Arrangements are described for monitoring cochlear implantation surgery. During surgical insertion of a cochlear implant electrode array into a patient cochlea, at least one measurement difference value is determined for at least one electrode contact currently located at a given insertion depth into the patient cochlea based on comparing current stimulus response data for the at least one electrode contact to prior stimulus response data for at least one prior electrode contact previously located at the given insertion depth. A potential trauma response is identified when the at least one measurement difference value exceeds a defined difference value.
