Validating Adhesive-Free Bioimpedance of the Leg in Mid-Activity and Uncontrolled Settings

• Published in: IEEE transactions on biomedical engineering Vol. 70; no. 9; pp. 2679 - 2689
• Main Authors: Nichols, Christopher J., Mabrouk, Samer A., Ozmen, Goktug C., Gazi, Asim H., Inan, Omer T.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.09.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adhesive wear; Adhesives; Atmospheric measurements; Biomedical monitoring; Electrical bioimpedance; Electrodes; Impedance; Impedance measurement; joint physiology; Leg; musculoskeletal health; Particle measurements; Patients; Telemedicine; textile electrodes; Textiles; Tracking; wearable sensing; Wearable technology
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2023.3262206

Objective: Musculoskeletal health monitoring is limited in everyday settings where patient symptoms can substantially change - delaying treatment and worsening patient outcomes. Wearable technologies aim to quantify musculoskeletal health outside clinical settings but sensor constraints limit usability. Wearable localized multi-frequency bioimpedance assessment (MFBIA) shows promise for tracking musculoskeletal health but relies on gel electrodes, hindering extended at-home use. Here, we address this need for usable technologies for at-home musculoskeletal health assessment by designing a wearable adhesive-free MFBIA system using textile electrodes in extended uncontrolled mid-activity settings. Methods: An adhesive-free multimodal wearable leg MFBIA system was developed in-lab under realistic conditions (5 participants, 45 measurements). Mid-activity textile and gel electrode MFBIA was compared across multiple compound movements (10 participants). Accuracy in tracking long-term changes in leg MFBIA was assessed by correlating gel and textile MFBIA simultaneously recorded in uncontrolled settings (10 participants, 80+ measurement hours). Results: Mid-activity MFBIA measurements with textile electrodes agreed highly with (ground truth) gel electrode measurements (average <inline-formula><tex-math notation="LaTeX">{{\bm{r}}}^2 = {\bm{\ }}0.95)</tex-math></inline-formula>, featuring <1-Ohm differences (0.618 ± 0.340 Ω) across all movements. Longitudinal MFBIA changes were successfully measured in extended at-home settings (repeated measures r = 0.84). Participant responses found the system to be comfortable and intuitive (8.3/10), and all participants were able to don and operate the system independently. Conclusion: This work demonstrates wearable textile electrodes can be a viable substitute for gel electrodes when monitoring leg MFBIA in dynamic, uncontrolled settings. Significance: Adhesive-free MFBIA can improve healthcare by enabling robust wearable musculoskeletal health monitoring in at-home and everyday settings.