Bilateral cochlear implantation: current concepts

Abstract

The goal of this review is to examine the most recent literature exploring the indications, outcomes, and long-term benefit of bilateral cochlear implantation in children and adults. The indications for cochlear implantation have expanded, as many unilaterally implanted individuals are able to achieve open-set word recognition. Despite the benefits seen in unilateral implantation, many individuals have difficulty perceiving speech in noisy environments. Bilateral cochlear implantation has made great strides in providing individuals access to sound information from both ears, allowing improved speech perception in quiet and in noise, as well as sound localization. Recently, the House Cochlear Implant study group released a position statement in which the group strongly endorsed bilateral cochlear implantation. Improved speech perception in quiet has also been demonstrated by many groups with bilateral implantation. Improved sound localization abilities have been shown to be dependent on interaural level differences. The binaural benefits of head shadow and summation have been long shown in bilaterally implanted individuals. Recently, a growth in squelch has been seen in these individuals likely as a result of increased experience with both implants. This may indicate neural integration of the inputs over time. The literature supports the binaural benefit of bilateral cochlear implantation with demonstrated improved speech perception outcomes in quiet and in noise, sound localization data, and subjective benefits.