Objective: To study the association between ear diseases and the ability of the middle ear to sense air pressure changes, we elucidated the appropriate conditions for measurements and confirmed the pressure-sensing regions while quantitatively assessing the pressure-sensing ability of normal ears and of ears with traumatic perforation of the tympanic membrane. Methods: In 318 normal ears (159 volunteers), an air pressure of 40 daPa s-1 was loaded on to the external auditory canals to measure the minimum pressure sensed by subjects as a result of air pressure changes. The minimum pressure was defined as the minimum sensory threshold for air pressure loading (MSTAP; daPa). In 40 of 318 normal ears (20 volunteers), the MSTAP was measured at 10 daPa s-1. Next, topical anesthesia was administered to 5 normal ears (5 volunteers), and the MSTAP was measured. In 7 ears with traumatic tympanic membrane perforation (7 cases), the MSTAP was also measured at the first medical examination. The data were analyzed using Stat View 5.0 (SAS Institute Inc., Cary, NC, USA). To test the significance of the data, the Mann-Whitney U-test and the Wilcoxon test were used. Results: The mean (±S.D.) MSTAP at 40 daPa s-1 was -39.2 ± 12.2 daPa with negative pressure and 39.5 ± 12.4 daPa with positive pressure. At 10 daPa s-1, the MSTAP was -70.3 ± 25.0 daPa with negative pressure and 72.5 ± 22.7 daPa with positive pressure, and both the mean and S.D. values were higher than those obtained at 40 daPa s-1. Briefly, the MSTAP at 40 daPa s-1 produced less variance than that at 10 daPa s-1. The MSTAP demonstrated gender- and age-related variations. Moreover, it increased after topical anesthesia was administered to the tympanic membrane. The MSTAP in patients with traumatic tympanic membrane perforation was -205.0 ± 26.3 daPa with negative pressure and 206.0 ± 26.7 daPa with positive pressure, and was significantly higher than that observed in case of normal ears. Conclusion: For obtaining accurate measurements while estimating the pressure-sensing ability of the middle ear, the rate of pressure loading should be considered. Although we assume that the middle ear has pressure-sensing regions other than the tympanic membrane, we conclude that the tympanic membrane is the most sensitive pressure-sensing region in the middle ear.
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