How does vHIT complement caloric testing?

• A. It measures low-frequency responses alone, and calorics measure high frequency
• B. It measures high-frequency responses and canal-specific VOR; calorics test low-frequency
• C. It replaces caloric testing entirely
• D. It measures vestibulospinal responses

Answer: (B)

vHIT complements caloric testing by sampling a different part of the vestibulo-ocular reflex spectrum. It tests high-frequency responses with rapid, small head impulses while tracking eye movements, which reveals how well each semicircular canal drives gaze stabilization during fast head movements. Because the impulses are aligned with the canal planes, vHIT provides canal-specific information about function in the horizontal, anterior, and posterior canals. Caloric testing uses warm and cold stimuli to create endolymph flow, provoking nystagmus at a very low frequency and primarily assessing the horizontal canal’s low-frequency VOR. Since these tests evaluate different frequencies and canals, using them together gives a fuller picture of vestibular function rather than relying on one test alone. Vestibulospinal responses aren’t what these tests measure. So, vHIT measures high-frequency responses and canal-specific VOR, while calorics test low-frequency responses.