A century-old test that still anchors vestibular diagnosis. Warm and cool water create a temperature gradient in the lateral canal; the resulting endolymph convection deflects the cupula, producing nystagmus that we can quantify and compare across ears.
The caloric test was introduced by Bárány in 1907.[Bárány 1907]Its mechanism — convection of endolymph driven by a thermal gradient — was confirmed by Coats & Smith's elegant 1967 demonstration that responses reverse in the prone position.[Coats & Smith 1967] Quantitative interpretation has used the Jongkees formula since 1962.[Jongkees 1962]
Figure 4.1 — Convection mechanism
Chapter 04.2
Quantifying asymmetry
The four irrigations produce four peak slow-phase velocities. Adjust the sliders or load a preset; UW and DP recalculate live.