Skin-electrode contact area in electrical bioimpedance spectroscopy. Influence in total body composition assessment

Abstract

Electrical Bioimpedance Spectroscopy (EBIS) has been widely use for assessment of total body composition and fluid distribution. (EBIS) measurements are commonly performed with electrolytic electrodes placed on the wrist and the ankle with a rather small skin-electrode contact area. The use of textile garments for EBI requires the integration of textrodes with a larger contact area surrounding the limbs in order to compensate the absence of electrolytic medium commonly present in traditional Ag/AgCl gel electrodes. Recently it has been shown that mismatch between the measurements electrodes might cause alterations on the EBIS measurements. When performing EBIS measurements with textrodes certain differences have been observed, especially at high frequencies, respect the same EBIS measurements using Ag/AgCl electrodes. In this work the influence of increasing the skinelectrode area on the estimation of body composition parameters has been study performing experimental EBIS measurement. The results indicate that an increment on the area of the skin-electrode interface did produce noticeable changes in the bioimpedance spectra as well as in the body composition parameters. This influence must be taken into consideration when designing and testing textile-enable EBIS measurement systems.

Analysis of Consistency of Transthoracic Bioimpedance Measurements Acquired with Dry Carbon Black PDMS Electrodes, Adhesive Electrodes, and Wet Textile Electrodes

“…Requiring a skilled professional or another person to help to place the electrodes for anatomical consistency increases the cost, reduces usability, and makes the system less suitable for daily home use by heart failure (HF) patients. To overcome this limitation, some studies have proposed using textile electrodes that are embedded into a wearable vest [ 6 , 7 , 8 ]. Wetting the textile electrodes improves the signal fidelity, because their impedance is several orders of magnitude higher than that of the hydrogel Ag/AgCl electrodes [ 9 ].…”

“…Thus, the wetting requirement is a major limitation of the textile-based electrode bioimpedance monitors. Moreover, the textile electrodes might shift with body movements, introducing further variability in the impedance measurement outcomes [ 7 , 8 ].…”

Combining Bioimpedance and EMG Measurements for Reliable Muscle Contraction Detection

“…High interface impedances of the current electrodes lead to high voltage drops over the electrode skin impedances. This issue has a significant impact on the design of the current source as well as on the voltage measurement circuit [24]. The usage of dry electrodes, as preferred in prostheses, with commonly high electrode skin impedances aggravates this issue [25], [26].…”

Textrode functional straps for bioimpedance measurements-experimental results for body composition analysis

“…As presented in Marquez et al 22 , modifying the constriction zone and a possible presence of electrode mismatch 23 may have an influence in the spectral impedance measurements. The influence of mismatch may be attributed to differences in the Z ep caused by differences in the skin-electrode interface depending on where on the surface of the body the electrodes are placed and/or by the differences of the effective contacting surface of the current and voltage electrodes.…”