| Project/Area Number |
09671732
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Yamagata University |
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Principal Investigator |
AOYAGI Masaru Yamagata Univ., School of Medicine, Professor, 医学部, 教授 (40107181)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Yutaka Yamagata Univ., School of Medicine, Assistant, 医学部, 助手 (70250925)
YOKOTA Masashi Yamagata Univ., School of Medicine, Associate Professor, 医学部, 助教授 (80166884)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | objective audiometry / steady-state response / automatic detection / computer analysis / amplitude modulation following response / multiple stimulation technique / phase spectral analysis / phase coherence |
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| Research Abstract |
Hearing threshold can be evaluated by 80-Hz amplitude-modulation following response (80-Hz AMFR) detected by phase coherence in a frequency specific manner in sleeping children. However, this method is time consuming. The aim of this project was to develop a objective audiometry device using multiple stimulation technique and automatic threshold detection techniques, by which audiogram can be obtained only by AMFR thresholds.
Mixed sinusoidally amplitude modulated tone consisted of several carrier frequencies and modulation frequencies for multiple simultaneous stimuli was produced using personal computer (NEC PC9821Xa7e) and programming software (LabVIEW). When the difference of modulation frequencies of mixed sinusoidally amplitude modulated tone was less than 10 Hz, two responses were detected clearly and simultaneously using phase coherence as a analyzing method for the automatic detection of threshold. However, the analyzing technique using phase coherence and magnitude-squared coh
… More
erence was not so time saving in the detection of responses. Therefore, we developed a new analyzing method for the detection of threshold for examination time saving. Scalp-recorded potential and modulation waveform were recorded simultaneously. Succeeding 10 points in the same phase (90 deg) on modulation waveform were used as triggers. Ten averaging waveforms consisted of 512 points of scalp-recorded potentials were obtained using each trigger and were analyzed by phase coherence.
Using this analyzing technique, examination time was shortened to about 30% comparing with conventional method developed by Fridman. Using this technique, the effect of masker frequency and intensity produced by a tone burst on AMER threshold was investigated for the estimation of frequency specificity of 80-Hz AMFR.The results suggested masking effect by tone burst on 80-Hz AMFR and frequency specificity of 80-Hz AMFR to be high enough.
Automatic objective audiometry device using this technique is now using clinically to correct the data for the estimation of frequency specificity and usefulness of multiple stimulation technique. Less
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