Thalamus as a neural marker of cognitive reserve in bilinguals with frontotemporal dementia

Abstract Bilingualism delays the onset of dementia symptoms and contributes to cognitive reserve. However, the neural basis of this mechanism remains elusive. The few studies that have investigated neural mechanisms of cognitive reserve and bilingualism have focused on Alzheimer’s disease. This study investigated the neural basis of cognitive reserve among persons with frontotemporal dementia (FTD) using regional brain volumes. Sixty-eight persons with FTD (42 bilinguals and 26 monolinguals) were included. After propensity score matching for age, sex, education, FTD subtype and clinical severity, there were 26 bilinguals and 26 monolinguals. The results showed that bilinguals had reduced thalamic volume compared to monolinguals despite having similar cognitive performance. The results indicate that bilinguals were able to tolerate more severe atrophy compared to monolinguals while maintaining comparable cognitive abilities. Our study therefore suggests that bilingualism contributes to cognitive reserve in persons with FTD.