Bioimpedance plethysmography with capacitive electrodes and sole force sensors: comparative trial

Abstract

Foot impedance plethysmography was implemented using two types of electrodes (dry and capacitive) and sole force sensors. The latter are commonly used for assessing diabetic foot ulcers (DFU). For impedance plethysmography, a tetrapolar configuration has been used with three different plantar setups: four skin contact electrodes, four capacitive contact electrodes and two Force Sensing Resistors (FSRs). In this work, FSRs have been considered as possible capacitive electrodes because the top substrate contains interdigitating conductive electrodes and a semiconductive polymer. All the measurements have been performed using a 1 mA/10 kHz excitation current and have been tried under the feet of a standing person to detect impedance plethysmography signals. Contact electrodes allow a good cardiac pulse signal while capacitive contact through the socks features mains interferences. Force sensing resistors with their force-dependent resistance in parallel to the capacitive coupling, were not able to detect cardiac pulse. But promising results can be anticipated from these findings provided higher frequencies are used and larger sensor areas to help detect altered skin states in diabetic foot.

A Smart Iot-Based Prototype System For Rehabilitation Monitoring

“…The FSR is connected to detect the pressure points under the foot to measure the amount of pressure applied by the test subjects [29,30], as shown in Fig. 5.…”

Toward noninvasive monitoring of plant leaf water content by electrical impedance spectroscopy

“…A common remedy in biomedical measurements is to use the four-electrode technique, minimizing the influence of electrode impedance. In addition, this eliminates the use of nonpolarizable electrodes such as Ag/AgCl electrodes, allowing the use of polarizable materials and even capacitive electrodes (Morales et al, 2021). Other EIS applications include the plant's response to environmental changes (Garlando et al, 2022), to different growth and stress conditions (Hamed et al, 2016) and to different plant water statuses (Jamaludin et al, 2015).…”