In an effort to further preserve residual acoustic hearing after cochlear implantation, it may be beneficial to incorporate anti-inflammatory agents into the electrode array for passive elution over a time course after implantation. This study aims to assess the ease and effectiveness of such an electrode design, and to assess the preliminary safety of use of such a device in the post-operative period. This study is a first-time-in-human study of the investigational device.

In the first instance, the aim of the current investigation is to obtain first experience in use of a Combined Device in the adult clinical population, and to assess tools and techniques that may be considered in future clinical studies of similar devices.

Inclusion Criteria:

1. Duration severe to profound hearing impairment in implanted ear of less than or equal to 30 years
2. Post-lingual hearing impairment defined as onset of hearing loss at greater than two years of age
3. Evidence of Pneumovax vaccination within three years of implantation date (for subjects to be implanted with the investigational device)

Exclusion Criteria:

1. Ossification or any other cochlear anomaly that might prevent complete insertion of the electrode array or increased risk of infection (i.e. dysplastic cochlea), as confirmed by medical examination and imaging including MRI
2. Current use of grommets or evidence of tympanic membrane perforation
3. Known allergic reaction to dexamethasone or similar medicine
4. Diagnosis of Auditory Neuropathy
5. Active middle ear infection or history of middle ear infection within past two years
6. Unrealistic expectations on the part of the subject regarding the possible benefits, risks, and limitations that are inherent to the surgical procedure and use of the prosthetic device
7. Unwillingness or inability of the candidate to comply with all investigational requirements
8. Additional disabilities that would prevent or restrict participation in the audiological and medical evaluations required of the clinical investigation