Multilingualism as a factor of resilience to Alzheimer's disease and related dementias in India

项目摘要/摘要 到2050年，三分之二的老年痴呆症患者将生活在低收入和中等收入国家(LMIC)。AS LMIC的死亡率继续下降，关键是要确定提供保护和 对阿尔茨海默病和相关痴呆的复原力(ADRD)。一些研究发现，说两种语言的人 与只讲一种语言的人相比，ADRD的风险降低了，但其他研究没有发现双语优势的证据。 这项研究的基本原理是，先前研究的模棱两可的发现在很大程度上是由 方法上的不一致限制了我们对双语在认知老化中的作用的理解，例如：1) 对潜在混杂因素的控制不足，限制了我们推断双语是否有直接影响的能力 关于认知或这些关系是否由于环境和社会文化因素，2)有限 包括神经病理标记物，以及3)很少注意双语者之间的组内差异， 例如第二语言(L2)习得年龄、熟练程度、语言使用频率、语言数量 口语，以及语言家族的多样性。印度提供了一个独特的机会来研究双语在 鉴于它在全国各地丰富的语言和社会文化多样性，它具有认知储备和复原力。整体而言 这项研究的目的是利用印度语言和社会人口景观的独特特征来 辨别双语是否会改变血液和神经成像生物标记物之间的关联 ADRD与认知和认知衰退。这项研究将分析现有的基于血浆的淀粉样蛋白测量方法。 以及来自印度纵向老龄化研究的tau病理学、MRI和认知评估--诊断 痴呆症评估(LASI-DAD)，这是一项关于印度老龄化和痴呆症的大型、具有人口代表性的研究。 具体地说，该项目将1)确定双语是否改变了ADRD之间的联系 生物标志物(基于血液或神经成像)和认知结果，2)评估 双语能力在不同的生活过程环境中对健康的决定因素是不同的，3)解构语言 在印度双语人群中使用，以了解双语带来认知储备的机制 防止ADRD的生物风险。我们假设双语将缓冲血液AD生物标记物的影响 (淀粉样蛋白和tau血浆水平)、皮质萎缩和白质完整性对基线认知和 在记忆、语言和执行功能方面，与单语者相比，认知能力下降。在……里面 此外，通过对双语的解构，我们假设二语习得年龄越早，双语程度越高 熟练程度、更多的日常多种语言使用、更多的语言习得数量和更远的距离 语言家族之间的认知储备将独立于令人困惑的社会文化因素(即， 教育、社会经济地位)。这项提议将通过揭示潜在的 对ADRD的复原力机制可以修改，并可转移给其他群体。

Project Summary/Abstract By 2050, two-thirds of older individuals with dementia will live in low-and middle-income countries (LMICs). As LMICs continue to experience a reduction in mortality, it is critical to determine factors that confer protection and resilience toward Alzheimer’s disease and related dementias (ADRD). Some studies find that bilinguals are at reduced ADRD risk compared to monolinguals, but other studies do not find evidence of a bilingual advantage. The rationale for this study is that the equivocal findings of prior research has been driven largely by methodological inconsistencies that limit our understanding of bilingualism’s role in cognitive aging such as: 1) inadequate control for potential confounders that limit our ability to infer whether bilingualism has a direct effect on cognition or whether these relationships are due to environmental and sociocultural factors, 2) limited inclusion of markers of neuropathology, and 3) little attention given to within-group differences among bilinguals, such as age of second language (L2) acquisition, proficiency, frequency of language use, number of languages spoken, and diversity of language families. India offers a unique opportunity to study the role of bilingualism in cognitive reserve and resilience, given its rich linguistic and sociocultural diversity across the country. The overall aim of the study is to leverage the unique features of India’s linguistic and sociodemographic landscape to discern whether bilingualism modifies the association between blood-based and neuroimaging biomarkers of ADRD and cognition and cognitive decline. This study will analyze available plasma-based measures of amyloid and tau pathologies, MRI, and cognitive assessments from the Longitudinal Aging Study in India–Diagnostic Assessment of Dementia (LASI-DAD), a large, population-representative study of ageing and dementia in India. Specifically, the project will 1) determine whether bilingualism modifies the association between ADRD biomarkers (blood-based or neuroimaging) and cognitive outcomes, 2) evaluate whether the protective effect of bilingualism differs across diverse life-course environmental determinants of health, and 3) deconstruct language use within bilinguals in India to understand the mechanisms by which bilingualism confers cognitive reserve against biological risk of ADRD. We hypothesize that bilingualism will buffer the effects of blood AD-biomarkers (amyloid, and tau plasma levels), cortical atrophy, and white matter integrity on baseline cognition and rate of cognitive decline compared to monolinguals in the domains of memory, language, and executive functioning. In addition, by deconstructing bilingualism, we hypothesize that earlier age of L2 acquisition, higher bilingual proficiency, greater daily multiple language use, higher number of languages acquired, and greater distance between language families will confer cognitive reserve, independent of confounding sociocultural factors (i.e., education, socioeconomic status). This proposal will enhance the field of ADRD by uncovering the underlying mechanisms of resilience to ADRD that may be modifiable and transferable to other populations.