videoHeadImpulseTest

The videoHeadImpulseTest, often abbreviated as vHIT, is a diagnostic tool used to assess the function of the vestibular system, specifically the semicircular canals. This non-invasive test involves the patient wearing lightweight, high-speed video goggles that record eye movements. The examiner then performs rapid, small-amplitude head impulses in different directions, covering all six semicircular canals.

During these impulses, the patient is instructed to maintain visual fixation on a target, typically a fixed point displayed within the goggles. If a semicircular canal is functioning normally, the eyes will remain fixed on the target due to the vestibulo-ocular reflex (VOR). If there is a deficit in the VOR for a particular canal, the eyes will lag behind the head movement, and the goggles' integrated eye-tracking system will detect this compensatory saccade (a rapid eye movement) made after the head impulse to catch up to the target.

The data collected by the vHIT allows clinicians to quantify the VOR gain for each individual canal. A reduced VOR gain indicates impaired function of that specific semicircular canal. The test is quick, typically taking only a few minutes to complete, and is considered highly sensitive for detecting peripheral vestibular dysfunction, particularly in cases of unilateral vestibular loss. It is a valuable tool in the diagnosis of conditions such as vestibular neuritis, labyrinthitis, and Meniere's disease.