The Study
Conversion of Mild Cognitive Impairment to Alzheimer’s Disease in Monolingual and Bilingual Patients
This study is like watching two groups of people over time. We see that people who speak two languages tend to get worse faster once they start having memory problems. But we can't be sure that speaking two languages causes that, because there could be other reasons. So, we can say being bilingual is linked to faster decline, but we can't say it causes it.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
The study looked at older people with mild memory problems and found that those who speak two languages had those problems start later, but once they started, the decline to Alzheimer's was faster.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 545 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Speaking two languages might help you stay mentally sharper longer, but once decline starts, it may progress more quickly.
- 2This is important for planning care.
- 3Bilingual people took about 1.8 years to go from mild cognitive impairment to Alzheimer's, while monolingual people took 2.8 years.
- 4Bilinguals were also older when they were diagnosed with mild cognitive impairment (77.8 vs 75.5 years) but there was no difference in age at Alzheimer's diagnosis.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Alzheimer disease and associated disorders
Year
2020
Authors
Matthias Berkes, E. Bialystok, F. Craik, A. Troyer, M. Freedman
Related Content
Claims (7)
Older people who speak two languages are usually diagnosed with mild memory problems later in life than people who speak only one language. On average, bilingual people get the diagnosis at about 77.8 years old, while monolingual people get it at about 75.5 years old. But this difference is only seen when we also consider whether they moved to the country or came from somewhere else.
People who speak two languages tend to go from having mild memory problems to full Alzheimer's disease more quickly than people who speak one language, even when you account for things like education, where they came from, gender, and family history. This faster decline isn't just because of those other factors.
Older adults with mild memory problems who speak two languages develop Alzheimer's disease faster than those who speak only one, on average about 1.8 years compared to 2.8 years.
In older adults with mild memory problems, people who speak two languages are diagnosed with Alzheimer's disease at about the same age as people who speak only one language. Even though the average ages are a bit different, the difference is too small to be considered a real difference.
Older adults with mild memory problems and no family history of Alzheimer’s who speak two languages tend to develop Alzheimer’s sooner than those who speak only one. But if they have a family history of Alzheimer’s, speaking two languages doesn’t change how quickly they develop it.
Speaking two languages lets the brain handle more damage before memory problems show up. But when those problems do appear, they get worse faster than in people who speak only one language.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.