Learning a second language does not protect the brain from dementia, though it may delay the appearance of symptoms, according to neurologist Alexander Tkachev, who spoke to RT.
Tkachev said the widely repeated idea that bilingualism guards against dementia is only partly true, and that science does not yet support the simplified formula of learning a second language to avoid the disease.
He said people who regularly use two languages throughout their lives can develop a greater cognitive reserve, which he described as the brain's ability to cope with age-related and pathological changes for longer by drawing on additional neural connections and redistributing mental workload more flexibly.
According to Tkachev, constantly switching between languages demands attention, control and the selection of the right words, which amounts to a fairly demanding daily workout for the brain. He said this does not make the brain immune to disease or stop pathological changes from accumulating, but researchers have observed that symptoms tend to appear later in bilingual people.
Prevention still matters most
Tkachev cautioned that learning a language should not replace established prevention measures. He said controlling blood pressure, cholesterol and diabetes, staying physically active, correcting hearing and vision loss, quitting smoking, getting proper sleep and maintaining social contacts have a far more convincing effect on reducing dementia risk.
Early signs often missed
Cognitive reserve is a concept used in neuroscience to describe the brain's capacity to maintain normal function despite damage or ageing, by relying on alternative networks or strategies built up through mentally engaging activity over a lifetime. Bilingualism has long been studied as one possible contributor to this reserve, alongside education and occupational complexity.
Neurologist Joe Verghese and geriatrician and dementia specialist Malaz Boustani have previously warned that early signs of dementia can be so subtle that they are mistaken for normal ageing or go unnoticed altogether.
