Single-Sided Deafness and Asymmetric Hearing Loss

Inclusion Criteria:

• Five years of age or older at the time of implantation

• Unilateral profound hearing loss, as defined by a pure-tone average (500, 1000, 2000, and 4000 Hz) of 90 dB or greater in the ear to be implanted

• Sensorineural hearing loss in the ear to be implanted, as defined by an air-bone gapless than or equal to 10 dB at two or more frequencies out of 500, 1000, 2000, and 4000 Hz and a diagnosed pathology of the outer or middle ear

• Normal hearing or mild to moderate hearing loss in the non-implanted ear, as definedby a pure-tone average (500, 1000, 2000, and 4000 Hz) of 55 dB or less

• Word recognition in the ear to be implanted of 5% or less on CNC word score in quiet

• Previous experience with an appropriately-fit Contralateral Routing of Signal (CROS)hearing aid, BI-Contralateral Routing of Signal (CROS) hearing aid, bone conduction,or traditional hearing aid, as deemed appropriate by investigator

• Fluent in English

Exclusion Criteria:

• Duration of profound hearing loss of 10 years or more

• Absence of cochlear development or non-functionality of cochlear nerve

• Other retrocochlear hearing loss

• Evidence of severe cochlear malformation (i.e., common cavity or ossification)

• External or middle ear infection

• Suspected developmental or cognitive concern

• Other medical contraindication for surgery or anesthesia