexible flat cable, was designed and developed for placement across targeted joints. It communicates wirelessly with PCs, where raw data from IMUs are collected. Through the application of the Madgwick filter, orientation of the units is obtained and finally joints angles are computed. The device was validated through bench testing using an orthopedic goniometer and field testing with an optoelectronic system. The in vivo validation involved 18 volunteers, including 10 healthy individuals and 8 individuals with lymphedema, who performed flexion-extension movements and walked on a treadmill (at speeds of 3 km/h and 5 km/h). Bench testing demonstrated strong correlation and agreement (r²=0.999, mean percentage error = -0.51°, standard deviation = 2.00°). Once worn by the participants, the device enabled the measurement of joint angles during flexion-extension exercises (r²=0.852, mean percentage error = 1.44°, standard deviation = 11.7°) and the extraction of step counting, step time and toe off during walk at different speeds. The developed wearable device exhibited robust performance in both bench and field testing. This device, designed specifically for lymphedema patients, offers valuable insights into limb function and exercise adherence, potentially improving personalized treatment strategies.