People who habitually speak two languages are better protected from senile dementia caused by Alzheimer’s disease: the disease in fact, in bilinguals, occurs later (even 5 years later than monolinguals) and with less intense symptoms.
The confirmation comes from an Italian study published in the journal “Proceedings of the National Academy of Sciences (PNAS)” and coordinated by Daniela Perani, director of the Unit of Molecular and Structural Neuroimaging of IRCCS, Ospedale San Raffaele and Professor at the Università Vita-Salute San Raffaele.
The researcher studied 85 patients with Alzheimer’s dementia, of which half Italian monolingual and half bilingual, through an imaging technique called FDG-PET (a type of positron emission tomography to measure the cerebral metabolism and functional connectivity between different brain structures).
In line with the results of previous studies, bilingual patients with Alzheimer were on average 5 years older, compared to monolingual, and have achieved high scores in some cognitive tests, designed to assess verbal memory and visual-spatial (the ability to recognize places and faces).
The use of FDG-PET has revealed that these patients, against the better cognitive performance, however, have a metabolism, in the damaged areas of the brain, typically affected by the disease, compared to monolingual patients.
According to the authors of the study, bilingualism constitutes a “cognitive reserve” that acts as a defense against the advance of dementia.
“I emphasize the benefits of speaking two languages as a defense from Alzheimer and also from other forms of dementia. Moreover, this applies also for the dialects: to be bilingual does not mean necessarily to speak Italian and English or Italian and German, but could also be, for example, Italian and a dialect of the area of origin”.
Describing his work, Perani adds: “We asked ourselves, how does this prove reserves brain in older adults with Alzheimer’s? The disease has manifested itself later than its occurrence and therefore had time to ruin large areas. This also slows the progression of disability. All thanks to the fact that when speaking two languages, one is forced to continuous switching between one and the other, and this happens – as mentioned – independently from the culture, the education and is own social level. “