Recent Developments in Bionic Hearing Restoration from the Round Window to the Inferior Colliculus

INTRODUCTION Auditory restoration with implant technology has been a great success story in otology and the ultimate limits of the technology are still not known. Today there are a wide variety of approaches and auditory prostheses for restoration of hearing, each with a precise indication for specific degrees and sites of hearing loss (Figure 1). Modern auditory prostheses range from implants that impart mechanical energy to the cochlea (middle ear implants, MEIs) via the ossicular chain or bypass a damaged ossicular chain and vibrate the round window directly (round window implants, RWI). Cochlear implants (CIs) bypass damaged inner ear cells and electrically stimulate the auditory nerve within the cochlea. The auditory brainstem implant (ABI) bypasses a damaged cochlea and auditory nerve auditory and directly stimulate the brainstem nuclei. The inferior colliculus implant (ICI) or auditory midbrain implant (AMI) bypass damaged brainstem nuclei to stimulate the inferior colliculus in the midbrain. With the refinements in implant technology, patient selection criteria for the various implant devices need to be periodically reconsidered with a view to obtaining increasingly high levels of speech recognition for the different etiologies. In general it is thought that the more peripheral the implant, the better the chance of success. Indeed the more peripheral implants (RW, MEIs, CIs and ABIs in non-NF2 patients) have been 第19回日本耳科学会特別講演3