Lifelong Bilingualism Functions as an Alternative Intervention for Cognitive Reserve Against Alzheimer's Disease

Abstract

Bilingualism has been reported to significantly delay the onset of dementia and plays an important role in the management of Alzheimer's disease (AD), a condition inducing impairment in the brain network and cognitive decline. Cognitive reserve is associated with the adaptive maintenance of neural functions by protecting against neuropathology. Bilingualism acts as a beneficial environmental factor contributing to cognitive reserve, although some potential confounding variables still need further elucidation. In this article, the relationship between bilingualism and cognitive reserve is discussed, interpreting the advantage of bilingualism in protecting against cognitive decline. In addition, the possible brain and biochemical mechanisms, supporting the advantageous effects of bilingualism in delaying the onset of dementia, involved in bilingualism are reviewed. Effectively, bilingualism can be considered as a pharmacological intervention with no side effects. However, the investigation of the pharmacological parameters of bilingualism is still at an early stage.

Psychometric reliability, validity, and generalizability of 3MSE scores among American Indian adults: the Strong Heart Study

“…For example, those who self-reported not using their Native language at all (i.e., English-only speakers) had the lowest score stability compared with those who spoke both English and their Native language. This finding is consistent with findings from other populations that multi-lingual speakers may have better cognitive function (Bialystok et al, 2008;Costa et al, 2008;Prior, 2010) or be protected against cognitive decline (Bialystok et al, 2007;Costumero et al, 2020;Craik et al, 2010;Crane et al, 2010;Guzman-Velez & Tranel, 2015;Ramakrishnan et al, 2017) perhaps via enhanced cognitive reserve, (Liu & Wu, 2021) especially from diseases that preferentially affect the temporal lobe (Schweizer et al, 2012) However, those with more education also had lower score stability than those with less education, which is inconsistent with expectation; however, education in this cohort was strongly confounded by traumatic childhood experiences at Boarding schools, and has been shown to have poor construct validity for baseline cognitive function in this population (A. M. , altogether emphasizing the need for more research on crystallized cognition and education as contextual factors in cognitive assessments.…”

“…For example, those who self-reported not using their Native language at all (i.e., English-only speakers) had the lowest score stability compared with those who spoke both English and their Native language. This finding is consistent with findings from other populations that multi-lingual speakers may have better cognitive function (Bialystok et al, 2008; Costa et al, 2008; Prior, 2010) or be protected against cognitive decline (Bialystok et al, 2007; Costumero et al, 2020; Craik et al, 2010; Crane et al, 2010; Guzman-Velez & Tranel, 2015; Ramakrishnan et al, 2017) perhaps via enhanced cognitive reserve,(Liu & Wu, 2021) especially from diseases that preferentially affect the temporal lobe (Schweizer et al, 2012)…”

Psychometric Properties of Controlled Oral Word Association (COWA) Test and Associations With Education and Bilingualism in American Indian Adults: The Strong Heart Study

“…Bilingual status has been associated with better executive function (Bialystok et al, 2008; Costa et al, 2008; Prior, 2010) and may protect against cognitive decline (Bialystok et al, 2007; Craik et al, 2010; Crane et al, 2010) via improved working memory and functional connectivity. In contrast, managing multiple languages, especially under pressure such as during standardized testing, may increase cognitive load, posing a disadvantage in efficient information processing (Adesope et al, 2010; Liu & Wu, 2021). Data from the SHS and CDCAI study suggest that higher bilingual capacity is inversely associated with test performance on COWA (Verney et al, 2019), supporting the hypothesis of higher cognitive load with delay in information processing for those reporting frequent use of other languages.…”

The Impact of Bilingualism on Cognitive Reserve as a Protectant Against Cognitive Decline

“…Therefore, it is important to make a distinction between "lifelong" and "acquired" bilingualism. Acquired bilingualism can be defined as the successful acquisition of proficiency in an additional language in or beyond adolescence, whereas lifelong bilingualism refers to the quality of speaking two languages from early childhood, 6 and thus being raised in an environment where more than one language is regularly used.…”