| Project/Area Number |
61570817
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Otorhinolaryngology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUNAI Hiroaki Lecturer, Faculty of Medicine, The University of Tokyo, 医学部(分), 講師 (90142249)
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| Co-Investigator(Kenkyū-buntansha) |
HORIUTI Yasuharu Assistant, Faculty of Medicine, The University of Tokyo, 医学部(分), 助手 (80167634)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Positive Slow Wave / Auditory Brainstem Response / 他覚的聴力検査 / 周波数選択性 / チューニングカーブ / 陽性緩余波 |
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| Research Abstract |
Through the present ressearch project from 1986 to 1987, the potential of application of vertex-positive slow wave ( PSW ) of the ABR was investigated.
In order to evaluate frequency specificity of the PSW, two experiments were performed. 1) A tone on tone simultaneous masking paradigm was used to determine tuning curves in rats. Tuning curves were constructed to define masker intensity that resulted in a 50% reduction in probe elicited PSW amplitude. Q_<10> values were distributed between 1.0 and 1.6. Maximum masker frequencies of the tuning curves were not necessarily equal to the frequency of probe without 2-kHz. 2) The same paradigm was used in human subjects. Q_<10> values were gradually increased with the increase in frequency. They were distributed between 1.0 and 5.3. Maximum masker frequencies of the tueing curves were not necessarily equal to the frequency of probe. These results indicate that the short tone burst stimuli may enable to assess certain auditory function at different frequencies, and they have wider frequencies' spread of the cochlear area around stimulus frequencies.
In order to get stabilized PSW in human subjects, two experiments were performed. 1) The wave evoked by short tone burst was subtracted from the the wave evoked by the stimulus which consists long duration and same rise-fall time as the short tone burst. Its results showed that the PSW recorded in human subjects were also elongated as the duration of a tone burst was increased. 2) The PSW were recorded from the scalp using non-cephalic reference electrode method. The study led us to the conclusion that the PSW were of maximal amplitude at the resion of C_z. A_1 and A_2 are active electrode, thus, amplitude of positive slow wave is higher than that from standard vertex-earlobe deviation.
There are some difficult problems in the clinical application of the positive slow weve of ABR. However, the results of the project indicate that it has potential as a tool for objective audiometry.
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