1987 Fiscal Year Final Research Report Summary
Biomedical Engineering Study on a Design of Cochlear Implants.
| Project/Area Number |
61490002
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Hokkaido University. |
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Principal Investigator |
IFUKUBE Tohru Research Institute of Applied Electricity, Hokkaido University Associate Professor, 応用電気研究所, 助教授 (70002102)
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| Co-Investigator(Kenkyū-buntansha) |
TERAYAMA Yoshihiko Medical School, Hokkaido University, 医学部, 教授 (90000976)
FUTAMI Ryouko Research Institute of Applied Electricity, Hokkaido University Assiatant Profess, 応用電気研究所, 助手 (20156938)
HOSHIMIYA Nozomu Research Institute of Applied Electricity, Hokkaido University Professor, 応用電気研究所, 教授 (50005394)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Cochlear Implant / Speech Processing / 刺激電極 |
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| Research Abstract |
A purpose of this research is to do fundamental experiments regarding an optimal design of the cochlear implant that electrically stimulates the survival auditory nerves for the deaf. Researches carried out are the following 4 points.
(1)It was investigated what kind of current distribution produces inside the cochlea of a human cadaver when electrodes were inserted into the cochlea. (2) A spwwch processor was developed on the basis of the above result and the discrimination ability of synthetic vowels was evaluated by a subject implanted with an eight channel cochlear prosthesis. (3) A new model of the electrode for the extracochlear implant was developed as a less invasive alternative to electrode insertion in the cochlea. (4) Such a speech coding method that discrimination of vowels is possible with single channel method was proposed and its efficacy was evaluated by an animal experiment.
As results, (1) a stimulation current path from the inside of the cochlea to the outside wlarifie
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d. It is found out that a stimulation current spreads largely outside the cochlea (T.Ifukube, 1987a). (2) A speech processor that had a function of lateral inhibition was designed in order to compensate for the wide current spread and its efficacy was confirmed by a recognition experiment of synthesis vowels (T.Ifukube, 1987b). (3)A Pt-Ir wire electrode covered with Polyvinyl alcohol gel including saline solution was developed as a stimulation electrode for a single channel extracochlear implant. The electrical characteristics of the electrode was checked and it was ascertained that the electrode had almost the same characteristics as human body (T.Ifukube, et al, 1988, J.Matsushima et al, 1988). (4) the speech processor for a single channel cochlear implant was designed which produced a time sequential stimulation pulses obtained by combining pitch signals and the second formant frequency of voices. The efficacy of this coding method was proved from a view point of compound action potential responded to stimulation that gave to the cochlea of guinea pig (T.Ifukube et al, 1988, K.Takahashi et al, 1988). Less
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