Abstract
Over 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.
Keywords
vestibular - vestibulo-ocular reflex - head impulse test - semicircular canal
