Electrode contact impedance sensitivity to variations in geometry
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Updated: May 22, 2026

A Method for Systematic Electrochemical and Electrophysiological Evaluation of Neural Recording Electrodes
Published on: March 3, 2014
Roberto Cardu1, Philip H W Leong, Craig T Jin
1ARCES, University of Bologna, Italy. rcardu@arces.unibo.it
Abstract:
Electrode contact impedance is a crucial factor in physiological measurements and can be an accuracy-limiting factor when performing electroencephalography and electrical impedance tomography. In this work, standard flat electrodes and micromachined multipoint spiked electrodes are characterized with a finite-element method electromagnetic solver and the dependence of the contact impedance on geometrical factors is explored. It is found that flat electrodes are sensitive to changes in the outer skin layer properties related to hydration and thickness, while spike electrodes are not. The impedance as a function of the effective contact area, number of spikes and penetration depth has also been studied and characterized.
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