Evaluation of Cochlear Implantation in Unilateral or Asymmetric Hearing Loss in Children.

Inclusion Criteria: * Child aged 4 to 6 years at the time of inclusion * Using spoken French as the primary mode of communication * Diagnosed with unilateral or asymmetric hearing loss : Unilateral is defined by severe to profound hearing loss in the affected ear (thresholds \> 70 dB at ≥ 4 frequencies, established by audiometry or ASSR) and normal hearing in the better ear (thresholds ≤ 25 dB between 500-4000 Hz, established by audiometry or ASSR). Asymmetric is defined by severe to profound hearing loss in the weaker ear (thresholds \> 70 dB at ≥ 4 frequencies, established by audiometry or ASSR) and mild hearing loss in the better ear (thresholds between 30-40 dB at ≤ 4 frequencies, established by audiometry or ASSR). * Written informed consent from both legal guardians (or the sole guardian, if applicable) * Affiliated with a health insurance system or entitled to coverage Exclusion Criteria: * Severe neurological disorder, identified by MRI and/or a neuro-pediatric assessment * Severe cognitive, child psychiatric, or developmental delay * Severe cochleo-vestibular malformation * Severe cochlear nerve malformation * Social circumstances preventing long-term follow-up * Family not proficient in spoken French * Patient fitted with a CROS or BiCROS system * Patient with a contraindication to implantation surgery or anesthesia (including lack of meningitis/pneumococcal vaccination)