• Maurits Van den Noort
  • Katrien Vermeire
  • Peggy Bosch
  • Heike Staudte
  • Trudy Krajenbrink
  • Lars Jaswetz
  • Esli Struys
  • Sujung Yeo
  • Pia Barisch
  • Benoit Perriard
  • Sook-Hyun Lee
  • Sabina Lim
A systematic review was conducted to investigate whether bilingualism has a protective effect against cognitive decline in aging and can protect against dementia. We searched the Medline, ScienceDirect, Scopus, and ERIC databases with a cut-off date of 31 March 2019, thereby following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) protocol. Our search resulted in 34 eligible studies. Mixed results were found with respect to the protective effect of bilingualism against cognitive decline. Several studies showed a protective effect whereas other studies failed to find it. Moreover, evidence for a delay of the onset of dementia of between 4 and 5.5 years in bilingual individuals compared to monolinguals was found in several studies, but not in all. Methodological differences in the set-up of the studies seem to explain these mixed results. Lifelong bilingualism is a complex individual process, and many factors seem to influence this and need to be further investigated. This can be best achieved through large longitudinal studies with objective behavioral and neuroimaging measurements. In conclusion, although some evidence was found for a cognitive reserve-enhancing effect of lifelong bilingualism and protection against dementia, to date, no firm conclusions can be drawn.
Original languageEnglish
Article number81
Number of pages37
JournalBehavioral Sciences
Issue number7
Publication statusPublished - Jul 2019

    Research areas

  • aging, bilingualism, cognitive decline, cognitive reserve hypothesis, dementia, onset

ID: 46811875