Multilingualism and Cognitive Reserve

During the last decades, different concepts of reserve have been postulated to account for the brain's capacity for resilience in the face of neurodegeneration. Lifelong bilingualism may be a reserve factor, delaying the onset of dementia by approximately four years. Nonetheless, the evidence remains inconsistent and the trajectory of the effects is not clear. For instance, it is unclear whether multilinguals have more cognitive benefits than bilinguals. This review aims to critically examine this question to delineate the major trends in the field. We first describe the overlap in the operationalization of reserve/resilience in order to provide a clear definition in support for such an approach in the field. We then review the bi-/multilingual literature to evaluate the current evidence for the question of whether bi-/multilingualism leads to increased reserve. Such considerations may lead to a re-evaluation of the construct in the bilingual literature and its implication in clinical studies.