Outcomes of cochlear implantation in adults with asymmetric hearing loss

To analyze speech recognition outcomes in adult cochlear implant recipients who have asymmetric sensorineural hearing loss between the two ears.

Retrospective cohort study of 35 adults with asymmetric hearing loss. Preoperative unaided pure-tone averages (PTA), and pre- and post-op (6 and 12 mo) aided Consonant Nucleus Consonant (CNC) words and sentence recognition scores were obtained for ears in isolation (opposite ear plugged). Patients were categorized according to the PTA of the implanted and contralateral ears as (a) moderate-severe, (b) moderate-profound, and (c) severe-profound.

A single tertiary care center.

Adults with asymmetric PTA implanted unilaterally at our institution.

Cochlear implantation with devices approved by the U.S. Food and Drug Administration.

Post-implantation word, phoneme, and sentence recognition in the cochlear implant alone testing condition.

Patients who were implanted in the worse-hearing ear (n = 21) performed significantly better on CNC words and phonemes at 6 and 12 months than patients who were implanted in the better-hearing ear (n = 14). Patients with the worse ear implanted also obtained 6 to 12% higher sentence recognition scores than the group received an implant in their better ear, although this difference is not statistically significant (p = 0.06 at 6 mo; p = 0.1 at 12 mo).

Patients with asymmetrical hearing loss who were implanted in the worse-hearing ear achieved 15% greater CNC word scores and 6 to 12% greater sentence scores than patients implanted in the better-hearing ear in the first year after surgery. Our results provide further support for clinicians to use caution if considering implanting the better-hearing ear in patients with asymmetric hearing loss.