Lesion site in idiopathic bilateral vestibulopathy: A galvanic vestibular-evoked myogenic potential study

CONCLUSION: The result suggests that patients with idiopathic bilateral vestibulopathy may have nerve lesions when the inferior nerve system is affected, while the inferior vestibular nerve system may be spared. OBJECTIVE: To clarify the lesion site in idiopathic bilateral vestibulopathy, an acquired bilateral vestibulopathy of unknown cause. MATERIAL AND METHODS: Two 75-year-old males diagnosed with idiopathic bilateral vestibulopathy were enrolled. Both showed absent or highly decreased responses on the caloric test on both sides. They underwent vestibular-evoked myogenic potential (VEMP) testing by means of acoustical and electrical stimulation. As acoustic stimulation, 95 dB nHL clicks and short tone bursts (500 Hz) were presented, while 3 mA (1 ms) short-duration galvanic stimuli were presented as electrical stimulation. Responses were recorded on the sternocleidomastoid muscles. RESULTS: Both patients showed unilateral absence of VEMPs with both acoustic and short-duration galvanic stimuli.