Semicircular canal versus otolithic involvement in idiopathic sudden hearing loss

OBJECTIVE: To evaluate the results of vestibular evoked myogenic potential testing in patients with idiopathic sudden hearing loss, and to correlate these results with the findings of caloric testing, the clinical appearance of vertigo and the influence of age. MATERIALS AND METHODS: Eighty-six patients with unilateral idiopathic sudden hearing loss and 35 healthy controls underwent a standard protocol of neurotological evaluation. Vestibular evoked myogenic potential responses were measured and compared with caloric responses. RESULTS: On the affected side, 30.2 per cent of patients showed abnormal vestibular evoked myogenic potential responses, while 52.3 per cent had abnormal caloric responses. A statistically significant relationship was found between the results of these two tests. A statistically significant relationship was also found between the type of vestibular lesion and the occurrence of vertigo. Advancing age correlated statistically with more extensive labyrinthic lesions. CONCLUSIONS: A combination of vestibular evoked myogenic potential and electronystagmography testing indicated the existence of vestibular involvement in many patients with idiopathic sudden hearing loss. Both tests are necessary in order to obtain a more thorough and in-depth knowledge of the pathophysiology of idiopathic sudden hearing loss.