Bilingual Alzheimer's Disease

描述（由申请人提供）：本项目研究双语和阿尔茨海默病（AD）对语言和认知加工的共同影响，目的是形成双语的心理语言学模型（目标1），测试AD的认知衰退模型（目标2），并表征双语AD的独特表现（目标3）。在美国，老年西班牙语-英语双语者的数量正在迅速增加，但几乎没有关于双语者AD概况的信息。利用三种不同的双语模型和三种AD认知衰退模型，我们对AD双语者在几个领域（单字生成和理解、言语流畅性、语言转换、跨语言入侵错误、翻译识别和句子阅读中双语激活管理）的双语衰退模式进行了具体预测。假设双语者不能“关闭一门语言”，我们测试了双语激活的隐式和显式影响，并检查了可能是AD双语者独有的影响（例如，语言和控制缺陷的综合表现，选择使用任何一种语言的增强效果，减少同源和假朋友效应）。我们假设阿尔茨海默病主要在疾病的初始阶段影响语义存储，而主导语言对这种变化更敏感。然而，我们认为双语AD也存在检索缺陷和语言控制问题，并且这些缺陷会随着疾病的进展和在最大程度上干扰语言的任务中影响非主导语言。在每项研究中，我们都考虑了结果是否适用于早期和晚期双语者，不平衡和平衡双语者，以及不同双语类型差异的含义。这些研究将限制双语和AD认知能力下降的模型，揭示控制在语言加工中的作用，确定双语AD的典型表现，同时确定允许AD双语者尽可能流利地交流的条件。

DESCRIPTION (provided by applicant): This project investigates the joint consequences of bilingualism and Alzheimer's disease (AD) for language and cognitive processing, with the goals of shaping psycholinguistic models of bilingualism (Aim 1), testing models of cognitive decline in AD (Aim 2), and characterizing unique aspects in the presentation of bilingual AD (Aim 3). Aging Spanish-English bilinguals are rapidly increasing in numbers in the USA, but almost no information is available on the profile of bilinguals with AD. Using three different models of bilingualism and three models of cognitive decline in AD, we derive specific predictions for the pattern of dual-language decline in bilinguals with AD for several domains (single word production and comprehension, verbal fluency, language switching, cross-language intrusion errors, translation recognition, and management of dual-language activation in sentence reading). Assuming that bilinguals cannot "shut a language off", we test the effects of dual-language activation implicitly and explicitly, and examine effects that may be unique to bilinguals with AD (e.g., integrated presentation of language and control deficits, enhanced effects of the option to use either language, reduced cognate and false-friend effects). We hypothesize that AD primarily affects semantic storage in initial stages of the disease and that the dominant language will be more sensitive to such changes. However, we propose that retrieval deficits and language control problems are also present in bilingual AD, and that these deficits will affect the nondominant language with disease progression and in tasks that maximize interference between languages. In each study we consider if the results generalize to early vs. late bilinguals, and unbalanced vs. balanced bilinguals, and the implications of differences across bilingual types. The proposed studies will constrain models of bilingualism and cognitive decline in AD, will reveal the role of control in language processing, and will determine the typical presentation of bilingual AD while also identifying the conditions that allow bilinguals with AD to communicate as fluently as possible.