Researchers in India have found that people who speak more than one language develop dementia later in life than people who only speak one language. The paper is published on Wednesday 6 November in the journal Neurology online.
Previous research has already suggested that speaking a second language may have benefits for the brain, and it’s thought that the continual need to switch between languages may help improve people’s thinking skills. Most of this research has been carried out in immigrant populations, but the latest research – led by a team at Nizam’s Institute of Medical Sciences in Hyderabad, India – looked at this further in a population of people who were living in their native country.
The team looked at medical records of 648 people living in India who had been diagnosed with dementia. Of these, 391 (60%) spoke at least two languages. When the researchers investigated the age when symptoms of dementia first appeared, they found that on average, people who spoke more than one language began to develop symptoms 4.5 years later than those who spoke only one language.
When they looked at the effect for different types of dementia, they found that being bilingual was linked to a 3.2-year delay in the onset of symptoms for Alzheimer’s disease, a six-year delay for frontotemporal dementia, and a 3.7-year delay for vascular dementia. Further investigation showed that bilingual people developed symptoms later even if they had no formal education and were unable to read or write.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“It’s not the first time research has highlighted potential benefits of speaking more than one language, but this is the largest study to date to investigate the subject. These findings lend weight to the theory that keeping the brain active may provide a form of ‘cognitive reserve’, helping to delay the onset of symptoms as diseases like Alzheimer’s develop. It would be useful to see further and larger studies of this type to be sure of the effects of bilingualism.
“Investment in research is vital to understand factors that influence when symptoms of dementia begin to appear. The numbers of people with dementia are set to increase as our population ages, and finding ways to delay the onset of the condition could make a real difference to people’s lives.”