Latent vestibular disorders in otosclerosis: an electronystagmographical study

ABSTRACT

The caloric vestibular nystagmus standardwasobtainedwhile processing the electronystagmograms in otosclerotic patients without any apparent vestibular pathology before operation in Kasr El-Einy Hospital, Cairo University. The mean duration of otosclerosis was 12 years [5-24 years], 10 males, 14 females, careful neurootological examinationand pure tone air and bone conduction audiometry, optokinetic nystagmus [OKN], spontaneous and positional as well as caloric induced nystagmus was examined in the supine and both lateral positions Seven patients had spontaneous nystagmus,therewas depressed caloric reaction [canal paresis], in 7 patients too, i.e. more than 50% having vestibular disturbances.The mean age of patients who had spontaneous nystagmus was 30 years and the duration of otosclerosis 6-17 years [mean 11 years]. The mean age of canal paresis patients was 36 years and duration of otosclerosis 6-24 years [mean 13 years] twelve patients show normal ENGfindings mean36 years. They suffered from otosclerosis for 12 years on average. [OKN] were normal in all patients.Thereweremeasurablehearing disturbances both air and bone conduction. In spite of a lack of subjective vertigo our objective findings of vestibular dysfunction were increased with longer duration of otosclerosis. The vestibular dysfunction of otosclerotic patients was more common than could be expected,and vestibular function tests must be done as additional diagnositic criteria in otosclerosis and in selection of patients before surgical interference ot minimize post operative sensory neural hearing loss