Introduction: Neurodegenerative disorders, including Alzheimer’s disease (AD) can result in memory dysfunction and cognitive impairments. Bilingualism and multilingualism have been shown to have preventative effects on AD due to influence on brain regions and the improvement of cognitive reserve (CR). The paper analyses studies explicating the role of bilingualism and multilingualism in AD progression by evaluating their effects on CR, brain pathology, and behavioral function. We hypothesize that both bilingualism and multilingualism delay onset of AD and help prevent symptoms related to AD by improving cognitive functioning.
Methods: For this comprehensive comparative analysis, we reviewed empirical research articles found through PubMed and other databases to investigate the effects of bilingualism and multilingualism on AD manifestation. Keywords such as ageing, multilingualism, bilingualism and AD were used, and research published before 2000 was excluded. Specific focus was placed on AD onset time and symptoms as a framework for severity evaluation. A total of 13 studies were chosen to be included in this review.
Results: Results suggest bilingualism and multilingualism play a role in the strengthening of different preventative factors, such as CR. Improved effects are evident throughout various brain structures, such as improved resistance to grey matter deterioration in bilinguals and multilinguals with AD. These protective effects are also observed in behavioural functionality, with improved executive function present in bilinguals and multilinguals. The effects of multilingualism on AD seem to be stronger than those of bilingualism.
Discussion: Bilinguals and multilinguals have a stronger CR, which is linked to improved neuroplasticity and neural circuit efficiency; these contribute to ameliorated memory retention. By analyzing the effect of bilingualism and multilingualism on AD progression, we aim to improve the understanding of therapeutic targets to alleviate the impact of symptoms and provide further avenues for testing.
Conclusion: Our review will aid in establishing alternative means of treatment and preventative methods to decrease cognitive impairment in AD patients. Elucidating bilingualism and multilingualism mechanisms of action in AD progression will strengthen our understanding of its protective measures. This analysis will allow exploration into new avenues with the ultimate goal of reducing the incidence and impact of AD.
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