Middle Ear Mechanics and Alternobaric Vertigo

Abstract

The effects of overpressure induced locally in the middle ear through free air communication between the middle ear and the external ear canal were compared with the effects of a relative overpressure of the same magnitude, induced indirectly by lowering the ambient pressure. The same vestibular response was seen and the main condition for inner ear stimulation was the fact that the overpressure should reach a certain level. However, a certain pressure difference between the ears is also involved. The overpressure seemed to affect the inner ear without involvement of the eardrum, and merely a movement of the eardrum could not be shown to affect the inner ear. The possibility of caloric stimulation due to temperature changes of the middle ear gas volume was also considered and excluded.