Choice of ear for cochlear implantation: implant the better- or worse-hearing ear?

BACKGROUND The availability of cochlear implants (CIs) has led to significant advances in hearing rehabilitation. Indications for implantation have expanded significantly since the technology was introduced, and many more patients today are considered eligible for the device. As indications have become less restrictive, patients with poor but serviceable hearing in at least one ear have been implanted. In such patients, implantation of the poorer ear allows the possibility of bimodal stimulation, utilizing a contralateral hearing aid (HA). However, implantation of the poorer ear has raised concerns that the implant could be less beneficial in an auditory system that has been long deprived of stimulation. Analysis of this question may be aided by addressing two related questions: 1) Is there a clear benefit to bimodal stimulation (utilizing one HA and one CI) over stimulation with one CI alone? 2) Does the degree of hearing loss preimplant affect the derived benefit from the implant? If the answer to the first is yes and the answer to the second is no, then the ideal ear to implant should be the poorer ear.