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Second Biennial Hearing Aid Research and Development Conference


September 22-24, 1997
National Institutes of Health
Bethesda, Maryland



Development of a Hearing-aid Database

Tatsuo Nakagawa, Yokohama National University, Japan

Over 500 analog and digital hearing-aids are available in Japan. A hearing-aid database was developed in 1992 and since then the data have been renewed every year. The program can be run by using a personal computer.

The hearing-aid database uses 10 classifiers: manufacture, types (BTE, ITE, etc.), size, amplification types (linear or non-linear), input options, directional or non-directional microphone, the Japanese Welfare Low application, number of programs (if programmable), method of program modification, and price. Acoustical characteristics of each hearing-aid are also stored in a standard format (JIS, 1986). The program shows score of adaptability for each selected hearing-aid to a given audiogram input. Its calculation is based on predicted gain to amplify Japanese long term average speech spectrum to his or her MCL.

From the latest hearing-aid database ('95 version), distribution of hearing-aids in Japan can be analyzed. For example, 92% of all hearing-aids in Japan are analog. 49% of analog hearing-aids are BTE and 58% of BTE hearing-aids are large in size. The microphones of 7% of BTE hearing-aids are directional. 37% of BTE hearing-aids have direct audio-input. Less than 10% of BTE hearing-aids amplify non-linearly. 85% of BTE hearing-aids have maximum gain of 50 to 60dB. More than 50% of BTE hearing-aids have 130 to 140dB maximum power output.

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