PDF(Pubmed)
Abstract：
The third window syndrome, often associated with the Tullio phenomenon, is currently most often observed in patients with a superior semicircular-canal dehiscence (SCD) but is not specific to this pathology. Clinical and vestibular tests suggestive of this pathology are not always concomitantly observed and have been recently complemented by the skull-vibration-induced nystagmus test, which constitutes a bone-conducted Tullio phenomenon (BCTP). The aim of this work was to collect from the literature the insights given by this bedside test performed with bone-conducted stimulations in SCD. The PRISMA guidelines were used, and 10 publications were included and analyzed. Skull vibration-induced nystagmus (SVIN), as observed in 55 to 100% of SCD patients, usually signals SCD with greater sensitivity than the air-conducted Tullio phenomenon (ACTP) or the Hennebert sign. The SVIN direction when the test is performed on the vertex location at 100 Hz is most often ipsilaterally beating in 82% of cases for the horizontal and torsional components and down-beating for the vertical component. Vertex stimulations are more efficient than mastoid stimulations at 100 Hz but are equivalent at higher frequencies. SVIN efficiency may depend on stimulus location, order, and duration. In SCD, SVIN frequency sensitivity is extended toward high frequencies, with around 400 Hz being optimal. SVIN direction may depend in 25% on stimulus frequency and in 50% on stimulus location. Mastoid stimulations show frequently diverging results following the side of stimulation. An after-nystagmus observed in 25% of cases can be interpreted in light of recent physiological data showing two modes of activation: (1) cycle-by-cycle phase-locked activation of action potentials in SCC afferents with irregular resting discharge; (2) cupula deflection by fluid streaming caused by the travelling waves of fluid displacement initiated by sound or vibration at the point of the dehiscence. The SVIN direction and intensity may result from these two mechanisms\' competition. This instability explains the SVIN variability following stimulus location and frequency observed in some patients but also discrepancies between investigators. SVIN is a recent useful insight among other bedside examination tests for the diagnosis of SCD in clinical practice.
摘要：
第三个窗口综合症,通常与图利奥现象有关，目前最常在上半规管裂开（SCD）的患者中观察到，但不是这种病理特有的。提示这种病理的临床和前庭测试并不总是同时观察到，并且最近通过颅骨振动引起的眼球震颤测试得到了补充。这构成了骨传导的Tullio现象（BCTP）。这项工作的目的是从文献中收集通过在SCD中进行骨传导刺激进行的床边测试给出的见解。使用了PRISMA指南，纳入和分析了10篇出版物。颅骨振动引起的眼球震颤（SVIN），在55％至100％的SCD患者中观察到，通常信号SCD的灵敏度高于空气传导Tullio现象(ACTP)或Hennebert信号。当在100Hz的顶点位置上进行测试时，SVIN方向通常在82％的情况下是水平和扭转分量的同侧跳动，而在垂直分量的情况下是向下跳动。顶点刺激在100Hz下比乳突刺激更有效,但在更高频率下是等效的。SVIN效率可能取决于刺激位置，订单,和持续时间。在SCD中，SVIN频率灵敏度向高频扩展，约400赫兹是最佳的。SVIN方向可能取决于刺激频率的25%和刺激位置的50%。乳突刺激显示在刺激侧之后频繁发散的结果。根据最近的生理数据，可以解释在25％的病例中观察到的眼球震颤后，这些数据显示了两种激活模式：（1）SCC传入者中动作电位的逐周期锁相激活，并具有不规则的静息放电；（2）由开裂点的声音或振动引起的流体位移的行波引起的流体流引起的杯偏转。SVIN的方向和强度可能来自这两种机制的竞争。这种不稳定性解释了在一些患者中观察到的刺激位置和频率后的SVIN变异性，但也解释了研究者之间的差异。SVIN是在临床实践中诊断SCD的其他床边检查测试中的最新有用见解。
