Hsin Cheng-Hung, Chao Pei-Chun, Lee Chia-Ying
Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan.
Brain and Language Laboratory, Institute of Linguistics, Academia Sinica, Taipei, Taiwan.
Front Psychol. 2023 Feb 15;14:1105346. doi: 10.3389/fpsyg.2023.1105346. eCollection 2023.
Speech comprehension involves context-based lexical predictions for efficient semantic integration. This study investigated how noise affects the predictability effect on event-related potentials (ERPs) such as the N400 and late positive component (LPC) in speech comprehension.
Twenty-seven listeners were asked to comprehend sentences in clear and noisy conditions (hereinafter referred to as "clear speech" and "noisy speech," respectively) that ended with a high-or low-predictability word during electroencephalogram (EEG) recordings.
The study results regarding clear speech showed the predictability effect on the N400, wherein low-predictability words elicited a larger N400 amplitude than did high-predictability words in the centroparietal and frontocentral regions. Noisy speech showed a reduced and delayed predictability effect on the N400 in the centroparietal regions. Additionally, noisy speech showed a predictability effect on the LPC in the centroparietal regions.
These findings suggest that listeners achieve comprehension outcomes through different neural mechanisms according to listening conditions. Noisy speech may be comprehended with a second-pass process that possibly functions to recover the phonological form of degraded speech through phonetic reanalysis or repair, thus compensating for decreased predictive efficiency.
言语理解涉及基于语境的词汇预测，以实现高效的语义整合。本研究调查了噪声如何影响言语理解中对事件相关电位（ERP）的可预测性效应，如N400和晚期正成分（LPC）。
在脑电图（EEG）记录过程中，要求27名听众分别在清晰和嘈杂条件下（以下分别称为“清晰言语”和“嘈杂言语”）理解以高可预测性或低可预测性单词结尾的句子。
关于清晰言语的研究结果显示了对N400的可预测性效应，其中在中央顶叶和额中央区域，低可预测性单词比高可预测性单词引发更大的N400波幅。嘈杂言语在中央顶叶区域对N400的可预测性效应降低且延迟。此外，嘈杂言语在中央顶叶区域对LPC显示出可预测性效应。
这些发现表明，听众根据听力条件通过不同的神经机制实现理解结果。嘈杂言语可能通过二次加工来理解，该二次加工可能起到通过语音重新分析或修复来恢复退化言语的语音形式的作用，从而补偿预测效率的降低。
