이식형 마이크로폰과 진동체를 갖는 인공중이의 이득 보상을 위한 주파수 특성 고찰
Study on frequency response of implantable microphone and vibrating transducer for the gain compensation of implantable middle ear hearing aid
2
조회
0
다운로드
1
인용
0
참고문헌
키워드
초록
ACROSS device, which is composed of an implantable microphone, a signal processor, and a vibrating transducer, is a fullyimplantable middle ear hearing device(F-IMEHD) for the recovery of patients with hearing loss. And since a microphone is implanted under skin and tissue at the temporal bones, the amplitude of the sound wave is attenuated by absorption and scattering. And the vibrating transducer attached to the ossicular chain caused also the different displacement from characteristic of the stapes. For the gain control of auditory signals, most of implantable hearing devices with the digital audio signal processor still apply to fitting rules of conventional hearing aid without regard to the effect of the implanted microphone and the vibrating transducer. So it should be taken into account the effect of the implantable microphone and the vibrating transducer to use the conventional audio fitting rule. The aim of this study was to measure gain characteristics caused by the implanted microphone and the vibrating transducer attached to the ossicle chains for the gain compensation of ACROSS device. Differential floating mass transducers (DFMT) of ACROSS device were clipped on four cadaver temporal bones. And after placing the DFMT on them, displacements of the ossicle chain with the DFMT operated by 1 mApeak current was measured using laser Doppler vibrometer. And the sensitivity of microphones under the sampled pig skin and the skin of 3 rat back were measured by stimulus of pure tones in frequency from 0.1 to 8.9 kHz. And we confirmed that the microphone implanted under skin showed poorer frequency response in the acoustic high-frequency band than it in the low- to mid-frequency band, and the resonant frequency of the stapes vibration was changed by attaching the DFMT on the incus, the displacement of the DFMT driven with 1 mArms was higher by the amount of about 20 dB than that of cadaver's stapes driven by the sound presssure of 94 dB SPL in resonance frequency range.
Abstract
ACROSS device, which is composed of an implantable microphone, a signal processor, and a vibrating transducer, is a fullyimplantable middle ear hearing device(F-IMEHD) for the recovery of patients with hearing loss. And since a microphone is implanted under skin and tissue at the temporal bones, the amplitude of the sound wave is attenuated by absorption and scattering. And the vibrating transducer attached to the ossicular chain caused also the different displacement from characteristic of the stapes. For the gain control of auditory signals, most of implantable hearing devices with the digital audio signal processor still apply to fitting rules of conventional hearing aid without regard to the effect of the implanted microphone and the vibrating transducer. So it should be taken into account the effect of the implantable microphone and the vibrating transducer to use the conventional audio fitting rule. The aim of this study was to measure gain characteristics caused by the implanted microphone and the vibrating transducer attached to the ossicle chains for the gain compensation of ACROSS device. Differential floating mass transducers (DFMT) of ACROSS device were clipped on four cadaver temporal bones. And after placing the DFMT on them, displacements of the ossicle chain with the DFMT operated by 1 mApeak current was measured using laser Doppler vibrometer. And the sensitivity of microphones under the sampled pig skin and the skin of 3 rat back were measured by stimulus of pure tones in frequency from 0.1 to 8.9 kHz. And we confirmed that the microphone implanted under skin showed poorer frequency response in the acoustic high-frequency band than it in the low- to mid-frequency band, and the resonant frequency of the stapes vibration was changed by attaching the DFMT on the incus, the displacement of the DFMT driven with 1 mArms was higher by the amount of about 20 dB than that of cadaver's stapes driven by the sound presssure of 94 dB SPL in resonance frequency range.
참고문헌 (12)
- J. I. Suzuki, "Early studies and the history of development of the middle ear implant in Japan", Advances in Audiology, 4, pp.1~14 (1998)
- H. Dillon, "Hearing Aids", pp.2~6 (2000), Thieme
- 이명원, "중이 이식형 보청기에서 DFMT의 진동에 의한 등골 및 고막 방향으로 전달되는 진동력 측정", 센서학회지, 18(4), pp.286~293 (2009), 한국센서학회
- F. M. Sink, "Vibrant semiimplantable heairng device with digital sound processing", Archives of Otolarygology -head & neck surgery, 127(12), pp.1433~1437 (2001)
- 이창우, "이식형 인공중이를 위한 압전 플로팅 매스 트랜스듀서의 제안", 센서학회지, 14(5), pp.322~330 (2005), 한국센서학회
- A. E. Deddens, "Totally implantable hearing aids:the effects of skin thickness on microphone function", American Journal of Otolaryngology, 11, pp.1~4 (1990)
- A. J. Needham, "The effects of mass loading the ossicles with a floating mass transducer on middle ear transfer function", Otology & Neurotology, 26, pp.218~224 (2005)
- M. Winter, "The use of reverse transfer function(RTF)in the fitting procedure of implantable heairng devices", Proceedings of the 4th International Symposium on Electronic Implats in Otology (2005)
- L. Rabiner, "Fundamentals of speech recognition", pp.11~37 (1993), Prentice Hall
- M. K. Kim, "Design of differential electromagnetic transducer for implantable middle ear hearing device using finite element method", Sensors and Actuators, 130, pp.234~240 (2006)