VHIT - Video Head Impulse Test
The Video Head Impulse Test (VHIT) is used to identify unilateral and bilateral vestibular deficits using clinician-applied, unpredictable head thrusts in the lateral, RALP and LARP planes. Micromedical utilizes the Vorteq angular rate sensor and binocular high speed cameras to measure the left and right sided Vestibular Ocular Reflex (VOR) gain of all six semi-circular canals (lateral, anterior and posterior) and to identify abnormal covert and overt catch-up saccades.A novel software algorithm eliminates the need for eye and head sensor calibration for each patient. The Vorteq sensor can then be placed in the vertical plane and does not need to be adjusted to the canal planes. This calibration algorithm significantly reduces test preparation time and improves accuracy of the test.The biggest advantages of the VHIT are 1) identifying side of lesion and 2) testing of all six semi-circular canals. While the caloric test can also identify side of lesion but is less comfortable to patient, takes longer and only tests the lateral canals. VHIT tests the VOR at functional frequencies above what the caloric and rotational chair test can perform.