Effects of endolymphatic hydrops on acoustic energy absorbance

Abstract

Background: The presence of endolymphatic hydrops (EH) may cause hearing loss and affect the transmission of acoustic energy to the inner ear.

Objectives: Acoustic energy absorbance on wideband acoustic immittance (WAI) was evaluated, focusing especially on EH in the vestibule.

Material and methods: A total of 32 ears from 16 patients who underwent 3-T magnetic resonance imaging (MRI) to evaluate the presence of EH were examined, retrospectively. The degree of EH in the vestibule was classified into three grades (no, mild, and significant), and pure tone audiometry (PTA) and WAI were measured before and after a glycerol drip.

Results: Ears with significant EH showed significantly higher hearing levels and air-bone gaps (ABG), and higher absorbance values on WAI at low frequencies (560–600 Hz) than ears with mild or no EH. Changes in absorbance values were observed in some ears without threshold change on PTA.

Conclusions and Significance: This study showed significantly higher absorbance values of acoustic energy with significant vestibular EH at low frequencies. Considering ABGs observed in ears with significant EH, the presence of EH in the vestibule might cause an obstacle to the transmission of acoustic energy to the inner ear.

Chinese abstract

背景：内淋巴积水（EH）的存在可能会导致听力下降并影响将声能传输到内耳。

目的：评估了对宽带声阻抗（WAI）的声能吸收, 着重探讨前庭EH。

材料和方法：回顾性检查了16位患者的32只耳朵。他们接受了3-T磁共振检查影像学（MRI）检测以评估EH的存在。 前庭EH的程度分为三个等级（无, 轻度和显著）, 在滴注甘油前后测量纯音测听（PTA）和WAI。

结果：具有明显EH的耳朵表现出明显较高的听力水平和气骨间隙（ABG）, 并且在低频（560–600 Hz）时, WAI的吸收值要比轻度EH或没有EH的耳朵高。对一些PTA没有阈值变化的耳朵, 观察到吸光度值的变化。

结论和意义：这项研究表明, 低频时, 显著前庭EH的声学能量吸收值明显更高。鉴于在具有显著EH的耳朵中可观察到ABG, 前庭EH的存在可能会阻碍声能向内耳的传输。

Keywords:

• Endolymphatic hydrops
• acoustic energy
• absorbance
• MRI

Disclosure statement

A Titan WBT was borrowed from the Diatec Company for this research. The Diatec Company had no influence on the results of the clinical research. The authors have no conflict of interest.