Auditory and vestibular disorders due to barotrauma.

In order to investigate auditory and vestibular disorders caused by barotrauma, 12 guinea pigs were exposed to compression and decompression between 1 absolute pressure (ATA) and 2 ATA in a pressure chamber. During the atmospheric pressure change, spontaneous nystagmus occurred in two thirds of the animals. Auditory dysfunction that showed the difference between the right and left ears was confirmed by auditory brain stem response and Preyer's reflex in the animals with spontaneous nystagmus. Damage to the organ of Corti was the most significant cause for the auditory dysfunction. Though findings attributed to the rupture of the round window membrane were recognized in four ears, the rupture or hemorrhage of the round window membrane was not the direct cause of the auditory dysfunction. The significance of the round window membrane rupture is discussed.