Bilateral cochlear implantation: current concepts.

PURPOSE OF REVIEW: Recent experience has shown an advantage of bilateral cochlear implantation over unilateral implantation. These documented benefits include improved speech perception in noisy environments and improved sound localization. Recently, investigators have studied the long-term benefit, evaluation of neural integration, programming, vestibular effects, and complications of bilateral cochlear implantation. This article summarizes the current research endeavors to improve our understanding and utilization of bilateral cochlear implantation.

RECENT FINDINGS: Numerous positive benefits of bilateral cochlear implantation have been confirmed. Patients receive significant head shadow benefit from bilateral implantation, and obtain nominal benefits from summation and squelch effects. Sound localization benefits have been confirmed. Speech perception in noise with bilateral implantation is significantly better than unilateral implantation and continues to improve 24 months after implantation. Areas for further improvement have also been identified. Despite technological improvements in speech processing strategies, measured intraaural time differences in bilateral cochlear implant recipients remain considerably greater than those with normal hearing. Programming challenges persist to optimize sound processing with bilateral implants. Vestibular effects of bilateral cochlear implantation appear safe but need further study. Important considerations including the duration of implant function, long-term complication rate, and improvements in implant technology will continue to strongly influence the role of bilateral cochlear implantation.

SUMMARY: Bilateral cochlear implantation provides advantages over unilateral implantation including improved speech perception in noise and improved sound localization. Further research is needed to define the optimal indications and to maximize the benefit of bilateral implantation.