Cochlear Implantation in Adults With Asymmetric Hearing Loss Clinical Trial

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

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