The Video Head Impulse Test (VHIT)

The Video Head Impulse Test(VHIT) is one of the newer tests to evaluate the structural and functional integrity of the vestibular system.It offers a much deeper insight into the functioning of the semicircular canals. The test measures the gain of the vestibular ocular reflex(VOR) separately in all the six cemicircular canalas. The anterior,posterior and lateral semicircular canals of the left side as well as these three canals of the right side are separately evaluated. Through the VHIT we can pinpoint whether the left anterior semicircular canal is fault or the right posterior canal is defective . So long with all the other vestibular function tests,the sensitivity of only the lateral semicircular canals could be ascertained but eith the video head impulse test all the six semicircular canals can be tested separately. This is the uniqueness of this test. The test is based on the clinical Halmagy’s head impulse test. It is a non-invasive and easy to perform, quick test that does not generate any unpleasant vertiginous or nauseating sensation for the patient unlike the VNG/ENG tests.In VHIT the vestibular system is stimulated at a speed of thousands of degrees per second which is the speed at which the head moves in our day to day activities and is hence a more physiological and practical test. The VHIT can be performed very easily even in children and in ears with a perforation in the ear drum.