[Pseudocaloric nystagmus (author's transl)].

The effect of bithermal caloric tests on the velocity of spontaneous nystagmus was retrospectively studied in 107 patients with unilateral vestibular areflexia. In 35 out of 107 patients, the velocity or pre-test nystagmus was not lower than 15 jerks in 30 seconds. In our series, spontaneous nystagmus before the caloric test was mostly seen in patients with neuritis or sudden deafness, and as a rule, the tests had little effect on the velocity of the nystagmus. In 7 out of 10 cases of areflexic Mènière's disease spontaneous nystagmus was revealed by caloric tests. Spontaneous pre-test nystagmus was present in 6 out of 29 cases of neurinoma; its velocity was always reduced during the caloric tests. In 14 out of 25 cases of head injury, areflexia was usually compensated. Vestibular compensation can now be defined as the absence of vertigo, of spontaneous nystagmus before and after caloric tests and directional predominance.