Cold and hot test

The hot and cold test is a test method that induces and observes the vestibular response by stimulating the semicircular canal with temperature. After receiving cold or heat stimulation through the external ear canal, the temperature change affects the outer semicircular canal through the tympanic membrane, tympanum, and bone wall. The internal lymph fluid changes its specific gravity due to thermal expansion and contraction, causing convection of the internal lymph fluid to "heat rise and fall" Phenomenon, the terminal crest deflects and stimulates the ampulla of the eyes to nystagmus.