A Ventilation Capacity Test for the Eustachian Tube Using a Soundproof Pressure Chamber

Abstract

Using a soundproof pressure chamber, we performed Bekesy air conduction audiometry at 1000 Hz under the following pressure conditions: 1) from atmospheric pressure (AP) to 200 mmH₂O below AP, 2) AP to 200 mmH₂O above AP, 3) AP to 700 mmH₂O below AP, and 4) AP to 700 mmH₂O above AP. In conditions l) and 2), the patient was instructed not to swallow until the pressure change was complete, then to swallow once every 15 seconds. The number of swallows required for hearing to return to the baseline level was counted. In conditions 3) and 4), the patient was told to swallow as many times as possible both before and after completion of the pressure change; maximum hearing level and the time needed for return to the baseline level were measured. Although all except one of the seven patients with suspected tubal dysfunction showed normal results with catheter insufflation and tympanometry, six of the seven showed abnormality and one reported the disappearance of ear stuffiness after the ventilation capacity test. We concluded that this test is useful not only for the diagnosis of tubal dysfunction but also as a possible therapy for aiding adaptation to changing environmental pressure.

Key Words:

• soundproof pressure chamber
• tubal dysfunction
• diagnosis
• therapy