轻度双侧听力损失儿童噪声下言语感知与频谱时间调制处理之间关系的证据：一项功能性近红外光谱研究

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中文摘要

目的： 轻度双侧听力损失（CHL）儿童，定义为听阈在20至40 dB HL之间，尽管在安静环境下言语感知接近正常，但在有背景噪声的不良声学条件下交谈仍存在困难。CHL中助听器获益证据不一，导致指南强调个体化管理，使临床医生难以建议干预选择。本研究的总体目标是探讨阈上神经处理对噪声下言语感知的影响，以及放大如何影响这一过程。我们主要关注听觉时间处理和频谱处理，这是听力损失成人噪声下言语感知的两个主要预测因素。
设计： 在11名神经典型CHL（6至14岁）和28名年龄匹配的神经典型听力正常儿童（CNH）中，采用空间释放掩蔽范式追踪在噪声下言语感知任务中达到70%准确率所需的信噪比。在三种条件下，目标词从前置扬声器（0°）呈现，而噪声（2人交谈嘈杂语）要么从同一前置扬声器呈现，要么从左或右扬声器（±45°方位角）呈现，同时将噪声副本在领先噪声后3毫秒从前置扬声器呈现，以模拟目标词与噪声之间的空间分离。使用功能性近红外光谱（fNIRS）客观评估对频谱和时间调制的神经敏感性。当儿童聆听未处理（参考）的宽带噪声、4 Hz幅度调制噪声或频谱纹波噪声时，记录双侧额颞区的fNIRS反应。
结果： CNH和CHL，无论未助听还是助听，均从噪声与目标言语之间的空间分离中获益相似。助听既未增强也未降低空间释放掩蔽的获益。助听CHL的fNIRS测量显示，与两种未助听条件和CNH相比，颞叶皮层（TC）对时间和频谱调制的皮层激活增加。助听状态下TC皮层活动高于未助听状态，可能反映了放大对言语相关声学特征的敏感性增强。此外，在CHL中，右侧额颞皮层对时间调制的较低皮层活动以及左侧TC对频谱调制的较高活动与达到70%准确率所需的较低信噪比相关。这些关联可能反映了CHL中噪声下言语感知的区域特异性和线索特异性贡献。在CNH中未发现关联。
结论： 我们的研究强调了助听器验配在改善CHL噪声下言语结局中的价值。虽然行为获益可能细微或不一致，但皮层数据揭示了放大对听觉处理的增强，尤其是在TC。我们的发现表明，阈上神经处理是CHL噪声下言语感知差异的基础。

英文摘要

OBJECTIVES: Children with mild bilateral hearing loss (CHL), defined as having thresholds between 20 and 40 dB HL, experience difficulties conversing in adverse acoustic conditions with background noise, despite having near-normal speech perception in quiet. Mixed evidence of hearing aid benefit among CHL has led to guidelines that emphasize individualized management, making it challenging for clinicians to suggest intervention options. The overarching goal of this study was to investigate the influence of suprathreshold neural processing on speech perception in noise and how it is influenced by amplification. We focused primarily on auditory temporal and spectral processing, the two main predictors of speech perception in noise among adults with hearing loss.
DESIGN: In 11 neurotypical CHL (6- to 14-yr-old) and 28 age-matched neurotypical children with normal hearing (CNH), the signal to noise ratio required to achieve 70% accuracy on a speech perception in noise task was tracked using a spatial release from masking paradigm. Across three conditions, target words were presented from a front loudspeaker (0°), while noise (2-talker babble) was presented either from the same front loudspeaker or from the left or right loudspeaker (±45° azimuth), with a copy of the noise being presented from the front loudspeaker 3-msec later from the lead noise to simulate spatial separation between the target words and noise. Neural sensitivity to spectral and temporal modulations was assessed objectively using functional near-infrared spectroscopy (fNIRS). The fNIRS responses were recorded in the bilateral frontotemporal area, when children listened to broadband noise that was unprocessed (reference), amplitude-modulated at 4 Hz, or spectrally modulated with spectral ripple noise.
RESULTS: CNH and CHL, whether unaided or aided, benefited similarly from the spatial separation between noise and target speech. Aiding neither enhanced nor deteriorated the benefit of spatial release from masking. fNIRS measures in aided CHL showed increased cortical activation to the temporal and spectral modulations in the temporal cortex (TC) compared to both unaided conditions and CNH. Higher aided than unaided cortical activity in the TC likely reflects enhanced sensitivity to speech-relevant acoustic features with amplification. Further, in CHL, lower cortical activity to temporal modulation in the right frontotemporal cortex and higher activity to spectral modulation in the left TC were associated with lower signal to noise ratio required to achieve 70% accuracy. The associations likely reflect region-specific and cue-specific contributions to speech perception in noise among CHL. No associations were found in CNH.
CONCLUSIONS: Our study highlights the value of hearing aid fitting in improving speech-in-noise outcomes in CHL. While behavioral benefits may be subtle or inconsistent, cortical data revealed enhancement in auditory processing with amplification, particularly in the TC. Our findings suggest that suprathreshold neural processing underlies the variation in speech perception in noise among CHL.