Simultaneous Bilateral Caloric Stimulation. Electronystagmographic Study [la Stimulation Calorique Bilaterale Simultanee Etude Electronystagmographique]

It is rare to find a vertical nystagmus on simultaneous stimulation in both normal subjects and in patients with vestibular lesions. Anyway, the appearance of a vertical nystagmus has no clinical significance. In normal individuals a horizontal nystagmus may appear when there is a simultaneous stimulation; but the angular velocity is always poor. The subtraction of responses to the isolated stimulations of each ear with water at 44°C and 30°C does not correspond to the responses of simultaneous stimulation at the same temperatures. Simultaneous excitation was better tolerated by the patients than isolated excitations. Simultaneous stimulation produces sensations of vertigo and neuro-vegetative symptoms of less intensity than the isolated stimulations. Study of the test has shown a sensitivity similar to the test of isolated stimulations.4913