**5. Conclusions**

To study the influence of piezoelectric transducer's stimulating sites on its hearing compensation performance, a human ear FE model, including the ear canal, the middle ear, and the cochlea, was constructed. The validity of this model was verified by three sets of comparisons. The results show the piezoelectric transducer provides better performance when simulating the stapes or RW membrane than stimulating other studied sites, especially at a high frequency. The incus body is the worst stimulating site for the piezoelectric transducer. Meanwhile, the performance of the RW membrane stimulation, as well as that of the stapes stimulation, are susceptible to the change of the excitation's direction. Considering most sensorineural hearing loss is severe at high-frequency, the piezoelectric transducer's orientation for RW stimulation or stapes stimulation should be guaranteed during the surgery.

**Author Contributions:** Conceptualization, H.L. and J.Y.; formal analysis, H.L.; funding acquisition, H.L.; methodology, H.L., Y.Z. and Z.R.; software, Y.Z.; writing—original draft, H.L. and J.Y.; writing—review and editing, Z.R.

**Funding:** This research was funded by National Natural Science Foundation of China, gran<sup>t</sup> number 51775547, and Top-notch Academic Program Development of Jiangsu Higher Education Institutions, gran<sup>t</sup> number PPZY2015B120.

**Acknowledgments:** We thank Xinsheng Huang and Lei Zhou for helping us prepare the CT images of the temporal bone.

**Conflicts of Interest:** The authors declare no conflict of interest.
