Vestibular disturbance in patients with large vestibular aqueduct syndrome (LVAS).

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.