Coelho de Sousa Sónia L, Marrufo Pérez Miriam I, Johannesen Peter T, Gómez Álvarez Marcelo, Lopez-Poveda Enrique A
Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, 37007 Salamanca, Spain.
Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, 37007 Salamanca, Spain; Departamento de Cirugía, Facultad de Medicina, Universidad de Salamanca, 37007 Salamanca, Spain.
Hear Res. 2025 Aug;464:109321. doi: 10.1016/j.heares.2025.109321. Epub 2025 May 24.
Adaptation to noise refers to the improvement in word-in-noise recognition as words are delayed a few hundred milliseconds in the noise. This adaptation is thought to reflect adjustments of the dynamic range of auditory neurons to the most frequent noise level. Evidence from a mouse model suggests that hidden hearing loss (HHL), a diminished auditory nerve response without a hearing loss, selectively impairs neural dynamic range adaptation to loud sound environments. The aim of the present study was to investigate whether HHL is associated with poor behavioral adaptation to loud noise in speech recognition. For 89 people (aged 19-86 years) with clinically normal hearing, we measured speech reception thresholds (SRTs; signal-to-noise ratios at 50 % recognition) for disyllabic words in stationary, speech-shaped noise. SRTs were measured for words delayed 50 and 800 ms in the noise and for noise levels of 55 and 78 dB SPL. Adaptation was calculated as the SRT improvement in the long-delay relative to the short-delay condition. Because adaptation is greater for vocoded than for natural words, words were processed through a tone vocoder. The response of the auditory nerve was assessed using the amplitude of the auditory brainstem response (ABR) wave I and the rate of growth (slope) of the wave I amplitude with increasing stimulus level. Adaptation occurred at the two noise levels but was greater for the louder noise than for the softer noise (2.3 dB vs 1.3 dB, respectively). This happened because SRTs were worse for the louder noise in the short but not in the long delay condition. The large variability in ABR wave I amplitude (0.10 to 0.54 μV) and slope (-0.004 to 0.023 μV/dB) suggested that the sample included participants with varying degrees of HHL of uncertain etiology (idiopathic). However, adaptation was not correlated with the wave I amplitude or slope, even after accounting for the potential confounding effect of elevated hearing thresholds in an extended frequency range. Findings suggest that adaptation to noise in speech recognition is greater at higher noise levels but provide no evidence that idiopathic HHL leads to reduced adaptation to noise in humans.
对噪声的适应是指当单词在噪声中延迟几百毫秒时，噪声中单词识别能力的提高。这种适应被认为反映了听觉神经元动态范围对最常见噪声水平的调整。来自小鼠模型的证据表明，隐性听力损失（HHL），即无听力损失但听觉神经反应减弱，会选择性地损害神经动态范围对大声环境的适应。本研究的目的是调查HHL是否与语音识别中对大声噪声的行为适应不良有关。对于89名临床听力正常的人（年龄在19 - 86岁之间），我们测量了在平稳、语音形状噪声中双音节单词的言语接受阈值（SRTs；50%识别率时的信噪比）。测量了在噪声中延迟50毫秒和800毫秒以及噪声水平为55 dB SPL和78 dB SPL时的SRTs。适应度计算为长延迟相对于短延迟条件下SRT的改善。由于对声码化单词的适应比对自然单词的适应更大，因此单词通过音调声码器进行处理。使用听觉脑干反应（ABR）波I的幅度以及波I幅度随刺激水平增加的增长率（斜率）来评估听觉神经的反应。在两个噪声水平下都出现了适应，但较大声的噪声比较柔和的噪声适应度更大（分别为2.3 dB和1.3 dB）。这是因为在短延迟条件下较大声噪声的SRT更差，但在长延迟条件下并非如此。ABR波I幅度（0.10至0.54 μV）和斜率（-0.004至0.023 μV/dB）的较大变异性表明，该样本包括了病因不明（特发性）、程度不同的HHL参与者。然而，即使在考虑了扩展频率范围内听力阈值升高的潜在混杂效应后，适应度也与波I幅度或斜率无关。研究结果表明，在语音识别中，较高噪声水平下对噪声的适应度更大，但没有证据表明特发性HHL会导致人类对噪声的适应度降低。
