Hornsby Benjamin W Y, Dundas J Andrew
Department of Hearing and Speech Science, Vanderbilt Bill Wilkerson Center, Vanderbilt University School of Medicine, Nashville, TN 37232-8242, USA.
J Am Acad Audiol. 2009 Apr;20(4):251-63. doi: 10.3766/jaaa.20.4.5.
Recent work using the Threshold Equalizing Noise (TEN) test as a gold standard suggests that the presence of cochlear dead regions in persons with moderate-to-severe hearing loss may be quite common. In addition, previous data suggest that certain characteristics of hearing loss, such as severe-profound high-frequency hearing loss or steeply sloping configurations may be more commonly associated with positive TEN findings. These findings, however, are based largely on studies including a relatively small number of participants and/or participants that were included based on specific audiometric criteria (e.g., the presence of severe high-frequency hearing loss). Likewise, results from many of these studies are limited to the frequency regions of 500-4000 Hz. There has been less work that has systematically evaluated the relationship between audiometric characteristics and TEN test findings, particularly in the frequency regions above 4000 Hz, on a large number of individuals with a wide range of hearing losses and hearing loss configurations.
The purpose of this study was to further examine the effects of audiometric characteristics such as degree and slope of hearing loss on the rate of positive, negative, and inconclusive findings on the TEN test over a wide frequency range (250-8000 Hz). Given that the functional impact of positive findings (i.e., findings suggestive of a dead region) may vary with the extent of potential damage, we were also interested in determining the relative occurrence of "patchy" versus contiguous positive findings on the TEN.
Fifty-nine adults (117 ears) with a wide range of SNHL participated. To examine results over a wide frequency range (250-8000 Hz), the TEN (SPL), rather than the TEN (HL), was utilized. Thresholds, in both ears, were measured in quiet and in the TEN (SPL). Results were categorized as positive (suggestive of a dead region), negative (not suggestive of a dead region), or inconclusive.
Consistent with past research, positive TEN (SPL) results were more common when hearing losses exceeded 60 dB HL; however, there was not a systematic increase in positive results with increases in threshold. In contrast to previous work, however, positive test results among individuals with milder hearing losses (< 60 dB HL) were not uncommon, suggesting a potential for false positive results. In regard to audiometric slope, also consistent with past research, slope of hearing loss was an inadequate predictor of TEN (SPL) results. Negative results (not suggestive of a dead region) were less common in participants with steeply sloping losses while positive test findings were unaffected by hearing loss slope. Although a large proportion of participants had positive results on the TEN (SPL), for most participants, these positive findings occurred in isolated (i.e., one or two frequencies) rather than in contiguous frequency regions.
The relatively large number of inconclusive results and the potential for false positive results makes interpreting the functional impact of TEN (SPL) results difficult, particularly when positive results are in the high (> 4000 Hz) frequencies. In addition, although a large proportion (84%) of study participants had positive findings on the TEN (SPL), the functional impact of these findings is not clear as, in the majority of cases, positive findings occurred at only one or two test frequencies.
近期将阈补偿噪声（TEN）测试作为金标准的研究表明，中重度听力损失患者中存在耳蜗死区的情况可能相当普遍。此外，先前的数据表明，听力损失的某些特征，如重度至极重度高频听力损失或陡坡型听力图，可能更常与TEN测试阳性结果相关。然而，这些发现很大程度上基于参与者数量相对较少和/或基于特定听力测试标准（如存在重度高频听力损失）纳入的研究。同样，这些研究中的许多结果仅限于500 - 4000 Hz的频率范围。系统评估听力测试特征与TEN测试结果之间关系的研究较少，特别是在4000 Hz以上的频率范围，针对大量具有广泛听力损失和听力图类型的个体。
本研究的目的是在较宽的频率范围（250 - 8000 Hz）内，进一步研究听力损失程度和斜率等听力测试特征对TEN测试阳性、阴性和不确定结果发生率的影响。鉴于阳性结果（即提示存在死区的结果）的功能影响可能随潜在损伤程度而变化，我们还对确定TEN测试中“散在性”与连续性阳性结果的相对发生率感兴趣。
59名患有广泛感音神经性听力损失（SNHL）的成年人（117只耳朵）参与了研究。为了在较宽的频率范围（250 - 8000 Hz）内检查结果，使用了TEN（声压级）而非TEN（听力级）。在安静环境和TEN（声压级）条件下测量双耳的阈值。结果分为阳性（提示存在死区）、阴性（不提示存在死区）或不确定。
与过去的研究一致，当听力损失超过60 dB HL时，TEN（声压级）阳性结果更常见；然而，阳性结果并未随阈值升高而系统性增加。然而，与先前的研究不同，轻度听力损失（< 6 dB HL）个体中的阳性测试结果并不罕见，提示存在假阳性结果的可能性。关于听力测试斜率，同样与过去的研究一致，听力损失斜率并不能充分预测TEN（声压级）结果。在陡坡型听力损失的参与者中，阴性结果（不提示存在死区）较少见，而阳性测试结果不受听力损失斜率的影响。尽管很大一部分参与者的TEN（声压级）结果为阳性，但对于大多数参与者而言，这些阳性结果出现在孤立的（即一两个频率）而非连续的频率区域。
相对大量的不确定结果以及假阳性结果的可能性使得解释TEN（声压级）结果的功能影响变得困难，特别是当阳性结果出现在高频率（> 4000 Hz）时。此外，尽管大部分（84%）研究参与者的TEN（声压级）结果为阳性，但这些结果的功能影响尚不清楚，因为在大多数情况下，阳性结果仅出现在一两个测试频率上。
