Clinical applications of furosemide-loading vestibular-evoked myogenic potential and the video head impulse test

Abstract

　The accumulation of neurophysiological knowledge and advances in electronic technology have enabled the recent development of novel examinations for vestibular function. One is the vestibular-evoked myogenic potential (VEMP), which has already been established as a functional examination for otolith organs. Here, as an application of VEMP, we will describe furosemide-loading VEMP, which is a new examination for the diagnosis of endolymphatic hydrops. The VEMP amplitude increases after furosemide administration in patients with Meniere's disease. Positive results are also seen in cases with occult endolymphatic hydrops that does not evoke symptoms. Another is the video head impulse test (vHIT), which enables vestibular examinations to be performed easily and quickly. The results of vHIT correspond with those of caloric testing in cases with vestibular neuritis. On the other hand, the results of vHIT do not agree with those of caloric testing in cases with Meniere's disease. Thus, vHIT cannot replace caloric testing in all patients with balance problems. However, the function of the vertical semicircular canal (anterior and posterior semicircular canal) can be evaluated using vHIT. To diagnose inferior vestibular neuritis, which is a new concept in vestibular disorders, vHIT and VEMP are required.