Electrode apparatus for non-invasively applying electrical stimulation to a human body portion via a skin interface. The apparatus comprises an electrode module 46 having an end 54 for defining an electrolyte application region between the module and the skin and a plurality of spaced apart electrodes that are electrically contactable to the skin via an electrolyte. Apparatus further comprises a controller configured to individually adjust electrical signals across or between each of the electrodes and each of one or more pairing electrodes. The controller may determine: a spatial distribution of current flow within the electrolyte an impedance or resistance of a sub-region of the electrolyte application region an impedance model of the body portion. The controller may selectively dispense electrolyte from a reservoir and/or remove electrolyte from the application region. The apparatus may comprise: an electrolyte containment for restricting leakage one or more sensors to measure one or more physiological stress indicators. Another electrode module with one or more electrodes and one or more shunt measurement conductors between electrodes. Also a method of estimating a dosage of electrical stimulation impinging on a target treatment region internal to a human body portion by determining an electrical field through the body portion.
