title: Test for pressure control capacity of the Eustachian tube.
abstract: Because of Eustachian tube controls middle ear pressure to maintain the best hearing level, we tested the equilibration capacity of the Eustachian tube by measuring hearing levels in a soundproof pressure chamber. The number of swallows to recover normal hearing after the chamber pressure reached -200 mm H2O (an index of equilibration capacity for the static pressure differences across the eardrum) was less than 9 in normal subjects. The worst level of hearing and the time required to recover normal hearing from the beginning of alteration in the chamber pressure to -700 mm H2O (indexes of equilibration capacity for dynamic pressure differences across the eardrum) were 0-17 dB and within 120s in normal subjects. It was difficult to determine definitive normal ranges of the equilibrium capacity of the Eustachian tube when positive pressure was applied.
authors.affiliation: Department of Otolaryngology, Shiga University of Medical Science, Otsu, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kitahara
authors.forename: A
authors.initials: A
authors.lastname: Kodama
authors.forename: H
authors.initials: H
authors.lastname: Ozawa
authors.forename: H
authors.initials: H
authors.lastname: Izukura
authors.forename: S
authors.initials: S
authors.lastname: Inoue
mesh_terms: D000328:Adult; D001273:Atmosphere Exposure Chambers; D001274:Atmospheric Pressure; D001301:Audiometry, Pure-Tone; D003679:Deglutition; D004432:Ear, Middle / Q000502:physiology; D005064:Eustachian Tube / Q000502:physiology*; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009622:Noise / Q000517:prevention & control; D011312:Pressure; D014432:Tympanic Membrane / Q000502:physiology