Video Hear Impulse Testing (vHIT)
The video head impulse test is an ear-specific test that detects disorders of the vestibulo-ocular reflex and identifies which ear is affected in cases of peripheral vestibular loss. The patient is asked to fix upon a target straight ahead, usually the nose of the examiner, while the examiner turns the patient’s head in the plane of a pair of semicircular canals. The rotations are of low amplitude but of high acceleration. It is the frequency of the head movement not the degree of excursion, so even patients who may have some restricted range of neck motion (ROM) can be comfortably tested. Patients with a vestibular loss will exhibit a corrective saccadic eye movement (a “catch-up” saccade) either during or after the head impulse and the gain of the head in comparison to the eye will not be equivalent.