Vestibular-evoked myogenic potentials in three patients with large vestibular aqueduct
Vestibular-evoked myogenic potentials in three patients with large vestibular aqueduct
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DOI：
10.1016/s0378-5955(04)00018-8
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发表时间：
2004-04-01
期刊：
影响因子：
2.8
通讯作者：
Kaga, K
中科院分区：
文献类型：
--
作者：
Sheykholeslami, K;Schmerber, S;Kaga, K
前庭导水管扩大(LVA)是一种常见的先天性内耳畸形，导致一些不寻常的前庭和听力症状。大多数病例表现为儿童双侧早发和进行性听力损失。内耳CT扫描大体形态正常。然而，对内耳成分的精确测量揭示了异常的尺寸，这可能是伴随而来的听觉和前庭功能障碍的原因。尽管对听力和前庭器官进行了广泛的研究，但球囊功能并未被研究。据我们所知，这是通过前庭诱发肌源性电位首次报告三例LVA患者的球囊功能障碍。常规听力图显示双侧重度感音神经性听力损失2例，混合型听力损失1例。其中两名患者主诉眩晕和眩晕，但患者的前庭评估结果正常。这一诊断是通过高分辨率CT扫描和头骨磁共振图像做出的，这些图像显示LVA没有其他异常。2例单侧前庭导水管扩大患者LVA测得的VEMP阈值为75~80dBnHL，而正常耳测得的阈值为95dBnHL。第三例混合型听力损失患者双侧LVA，尽管在低频有较大的气骨间隙，但仍有VEMP反应。这位患者的VEMP波幅较大，阈值较低(患者接受了鼓室成形术，但听力没有改善)。其他患有Tullio现象和上半规管裂开的患者的这些发现和结果也显示出较低的VEMP阈值，证实了“第三窗口”的理论，即允许体积和压力位移，从而使前庭感应器更大的偏转，这将使前庭器官对声音和压力的变化更敏感。(C)2004年，爱思唯尔出版。
An enlarged vestibular aqueduct (LVA) is a common congenital inner ear anomaly responsible for some unusual vestibular and audiological symptoms. Most of the cases show bilateral early onset and progressive hearing loss in children. The gross appearance on CT scan of the inner ear is generally normal. However, precise measurements of the inner ear components reveal abnormal dimensions, which may account for the accompanying auditory and vestibular dysfunction. Despite extensive studies on hearing and the vestibular apparatus, saccular function is not studied. To our knowledge this is the first report of saccular malfunction in three patients with LVA by means of vestibular evoked myogenic potentials. Conventional audiograms revealed bilateral severe sensorineural hearing loss in two patients and mixed type hearing loss in one patient. Two of the patients complained about vertigo and dizziness but vestibular assessments of the patients showed normal results. The diagnosis had been made by high-resolution CT scans and MR images of the skull that showed LVA in the absence of other anomalies. The VEMP threshold measured from the ear with LVA in two patients with unilateral enlargement of the vestibular aqueduct was 75-80 dB nHL whereas the threshold from normal ears was 95 dB nHL. The third patient with mixed type hearing loss and bilateral LVA had VEMP responses despite a big air-bone gap in the low frequency range. The VEMP in this patient was greater in amplitude and lower in threshold in the operated ear (the patient had a tympanoplasty which did not improve her hearing). These findings and results of other patients with Tullio phenomenon and superior semicircular canal dehiscence, who also showed lower VEMP threshold, confirmed the theory of a 'third window' that allows volume and pressure displacements, and thus larger deflection of the vestibular sensors, which would cause the vestibular organ to be more responsive to sound and pressure changes. (C) 2004 Published by Elsevier B.V.