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 40daPas(-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 10daPas(-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 40daPas(-1) was -39.2+/-12.2daPa with negative pressure and 39.5+/-12.4daPa with positive pressure. At 10daPas(-1), the MSTAP was -70.3+/-25.0daPa with negative pressure and 72.5+/-22.7daPa with positive pressure, and both the
mean and S.D. values were higher than those obtained at 40daPas(-1). Briefly, the MSTAP at 40daPas(-1) produced less
variance than that at 10daPas(-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+/-26.3daPa with negative pressure and 206.0+/-26.7daPa 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.
