Age, Hearing Loss, and Sentence Comprehension: Neural Correlates

描述（由申请人提供）：成人老龄化代表了下降和补偿的平衡。这项资助调查了成年人衰老的相互作用，与年龄相关的听力下降，以及作为理解口语句子能力基础的神经网络的参与。在行为水平上对这种平衡的理解已经取得了很好的进展，但对携带这些效应的潜在神经基质的了解要少得多。在这个补助金，我们解决听觉句子理解的神经基础，这是如何影响知觉的努力，由于降低听力敏锐度，和中央认知负荷，如句法复杂性，语速，工作记忆的要求，以及语义和句法的歧义，发生在日常话语。我们是由一个新的模型的句子处理，涉及几个可分离的神经基板，成为从事取决于被处理的材料的认知和感知的需求。我们的受试者将是健康的年轻人和老年人，具有良好的听力敏锐度和轻度至中度听力损失。我们测试我们的神经认知模型使用新的成像方法，结合联合收割机功能磁共振BOLD激活研究与结构成像的灰质厚度和白色物质的投影，整合皮质区。我们假设，由于大脑区域之间的白色物质投射有限，以及背外侧前额叶皮层的皮质变薄，这种在句子处理过程中选择性工作记忆和决策的模型在衰老过程中部分崩溃。我们还评估了潜在的补偿机制。目标1考察句法复杂性和语速的影响，目标2专门操纵句子内的工作记忆负荷，目标3调查解决句子处理过程中遇到的词汇和句法歧义所需的决策。拟议的研究将填补我们对认知老化和年龄相关性听力损失对老年人日常言语理解的相互作用的认识中的一个关键空白。这项工作也可以作为早期检测病理变化的框架，因为它影响了衰老大脑的语言理解。)

DESCRIPTION (provided by applicant): Adult aging represents a balance of decline and compensation. This grant investigates the interacting effects of adult aging, age-related declines in hearing acuity, and engagement of the neural networks that underlie the ability to comprehend spoken sentences. Good progress has been made in understanding this balance at the behavioral level, but far less is known about the underlying neural substrates that carry these effects. In this grant we address the neural basis for aural sentence comprehension and how this is affected by perceptual effort due to reduced hearing acuity, and central cognitive loads such as those imposed by syntactic complexity, speech rate, working memory demands, and the semantic and syntactic ambiguities that occur in everyday discourse. We are guided by a novel model of sentence processing that implicates several dissociable neural substrates that become engaged depending on the cognitive and perceptual demands of the materials being processed. Our subjects will be healthy young and older adults with good hearing acuity and with mild-to-moderate hearing loss. We test our neurocognitive model using novel imaging methods that combine fMRI BOLD activation studies with structural imaging of gray matter thickness and white matter projections that integrate cortical areas. We hypothesize that this model of selective working memory and decision-making during sentence processing partially breaks down during aging because of limited white matter projections between brain regions, and cortical thinning in dorsolateral prefrontal cortex. We also assess potential compensatory mechanisms. Aim 1 examines effects of syntactic complexity and speech rate, Aim 2 specifically manipulates working memory load within sentences, and Aim 3 investigates decision-making needed to resolve lexical and syntactic ambiguities encountered during sentence processing. The proposed studies will close a critical gap in our knowledge of the interacting effects of cognitive aging and age-related hearing loss on everyday speech comprehension in older adults. This work may also serve as a framework for early detection of pathological change as it affects language comprehension in the aging brain.) )