Niesten Marlien E F, Hamberg Leena M, Silverman Joshua B, Lou Kristina V, McCall Andrew A, Windsor Alanna, Curtin Hugh D, Herrmann Barbara S, Grolman Wilko, Nakajima Hideko H, Lee Daniel J
Department of Otorhinolaryngology - Head and Neck Surgery, University Medical Center, Utrecht, The Netherlands.
Audiol Neurootol. 2014;19(2):97-105. doi: 10.1159/000353920. Epub 2014 Jan 9.
Superior canal dehiscence (SCD) is caused by an absence of bony covering of the arcuate eminence or posteromedial aspect of the superior semicircular canal. However, the clinical presentation of SCD syndrome varies considerably, as some SCD patients are asymptomatic and others have auditory and/or vestibular complaints. In order to determine the basis for these observations, we examined the association between SCD length and location with: (1) auditory and vestibular signs and symptoms; (2) air conduction (AC) loss and air-bone gap (ABG) measured by pure-tone audiometric testing, and (3) cervical vestibular-evoked myogenic potential (cVEMP) thresholds. 104 patients (147 ears) underwent SCD length and location measurements using a novel method of measuring bone density along 0.2-mm radial CT sections. We found that patients with auditory symptoms have a larger dehiscence (median length: 4.5 vs. 2.7 mm) with a beginning closer to the ampulla (median location: 4.8 vs. 6.4 mm from ampulla) than patients with no auditory symptoms (only vestibular symptoms). An increase in AC threshold was found as the SCD length increased at 250 Hz (95% CI: 1.7-4.7), 500 Hz (95% CI: 0.7-3.5) and 1,000 Hz (95% CI: 0.0-2.5), and an increase in ABG as the SCD length increased at 250 Hz (95% CI: 2.0-5.3), 500 Hz (95% CI: 1.6-4.6) and 1,000 Hz (95% CI: 1.3-3.3) was also seen. Finally, a larger dehiscence was associated with lowered cVEMP thresholds at 250 Hz (95% CI: -4.4 to -0.3), 500 Hz (95% CI: -4.1 to -1.0), 750 Hz (95% CI: -4.2 to -0.7) and 1,000 Hz (95% CI: -3.6 to -0.5) and a starting location closer to the ampulla at 250 Hz (95% CI: 1.3-5.1), 750 Hz (95% CI: 0.2-3.3) and 1,000 Hz (95% CI: 0.6-3.5). These findings may help to explain the variation of signs and symptoms seen in patients with SCD syndrome.
上半规管裂（SCD）是由弓状隆起或上半规管后内侧方面缺乏骨质覆盖所致。然而，SCD综合征的临床表现差异很大，因为一些SCD患者无症状，而另一些患者有听觉和/或前庭方面的主诉。为了确定这些观察结果的依据，我们研究了SCD的长度和位置与以下方面的关联：（1）听觉和前庭体征及症状；（2）通过纯音听力测试测量的气导（AC）损失和骨气导差（ABG），以及（3）颈前庭诱发肌源性电位（cVEMP）阈值。104例患者（147只耳）采用一种沿0.2毫米径向CT断层测量骨密度的新方法进行了SCD长度和位置测量。我们发现，有听觉症状的患者与无听觉症状（仅有前庭症状）的患者相比，其裂孔更大（中位长度：4.5对2.7毫米），且起始位置更靠近壶腹（距壶腹的中位位置：4.8对6.4毫米）。在250赫兹（95%可信区间：1.7 - 4.7）、500赫兹（95%可信区间：0.7 - 3.5）和1000赫兹（95%可信区间：0.0 - 2.5）时，随着SCD长度增加，AC阈值升高；在250赫兹（95%可信区间：2.0 - 5.3）、500赫兹（95%可信区间：1.6 - 4.6）和1000赫兹（95%可信区间：1.3 - 3.3）时，随着SCD长度增加，ABG也升高。最后，在250赫兹（95%可信区间：-4.4至-0.3）、500赫兹（95%可信区间：-4.1至-1.0）、750赫兹（95%可信区间：-4.2至-0.7）和1000赫兹（95%可信区间：-3.6至-0.5）时，较大的裂孔与较低的cVEMP阈值相关，在250赫兹（95%可信区间：1.3 - 5.1）、750赫兹（95%可信区间：0.2 - 3.3）和1000赫兹（95%可信区间：0.6 - 3.5）时，起始位置更靠近壶腹。这些发现可能有助于解释SCD综合征患者体征和症状的差异。
