Manchester Centre for Audiology and Deafness, School of Health Sciences, University of Manchester, Manchester, United Kingdom.
Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom.
Ear Hear. 2022;43(4):1208-1221. doi: 10.1097/AUD.0000000000001175. Epub 2022 Mar 11.
The threshold equalizing noise (TEN(HL)) is a clinically administered test to detect cochlear "dead regions" (i.e., regions of loss of inner hair cell [IHC] connectivity), using a "pass/fail" criterion based on the degree of elevation of a masked threshold in a tone-detection task. With sensorineural hearing loss, some elevation of the masked threshold is commonly observed but usually insufficient to create a "fail" diagnosis. The experiment reported here investigated whether the gray area between pass and fail contained information that correlated with factors such as age or cumulative high-level noise exposure (>100 dBA sound pressure levels), possibly indicative of damage to cochlear structures other than the more commonly implicated outer hair cells.
One hundred and twelve participants (71 female) who underwent audiometric screening for a sensorineural hearing loss, classified as either normal or mild, were recruited. Their age range was 32 to 74 years. They were administered the TEN test at four frequencies, 0.75, 1, 3, and 4 kHz, and at two sensation levels, 12 and 24 dB above their pure-tone absolute threshold at each frequency. The test frequencies were chosen to lie either distinctly away from, or within, the 2 to 6 kHz region where noise-induced hearing loss is first clinically observed as a notch in the audiogram. Cumulative noise exposure was assessed by the Noise Exposure Structured Interview (NESI). Elements of the NESI also permitted participant stratification by music experience.
Across all frequencies and testing levels, a strong positive correlation was observed between elevation of TEN threshold and absolute threshold. These correlations were little-changed even after noise exposure and music experience were factored out. The correlations were observed even within the range of "normal" hearing (absolute thresholds ≤15 dB HL).
Using a clinical test, sensorineural hearing deficits were observable even within the range of clinically "normal" hearing. Results from the TEN test residing between "pass" and "fail" are dominated by processes not related to IHCs. The TEN test for IHC-related function should therefore only be considered for its originally designed function, to generate a binary decision, either pass or fail.
阈值均衡噪声（TEN(HL)）是一种临床应用的测试方法，用于检测耳蜗“死区”（即内毛细胞[IHC]连接丧失的区域），使用基于掩蔽阈值在音调检测任务中升高程度的“通过/失败”标准。在感音神经性听力损失中，通常会观察到掩蔽阈值的一些升高，但通常不足以导致“失败”诊断。本实验研究了通过/失败之间的灰色区域是否包含与年龄或累积高水平噪声暴露（>100 dBA 声压级）等因素相关的信息，这些信息可能表明除了更常见的外毛细胞损伤之外，耳蜗结构的其他损伤。
招募了 122 名（71 名女性）接受感音神经性听力损失筛查的参与者，他们被分类为正常或轻度。他们的年龄范围为 32 至 74 岁。他们在四个频率（0.75、1、3 和 4 kHz）和两个感觉水平（每个频率的纯音绝对阈值以上 12 和 24 dB）下进行 TEN 测试。测试频率选择为明显远离或位于 2 至 6 kHz 区域，在该区域，噪声引起的听力损失首次在听力图中表现为切迹。累积噪声暴露由噪声暴露结构化访谈（NESI）评估。NESI 的元素还允许根据音乐经验对参与者进行分层。
在所有频率和测试水平下，TEN 阈值升高与绝对阈值之间存在强烈的正相关。即使在考虑噪声暴露和音乐经验因素后，这些相关性也几乎没有变化。即使在“正常”听力范围内（绝对阈值≤15 dB HL）也观察到了相关性。
使用临床测试，即使在临床“正常”听力范围内也可以观察到感音神经性听力缺陷。在“通过”和“失败”之间的 TEN 测试结果主要由与 IHC 无关的过程主导。因此，TEN 测试不应仅用于其最初设计的功能，即生成通过/失败的二进制决策。
