Neural mechanisms of speech learning in older adults

描述(申请人提供)：健康的老年听众表现出认知能力和复杂的言语感知能力的下降。现实世界中复杂的语音感知，包括听由多个说话者产生的高度可变的语音(音素)和在噪音中听语音，已经被证明需要认知资源。这项新提出的研究的首要目标是检验这样一种假设，即认知训练先于复杂的言语训练将导致健康老年人在现实世界中更好的言语交流能力。这一假说基于老化大脑的下降补偿模型，该模型假设感觉能力(听觉皮质)的下降可以通过增加一般认知皮质区域的参与来补偿，如前额叶皮质，这是认知训练所应提供的。PI目前的R01正在研究年轻人的语音学习，假设复杂语音学习(多人/高变异性语音到单词的学习)的有效性是由认知大脑区域(听觉注意力的顶上小叶和工作记忆的前额叶)介导的。这个K02奖项的目的是允许PI将他目前在年轻人中的工作扩展到老年人群，包括检查在噪音训练中在多人说话的声音到单词和言语训练之前规定认知训练的有效性的神经生理学基础。根据递减补偿模型，我们假设训练后认知脑区的参与对复杂言语学习的成功至关重要。这项研究涉及老年人的两个重要问题是，这一群体寻求退休后认知刺激活动的趋势，包括有效的第二语言学习计划，以及为了充分参与(嘈杂的)日常环境，需要克服中枢听觉缺陷(主要抱怨在噪音中的言语感知困难)。K02奖还将允许PI接受老年学(包括老年人的神经成像)和临床研究设计方面的教学和实验室培训，为他作为临床医生-翻译研究员的终身职业生涯做好准备。 与公共健康相关：许多老年人在餐馆等真实环境中理解语言时会遇到困难。据报告，一些老年人避免社交(例如，在餐馆就餐)，因为他们很难在这样的环境中进行交流。虽然这种困难可能与他们的耳朵有关，也可能与声音大到他们听不到的事实有关，但影响记忆和注意力的大脑功能下降也可能起到重要作用。我们的研究将试图探索，在对真实世界环境进行言语感知训练之前，首先关注记忆和注意力的训练是否会导致老年人更好地进行整体口语交流；另一个目标是检查潜在的大脑对这种可能的改善的反应。

DESCRIPTION (provided by applicant): Healthy older listeners show decline in cognitive and complex speech perception abilities. Complex speech perception in the real-world, including listening to highly variable speech sounds (phonemes) produced by multiple talkers and listening to speech in noise, has been shown to require cognitive resources. The overarching goal of the newly proposed research is to test the hypothesis that cognitive training preceding complex speech training will result in better real-world speech communication abilities in healthy older adults. This hypothesis is grounded in the decline-compensation model of the aging brain, which postulates that decline in sensory abilities (auditory cortex) can be compensated by increased engagement of general cognitive cortical regions such as the prefrontal cortex, which cognitive training is expected to provide. The PI's current R01 is examining speech learning in younger adults, with the hypothesis that efficacy of complex speech learning (multi-talker/high-variability sound-to-word learning) is mediated by cognitive brain regions (superior parietal lobule for auditory attention and prefrontal cortex for working memory). The purpose of this K02 award is to allow the PI to extend his current work in younger adults to the elderly population, including examinations of the neurophysiological underpinnings of the efficacy of prescribing cognitive training before multi-talker sound-to-word and speech in noise training. Per the decline-compensation model, we hypothesize that the engagement of cognitive brain regions post-training is critical to the success in complex speech learning. The two important issues concerning older adults addressed by this research is the trend for this population to seek cognitively stimulating post-retirement activities including effective second language learning programs and the need to overcome central auditory deficits (with speech perception in noise difficulty being the chief complaint) in order to participate fully in (noisy) everyday environments. This K02 award will also allow the PI to receive didactic and laboratory training in gerontology (including neuroimaging in older adults) and clinical research designs to prepare him for a life-long career as a clinician-translational researcher. PUBLIC HEALTH RELEVANCE: Many older adults experience difficulty understanding speech in real-world environments such as restaurants. Some elderly individuals reportedly avoid socializing (e.g., dining in restaurants) because it is difficult for them to communicate in such environments. While this difficulty can be related to their ears and to the fact that sounds are not loud enough for them to hear, reduced brain functions affecting memory and attention might also be playing a major role. Our research will seek to explore whether training focusing first on memory and attention prior to speech perception training of real-world environments could result in better overall spoken language communication in older adults; an additional goal is to examine the underlying brain responses to such possible improvements.