Mechanism of hearing disturbance due to alteration in atmospheric pressure.
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.
Kitahara
M
M
Department of Otolaryngology, Shiga University of Medical Science, Otsu, Japan.
Kodama
A
A
Ozawa
H
H
Izukura
H
H
D000328:Adult; D001273:Atmosphere Exposure Chambers; D001274:Atmospheric Pressure; D001301:Audiometry, Pure-Tone; D001844:Bone Conduction / Q000502:physiology*; D004424:Ear Canal / Q000502:physiology; D004432:Ear, Middle / Q000502:physiology; D004867:Equipment Design; D005064:Eustachian Tube / Q000502:physiology; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009622:Noise / Q000517:prevention & control; D011312:Pressure; D012405:Round Window, Ear / Q000502:physiology