CERVO Brain Research Center, Québec City, QC, Canada; Université Laval, Département de réadaptation, Québec City, QC, Canada.
CERVO Brain Research Center, Québec City, QC, Canada; Université Laval, Département de réadaptation, Québec City, QC, Canada.
Neuroimage. 2021 Feb 15;227:117675. doi: 10.1016/j.neuroimage.2020.117675. Epub 2020 Dec 24.
Speech perception can be challenging, especially for older adults. Despite the importance of speech perception in social interactions, the mechanisms underlying these difficulties remain unclear and treatment options are scarce. While several studies have suggested that decline within cortical auditory regions may be a hallmark of these difficulties, a growing number of studies have reported decline in regions beyond the auditory processing network, including regions involved in speech processing and executive control, suggesting a potentially diffuse underlying neural disruption, though no consensus exists regarding underlying dysfunctions. To address this issue, we conducted two experiments in which we investigated age differences in speech perception when background noise and talker variability are manipulated, two factors known to be detrimental to speech perception. In Experiment 1, we examined the relationship between speech perception, hearing and auditory attention in 88 healthy participants aged 19 to 87 years. In Experiment 2, we examined cortical thickness and BOLD signal using magnetic resonance imaging (MRI) and related these measures to speech perception performance using a simple mediation approach in 32 participants from Experiment 1. Our results show that, even after accounting for hearing thresholds and two measures of auditory attention, speech perception significantly declined with age. Age-related decline in speech perception in noise was associated with thinner cortex in auditory and speech processing regions (including the superior temporal cortex, ventral premotor cortex and inferior frontal gyrus) as well as in regions involved in executive control (including the dorsal anterior insula, the anterior cingulate cortex and medial frontal cortex). Further, our results show that speech perception performance was associated with reduced brain response in the right superior temporal cortex in older compared to younger adults, and to an increase in response to noise in older adults in the left anterior temporal cortex. Talker variability was not associated with different activation patterns in older compared to younger adults. Together, these results support the notion of a diffuse rather than a focal dysfunction underlying speech perception in noise difficulties in older adults.
言语感知能力可能具有挑战性，尤其是对于老年人而言。尽管言语感知在社交互动中很重要，但这些困难的根本机制仍不清楚，且治疗选择也很有限。虽然有几项研究表明，皮质听觉区域的衰退可能是这些困难的一个标志，但越来越多的研究报告称，除了听觉处理网络之外，其他区域（包括参与言语处理和执行控制的区域）也出现了衰退，这表明潜在的神经功能紊乱可能具有弥散性，但尚未就潜在的功能障碍达成共识。为了解决这个问题，我们进行了两项实验，在这两项实验中，我们研究了在背景噪声和说话人变异性被操纵的情况下，年龄对言语感知的影响，这两个因素已知对言语感知不利。在实验 1 中，我们研究了 88 名年龄在 19 岁至 87 岁的健康参与者的言语感知、听力和听觉注意力之间的关系。在实验 2 中，我们使用磁共振成像（MRI）检查了皮质厚度和 BOLD 信号，并通过实验 1 中的 32 名参与者使用简单的中介方法将这些测量结果与言语感知表现相关联。我们的结果表明，即使考虑到听力阈值和两种听觉注意力测量，言语感知也会随着年龄的增长而显著下降。与噪声相关的年龄相关的言语感知下降与听觉和言语处理区域（包括颞上回、腹侧前运动皮层和额下回）以及执行控制区域（包括背侧前岛叶、前扣带皮层和内侧前额叶皮层）的皮质变薄有关。此外，我们的结果表明，与年轻成年人相比，老年成年人的右颞上回的大脑反应与言语感知表现相关，而老年成年人的左颞前回对噪声的反应增加。说话人变异性与老年人和年轻人相比，没有不同的激活模式。综上所述，这些结果支持了一种观点，即老年人在噪声环境中言语感知困难的根本机制是弥散性的，而不是局灶性的。
