Vestibular Disturbance in Patients with Large Vestibular Aqueduct Syndrome (LVAS)

Abstract

Large vestibular aqueduct syndrome (LVAS) is a common inner ear anomaly responsible for some unusual vestibular and audiological symptoms. The gross appearance of CT scan of the inner ear is generally normal. However, precise measurement of the inner ear components reveals abnormal dimensions, which may account for accompanying auditory or vestibular dysfunction. It has been reported that sudden increase in cerebrospinal fluid pressure can cause further deterioration of hearing due to transmission of pressure to the inner ear through the enlarged vestibular aqueduct. However, vestibular function is not often studied. In this report, audiovestibular function of 10 patients with large vestibular aqueducts was analysed and compared with the severity of the radiological deformity. The literature was reviewed and typical findings were discussed to emphasize varying aspects of audiovestibular function. It was found that some patients with LVAS have some spontaneous or provoked vestibular disturbance such as vertigo after watching revolving objects. The mean value of electronystagmographic abnormality in patients with hearing loss is greater than in patients with normal hearing. However, there is no statistical correlation between the level of hearing loss, electronystagmographic abnormality and severity of radiological deformity.

Clinical Implication of Caloric and Video Head Impulse Tests for Patients With Enlarged Vestibular Aqueduct Presenting With Vertigo

“…Previous studies have drawn inconsistent conclusions on this relationship. Yetiser et al ( 35 ) found no correlation between the level of electronystagmographic abnormality and the severity of radiological deformity in a series of 10 EVA patients. Ishida et al ( 36 ) studied nine patients with EVA and found that the morphology of SCCs was associated with vertigo, the large lateral SCC fluid-containing ratio was closely associated with the presence of vertigo, but the endolymphatic duct and sac volume was not related to the pathophysiology of vestibular function.…”

Nystagmus in Enlarged Vestibular Aqueduct: A Case Series

“…In prior research on EVA and vertigo, Sigiura 7 associated episodic vertigo with fluctuating hearing loss in 12 patients, but this association has not been confirmed in Grimmer’s cohort of 32. 8 The most common vestibular test abnormality seen in patients with EVA is reduced caloric response, found in 80-86% of patients in Yetiser 5 and Berrettini’s 6 published series. Selection of patients undergoing vestibular testing is probably biased towards those with vestibular complaints, but the incidence of reduced caloric responses in these 21 patients appears to be greater than the frequency of active vestibular complaints, since only 11 complained of vertigo.…”

Large Vestibular Aqueduct-Associated Symptoms: Endolymphatic Duct Blockage as a Surgical Treatment

“…LVA is diagnosed by a temporal bone high resolution computed tomography (HRCT) scan. In 1978, Valvassori and Clemis reported the first clinical case of LVA; from this point on, the vestibular aqueduct has been considered enlarged if the axial plane of the CT scan shows a width of at least 1.5 mm at the midpoint and 2.0 mm at the operculum [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

“…The mechanism of hearing loss associated with this anatomical anomaly is still not very clear. However, individuals with LVA may also experience episodic vertigo or dizziness that can affect their quality of life [ 6 ]. Only a few studies have focused on vertigo in patients with LVA, and no previous reports have discussed the prevalence or the management of vestibular symptoms caused by LVA.…”

“…In these cases, auditory data have been more frequently studied and analyzed in the literature than vestibular complaints. To our knowledge, few descriptions of such vestibular signs and symptoms are extant in the literature; existing reports range from mild instabilities to real, episodic vertigo [ 6 ]. This discrepancy in patients with LVA is likely due to small sample sizes, different follow-up periods, ascertainment bias due to recruitment method subjects or a combination of these factors.…”