The method of masticatory movement noise reduction using the dual channel implantable microphone

Abstract

The input part of fully implantable hearing devices (FIHDs) was using the implantable microphone that was implanted under the skin of the temporal bone. So, implantable microphone`s characteristics can be affected by the masticatory movement and moving artifacts. In this paper, the 2-channel implantable microphone was designed for masticatory movement noise reduction. For in vivo experiment, the fabricated microphone was implanted in the rabbit. And then, the 1 kHz pure-tone sound by a speaker was applied to the rabbit, and the feeds were given simultaneously to the rabbit. The measured signal was processed using the adaptive filter with least mean square (LMS) algorithm for noise reduction. To confirm performance of proposed method, the correlation coefficient and signal to noise ratio (SNR) before and after the signal processing were calculated.

Mastication noise reduction method for fully implantable hearing aid using piezo-electric sensor

“…The conventional methods did not consider the biomechanical problems associated with mastication movement. Jenkins et al [12] and Woo et al [13] studied mastication noise at FIHDs with a microphone. However, because mastication noise is generated as vibrations from the jawbone, the microphone is not suitable because of problems related to biocompatibility.…”

“…However, they did not consider the anatomical vibration effect for an implanted microphone. Woo et al [13] studied anatomical mastication with dual-channel microphones and an adaptive filter. However, the adaptive filter is not suitable for hearing devices owing to its excessive computation, and the microphones cannot be affected by the acoustic sounds.…”