Bilingualism and aging: the case of primary progressive aphasia

Bilingualism is becoming the norm in our increasingly global, but also aging society. Whereas increased bilingualism is generally seen as a positive trend because it may have a beneficial effect on executive functions, the aging of our global population is not as it goes hand in hand with the proliferation of dementias. Our goal in the current project is to investigate the relationship between bilingualism, executive functions and dementias. We will focus on people with primary progressive aphasia (PPA): a dementia specifically impairing language skills in the initial stage. In our project, these PPA patients will receive language therapy focused on problem areas in their first language (L1) complemented with cerebellar transcranial direct current stimulation (tDCS) in order to reinvigorate neural activation. This project will investigate the effect of tDCS combined with language therapy on (1) the most severely impaired L1 and L2 skills, (2) the neural pathways implicated in speech and language functions via volume comparisons through diffusion tensor imaging (DTI), and (3) domain-general executive functions subserving amongst others language control, which is of essential importance to bilinguals. It is expected that this project will broaden our understanding of language functions in the aging bilingual brain. With this project, we hope to contribute to ongoing discussions on the role of bilingualism in protecting against the first symptoms of neurodegenerative diseases