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The effect of bilingualism on the brain is modulated by language experience
Author(s) -
Calabria Marco,
Voits Toms,
Rothman Jason,
Robson Holly,
Marín Lidón Marín,
Costumero Víctor,
Aguirre Naiara,
Pliatsikas Christos
Publication year - 2021
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.054437
Subject(s) - neuroscience of multilingualism , cognitive reserve , psychology , grey matter , cognition , neural correlates of consciousness , cognitive psychology , dementia , audiology , developmental psychology , neuroscience , medicine , cognitive impairment , disease , pathology , magnetic resonance imaging , white matter , radiology
Background Research has shown that lifelong bilingualism may contribute to cognitive reserve in neurodegenerative diseases as shown by a delay of the age at symptom onset in bilinguals with different types of dementia. However, the study of the neural mechanisms behind this bilingual advantage is limited, especially for the preclinical stages of dementia, such as Mild Cognitive Impairment (MCI). Additionally, most of the studies have operationalised bilingualism as a dichotomous variable, despite the fact that language experience results from a combination of different factors (language usage, frequency of language switching, age of second language acquisition, and language proficiency). Method In the present study we investigated cortical and subcortical grey matter structure volume, and episodic memory performance, in a group of bilingual individuals with MCI by considering their linguistic profile. Specifically, we compared active bilingual speakers of Spanish and Catalan and bilinguals who have good knowledge of their second language but without any active usage of it. This classification is based on the results of a previous study in which we found that actively speaking the two languages promotes the delay of symptoms in individuals with MCI. Result The results reveal that active bilingualism significantly delays the onset of MCI symptoms. Additionally, active bilingualism is also shown to result in increased cortical grey matter in the right supramarginal gyrus, increased bilateral hippocampal volume and reshaping of the right amygdala and right caudate nucleus. Conclusion These results are compatible with the hypothesis that bilingualism protects against cognitive decline via neural compensation mechanisms and by increasing neural efficiency in individuals with MCI.