Auditory abilities after cochlear implantation in adults with unilateral deafness: a pilot study

This pilot study examined speech recognition, localization, temporal and spectral discrimination, and subjective reports of cochlear implant (CI) recipients with unilateral deafness.

Three adult male participants with short-term unilateral deafness (<5 yr) participated. All had sudden onset of severe-to-profound hearing loss in 1 ear, which then received a CI, and normal or near normal hearing in the other ear. Speech recognition in quiet and noise, localization, discrimination of temporal and spectral cues, and a subjective questionnaire were obtained over several days. Listening conditions were CI, normal hearing (NH) ear, and bilaterally (CI and NH).

All participants had open-set speech recognition and excellent audibility (250-6,000 Hz) with the CI. Localization improved bilaterally compared with the NH ear alone. Word recognition in noise was significantly better bilaterally than with the NH ear for 2 participants. Sentence recognition in various noise conditions did not show significant bilateral improvement; however, the CI did not hinder performance in noise even when noise was toward the CI side. The addition of the CI improved temporal difference discrimination for 2 participants and spectral difference discrimination for all participants. Participants wore the CI full time, and subjective reports were positive.

Overall, the CI recipients with unilateral deafness obtained open-set speech recognition, improved localization, improved word recognition in noise, and improved perception of their ability to hear in everyday life. A larger study is warranted to further quantify the benefits and limitations of cochlear implantation in individuals with unilateral deafness.