Short Course: The Biomedical-Electrode Tissue Interface: A Simple Explanation of a Complex Subject

Biomedical electrodes are used in various forms in a wide range of biomedical applications. Good electrode design is not as simple as is often assumed, and all electrode designs are not equal in performance. One must not simply choose an electrode with as conductive a sensing element as possible, which unfortunately, was and still is the case in many designs, especially in the emerging area of ?wearable sensing?. Monitoring bioelectrodes, if they are not chosen/designed correctly, give rise to significant problems that make biosignal analysis difficult, if not impossible. Both the electrode?electrolyte interface and the skin under the electrode (collectively known as the contact) give rise to potentials and impedances that can distort the measured biosignal. The potentials and impedances of the electrode?electrolyte interface and of the skin will therefore be studied in some depth using a simple yet effective model to give a sound working knowledge of biomedical electrode technology and design.