pedi-cochlear-implant-slides-071219

pedi-cochlear-implant-slides-071219 - Pediatric Bilateral...

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Unformatted text preview: Pediatric Bilateral Cochlear Pediatric Bilateral Cochlear Implantation Implantation Chad Simon, MD Chad Simon, MD Tomoko Makishima, MD Tomoko Makishima, MD University of Texas Medical Branch University of Texas Medical Branch Dept. of Otolaryngology Dept. of Otolaryngology Grand Rounds Presentation Grand Rounds Presentation December 19, 2007 December 19, 2007 Overview Overview History Hardware Indications Surgical Procedure Bilateral Hearing and its Benefits Bimodal Listening Bilateral Implantation Conclusions Overview Overview History Hardware Indications Surgical Procedure Bilateral Hearing and its Benefits Bimodal Listening Bilateral Implantation Conclusions History History Cochlear implants as we know them now are the result of intensive research over the last four decades. However, there is a long history of attempts to provide hearing by the electrical stimulation of the auditory system. The centuries old interest in the biologic application of electricity was the basis for the development of cochlear implants. Volta Volta In the late 18th century, Alessandro Volta discovered the electrolytic cell Volta was the first to stimulate the auditory system electrically, by connecting a battery to two metal rods that were inserted into his ears When the circuits were completed, he received the sensation of ‘une recousse dans la tate’ (“a boom within the head”), followed by a sound similar to that of boiling of thick soup. Auditory Nerve Potentials Auditory Nerve Potentials The work of Wever and Bray (1930) demonstrated that the electrical response recorded from the vicinity of the auditory nerve of a cat was similar in frequency and amplitude to the sounds to which the ear had been exposed. The Importance of the The Importance of the Cochlea Cochlea Meanwhile, the Russian investigators Gersuni and Volokhov in 1936 examined the effects of an alternating electrical stimulus on hearing. They also found that hearing could persist following the surgical removal of the tympanic membrane and ossicles, and thus hypothesized that the cochlea was the site of stimulation. Stimulating the Auditory Stimulating the Auditory Nerve Nerve In 1950, Lundberg performed one of the first recorded attempts to stimulate the auditory nerve with a sinusoidal current during a neurosurgical operation. His patient could only hear noise. Stimulating the Auditory Stimulating the Auditory Nerve Nerve A more detail study followed in 1957 by Djourno and Eyries They provided the first detailed description of the effects of directly stimulating the auditory nerve in deafness They placed a wire on the auditory nerves that were exposed during an operation for cholesteatoma. When the current was applied to the wire, the patient described generally high-frequency sounds that resembled a “roulette wheel” or a “cricket” The signal generator provided up to 1,000-Hz and the...
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This note was uploaded on 12/28/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

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pedi-cochlear-implant-slides-071219 - Pediatric Bilateral...

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