Margolis R H, Saly G L, Hunter L L
Otitis Media Research Center, Department of Otolaryngology, University of Minnesota, Minneapolis 55455, USA.
Ear Hear. 2000 Jun;21(3):206-11. doi: 10.1097/00003446-200006000-00003.
This study was undertaken to determine the relationship between extended-high-frequency (EHF) hearing losses and wideband middle ear impedance in children with chronic otitis media (OM) histories.
Children with OM histories were selected from a prospective study cohort if they had normal tympanograms, no air-bone gaps, and no otoscopic evidence of active OM at the time of testing. OM subjects were divided into two groups, those with Better Hearing in the EHF range and those with Worse Hearing in the EHF range. The OM groups were compared with an age-matched, healthy Control group that had no more than five documented episodes of OM and no more than two in any 1 yr. All children were 9 to 16 yr of age. Subjects were tested by standard audiometric methods in the conventional audiometric range (0.25 to 8.0 kHz) and the EHF range (8 to 20 kHz). Middle ear impedance and reflectance were measured with an experimental system over the frequency range 0.25 to 10.08 kHz.
The Worse Hearing OM group had slightly poorer hearing in the conventional audiometric frequency range compared with the other two groups. The Better Hearing OM group and the Control group had nearly identical EHF hearing. The Worse Hearing OM group had significantly poorer EHF hearing compared with the other two groups, the difference increasing exponentially with frequency. Middle ear impedance differences among groups were confined to low frequencies (<2 kHz). The Control group had significantly higher negative reactance than the two OM groups. There were no significant group differences in impedance or reflectance in the high frequencies (2 to 10 kHz).
The results of this study confirm those of previous reports that children who have recovered from chronic OM have significantly poorer hearing in the EHF range compared with children without significant OM histories. The EHF hearing losses that occur in children with OM histories are strongly frequency dependent, suggesting a preferential effect on the base of the cochlea. Middle ear impedance and reflectance differences do not account for the EHF hearing losses observed in children with OM histories. The results support the hypothesis that OM-related EHF hearing losses are cochlear in origin.
本研究旨在确定有慢性中耳炎（OM）病史的儿童中，扩展高频（EHF）听力损失与宽带中耳阻抗之间的关系。
从一项前瞻性研究队列中选取有OM病史的儿童，条件是他们在测试时鼓室图正常、无气骨导差且耳镜检查无活动性OM迹象。OM受试者分为两组，即EHF范围内听力较好组和EHF范围内听力较差组。将OM组与年龄匹配的健康对照组进行比较，该对照组记录的OM发作不超过5次，且在任何1年中不超过2次。所有儿童年龄在9至16岁。受试者通过标准听力测试方法在传统听力范围（0.25至8.0 kHz）和EHF范围（8至20 kHz）进行测试。使用实验系统在0.25至10.08 kHz频率范围内测量中耳阻抗和反射率。
与其他两组相比，听力较差的OM组在传统听力频率范围内的听力略差。听力较好的OM组和对照组的EHF听力几乎相同。与其他两组相比，听力较差的OM组的EHF听力明显较差，且差异随频率呈指数增加。组间中耳阻抗差异局限于低频（<2 kHz）。对照组的负电抗明显高于两个OM组。在高频（2至10 kHz），阻抗或反射率无显著组间差异。
本研究结果证实了先前报告的结果，即与无明显OM病史的儿童相比，从慢性OM中恢复的儿童在EHF范围内的听力明显较差。有OM病史的儿童出现的EHF听力损失强烈依赖于频率，提示对耳蜗底部有优先影响。中耳阻抗和反射率差异不能解释有OM病史儿童中观察到的EHF听力损失。这些结果支持了与OM相关的EHF听力损失起源于耳蜗的假说。
