In 2014 radiological lesions at one or more semicircular canals (SCC) were described using CT & MR imaging in subjects presenting advanced hearing and vestibular deterioration caused by the p.P51S mutation in COCH. Similar lesions were also described in other non-genetic advanced hearing and vestibular deterioration as well. With this prospective observational study it is the purpose to inventory imaging results of candidates for cochlear implantation which are routinely performed during the preoperative work up, since these patient present severe hearing impairment at both ears. A considerable part of them might present vestibular deterioration as well. It is the purpose to detect possible presence of these SCC lesions on CT and MR in this population and the prevalence of these lesions compared to DFNA9 patients.

Inclusion Criteria:

• must be eligible for cochlear implantation
• must be 18 years of age or older

Exclusion Criteria:

• <18 years of age
• not eligible to undergo vestibular tests, especially videonystagmography
• contra-indication for MR or CT

-all patients with severe hearing loss who are eligible for cochlear implantation who do not carry the p.P51S mutation in COCH and are at least 18 years of age