双侧气导声源定位是通过耳间时间差、强度差以及频谱特征实现。单侧传导性聋近年来广泛应用骨传导助听装置改善听觉功能，但对声源定位功能的改善并不理想。由于骨导与气导传音至耳蜗的途径不同，骨导植入耳与健耳的耳间时间及强度差的不匹配是导致声源定位功能恢复不理想的可能原因。同时，前期研究发现骨导低频谐波失真现象及其对基底膜振动的影响，提示骨导低频谐波失真也可能是声源定位的重要影响因素。本项目在已构建的单侧骨传导声源定位模型的基础上，通过人颅离体实验及猫或大动物在体实验，采用激光多普勒测振仪测量双耳间的鼓膜脐、鼓岬、镫骨足板及基底膜幅值响应差异、峰值时间差或波形相位差，对骨传导与气导途径的动力学特性差异进行分析。 同时，应用已有的整颅（包含中耳、耳蜗）有限元模型，对耳间时间差模拟分析，以期明确单侧传导性聋骨导植入后声源定位功能不佳的影响因素，为单侧传导性聋植入骨导助听装置的改进提供理论依据。

The human auditory system uses several prompts for sound localization, including the interaural time and level differences and the spectral information. Bone conduction hearing devices have been used to improve hearing in patients with unilateral conductive hearing loss, but it provides little help in sound localization. The poor ability for sound localization may be attributed to mismatching the time- and level-differences between the ear implanted with bone-anchored hearing aids (BAHA) and the normal ear because of different pathways between air and bone conductions. Furthermore, our previous study has found that the harmonic distortion at low frequency arising from bone conduction and its influence on basilar membrane motion may be an important factor in realization of sound localization. In this proposed project, the differences of amplitude response, peak time and waveform phase between the umbo, promontory tympani, stapes footplate, and basilar membrane will be measured with Laser Doppler Vibrometry in cadaveric head and the cat, pig or ox on the basis of constructed unilateral bone conduction model. The dynamic characteristics of the bone and air conductions will be carefully analyzed. The 3-dimensional finite element model constructed from the whole skull will be applied to explore the interaural time difference. This study aims to clarify the mechanism of sound localization in patients with unilateral conductive hearing loss and implanted with BAHA and to provide theoretical basis for bone conduction hearing devices implantation.