Many older adults are struggling with understanding spoken language, particularly when background noise interferes with comprehension. In the present study, we investigated a potential interaction between two well-known factors associated with greater speech-in-noise (SiN) reception thresholds in older adults, namely a) lower working memory capacity and b) age-related structural decline of frontal lobe regions.

In a sample of older adults (N = 25) and younger controls (N = 13) with normal pure-tone thresholds, SiN reception thresholds and working memory capacity were assessed. Furthermore, T1-weighted structural MR-images were recorded to analyze neuroanatomical traits (i.e., cortical thickness (CT) and cortical surface area (CSA)) of the cortex.

As expected, the older group showed greater SiN reception thresholds compared to the younger group. We also found consistent age-related atrophy (i.e., lower CT) in brain regions associated with SiN recognition, namely the superior temporal lobe bilaterally, the right inferior frontal and precentral gyrus, as well as the left superior frontal gyrus. Those older participants with greater atrophy in these brain regions showed greater SiN reception thresholds. Interestingly, the association between CT in the left superior frontal gyrus and SiN reception thresholds was moderated by individual working memory capacity. Older adults with greater working memory capacity benefitted more strongly from thicker frontal lobe regions leading to better SiN recognition.

Overall, our results fit well into the literature showing that age-related structural decline in auditory- and cognition-related brain areas is associated with greater SiN reception thresholds in older adults. However, we highlight that this association changes as a function of individual working memory capacity. We therefore believe that future interventions to improve SiN recognition in older adults should take into account the role of the frontal lobe as well as individual working memory capacity.

许多老年人正在努力理解口语，尤其是当背景噪音干扰理解时。在本研究中，我们调查了与老年人更高的噪声中语音 (SiN) 接收阈值相关的两个众所周知的因素之间的潜在相互作用，即 a) 较低的工作记忆能力和 b) 年龄相关的额叶结构衰退叶区域。

在具有正常纯音阈值的老年人 (N = 25) 和年轻对照 (N = 13) 样本中，评估了 SiN 接收阈值和工作记忆容量。此外，记录 T1 加权结构 MR 图像以分析皮质的神经解剖学特征（即皮质厚度 (CT) 和皮质表面积 (CSA)）。

正如预期的那样，与年轻组相比，年长组显示出更高的 SiN 接收阈值。我们还在与 SiN 识别相关的大脑区域中发现了与年龄相关的一致萎缩（即下 CT），即双侧颞上叶、右侧额下回和中央前回，以及左侧额上回。这些大脑区域萎缩程度较大的老年参与者表现出更高的 SiN 接收阈值。有趣的是，左侧额上回 CT 与 SiN 接收阈值之间的关联受个人工作记忆容量的影响。具有更大工作记忆能力的老年人从更厚的额叶区域中获益更多，从而导致更好的 SiN 识别。

总体而言，我们的结果非常符合文献，表明与年龄相关的听觉和认知相关大脑区域的结构性下降与老年人更高的 SiN 接收阈值相关。然而，我们强调这种关联会随着个人工作记忆容量的变化而变化。因此，我们认为，未来改善老年人 SiN 识别的干预措施应考虑到额叶的作用以及个人工作记忆能力。