| Project/Area Number |
15500382
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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 |
Rehabilitation science/Welfare engineering
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| Research Institution | Kitasato University |
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Principal Investigator |
MATSUHIRA Toshimasa Kitasato University, School of Allied Health Science, Professor, 医療衛生学部, 教授 (50131032)
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| Co-Investigator(Kenkyū-buntansha) |
SANO Hajime Kitasato University, School of Medicine, Lecturer, 医学部, 講師 (80205997)
SUZUKI Keiko Kitasato University, School of Allied Health Science, Lecturer, 医療衛生学部, 講師 (40286381)
HARA Yuki Kitasato University, School of Allied Health Science, Assistant, 医療衛生学部, 助手 (50276185)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2004: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | bone conduction hearing aid / hearing aid fitting / functional gain / mechanical coupler / acousto-mechanical sensitivity level / air-bone gap / conductive hearing loss / bone conduction speech recognition threshold / 聴力レベル表示 / 非線形増幅 / 装用利得 / 人工マストイド |
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| Research Abstract |
1.Validity of performance estimation of bone conduction hearing aid.
Validity of a formula estimating aided threshold of a bone conduction hearing aid from the pure-tone thresholds of the wearer and the output characteristics of the hearing-aid (acousto-mechanical sensitivity level, AMSL_<HL>) was examined. For subjects with conductive hearing loss and normal hearing adults whose bilateral ear canals were plugged to make simulated hearing loss, aided thresholds of a bone conduction hearing aid were measured and they were compared with the estimation using the above formula. The results suggested that although the estimation errors (in standard deviation) for the subjects of both groups were a little larger (about 4 dB and 7 dB respectively) than those for the air conduction hearing aids, this estimation has a potential of clinical use when the AMSL_<HL> of the hearing aids are provided by manufacturers.
2.Prescription of output characteristics of bone conduction hearing aid
As the maximum
… More
output level of bone conduction hearing aid is limited to around 70dBHL, linear amplification cannot provide enough loudness to daily speech level without distortion of louder sound. Considering this condition, it was concluded that optimum amplification lies between the linear amplification with AMSL_<HL> of -20dB, and the following prescription ; linear amplification with AMSL_<HL> of 0dB for input level lower than 50dBHL, and nonlinear amplification with compression ratio of 2:1 for input level of 50 to 90dBHL. We are planning further clinical study to determine the optimum prescription
3.Reference levels of bone conduction speech recognition threshold
The vibratory force levels of three types of bone conduction receivers corresponding to the mean speech recognition thresholds for the 67-S Japanese speech audiometric test lists were measured for 20 normal hearing listeners, and compared with those recommended in JIS T1201-2. Although each of the three levels was within 2.5dB of the recommended value, statistically significant inter-receiver differences were observed. These differences were considered to originate primarily from inter-receiver differences of frequency response and, from sound radiation from the bone vibrator. These findings indicate that the reference level for speech for individual receivers must be determined in instances where the frequency response of the bone conduction receiver is not specified Less
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