Video Head Impulse Testing: From Bench to Bedside.
AbstractOver 30 years ago, the head impulse test (HIT) was measured with search coil recordings and it provided robust evidence for a new test of vestibular function that could detect impairment of a single semicircular canal, that is, the lateral canal. Over the next two decades, the diagnostic spectrum of HIT was expanded to the testing of vertical canals, differentiation of central from peripheral vestibulopathy, and incorporation of visual interaction - the suppressed head impulse. However, HIT measurement was limited to very few specialized laboratories that were able to maintain the time-consuming and expensive operation of the scleral search coil system, which is the gold standard in eye movement recording. The video HIT (vHIT) was validated for the first time over 10 years ago, against the search coils, and its introduction into dizzy clinics worldwide has revolutionized the practice of neuro-otology. Here we review the basic physiology, practical aspects, and clinical application of the vHIT.