Correlations Between Subjective and Objective Responses to Cochlear Implant Stimulation

Inclusion Criteria: Incident case cohort: * Age ≥ 18 years (18 years or older) * Scheduled for first-time unilateral cochlear implantation within the next 3 months * Informed about the study and did not object (non-opposition) Cross-sectional sample of prevalent cases: * Age ≥ 18 years (18 years or older) * Underwent unilateral cochlear implantation more than 1 year ago * Has used the implant for more than 1 year (interval between implantation surgery and study inclusion \> 1 year) * Informed about the study and did not object (non-opposition) Exclusion Criteria: Exclusion Criteria - applies to both the incident case cohort and the cross-sectional sample of prevalent cases: * Prior middle or inner ear surgery * Cognitive impairment or insufficient comprehension of French that would prevent understanding of study procedures or accurate measurement of comfort thresholds during programming * Peripheral facial palsy * Bilateral cochlear implantation * Patient under legal guardianship/court-ordered protection Additional exclusion - cross-sectional sample of prevalent cases only: \- More than half of the electrodes not inserted (i.e., \<50% electrode insertion) Secondary exclusion criteria - Incident case cohort: * More than half of the electrodes not inserted (\<50% electrode insertion) * Postoperative peripheral facial nerve palsy following the implantation surgery