Caloric Tests In Passive Vascular Congestion Of The Labyrinth: An Electronystagmographic Study

Abstract

In order to evaluate the effect of passive venous congestion of the labyrinth on caloric induced nystagmus, thirty normal subjects were given caloric tests in the “head up” and “head down” positions. The horizontal semicircular canal was kept in a vertical position with the ampullated end upwards when the head was in the “down” position and venous congestion was produced. The resulting nystagmus was recorded by an electronystagmograph. A comparison of the response of the labyrinth in the “head up” and “head down” positions reveals that the response is diminished in the “head down” position; more so with cold irrigation. Thus it has been shown that passive venous congestion produces an effect on caloric induced nystagmus.