Measuring a neural response to a stimulus comprises applying an electrical stimulus, then imposing a delay during which the stimulus electrodes are open circuited. During the delay, a neural response signal present at sense electrodes is measured with a measurement amplifier, while ensuring that an impedance between the sense electrodes is sufficiently large that a voltage arising on the sense electrode tissue interface in response to the stimulus is constrained to a level which permits assessment of the neural response voltage seen at the sense electrode. For example the input impedance to the measurement amplifier (ZIN) can bewhere ZC is the sense electrode(s) constant phase element impedance, Vs1−；Vs2 is the differential voltage arising on the sense electrode tissue interface, and VE is the neural response voltage seen at the sense electrode.
