Pressure Test in Normal Subjects

Abstract

Changes in hearing after pressure test have not been evaluated in normal subjects. In this study, changes in hearing after under and over pressure tests were examined using 20normal subjects. In the underpressure test, the subjects were placed in a supine position in the sound-proof pressure chamber. The pressure was first decreased to - 500 mmH₂O and after 5 minutes to- 700 mmH₂O. The pressure was maintained at this level for another 5minutes and then increased to 0 mmH₂O. This procedure was carried out 3 times in succession. While the chamber pressure was below 0 mmH₂O, the subjects were instructed to avoid active equilibration of the middle ear pressure. When the chamber pressure was raised to 0 mmH₂O, they were instructed to equilibrate the middle ear pressure and if necessary Politzerization or catheterization of the Eustachian tube was performed. In the overpressure test, the pressure was first increased to 500 mmH₂O and then 700 mmH₂O. In both the negative and positive pressure tests,10 dB gains (or loss) at either 250,500,1,000 Hz were observed in few cases.