Yu Zhao1, Yumeng Zhang1, Houguang Liu1, Xinsheng Huang2 
School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou, P. R. China.
2Department of Otolaryngology, Zhongshan Hospital affiliated to Fudan University,
 Shanghai, P.R. China.

In order to study the effect of the actuator stimulating position on the performance of bone conduction hearing aids, the bone conduction sound transmission mechanism was studied. To facilitate this study, a coupled a finite element (FE) model of the human head and the ear was built. Firstly, a series of micro-CT images of a human head was used to establish an FE model of the human head, and the reliability of the model was verified by comparing the model-predicted mechanical impedance of the excitation position and the acceleration response of the promontory with the experimental data. Secondly, an FE model of human ear, which consists of the ear canal, the middle ear, and the spiral cochlea incorporating the cochlear third windows was also established and verified. Then, based on these two FE models, we constructed a coupled FE model of the human head and the ear via coupling the corresponding nodes, and applied the force excitation at different sites on the model’s head. Finally, through comparative analysis of the dynamic response characteristics of the basilar membrane in the coupled FE model, the effect of different excitation positions of the actuator on the hearing compensation performance of the bone conduction hearing aid was studied. The results show that the best excitation position for the bone conduction’s actuator is near the cochlea, especially the one close to the mastoid. Besides, stimulating the human head close to the cochlea would improve the bone conduction’s performance at low-mid frequencies.

Acknowledgements: This work was supported by the National Natural Science Foundation of China (grant number 51775547).