Lifelong Bilingualism Maintains White Matter Integrity in Older Adults

Previous research has shown that bilingual speakers have higher levels of cognitive control than comparable monolinguals, especially at older ages. The present study investigates a possible neural correlate of this behavioral effect. Given that white matter (WM) integrity decreases with age in adulthood, we tested the hypothesis that bilingualism is associated with maintenance of WM in older people. Using diffusion tensor imaging, we found higher WM integrity in older people who were lifelong bilinguals than in monolinguals. This maintained integrity was measured by fractional anisotropy (FA) and was found in the corpus callosum extending to the superior and inferior longitudinal fasciculi. We also hypothesized that stronger WM connections would be associated with more widely distributed patterns of functional connectivity in bilinguals. We tested this by assessing the resting-state functional connectivity of frontal lobe regions adjacent to WM areas with group differences in FA. Bilinguals showed stronger anterior to posterior functional connectivity compared to monolinguals. These results are the first evidence that maintained WM integrity is related to lifelong naturally occurring experience; the resulting enhanced structural and functional connectivity may provide a neural basis for “brain reserve.

The many shades of bilingualism: language experiences modulate adaptations in brain structure

Recent years have seen an expansion in the research related to structural brain adaptations related to the acquisition and processing of additional languages. However, the accumulating evidence remains to a great extent inconsistent, with a large variety of cortical, subcortical and cerebellar effects reported in various studies. Here we propose that the variability in the data can be explained by the differences in the language background and experiences of the tested samples. We also propose that the field should move away from monolithic bilingual vs. monolingual comparisons; instead, it should focus on the experiences of the bilingual groups as predictors of structural changes in the brain, and also employ longitudinal designs to test the dynamic effects of active bilingualism. The implications of the proposed approaches for the suggested benefits of bilingualism on ageing and patient populations are also discussed

Bilingualism/Multilingualism to Protect Against Cognitive Decline in Alzheimer’s Disease and Other Forms of Dementia: A Systematic Review

Given a growing incidence of Alzheimer’s disease and lack of treatments, prevention is a popular topic in both research literature (Angevaren et al., 2008; Orrell & Sahakian, 1995) and in news articles (Iacono et al., 2009). A cognitive reserve is a skill that improves cognitive functioning in executive controls. Bilingualism is believed to be a practice that increases cognitive reserve, which could delay the onset of Alzheimer’s disease. The purpose of this project was to analyze the possibility that bilingualism or multilingualism could create a cognitive reserve to delay the onset of Alzheimer’s disease and other dementia-related diseases. This systematic review asks the question: Can bilingualism and multilingualism function as a protective mechanism and create a cognitive reserve to delay the onset and progression of Alzheimer’s disease and other dementia-related diseases? The PRISMA approach was used and evidence was gathered from the databases of PubMed and Web of Science. Evidence was screened for inclusion and appraised for quality by following similar criteria to the study from Mukadam and collegues (2017). The results of the studies were summarized through tables and comparisons. Neural reserve and cognitive reserve studies investigating both structural and behavioral differences found greater statistical differences for bilinguals and multilinguals, showing a potential benefit of language usage towards preventing Alzheimer’s disease and other dementia-related disease. Studies only investigating cognitive reserve did not find as overwhelming evidence for multiple language use to delay such diseases. I hope to clarify the debatable role of multiple languages to create a cognitive reserve that may delay Alzheimer’s disease and other forms of dementia

Understanding structural plasticity in the bilingual brain: The Dynamic Restructuring Model

Research on the effects of bi-/multilingualism on brain structure has so far yielded variable patterns. Although it cannot be disputed that learning and using additional languages restructures grey (cortical, subcortical and cerebellar) and white matter in the brain, both increases and reductions in regional volume and diffusivity have been reported. This paper revisits the available evidence from simultaneous and sequential bilinguals, multilinguals, interpreters, bimodal bilinguals, children, patients and healthy older adults from the perspective of experience-based neuroplasticity. The Dynamic Restructuring Model (DRM) is then presented, a three-stage model accounting for, and reinterpreting, all the available evidence by proposing a time-course for the reported structural adaptations, and by suggesting that these adaptations are dynamic and depend on the quantity and quality of the language learning and switching experience. This is followed by suggestions for future directions for the emerging field of bilingualism-induced neuroplasticit

Creating Appropriate Clinical Guidelines for The Bilingual Population with Acquired Brain Injuries

While there is a growing bilingual demographic in the United States, relatively little is known about treating this population should they experience a brain injury. This is a growing area of interest, as research has demonstrated that the acquisition of a second language promotes neuroplastic changes that then impact brain functioning pre- and post-brain-injury. Given bilingualism’s cognitive complexity, clinicians are left with challenges on how best to tailor treatment for brain-injured bilingual populations. Therefore, the focus of this review was to provide clinical recommendations to clinicians performing assessments with bilingual individuals with acquired brain injuries. The goal was for the guidelines provided to aid in the augmentation of appropriate strategies for neurorehabilitation to maximize linguistic, cognitive, and communicative improvement, leading to social readaptation and a better quality of life

Dvojezičnost in jezikovno izobraževanje za izboljšanje kognitivnega zdravja starejših ljudi

This article explores whether lifelong bilingualism can be associated with delayed age-related cognitive decline, with cognitive (or brain) reserve as the mechanism that compensates by positively increasing the functional capacity of the brain for older persons. A structural review of recent psychoneurolinguistic studies shows that older bilinguals display several years of delay in dementia symptoms as compared to monolinguals, as well as that positive effects exist in bilingual brain networks, also related to other neurodegenerative disorders. The field is clearly missing an established methodology, nevertheless, lifelong bilingualism can be considered to induce cognitive reserve. Drawing from these implications, we hypothesize that successful ageing could be facilitated by the active use of multiple languages, and in this light, we discuss language education for older persons, the role of Third Age Universities, the implementation of crucial aspects in such courses, and the proper assessment of the effectiveness of language proficiency and cognition.V članku raziskujemo, ali lahko vseživljenjsko dvojezičnost povezujemo z zamikom starostnega pešanja kognitivnih sposobnosti in kognitivno rezervo kot mehanizmom, ki pozitivno vpliva na možganske zmogljivosti pri starejših ljudeh. Pregled novejših psiho- in nevrolingvističnih študij kaže, da pri starejših dvojezičnih osebah prihaja do večletnega zamika pojava simptomov demence v primerjavi z enojezičnimi osebami ter da obstajajo pozitivni učinki dvojezičnih možganskih mrež, prav tako povezani z drugimi nevrodegenerativnimi boleznimi. Na tem področju manjka metodologija, vendar pa lahko vseživljenjsko dvojezičnost povezujemo tudi s kognitivno rezervo. Na tej podlagi lahko postavimo hipotezo, da k zdravemu staranju lahko pripomore tudi aktivna raba več jezikov, na podlagi tega pa razpravljamo o jezikovni izobrazbi za starejše ljudi, vlogi univerz za tretje življenjsko obdobje, izvajanju kritičnih vidikov tovrstnih tečajev ter ustrezni oceni učinkovitosti znanja jezikov in kognicije

Bilingualism: Consequences for Mind and Brain

Building on earlier evidence showing a beneficial effect of bilingualism on children’s cognitive development, we review recent studies using both behavioral and neuroimaging methods to examine the effects of bilingualism on cognition in adulthood and explore possible mechanisms for these effects. This research shows that bilingualism has a somewhat muted effect in adulthood but a larger role in older age, protecting against cognitive decline, a concept known as “cognitive reserve”. We discuss recent evidence that bilingualism is associated with a delay in the onset of symptoms of dementia. Cognitive reserve is a crucial research area in the context of an aging population; the possibility that bilingualism contributes to cognitive reserve is therefore of growing importance as populations become increasingly diverse

Linguistic immersion and structural effects on the bilingual brain: a longitudinal study

Learning and using additional languages can result in structural changes in the brain. However, the time course of these changes, as well as the factors the predict them, are still not well understood. In this longitudinal study we test the effects of bilingual immersion on brain structure of adult sequential bilinguals not undergoing any language training, who were scanned twice, three years apart. We observed significant increases in grey matter volume in the lower left cerebellum, mean white matter diffusivity in the frontal cortex, and reshaping of the left caudate nucleus and amygdala and bilateral hippocampus. Moreover, both prior length of immersion and L2 age of acquisition were significant predictors of volumetric change in the cerebellum. Taken together, these results indicate that bilingualism-induced neurological changes continue to take place across the lifespan and are strongly related to the quantity and quality of bilingual immersion, even in highly-immersed adult bilingual populations