Portable knee health monitoring system by impedance spectroscopy based on audio-board

G. Scandurra, E. Cardillo, G. Giusi, C. Ciofi, E. Alonso, R. Giannetti

Electronics Vol. 10, nº. 4, pp. 460-1 - 460-21

Summary:

Knee injuries are among the most common health problems in the world. They not only affect people who practice sports, but also those who lead a rather sedentary life. Factors such as age, weight, working and leisure activities can affect the health of the knees, causing disorders such as inflammation, edema, deterioration of cartilage and osteoarthritis. Although for the diagnosis and treatment of the various pathologies it is always advisable to contact orthopedists and specialized structures, it would often be useful to monitor the state of health of the knees in order to evaluate the healing (or worsening) process and the effects of sport/motion activities or rehabilitation. In this perspective, a portable knee health monitoring system was developed to be used at home or in gyms and sports environments in general. Besides requiring a simple custom front end, the system relies on a PC audio board capable of a sampling rate of 192 kHz to perform bioimpedance measurements at frequencies in excess of 50 kHz. A simple numerical calibration procedure allows to obtain high accuracy while maintaining low hardware complexity. The software developed for the operation of the system is freely available to any researcher willing to experiment with the bioimpedance measurement approach we propose, ensuring the conditions of portability and low complexity. Primary (intracellular and extracellular resistances and cell membrane capacitance) and secondary (real and imaginary parts of the total impedance) bioimpedance parameters can be obtained and analyzed through direct measurements with reference to an equivalent circuit model. The functionality of the system has been tested on nine subjects with different well-known health conditions, providing encouraging results in terms of the ability to correlate bioimpedance measurements to the health status of the knees. If proper clinical trials were to confirm our preliminary results, a system such as the one we propose could be used for fast and frequent monitoring of knee joints, thus possibly reducing the frequency at which complex and expensive medical exams, sometimes involving long waiting lists, must be performed.

Spanish layman's summary:

En la rehabilitación médica es importante la evaluación del progreso de la terapia; los exámenes necesarios suelen ser costosos o tienen grandes colas de espera. En este artículo se explora el uso de mediciones de bioimpedancia para acelerar los controles de rutina en el caso de lesiones de rodilla.

English layman's summary:

One important factor in medical rehabilitation is the continuous assessment of the therapy progress; the required checks are often expensive or have large waiting queues. In this article, we explore using simple bio-impedance measurements to speed up routine checks in the case of knee injuries.

Keywords: impedance spectroscopy; knee health; bioimpedance; portable system; calibration; simulation

JCR Impact Factor and WoS quartile: 2,690 - Q3 (2021)

DOI reference: https://doi.org/10.3390/electronics10040460

Published on paper: February 2021.

Published on-line: February 2021.

Citation:
G. Scandurra, E. Cardillo, G. Giusi, C. Ciofi, E. Alonso, R. Giannetti Portable knee health monitoring system by impedance spectroscopy based on audio-board. Electronics. Vol. 10, nº. 4, pp. 460-1 - 460-21, February 2021. [Online: February 2021]