covered causes from one pulse to another the appearance or disappearance of electrochemical phenomena in the vicinity of the active electrodes application_number US 201414173317 A description an electrophysiological measurement diagnostic system according to the invention will now be described this system is founded on an active operating principle in direct current mode as distinguished in particular from the impedance measurement systems of the prior art the disadvantages of which were recalled above following a certain number of tests the applicants observed that the application of a low dc voltage at the terminals of a pair electrodes distant from one another anode and cathode produced different electrochemical behaviours at the anode and cathode in particular it was observed that chloride ions c1 u2212 react to the anode whereas a reaction to hydrogen ions is witnessed at the cathode one object of the invention is to be able to differentiate between the behaviour of the anode on the one hand and the cathode on the other hand based on this principle the applicants discovered that it was possible to use the electrodes in two ways one in the presence of a current and under a potential difference which can vary so as to observe the evolution of the electrochemical phenomena at the anode and at the cathode and the other in the presence of a negligible high impedance current in at least one other electrode.