In humans, surface electrophysiological recordings of the cochlear nerve in response to a sound stimulus provide information about the cochlear's ability to encode sound. Depending on the stimulus, the fine structure and temporal envelope of the signal will vary, allowing us to determine its characteristics. By phenotyping patients before surgery using subjective and objective audiometric tests, it will be possible to isolate for each patient the moment when the fine structure disappears and when the temporal envelope is effective.