The Claim
Among patients diagnosed with dementia, the rate of cognitive decline over a four-year period, as measured by Mini-Mental State Examination (MMSE) scores, is similar for bilingual and monolingual individuals, indicating that bilingualism does not alter the progression of dementia after symptom onset.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
People with dementia who speak two languages lose their thinking skills at the same speed as people who speak one language, when measured over four years. So speaking two languages doesn't change how fast the disease gets worse after it starts.
See the scientific wording
Among patients diagnosed with dementia, the rate of cognitive decline over the four years following diagnosis is similar for bilingual and monolingual individuals, as measured by Mini-Mental State Examination (MMSE) scores, suggesting that bilingualism does not alter the progression of dementia after symptoms have appeared.
People who speak two languages from early life build a 'backup' in their brains. This backup keeps the brain working normally even when damage starts, so symptoms of memory loss appear later. But once the damage becomes too big and symptoms show, the disease continues to harm the brain at the same speed for everyone, whether they speak one or two languages. So the rate of getting worse is the same.
What the research says
1 studyStudy: Bilingualism as a protection against the onset of symptoms of dementia.
This study shows that once someone has dementia, the speed of memory decline is the same whether they speak one or two languages.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.