Evaluate the Cochlear™ Nucleus® S-Round Window (S-RW) implant in newly implanted adults with broader requirements to be considered an eligible candidate.

The Food and Drug Administration recently approved the Cochlear Nucleus Hybrid L24 Implant System (P130016) for individuals aged 18 years and older who present with bilateral residual low frequency hearing sensitivity and severe to profound high frequency sensorineural hearing loss with limited benefit from appropriately fitted bilateral amplification. Additionally, the Nucleus Hybrid S12 Implant has been under evaluation since 2007 (IDE G#070016). The Nucleus Hybrid S-RW is a modification of the current Hybrid S12 implant. The Hybrid S-RW is designed to support implantation via a round window (RW) approach while maintaining the same relative insertion depth as the previous Hybrid S12 when implanted via cochleostomy

Inclusion Criteria:

1. Eighteen years of age or older at the time of implantation
2. Sensorineural hearing loss with the following requirements: a pure tone threshold less (better) than or equal to 60 dB HL at 500 Hz,less than (better) or equal to 80 dB HL at 1500 Hz, and high frequency severe to profound (a threshold average of 2000, 3000, & 4000 Hz) of > 60dB HL.
3. Minimum of 30 days experience with appropriately fit bilateral amplification, fit as described in the Fitting and Use of Hearing Aids section below
4. Aided monosyllabic word score (e.g., CNC Word Test) (mean of two lists) between 20% and 60%, inclusive (i.e., 20% score 60%), in the ear to be implanted
5. Aided monosyllabic word score (e.g., CNC Word Test) (mean of two lists) in the contralateral ear equal to, or better than, the ear to be implanted but not more than 80%
6. Willingness to use bimodal stimulation (i.e., a cochlear implant on one ear and a hearing aid on the contralateral ear) through 12-months post-activation

Exclusion Criteria:

1. Individuals aged greater than 75 years
2. Duration of severe to profound hearing loss (above 2kHz) greater than 20 years
3. Medical or psychological conditions that contraindicate undergoing surgery as determined by the Investigator
4. Ossification or any other cochlear anomaly that might prevent complete insertion of the electrode array
5. Conductive overlay of 15 dB or greater at two or more frequencies, in the range 500 to 1000 Hz
6. Deafness due to lesions of the acoustic nerve or central auditory pathway
7. Active middle-ear infection or tympanic membrane perforation in the presence of active middle ear disease
8. Unrealistic expectations on the part of the subject, regarding the possible benefits, risks, and limitations that are inherent to the surgical procedure(s) and prosthetic devices as determined by the Investigator
9. Unwillingness or inability of the candidate to comply with all investigational requirements as determined by the Investigator
10. Additional handicaps that would prevent or restrict participation in the audiological evaluations as determined by the Investigator.

1 year