Brooks D N
J Am Aud Soc. 1979 Sep-Oct;5(2):112-7.
Marked asymmetry of auditory function between left and right ears would normally be indicative of some abnormality. This study was designed to investigate the limits of tympanometric symmetry in normal individuals. A limiting ratio of 4/3 between left and right ear compliances is suggested. Applying this criterion and strict criteria for normality of middle ear pressure and reflex thresholds, a value for middle ear compliance was obtained with a considerably smaller range for "normality" than from previous studies. A marked difference between middle ear compliances of male and female subjects was observed, and evidence was adduced to suggest that this was due to differences in size of the ear canal and tympanic membrane.
通常情况下，双耳听觉功能的显著不对称表明存在某种异常。本研究旨在调查正常个体中耳声导抗对称性的限度。建议左右耳顺应性的极限比值为4/3。应用该标准以及中耳压力和反射阈值正常的严格标准，得出的中耳顺应性“正常”范围比以往研究的范围小得多。观察到男性和女性受试者的中耳顺应性存在显著差异，并有证据表明这是由于外耳道和鼓膜大小的差异所致。
