Video Head Impulse Test in Benign Paroxysmal Positional Vertigo

Abstract

T he vestibular system is the apparatus of the inner ear that provides stable vision during head movements. The semicircular canals are sensory organs part of the vestibular system. Semicircular canals are three pairs, oriented 90 degrees to each other, and they are sensitive to angular stimulation. The video head impulse test (vHIT) is the newest objective test of dynamic semicircular canal (SCC) function. Patients with a deficient vestibulo-ocular reflex (VOR) cannot stabilize their gaze during head impulse testing. They re-fixate the target with compensatory saccades, i.e., quick eye movements in the opposite direction of those of the head Overt saccades, which occur after the head movement, can be detected during clinical examination.Covert saccades, which occur during the head movement, require search-coil or video head impulse testing (vHIT) to be observed. High-speed digital video cameras have recently been used to record the HIT (video head impulse test or vHIT) and at least four different devices are in clinical use worldwide. vHIT quantifies the loss in each individual SCC through measuring the VOR gain and both the overt, and covert corrective catch-up saccades. This study was designed to compare the results of BPPV patients using VNG the gold standard tool for vestibular assessment and the new vHIT.