The primary objective of this research is to evaluate the relationships between multiple data from cochlear implant (CI) adult users to and to estimate predictive models of their fitting parameters. In a group of patients, the Electrically-evoked Compound Action Potentials (ECAP) will be collected intra-operatively and the correlation with demographic data (deafness duration, age deafness onset, etiology, duration of cochlear implant use of CI), auditory performances and subjective measures used for implant fitting (hearing threshold and most comfortable level) will be calculated. In a second group of experienced users (more than 9months of use of their CI), ECAP and Electrically-evoked Auditory Brainstem Response (EABR) will be collected after 9 months of CI experience and after 12 months or more of use. Correlation analyzes with demographic data, performance and fitting parameters will be performed as well. Statistical predictive models for both fitting at the activation or in experienced users should be developed according to the correlation analysis.