Clinical Trial to Compare Two Surgical Approaches to the Cochlea

Inclusion Criteria: * Individuals aged 18 years and older who have clinically established post-linguistic sensorineural hearing loss. * CI candidate based on local or national reimbursement criteria. * Cochlear implantation with a CI632. * Preoperative 500 Hz pure-tone air conduction threshold \<80 dB hearing level (HL) in the ear to be implanted. * Willing and able to provide written informed consent. Exclusion Criteria: * Previous or existing CI recipient. * Ossification or other anatomical abnormalities of the cochlea or its windows possibly affecting normal electrode array insertion. * Abnormal cochlear nerve anatomy on preoperative CT or MRI. * Subjects who are unable to undergo CT or MRI. * Deafness due to acoustic nerve or central auditory pathway lesions. * Diagnosis of auditory neuropathy. * Active middle ear infection. * Additional handicaps that would prevent participation in study evaluations. * Unrealistic expectations from the participant regarding the possible benefits, risks, and limitations inherent to the CI procedure and the investigation. * Cochlear employees or employees of Contract Research Organisations or contractors engaged by Cochlear for the purposes of this investigation.