To start, the advantage of bilingualism is known to improve on many cognitive functions during an individual’s lifetime. For example, memory and multi-tasking are two significant functional qualities that have been associated with bilingualism. However, as people become older, these skills inevitably deteriorate due to age-related cognitive decline. As a result, it's interesting looking into how bilinguals' cognitive performance changes as they become older.
In a review article, “Early bilingualism, language attainment, and brain development,” Berken et al. (2016) discuss brain neuroplasticity and how language development in sequential and simultaneous bilinguals is an ideal model for determining neuroplasticity throughout individuals’ life. This article draws on information from various studies that include neuroimaging modalities, including positron emission tomography (PET), task-based and resting state functional magnetic resonance imaging (fMRI), and structural MRI. The first study review focused on task based functional activation and determined the brain regions that are confined by a sensitive period based on age of learning, regardless of proficiency, for speech production and reading. The next study focused on resting state functional connectivity and establish whether language processing region connection patterns in the brain alter as a function of early vs. late language experience. The last study review focused on brain anatomical correlates and investigate the impact of early versus late second language exposure on brain anatomical development. Additionally, the study evaluated whether similar or distinct brain substrates develop in early and late bilinguals to acquire native-like second language ability. The results of the article included that when two languages are learnt at the same time at birth, the brain function and structure are more organized. There are significant changes in language development when two languages are learnt concurrently versus sequentially, with simultaneous acquisition appearing to be the most efficient in terms of brain circuitry connectivity. Overall, it has been demonstrated that the later a second language is learned, the more neuroplastic changes are limited.
In the research article, “Neuroplasticity across the lifespan and aging effects in bilinguals and monolinguals” Maschio et al. (2018) investigated the neuroplastic effects of multilingual experience on the executive control (EC) network in young and aging populations and assess the extent to which such changes might predict executive control ability across age groups. The researchers measured EC efficiency using gray matter volume (GMV) as an indication of neural reserve and response time (RT) functioning through the Flanker task. The results included bilinguals demonstrating stronger GMV than monolinguals in key regions throughout age in the context of age-related generalized GM degradation. Additionally, while EC function was strongly linked to GMV in monolingual seniors, this was not the case in bilingual individuals in either group. Greater GMV had a behavioral benefit on EC function in older individuals. Therefore, this suggests that bilinguals have delayed age-related cognitive decline.
Moreover, both these articles suggest the beneficiary features of bilingualism based on cognitive function. It is intriguing to note that the increase of gray matter in bilingual seniors had a productive impact on behavioral skills (Maschio et al., 2018) This demonstrates that the neural circuitry, as discussed in the first article, is more efficient which further aids in the cognitive functioning of bilingual individuals. Both these articles suggest that bilingualism helps with age related cognitive decline due to the increase of neural network activity through language learning regions within the brain.
References
Berken, J. A., Gracco, V. LI ., & Klein, D. (2016). Early bilingualism, language attainment, and
brain development. Neuropsychologia, 98, 220–227. https://doi.org/10.1016/j.neuropsychologia.2016.08.031
Del Maschio, N., Sulpizio, S., Gallo, F., Fedeli, D., Weekes, B. S., & Abutalebi, J. (2018).
Neuroplasticity across the lifespan and aging effects in bilinguals and monolinguals. In Brain and Cognition (Vol. 125, pp. 118–126). Elsevier BV. https://doi.org/10.1016/j.bandc.2018.06.007
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