Voluntary increase of acoustic middle ear impedances with simultaneous sound attenuation associated with mild hyperacusis (VIMH)

Abstract

Background: Acoustic impedances, as measured with tympanometers, change with the pressure in the middle ears, or reflexively as a response to a range of stimuli. A few persons are able to influence their acoustic impedances voluntarily.

Aims/objectives: To describe this phenomenon and its clinical consequences.

Material and methods: Presentation of five case reports with measurements of the acoustic impedances, hearing thresholds, and otoacoustic emissions (TEOAE) in the relaxed state and while the change in acoustic impedance was invoked.

Results: All five subjects were able to voluntarily increase the acoustic impedance of their ears for short periods of time. While the change was active, TEOAE levels decreased by 0.8–9.7 dB and a mild transient conductive hearing loss in the low frequencies occurred. Four out of the five subjects reported a mild hyperacusis when the voluntary change was not invoked and showed unusual features in their acoustically evoked reflex.

Conclusions and significance: Subjects who can control their acoustic impedances voluntarily seem to have an increased prevalence of mild hyperacusis. Our results suggest interference of the voluntary control with the acoustic stapes reflex as a mechanism and we propose to name this phenomenon ‘Voluntary Impedance increase with Mild Hyperacusis’, or VIMH.

Chinese abstract

背景：用鼓室计测量的声阻抗, 随着中耳压力的变化而变化, 或者对一系列刺激而作出反射性反应。一些人能够自发控制他们的声阻抗。

目的：描述这种现象及其临床后果。

材料和方法：五份病例报告中测量了放松状态下以及激发声阻抗变化时的声阻抗、听力阈值和耳声发射（TEOAE）。

结果：五名受试者均能在短时间内自发提高耳部声阻抗。当变化活跃时, TEOAE水平降低了0.8-9.7db, 在低频下出现轻微的短暂传导性听力损失。五名受试者中有四名报告称, 在未激活自发性变化的情况下出现轻微听觉过敏, 并且在听觉诱发反射方面表现出异常特征。

结论和意义：能够自发控制声阻抗的受试者似乎有轻度听觉过敏发病率的增加。我们的研究结果表明, 作为一种机制, 主动控制干扰听觉镫骨反射。我们建议将这一现象命名为“自发阻抗随轻度听觉过敏而增加”, 即VIMH。

Keywords:

• Stapedius
• compliance
• middle ear
• hyperacusis
• voluntary control
• conductive hearing loss
• stapedius reflex

Disclosure statement

The authors report no conflict of interest.