A practical guide to cochlear implantation in adults with long durations of monaural sound deprivation

Abstract

Objective: This paper aims to summarize published findings by the authors and integrate these within current literature to support clinical guidelines when choosing an ear for cochlear implantation in adults with long-term monaural sound deprivation. Study sample: Four retrospective cohort studies based on data collected in five cochlear implantation centres with adults with bilateral hearing loss who used a single hearing aid for at least 15 years prior to unilateral or bilateral cochlear implantation. Design: Review, integration and interpretation of retrospective cohort studies to support clinical recommendations. Results: In this population, the prelingual nature of the hearing loss and the duration of bilateral significant hearing loss were the most reliable predictors of cochlear implantation outcomes. Importantly, the duration of sound deprivation in the ear to be implanted was not a significant predictor of speech recognition scores after cochlear implantation and should carry less weight in making recommendations. Conclusions: In most adults with postlingual hearing loss and long-term monaural sound deprivation, the sound-deprived sound deprivation ear should be preferred for implantation. For adults with prelingual deafness and monaural sound deprivation, the decision should weigh the risks of obtaining poorer results with the cochlear implant compared to the benefits of accessing binaural hearing.

Key Words:

• Sound deprivation
• cochlear implant
• hearing asymmetry
• choice of ear

Acknowledgements

The authors thank the numerous clinicians within the five collaborating cochlear implantation centres for their time and support; Professor Björn Lyxell for continuous guidance; as well as Dr Valerie Looi for reviewing the manuscript. These studies were supported by (1) the HEARing CRC, established and supported by the Cooperative Research Centres Programme – Business Australia, (2) Macquarie University’s Research Excellence Scheme, and (3) the Linnaeus Centre HEAD (The Swedish Institute for Disability Research).