Department of Radiology, Capital Medical University, Beijing Tongren Hospital, Beijing, China;Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, China.
Departments of Radiology, Capital Medical University, Beijing Friendship Hospital, Beijing, China.
J Int Adv Otol. 2021 Jul;17(4):319-324. doi: 10.5152/iao.2021.9449.
Although many studies have suggested that air cells may play an important role in sigmoid sinus diverticulum and/or dehiscence (SSDD)-induced pulsatile tinnitus (PT), the exact effects remain unclear. This study aims to quantitatively investigate the effect of different degrees of pneumatization of temporal bone on sound transmission from the sigmoid sinus to the tympanic cavity.
In the clinical study, 25 patients were enrolled to measure the sound intensity and frequency of SSDD-induced PT. In the experimental study, sound inputs at different frequencies at the dehiscent sigmoid plate were measured and compared among realistic object models of different degrees of pneumatization, when sound intensity in the tympanic cavity was fixed as the level of the PT sound intensity sensed by patients.
The sound intensity sensed by PT patients was 34.0 ± 13.0 dB SPL, which represented the sound intensity in the tympanic cavity transmitted from the dehiscent sigmoid plate. In the experimental study, when sound received in the tympanic cavity was fixed at 34 dB SPL, the mean inputs of sound intensity at the dehiscent sigmoid plate were 46.9, 46.2, 45.2, 47.1, 57, 57.4, and 74.1 dB SPL in a hypo-pneumatized model; 42.6, 43, 41.5, 43.2, 47.3, 58.2, and 78.8 dB SPL in a moderately pneumatized model; 52.6, 52.8, 48.1, 61, 64.2, 82.4, and >87.3 dB SPL in a well-pneumatized model; and 47.2, 46.2, 45.4, 49.4, 54.9, 66.6, and 77.7 dB SPL in hyper-pneumatized model, with increased sound frequencies (125-8000 Hz). The mean sound transmission distances were 41.7 mm, 45.2 mm, 47.6 mm, and 48.4 mm in successively better pneumatized models.
Sound reduces while passing through air cells and attenuation is lowest in the moderately pneumatized temporal bone, followed by the hypo- and hyper-pneumatized temporal bones, and the highest in the well-pneumatized temporal bone. Lower-frequency sound attenuation (≤1000 Hz) is less than that of higher-frequency sound (>1000 Hz).
尽管许多研究表明气房可能在乙状窦憩室和/或乙状窦骨裂（SSDD）引起的搏动性耳鸣（PT）中发挥重要作用，但确切的影响仍不清楚。本研究旨在定量研究不同程度颞骨气化对声音从乙状窦向鼓室传播的影响。
在临床研究中，招募了 25 名患者测量 SSDD 引起的 PT 的声音强度和频率。在实验研究中，在不同程度气化的真实物体模型中测量和比较不同频率的声音输入，当鼓室中的声音强度固定为患者感知的 PT 声音强度的水平时。
PT 患者感知的声音强度为 34.0±13.0dB SPL，代表从乙状窦骨裂处传入鼓室的声音强度。在实验研究中，当鼓室接收到的声音固定在 34dB SPL 时，在低气化模型中，乙状窦骨裂处声音强度的平均输入为 46.9、46.2、45.2、47.1、57、57.4 和 74.1dB SPL；在中度气化模型中为 42.6、43、41.5、43.2、47.3、58.2 和 78.8dB SPL；在良好气化模型中为 52.6、52.8、48.1、61、64.2、82.4 和>87.3dB SPL；在高气化模型中为 47.2、46.2、45.4、49.4、54.9、66.6 和 77.7dB SPL，声音频率增加（125-8000Hz）。依次更好的气化模型的平均声音传输距离分别为 41.7mm、45.2mm、47.6mm 和 48.4mm。
声音在通过气房时会减弱，中度气化的颞骨衰减最低，其次是低气化和高气化的颞骨，而在完全气化的颞骨中衰减最高。低频声音衰减（≤1000Hz）小于高频声音衰减（>1000Hz）。
