Contrasting benefits from contralateral implants and hearing aids in cochlear implant users

In recent years a substantial number of studies have reported results from cochlear implant users who increasingly are being fitted with a contralateral hearing aid or second implant. Often outcomes are discussed in relation to the benefits available to listeners with normal hearing in both ears. The objective of this paper is to consider the available cues that are degraded in different ways when a cochlear implant is combined with a contralateral hearing aid or second implant, and to review the literature in that context. It is found that the data largely confirm the expectations that arise from those considerations, and that outcomes differ substantially for the two types of listeners, with a greater emphasis on better ear selection and comparison of information at the two ears for bilateral implant users, and conversely, on the complementary use of information from the two ears in bimodal listeners.

► Cochlear implant users benefit from the use of contralateral implant or hearing aid.
► A second implant provides spatial hearing benefits mainly due to the head shadow.
► A contralateral hearing aid provides complementary spatio-temporal information.