Moore Brian C J
All India Institute of Speech and Hearing, Mysore, India.
Ear Hear. 2007 Apr;28(2):231-41. doi: 10.1097/AUD.0b013e31803126e2.
To estimate the prevalence of dead regions in adult subjects with sensorineural hearing impairment as a function of audiometric threshold and frequency and to assess the extent to which the presence/absence of a dead region can be predicted from the audiogram, gender, or age.
Data were obtained from a random sample of adults attending an audiology clinic in Mysore, India. Audiometric air and bone conduction thresholds and tympanometry were used to identify 317 subjects (592 ears) with sensorineural hearing loss. Their ages ranged from 17 to 95 yr (mean = 57 yr). The threshold-equalizing noise hearing level (TEN (HL)) test, administered using the TEN(HL)-test CD and an audiometer, was used to determine the presence or absence of dead regions in these subjects for test frequencies ranging from 0.5 to 4 kHz. Nine subjects had to be excluded as the absolute thresholds were too high for the TEN(HL) test to be administered. Of the remaining 308 subjects (556 ears), 209 (68%) were male and 99 (32%) were female. The hearing losses ranged from mild to severe.
Results are presented only for frequencies and ears for which the TEN level could be made high enough to produce at least 10 dB of masking. Classifying by subject, 177 (57.4%) were found to have a dead region in one or both ears for at least one frequency. Fifty-four women (54.5%) and 123 men (58.8%) had dead regions in one or both ears. Classifying by ear, 256 (46%) were diagnosed as having a dead region at one frequency or more: 233 ears (41.9%) had only a high-frequency dead region, 13 ears (2.3%) had only a low-frequency dead region, and 10 ears (1.8%) had a dead region at both low and high frequencies, with a surviving middle-frequency region. It was not possible to achieve both high sensitivity and high specificity when attempting to predict the presence/absence of a dead region from the audiogram. However, for each test frequency, 59% or more of ears had a dead region when the absolute threshold was above 70 dB HL. A very steep slope of the audiogram is suggestive of a high-frequency dead region but does not provide a reliable diagnostic method. Chi-square tests indicated that the prevalence of dead regions did not vary significantly with age or gender.
The results indicate a relatively high prevalence of dead regions in adults with sensorineural hearing impairment, especially for frequencies at which the hearing loss exceeds 70 dB HL.
评估感音神经性听力损失成年受试者中死区的患病率与听阈及频率的关系，并评估能否根据听力图、性别或年龄预测死区的存在与否。
数据来自印度迈索尔一家听力诊所的成年随机样本。采用气导和骨导听阈测量及鼓室图来确定317例（592耳）感音神经性听力损失患者。他们的年龄在17至95岁之间（平均57岁）。使用TEN(HL)测试CD和听力计进行的阈上噪声听力级（TEN(HL)）测试，用于确定这些受试者在0.5至4kHz测试频率下是否存在死区。9例受试者因绝对听阈过高无法进行TEN(HL)测试而被排除。其余308例（556耳）受试者中，209例（68%）为男性，99例（32%）为女性。听力损失程度从轻度到重度不等。
仅给出TEN水平足以产生至少10dB掩蔽的频率和耳的结果。按受试者分类，177例（57.4%）被发现至少在一个频率下一只或两只耳朵存在死区。54例女性（54.5%）和123例男性（58.8%）一只或两只耳朵存在死区。按耳朵分类，256耳（46%）被诊断在一个或多个频率存在死区：233耳（41.9%）仅有高频死区，13耳（2.3%）仅有低频死区，10耳（1.8%）在低频和高频均存在死区，中频区域尚存。试图根据听力图预测死区的存在与否时，无法同时实现高敏感性和高特异性。然而，对于每个测试频率，当绝对听阈高于70dB HL时，59%或更多的耳朵存在死区。听力图斜率非常陡峭提示高频死区，但并非可靠的诊断方法。卡方检验表明，死区患病率在年龄和性别上无显著差异。
结果表明，感音神经性听力损失成年患者中死区患病率相对较高，尤其是听力损失超过70dB HL的频率。
