Kenyon E L, Leidenheim S E, Zwillenberg S
University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford 08002, USA.
Mil Med. 1998 Sep;163(9):647-50.
There are patients who have normal hearing below 3,000 Hz and normal speech discrimination who still complain of hearing difficulty, especially when background noise is present. The objective of this study is to document the fact that these individuals have a significant hearing impairment that is not detected with routine testing. We retrospectively reviewed 67 audiograms selected for 50-dB loss or greater at 3, 4, 6, and 8 kHz and speech discrimination scores better than 80%. Patients in this group had also previously undergone speech discrimination testing in the presence of 50-dB calibrated cafeteria noise at the time of the initial audiogram. Identical testing was carried out on 48 control subjects without hearing loss. The speech discrimination scores of the hearing-impaired group were lower than in the control group when tested in a quiet booth (88.2 and 98.2%, respectively). The significant finding was the change in the speech discrimination score when tested in noise. We found that the study group had a 33.1% loss in speech discrimination when tested in the presence of background noise. The control group had only a 5.2% loss in speech discrimination in the presence of the same noisy background; this was statistically different (p = 0.001). Our conclusion is that patients complaining of hearing loss who have normal low- to mid-frequency hearing and good speech discrimination should be tested in the presence of noise to adequately document their degree of impairment. Our findings also support the theories of signal attenuation and secondary auditory pathway distortions as causes of the loss of speech discrimination.
有些患者在3000赫兹以下听力正常，言语辨别能力也正常，但仍抱怨听力有困难，尤其是在有背景噪音的情况下。本研究的目的是证明这些个体存在明显的听力障碍，而常规测试并未检测到。我们回顾性分析了67份听力图，这些听力图在3、4、6和8千赫兹处有50分贝或更大的听力损失，且言语辨别分数高于80%。该组患者在初次听力图检查时也曾在50分贝校准的自助餐厅噪音环境下进行言语辨别测试。对48名无听力损失的对照受试者进行了相同的测试。在安静的隔音室中测试时，听力受损组的言语辨别分数低于对照组（分别为88.2%和98.2%）。显著的发现是在噪音环境下测试时言语辨别分数的变化。我们发现，研究组在有背景噪音的情况下进行测试时，言语辨别能力损失了33.1%。对照组在相同的噪音背景下，言语辨别能力仅损失了5.2%；这在统计学上有显著差异（p = 0.001）。我们的结论是，对于抱怨听力损失但低频到中频听力正常且言语辨别能力良好的患者，应在有噪音的情况下进行测试，以充分记录其损伤程度。我们的研究结果也支持信号衰减和次级听觉通路畸变理论是言语辨别能力丧失的原因。
