14 Jan Bilingualism Can Preserve White Matter in Brain
Medical Research: What is the background for this study? What are the main findings?
Response: It has been proposed that lifelong bilingualism preserves the white matter structure of older bilinguals because of the increased cognitive demands that come with handling two languages for their entire life. We wanted to extend this by investigating whether active (or “immersive”) bilingualism in younger late bilinguals would give similar results.
We showed increased white matter integrity (or myelination) in several white matter tracts that have also been shown to be better preserved in older lifelong bilinguals, compared to monolinguals. Based on our findings, we propose that any benefit of bilingualism to the brain structure is simply an effect of actively handling two languages without presupposing lifelong usage- our participants were only about 30 years old and had been active bilinguals for only about 7-8 years. In other words, immersive bilingualism, even in late bilinguals, leads to structural changes that can bring about benefits in older age, by assisting in the preservation of the white matter structure in the brain.
Medical Research: What should clinicians and patients take away from your report?
Response: The next logical step for this research would be a longitudinal study, when newly arrived bilinguals will be scanned several times within a 3-year period (or even longer), in order to investigate the time-course of these effects, and make a stronger case for the benefits to the brain of immersive bilingualism. Additionally, this research should be accompanied by a series of behavioural and cognitive tests, to investigate whether these structural changes may have a more general effect on the cognition of bilinguals, as it has already been proposed for older bilinguals only.
Medical Research: What recommendations do you have for future research as a result of this study?
Response: We should be careful with the clinical implications of our report, for the simple reason that we did not test patients. We have evidence from previous studies that bilingualism slows down deterioration of the white matter in older age, active as a sort of “neuroprotection”, and our study shows that this structural “reinforcement” can start at a younger age in an immersive environment. It is possible that these changes may bring about cognitive benefits for the bilinguals- however, this was not investigated in our present study.
Pliatsikas C., Moschopoulou, E., & Saddy, D. (in press): The effects of bilingualism on the white matter structure of the brain. To appear in the Proceedings of the National Academy of Sciences. DOI:10.1073/pnas.1414183112