Mechanism of Hearing Disturbance due to Alteration in Atmospheric Pressure

Abstract

We used a soundproof pressure chamber to examine how the changes in atmospheric pressure as experienced in daily life reduces bone conduction in a total of 48 normal adults. The subjects were given special ear plugs that connected external auditory canal to the pressure gauge and a small pump located outside the chamber, and were instructed not to swallow, to avoid active opening of the Eustachian tube. The chamber pressure was increased (or decreased) to ±500 mmH₂O at a rate of 33 mmH₂O/s. Then pressure in the external auditory canal was increased (or decreased) gradually after the chamber pressure had reached ±500 mmH₂O, to equilibrate the pressure across the ear drum. Bone conduction did not recover the level before increase (or decrease) in the chamber pressure. We conclude that at least a minor part of the deterioration in bone conduction after changes in the chamber pressure was caused by displacement of the round window membrane.

Key Words:

• pressure chamber
• deterioration in hearing
• mechanism of hearing disturbance