Cochlear Implantation in Pediatric Cases of Unilateral Hearing Loss

Unilateral hearing loss (UHL) is a term used to describe a substantial hearing loss in one
ear and normal hearing in the contralateral ear. Despite normal hearing in one ear, these
individuals experience reduced speech perception in noise, variable abilities on localization
tasks, increased reports of hearing handicap, reduced quality of life, and often, they obtain
limited or no benefit from conventional amplification. In the United States, the prevalence
of UHL in children ranges from 0.03% to 3%, depending on the age of the child.

Cochlear implantation performed for children with bilateral, severe to profound deafness has
significant impacts on several aspects of child development.

The practice of providing cochlear implants to children who have significant hearing loss in
one ear is of great interest and is occurring with greater frequency as reported in case
studies and small set clinical reports. The primary purpose of this feasibility study is to
demonstrate the effectiveness of cochlear implantation in children, age 3 years 6 months to 6
years, 6 months, with moderate to profound UHL. Postoperative results will be evaluated with
speech perception measures, localization tasks, hearing in noise tasks, and subjective
reports.

i) Inclusion Criteria

1. Unilateral moderate-to-profound sensorineural hearing loss.

1. Unaided residual hearing thresholds that yield a PTA at frequencies 500Hz, 1K Hz
and 2K Hz of ≥70 dB HL in the ear to be implanted. It is possible that subjects
may have hearing at other frequencies not included in this average.

2. Hearing thresholds in the contralateral ear of ≤25 dB HL

2. Between 3 years, 6 mos and 6 years, 6 mos of age at implantation.

3. Anatomically normal cochlear nerve

4. Cochlear anatomy that is amenable to cochlear implantation as evaluated by imaging
(modality at the physician's discretion) including:

1. Normal cochlear anatomy or

2. Incomplete Partition Type II (IP2) with or without Enlarged Vestibular Aqueduct
(EVA) or

3. EVA with normal partitioning

5. No evidence of progressive hearing loss.

6. Willing to undergo 4 week hearing aid trial as warranted based on achieving desired
audibility when fitted via real ear DSL method.

7. Aided word recognition in the ear to be implanted of 30% or less as measured with CNC
words (50-word list)

1. When listening with an appropriately fit hearing aid and masking applied to the
contralateral ear (Turner, 2004).

2. Aided testing will be conducted in a sound-proof booth with the participant
seated 1 meter from the sound source, facing 0° azimuth. Recorded materials will
be presented at 60 dB SPL.

3. The hearing aid output will be measured using DSL targets.

8. Realistic parental expectations: a verbal acknowledgement of the potential benefits
and risks, and postoperative variation in performance. For instance, cochlear
implantation will not restore normal hearing.

9. Willing to obtain recommended meningitis vaccinations per CDC recommendations.

(9) Development and cognition within the normal range as measured by the Leiter-R test of
nonverbal intelligence and cognitive abilities and the Bracken Basic Concept Scale
-Revised.

(10) Parental commitment to study parameters including being able and willing to
participate in evaluation schedule, involvement in prescribed therapy, and travel to
investigational site and study-related activities.

ii) Exclusion Criteria

1. English is not primary language of the home

1. Speech perception materials are presented in English

2. Parental questionnaires are administered in English

2. Conductive hearing loss in either ear

3. Compromised auditory nerve

4. Ossification of the cochlea

5. Inability to participate in follow-up procedures (i.e., unwillingness, geographic
location)

6. History of condition that contraindicates middle or inner ear surgery or anesthesia
(i.e. otitis media refractory to treatment)

7. Case of sudden sensorineural hearing loss that has not been first evaluated by a
physician