Predicting secondary endolymphatic hydrops in patients with noise-induced hearing loss

Abstract

Background

Long-term noise exposure may damage the cochlea and endolymph resorption system, which induces episodic vertigo and/or fluctuating hearing loss in later years.

Objective

This study adopted clinical symptoms, inner ear test battery, and/or magnetic resonance (MR) imaging to evaluate development of secondary endolymphatic hydrops (EH) in patients with noise-induced hearing loss (NIHL).

Methods

Forty NIHL patients with secondary EH were assigned to Group A. Another 40 age-and sex-matched NIHL patients without EH were assigned to Group B. All patients underwent an inner ear test battery. MR imaging was performed when diagnosis of EH was equivocal via above testing.

Results

Group A had significantly higher mean hearing levels (MHLs) than Group B at 1000, 2000, 4000, and 8000 Hz. Both groups displayed a significantly declining sequence of abnormality rates of the inner ear test battery. Under receiver operating characteristic (ROC) curve analysis, the cutoff threshold at 4 kHz for predicting the presence of secondary EH in NIHL patients was 52 dBHL, with a sensitivity of 62% and a specificity of 69%.

Conclusions

NIHL patients revealing a typical 4 kHz dip-type audiogram with dip threshold >52 dBHL may predict development of secondary EH. A longitudinal follow-up coupled with MR imaging is required for confirmation.

Chinese abstract

背景：长期暴露于噪音可能会损害耳蜗和内淋巴吸收系统, 这会在晚年诱发发作性眩晕和/或波动性听力损失。

目的：本研究采用临床症状、内耳系列测试和/或磁共振(MR) 成像评估噪声性听力损失 (NIHL)患者的继发性内淋巴积水 (EH) 的发生。

方法：40 名具继发性 EH的 NIHL患者被分配到 A 组。另外 40 名年龄和性别匹配的没有 EH 的 NIHL 患者被分配到 B 组。所有患者都接受了内耳系列测试。当通过上述测试对 EH 的诊断模棱两可时才进行 MR 成像。

结果：在 1000、2000、4000 和 8000 赫兹 , A 组的平均听力水平 (MHL) 明显高于 B 组。两组均显示内耳系列测试的异常率显著下降趋势。根据接受者操作特征 (ROC) 曲线分析, 在4千赫兹, 预测 NIHL 患者继发性 EH 存在的阈值为 52 dBHL, 敏感性为 62%, 特异性为 69%。

结论：NIHL 患者显示典型的 4 kHz 倾向型听力图, 倾向阈值 >52 dBHL可以预测继发性 EH 的发生。如要确认, 需要进行纵向随访并结合 MR 成像。

Keywords:

• Noise-induced hearing loss
• acoustic trauma
• noise
• secondary endolymphatic hydrops

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the National Science Council, Taiwan [MOST 110-2314-B002-005].