Observations on conduction of caloric stimulation to the middle ear cavity by thermoscanning.

Abstract

To elucidate the ways in which caloric stimulation conducts and the temperature recovers on the temporal bone by the caloric stimulation test. Four cases examined temperature changes of the bony lateral semicircular canal eminence with thermal images by caloric stimulation tests. Changes in the heat distribution were observed by means of a Thermoscan (Nihondenki Sanei Thermotracer 6T67R, Tokyo, Japan). The temperature began to decrease from the external canal and the decrease reached the posterior cranial fossa plate through the middle ear cavity while the stimulation continued. After the end of stimulation, the stimulation advanced in the direction opposite to the order in which it was transmitted and recovered in a manner resembling a mirror image despite the difference in speed. The way in which the caloric stimulation was conducted and the way in which the temperature recovered were in the opposite direction.