1.Beihang University;2.Chongqing University;3.Beijing Tongren Hospital
摘要：目的 搏动性耳鸣的耳鸣声与患者心跳合拍，多于颅内存在客观性的声源。乙状窦被普遍认为是搏动性耳鸣的一个重要声源，静脉声通过颞骨蜂房气腔传导至鼓室。有假设认为颞骨蜂房过度气化可放大静脉声，引发搏动性耳鸣，但尚无定量化的生物力学研究。方法 本文通过体外实验模拟乙状窦静脉声的产生、传导，并对鼓膜处接收到的声信号进行时域和时频域分析。结果 骨板缺损时，所有蜂房的静脉声都有高声压、脉动性。气化一般蜂房静脉声声压最高。骨板完整时，所有蜂房的静脉声脉动性微弱，且声压接近背景声。不同气化程度蜂房接收到的静脉声脉动性频段各不相同。结论 气化一般蜂房的静脉声放大效果最好，气化不足蜂房对静脉声的放大效果最差。颞骨蜂房气化程度不是导致致病静脉声的充分或必要条件。乙状窦沟骨板缺损是导致致病静脉声的充分条件。当骨板缺损时，所有气化等级的蜂房都可引发静脉噪声。当骨板完整时，三个气化等级的蜂房都不会引发静脉噪声。
Abstract：Objective Pulsatile tinnitus (PT) is a pulse-synchronous tinnitus. Many PT cases have objective sound source in the patient’s head. Sigmoid sinus (SS) is widely suggested to be a primary sound source of PT, and the SS venous sound might transmit into tympanic cavity through temporal bone air cells (TBAC). The hypothesis suggested that the hyperpneumatization of TBAC might amplify the venous sound and induce PT, but presently without quantitative research in view of biomechanics. Method Through the in vitro experiment, the generation and transmission pathways of the venous sound were simulated. The sound signals at the position of eardrum were recorded and analyzed. Result In case of cortical plate dehiscence, the high pressure and pulse-synchronous venous sounds were received at eardrum. The highest sound pressure occurred in the normal pneumatization case. In case of cortical plate intactness, the non-pulsatile venous sounds with pressure close to the background control sound were received at eardrum. TBAC with different pneumatization grades would transmit venous sound in different frequency range. Conclusion Normal pneumatization TBAC exhibits the highest amplification on venous sound, while hypopneumatization TBAC exhibits the lowest amplification on venous sound. The pneumatization grade of TBAC is neither sufficient nor essential condition of pathogenic venous sound, while the cortical plate dehiscence is the sufficient condition of pathogenic venous sound.In case of cortical plate dehiscence, TBAC with all pneumatization grades would induce venous sound. In case of cortical plate intactness, TBAC with all pneumatization grades would not induce venous sound.