功能近红外光谱(fNIRS),一种非侵入性的光学神经成像技术,是便携式和无声的,已成为评估听力脆弱个体的听觉大脑功能的有前途的工具。这项研究,第一次,使用fNIRS评估老年人语音噪声处理的神经可塑性。十个老年人,其中大多数患有中度至轻度听力损失,参加了为期4周的噪音演讲训练。他们在噪声中的语音表现和fNIRS大脑对语音的反应(噪声中的听觉句子),非语音(噪声中的频谱旋转语音)和视觉(闪烁的棋盘)刺激在训练前(T0)和训练后(训练后立即进行评估,T1;并且在保留4周后,T2).行为上,保留后语音噪声性能得到改善(T2与T0),但训练后不立即(T1与T0)。神经上,我们有趣地发现大脑对言语的反应与保留后左听觉皮层的非言语显着降低(T2与T0和T2与T1),我们将其解释为语音聆听过程中背景噪声的抑制处理以及显着的行为改善。同时,多个时间区域内和之间的功能连通性,在保留后的言语状况下,顶叶和额叶显着增强(T2与T0)。我们还发现,在出现显著的行为改善之前,神经发生了变化。与训练前相比,对言语的反应与训练后,左额叶/前额叶皮层的非言语性均显着降低(T1与T0)和保留(T2与T0),反映可能减轻倾听的努力。最后,训练后立即响应视觉刺激,听觉和高级非听觉(顶叶和额叶)皮层之间的连通性显着降低(T1与T0),表明视觉处理期间语音相关区域的跨模态接管减少。因此,结果表明,不仅可以同时观察到神经可塑性,但在此之前,噪声中语音感知的行为变化。据我们所知,这是首个评估老年人语音听觉神经可塑性的fNIRS研究.因此,它通过说明在听力脆弱的个体中使用fNIRS检测神经可塑性的前景,为当前的研究提供了重要的意义。
Functional near-infrared spectroscopy (fNIRS), a non-invasive optical neuroimaging technique that is portable and acoustically silent, has become a promising tool for evaluating auditory brain functions in hearing-vulnerable individuals. This study, for the first time, used fNIRS to evaluate neuroplasticity of speech-in-noise processing in older adults. Ten older adults, most of whom had moderate-to-mild hearing loss, participated in a 4-week speech-in-noise training. Their speech-in-noise performances and fNIRS brain responses to speech (auditory sentences in noise), non-speech (spectrally-rotated speech in noise) and visual (flashing chequerboards) stimuli were evaluated pre- (T0) and post-training (immediately after training, T1; and after a 4-week retention, T2). Behaviourally, speech-in-noise performances were improved after retention (T2 vs. T0) but not immediately after training (T1 vs. T0). Neurally, we intriguingly found brain responses to speech vs. non-speech decreased significantly in the left auditory cortex after retention (T2 vs. T0 and T2 vs. T1) for which we interpret as suppressed processing of background noise during speech listening alongside the significant behavioural improvements. Meanwhile, functional connectivity within and between multiple regions of temporal, parietal and frontal lobes was significantly enhanced in the speech condition after retention (T2 vs. T0). We also found neural changes before the emergence of significant behavioural improvements. Compared to pre-training, responses to speech vs. non-speech in the left frontal/prefrontal cortex were decreased significantly both immediately after training (T1 vs. T0) and retention (T2 vs. T0), reflecting possible alleviation of listening efforts. Finally, connectivity was significantly decreased between auditory and higher-level non-auditory (parietal and frontal) cortices in response to visual stimuli immediately after training (T1 vs. T0), indicating decreased cross-modal takeover of speech-related regions during visual processing. The results thus showed that neuroplasticity can be observed not only at the same time with, but also before, behavioural changes in speech-in-noise perception. To our knowledge, this is the first fNIRS study to evaluate speech-based auditory neuroplasticity in older adults. It thus provides important implications for current research by illustrating the promises of detecting neuroplasticity using fNIRS in hearing-vulnerable individuals.