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BioMed Research International
Volume 2014, Article ID 350504, 17 pages
Review Article

Electroacoustic Stimulation: Now and into the Future

1Bionics Institute, Melbourne, VIC 3002, Australia
2Department of Psychology, University of Melbourne, Melbourne, VIC 3010, Australia
3Department of Otolaryngology, University of Melbourne, Melbourne, VIC 3010, Australia
4Department of Medical Bionics, University of Melbourne, Melbourne, VIC 3010, Australia

Received 16 May 2014; Accepted 4 August 2014; Published 4 September 2014

Academic Editor: Ramesh Rajan

Copyright © 2014 S. Irving et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Cochlear implants have provided hearing to hundreds of thousands of profoundly deaf people around the world. Recently, the eligibility criteria for cochlear implantation have been relaxed to include individuals who have some useful residual hearing. These recipients receive inputs from both electric and acoustic stimulation (EAS). Implant recipients who can combine these hearing modalities demonstrate pronounced benefit in speech perception, listening in background noise, and music appreciation over implant recipients that rely on electrical stimulation alone. The mechanisms bestowing this benefit are unknown, but it is likely that interaction of the electric and acoustic signals in the auditory pathway plays a role. Protection of residual hearing both during and following cochlear implantation is critical for EAS. A number of surgical refinements have been implemented to protect residual hearing, and the development of hearing-protective drug and gene therapies is promising for EAS recipients. This review outlines the current field of EAS, with a focus on interactions that are observed between these modalities in animal models. It also outlines current trends in EAS surgery and gives an overview of the drug and gene therapies that are clinically translatable and may one day provide protection of residual hearing for cochlear implant recipients.