Human ear finite element model study of the effects of ear canal and middle ear cavity on air conduction and bone conduction

Abstract

Objective:To study the influence of the ear canal and middle ear cavity on air conduction and bone conduction. Method:A finite element model of the human middle ear was established. By establishing the external ear canal and the middle ear cavity, we evaluated the effects of the external canal and the middle ear cavity on air conduction and bone conduction. Result:In air conduction, the external canal improved the stapes response at the frequency range of 0.5 kHz to 6 kHz, and the maximum increase was 11 dB at 3 kHz. The middle ear cavity mainly reduced the response of stapes at mid-low frequency, with the drops of 2-4 dB under 2 kHz; in bone conduction, ear canal slightly reduced the low-frequency response, but increased the response of the stapes at the mid-high frequency, with a maximum increase of 1.9 dB at 1.5 kHz. The middle ear cavity mainly increased the stapes response at mid-frequency near 1.5 kHz, with a maximum increase of 2.5 dB. Conclusion:Our results show that, in air conduction, the ear canal significantly increases the middle-frequency response, while the middle ear cavity decreases the low-mid frequency response. Whereas, the ear canal and the middle ear cavity have slightly effect on bone conduction.