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A cochlear implant (CI) is an electronic device that restores partial hearing for patients with advanced hearing loss who gain limited benefit from a conventional hearing aid. Part of the device is surgically implanted under the skin and an electrode is placed within the cochlea to directly stimulate the auditory nerve, bypassing the damaged portions of the inner ear. Over the past 50 years, tremendous advancements have been made in cochlear implantation, from merely eliciting sound via direct stimulation of the auditory nerve to restoring functional hearing in hundreds of thousands of patients. Continued innovations in cochlear implantation technology, including shorter more flexible electrodes, smaller devices, incorporation of hearing aid technology, evolving speech-processing strategies, and refinements in surgical technique, including atraumatic, “soft surgery” principles and the development of alternative surgical approaches, have led to improved outcomes.
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Today, cochlear implantation serves as the gold standard for auditory rehabilitation of advanced sensorineural hearing loss (SNHL) and poor speech perception for both adults and children. For children with prelingual or perilingual SNHL, early cochlear implantation has been shown to have positive benefits on auditory system development, language acquisition, and integration into society. In addition, cochlear implantation has demonstrated one of the highest cost-effectiveness ratings of common medical interventions, particularly in children. As a result, FDA CI candidacy criteria have expanded to include patients as young as 1 year of age and many centers now advocate for even earlier implantation when the diagnosis of profound hearing loss can be confidently confirmed and the child has failed to demonstrate adequate progress with conventional hearing aid use and rehabilitation. Worldwide, the number of implants is rapidly increasing. As with many other technology-driven medical treatment modalities, recent innovations in microcircuitry and computer science are continuing to drive the performance profiles of CIs to new heights.
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Holman
MA, Carlson
ML, Driscoll
CL,
et al. Cochlear implantation in children 12 months of age and younger.
Otol Neurotol. 2013;34(2):251–258.
[PubMed: 23444471]
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Carlson
ML, Sladen
DP, Haynes
DS,
et al. Evidence for the expansion of pediatric cochlear implant candidacy.
Otol Neurotol. 2015;36(1):43–50.
[PubMed: 25275867]
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COCHLEAR IMPLANT DESIGN
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All modern CI systems function by the use of the same basic components. The external components include the microphone, battery, speech processor, external magnet, and transmitter antenna. The internal components include the internal magnet, antenna, receiver-stimulator, and electrode array (Figure 71–1). Sound is first detected by a ...