Extensive evidence supports the association between age-related hearing loss (ARHL) and cognitive decline. It is, however, unknown whether a causal relationship exists between these two, or whether they both result from shared mechanisms. This paper intends to study this relationship through a comprehensive review of MRI findings as well as evidence of cellular alterations. Our review of structural MRI studies demonstrates that ARHL is independently linked to accelerated atrophy of total and regional brain volumes and reduced white matter integrity. Resting-state and task-based fMRI studies on ARHL also show changes in spontaneous neural activity and brain functional connectivity; and alterations in brain areas supporting auditory, language, cognitive, and affective processing independent of age, respectively. Although MRI findings support a causal relationship between ARHL and cognitive decline, the contribution of potential shared mechanisms should also be considered. In this regard, the review of cellular evidence indicates their role as possible common mechanisms underlying both age-related changes in hearing and cognition. Considering existing evidence, no single hypothesis can explain the link between ARHL and cognitive decline, and the contribution of both causal (i.e., the sensory hypothesis) and shared (i.e., the common cause hypothesis) mechanisms is expected.

中文翻译：

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与年龄相关的听力损失和认知能力下降：MRI 和细胞证据

大量证据支持年龄相关性听力损失 (ARHL) 与认知能力下降之间的关联。然而，尚不清楚这两者之间是否存在因果关系，或者它们是否都源于共享机制。本文旨在通过对 MRI 结果和细胞改变证据的全面审查来研究这种关系。我们对结构性 MRI 研究的回顾表明，ARHL 与总脑容量和区域脑容量加速萎缩以及白质完整性降低独立相关。ARHL 的静息状态和基于任务的 fMRI 研究也显示自发神经活动和大脑功能连接的变化；和大脑区域的改变，分别支持独立于年龄的听觉、语言、认知和情感处理。尽管 MRI 结果支持 ARHL 与认知能力下降之间存在因果关系，但也应考虑潜在共享机制的贡献。在这方面，对细胞证据的审查表明，它们可能是与年龄相关的听力和认知变化背后的共同机制。考虑到现有证据，没有单一的假设可以解释 ARHL 与认知能力下降之间的联系，并且可以预期因果（即感觉假设）和共享（即共同原因假设）机制的贡献。