Brantberg Krister, Verrecchia Luca, Westin Magnus
Department of Audiology and Neurotology, Karolinska University Hospital, Stockholm, Sweden.
Audiol Neurootol. 2016;21(6):365-371. doi: 10.1159/000450936. Epub 2017 Jan 13.
A key feature of superior canal dehiscence (SCD) syndrome is supranormal hearing of body sounds. The aim of the present study was to quantify this phenomenon and to ascertain whether auditory sensitivity to body vibrations can distinguish SCD patients. Hearing thresholds in response to vibration at the vertex, at the spinous process of the 7th cervical vertebra, and at the medial malleolus were tested in 10 SCD patients and 10 controls. Both patients and controls had insert earphones in both ears. The insert in the test ear was blocked while masking was presented to the other ear. Vibration in the frequency range of 125-1,000 Hz was presented to each of the 3 stimulation sites. The SCD patients were found to have significantly lower hearing thresholds compared with controls. The two study groups reacted differently with respect to frequency. The SCD patients showed an enhanced sensitivity for the lower stimulus frequencies. The difference was, however, rather independent of stimulus presentation site. The findings suggest that hearing thresholds in response to low-frequency body vibration at sites distant from the ears can distinguish SCD patients. The present findings may also support the idea that auditory sensation to body vibrations is a response related to soft tissue conduction.
半规管裂（SCD）综合征的一个关键特征是对身体声音的超常听力。本研究的目的是量化这一现象，并确定对身体振动的听觉敏感性是否能够区分SCD患者。对10名SCD患者和10名对照者测试了在头顶、第七颈椎棘突和内踝处对振动的听力阈值。患者和对照者双耳均佩戴插入式耳机。在对另一耳进行掩蔽时，测试耳中的插入式耳机被堵住。在125 - 1000Hz频率范围内的振动被施加到三个刺激部位中的每一个。结果发现，与对照者相比，SCD患者的听力阈值显著更低。两个研究组在频率方面反应不同。SCD患者对较低刺激频率表现出更高的敏感性。然而，这种差异相当独立于刺激呈现部位。这些发现表明，在远离耳朵的部位对低频身体振动的听力阈值可以区分SCD患者。目前的发现也可能支持这样一种观点，即对身体振动的听觉感受是一种与软组织传导相关的反应。
