Bilingualism and delayed clinical manifestation of Alzheimer’s disease: A systematic review

Bilingualism and delayed clinical manifestation of Alzheimer’s disease: A systematic review

/ Vol 9-Nº 2 jul-dic 2026 /

Gladiliz Rivera-Delpín, MA1, 2; Elixmahir Dávila-Marrero, PhD1 & Giovanni Tirado-Santiago, PhD1

ABSTRACT

Objective: Motivated by the Cognitive Reserve (CR) theory, this systematic review examines the relation between bilingualism and the onset of Alzheimer’s disease (AD). Method: Guided by PRISMA, this review identified and evaluated empirical studies comparing bilingual and monolingual adults on age at symptom onset or diagnosis of MCI and AD. Searches were conducted in Web of Science and PubMed using predefined keywords linked to bilingualism, AD, and cognitive reserve. Inclusion criteria required primary comparative studies that applied validated diagnostic criteria, used standardized cognitive measures, and reported age of onset or diagnosis for both groups. Data were extracted on study design, participant characteristics, diagnostic criteria, and age at onset.

Results: Across studies, several findings suggest that bilingual individuals may experience a later onset of cognitive symptoms relative to monolingual peers. Reported delays range from approximately 3.2 to 7.2 years for the emergence of clinical complaints associated with MCI and AD. In line with the CR hypothesis, lifelong bilingual language use may strengthen neural efficiency and resilience, delaying clinical decline. Nonetheless, findings should be interpreted cautiously given mixed results, methodological variability, heterogeneous definitions of bilingualism, and potential publication bias.

Conclusion: Findings from several retrospective observational studies suggest that bilingualism may be associated with delayed clinical manifestation of AD symptoms in some populations. This finding has important implications for cognitive health and may open up new research and treatment options.

1 Department of Psychology, University of Puerto Rico, Río Piedras Campus, 2 Brigham and Women’s Hospital, Harvard Medical School

*Corresponding author’s information:

14, 253 Av. Universidad Ste. 1401 San Juan, Puerto Rico 00925
Correo electrónico:
gladiliz.rivera@upr.edu

Keywords:

Cognitive reserve, Alzheimer’s disease, Mild Cognitive Impairment, Dementia, Bilingualism