THE EFFECT OF ATMOSPHERIC PRESSURE ON ALTERATIONS OF THE TYMPANIC MEMBRANE AND HEARING LOSS

• Published in: JIBI INKOKA TEMBO Vol. 43; no. 6; pp. 498 - 506
• Main Authors: Sakoda, Kazuho, Mouri, Mitsuhiro, Amatsu, Mutsuo
• Format: Journal Article
• Language: Japanese
• Published: Society of Oto-rhino-laryngology Tokyo 2000; 耳鼻咽喉科展望会
• Subjects: atmospheric pressure; external auditory canal; hearing threshold shift; tympanic membrane; 外耳道; 大気圧; 聴力閾値検査; 鼓膜
• ISSN: 0386-9687; 1883-6429
• DOI: 10.11453/orltokyo1958.43.498

Changes of atmospheric pressure not only cause a sensation of fullness, but also hearing loss and alterations of the tympanic membrane (TM). To determine the relationship between morphological alterations of the TM and hearing loss, positive and negative pressures were applied to the external auditory canal (EAC) in seven normal individuals. The EAC was closed with a tight air plug. A rigid endscope, and a polyethylene tube for application of pressure, were inserted through the plug. The air pressure applied through the tube was varied gradually from -300 to +300 daPa, while the TM was examined endoscopically and all findings were recorded on videotape. Multiple spots were marked on the TM to assist in evaluating the grade of alteration. Hearing tests were also done while the pressure was changed by 20-daPa intervals. Analysis of the movement of all spots on the TM showed that the pars flaccida and posterosuperior quadrant were the most mobile regions. Although application of 60 daPa caused marked alteration of the TM which was supposed to induce hearing loss, the hearing threshold shift in all subjects was less than 5 dB. In general, threshold shifts of more than 5 dB were obtained with a pressure between 60 daPa and 160 daPa. However, there was no great difference in the alteration of the TM between 60 daPa and 160 daPa. Based on the above findings, we concluded that morphological changes of the TM played little part in hearing threshold shifts.