CLINICAL RESULTS OF COCHLEAR IMPLANT AND MECHANISM OF SPEECH PERCEPTION

• Published in: JIBI INKOKA TEMBO Vol. 39; no. 6; pp. 594 - 603
• Main Author: Funasaka, Sotaro
• Format: Journal Article
• Language: Japanese
• Published: Society of Oto-rhino-laryngology Tokyo 1996
• Subjects: active cochlea; cochlear implant; language performance; SPECTRA-22; speech perception mechanism
• ISSN: 0386-9687; 1883-6429
• DOI: 10.11453/orltokyo1958.39.594

This paper describes first the system of the cochlear implant (Nucleus SPECTRA-22, Cochlear Pty. Ltd.) and speech perception test results performed on monosyllables, words and sentences in conditions under quiet and multitalker noise, with or without lipreading. These results indicate that the cochlear implant is very effective for a completely deaf or a profoundly deaf patient to restore the conversation ability. This device is also useful for a pre-or a perf-lingual infant to develop speech, although Japan is far behind from the United States and western Europe, by the teachers'opposition of schools for the deaf. Regarding this situation, the author has establishe children's center privately with the aid of volunteers, most of whom have raised at least two of their own children. It works well so far. Secondly, recent development of cochlear physiology is stated, that is, outer hair cells can regulate the vibration of the basilar membrane to enable a sharp frequency analysis, and this leads to the concept of active cochlea. The damage of outer hair cells results in deterioration of the frequency analysis and a precise loudness increment as well as threshold elevation. A hearing aid is not effective for the patient with severe hearing loss due to inner ear damage, since it does not compensate the deteriorated frequency analysis that is important for speech sound perception. Thirdly this paper states the brain mechanism of speech perception relative to the application of the cochlear implant for very young children.