Restoring hearing symmetry with two cochlear implants or one cochlear implant and a contralateral hearing aid.

With today's technology and the demonstrated success of cochlear implantation, along with expanded candidacy criteria, the opportunity to provide optimal hearing to both ears for individuals with severe-to-profound hearing loss is greater than ever. This article reviews the advantages of binaural hearing and the disadvantages of hearing with only one ear or hearing with two ears with significantly different sound thresholds. A case study is presented that demonstrates the benefit of bimodal hearing (i.e., a cochlear implant [CI] in one ear and a contralateral hearing aid [HA]) in a nontraditional CI candidate with asymmetrical hearing thresholds. Then, selected studies in adult recipients who use a CI and contralateral HA or who use two CIs are summarized. The data overall demonstrate that bilateral CI recipients, traditional bimodal recipients, and nontraditional bimodal recipients experience substantial binaural hearing advantages, including improved speech recognition in noise, localization, and functional everyday communication. These results indicate that bilateral stimulation of the auditory system through a CI and contralateral HA or two CIs is beneficial and should become standard clinical practice.