Cochlear Implantation in Adults With Asymmetric Hearing Loss Clinical Trial

This longitudinal study evaluates the possible benefit of cochlear implantation in the poor ear of adults with asymmetric hearing loss who continue to use a hearing aid in the better hearing ear.

The study will be conducted as a multicenter, prospective, single-arm clinical trial, evaluating the efficacy and safety of cochlear implantation in patients with asymmetric hearing loss. A repeated-measures analysis will be employed whereby patients will act as their own controls. Participants will be recruited from surgeons and audiologists in Otolaryngology departments at the participating sites.

Participants will be evaluated at multiple intervals using a variety of test measures (addressing sound localization, understanding speech in noise, understanding speech in quiet, and quality of life).

Prior to receiving a cochlear implant (CI) in the poor hearing ear, participants will be evaluated as follows:

* Hearing aid (HA) in the better ear alone
* HA in the poor ear alone
* Bilateral HAs

Participants who have not previously used a poor-ear hearing aid or BiCROS hearing aid will complete a 1-2 week trial and be evaluated at the end of the trial. If performance is better with the alternate therapy (bilateral hearing aids or BiCROS hearing aid) than the better ear alone performance and the participant prefers the alternate therapy, the participant will not continue in the study.

Participants who do continue in the study will be evaluated at several post-implant intervals. Post-implant evaluations will occur at 3, 6, 9, and 12 months after initial stimulation of the CI. Participants will be evaluated as follows:

* HA in the better ear alone
* CI in the poor ear alone
* HA and CI together

Eligibility Criteria:
Inclusion Criteria:

* 18 years of age or older
* English as the native language
* Have a desire for functional binaural hearing
* Have failed a previous hearing aid (HA) treatment for asymmetric hearing loss (BiCROS or poor ear HA) or willing to complete a trial if necessary
* Willingness to comply with all study requirements
* Ability to provide informed consent
* Poor ear (ear to be implanted):

  * Pure-tone average (PTA) at .5, 1 and 2 kilohertz (kHz) \> 70 dB HL (hereafter referred to as severe to profound hearing loss - SPHL)
  * Aided word recognition score (CNC Word Test) at 60 dB SPL ≤ 30%
  * Duration of SPHL ≥ 6 months
  * Onset of hearing loss ≥ 6 years of age
* Better ear:

  * PTA at .5, 1, 2, 4 kHz of 40 to 70 dB HL
  * Currently using a HA
  * Aided word recognition score (CNC Word Test) at 60 dB SPL \> 40%
  * Stable hearing for the previous 1-year period. "Stable" is defined as thresholds that have not changed by more than 10 dB at 2 or more octave interval audiometric frequencies

Exclusion Criteria:

* Medical condition that contraindicates surgery
* Actively using an implantable device in the ear to be implanted
* Known cochlear malformation or obstruction that would preclude full insertion of the electrode array in the ear to be implanted
* Hearing loss of neural or central origin
* Unrealistic expectations related to the benefits and limitations of cochlear implantation
* Unwillingness or inability to comply with all investigational requirements