Bi-multilingual Language Engagement Shapes the Brain’s Functional Connectivity: An Aging Study on Resting State Brain Rhythms Correlated to Executive Functions

Abstract

Bi-multilingualism have been argued to help maintain cognitive functioning in aging through increased resilience to cognitive decline, known as cognitive reserves (CR). Researchers have argued that bi-multilingualism imposes unique cognitive demands that can change the brain’s structural and functional integrity. In order to investigate the effects of multilingual engagement on cognition, behaviourally and neurologically, resting state (RS) oscillations were collected through electroencephalography (EEG) in healthy Norwegian-English bi multilingual adults in various stages of adulthood. Additionally, behavioural responses in terms of reaction times (RT) were captured through a non-linguistic flanker task and further correlated to RS dynamics. Negative main effects of language experience, operationalised as multilingual diversity (MLD), were found in the alpha and gamma bands, while also indications in said frequency bands indicated a flattening effect of age-related cognitive decline for those with a higher MLD. The MLD did not indicate increased flanker efficiency, where only older age significantly increased RTs. No correlations were found between the RS functional connectivity and flanker performance. These findings might suggest that higher multilingual engagement will slow down the age-related decline in the brain’s functional connectivity, as this negative main effect of MLD is likely due to no CR trade-off for the younger participants.