Method and Apparatus for Detecting Neural Injury

An implantable device for monitoring for neural injury has a plurality of electrodes including stimulus electrodes and sense electrodes. A stimulus source provides a stimulus to be delivered to a nerve in order to give rise to an evoked action potential. Measurement circuitry records a neural compound action potential signal sensed at the sense electrodes. A stream of control stimuli are applied to the nerve over time and the evoked neural responses are measured. A diagnostic parameter of the measured neural responses is monitored over time, in order to detect a change in the diagnostic parameter. If a change in the diagnostic parameter occurs over time, an indication is output that neural injury has occurred.