Aural suction without vertigo.

Vertigo induced by aural suction was abolished by maintaining a constant temperature in the mastoid cavity during the procedure. This was achieved using humidified air at 38 degrees C at the wider end of the aural speculum. The cavity temperature fell by a maximum of 0.2 degrees C (average) in 24 patients, none of whom experienced rotatary vertigo despite prolonged suction. This contrasted with a maximum temperature drop of 8.9 degrees C (average) in the same group of patients, 18 of whom then suffered vertigo and nystagmus, when the cavity temperature was not controlled during suction.