Speaking Two Languages May Delay Dementia Symptoms
Study of case records found it staved off signs of the disease by more than four years
"This illustrates that there may yet be many ways to help stave off dementia, once we have sufficient ways to stimulate the brain," Gandy said.
There have been other studies that have shown that people who are bilingual have a delayed onset of Alzheimer's disease, Rao said.
"This is another thing we can add to the list of mental abilities that seem to preserve brain function despite the fact that the brain may be ravaged by a disease like Alzheimer's disease and other forms of dementia," Rao added.
For the study, Bak's team evaluated the case records of 648 people from India who had been diagnosed with dementia. Of these patients, 391 spoke two or more languages.
Of those studied, there were 240 people with Alzheimer's disease, the rest had other types of dementia including vascular dementia, frontotemporal dementia, dementia with Lewy bodies and mixed dementia. Of the total studied, 14 percent were illiterate.
Those who spoke two languages developed the symptoms of Alzheimer's disease, frontotemporal dementia and vascular dementia later than people who spoke only one language, the investigators found. This later development of dementia was also found in people who could not read.
There was no added benefit in speaking more than two languages, the researchers pointed out.
The benefit of being bilingual was independent of other factors, such as education, sex, occupation or whether patients came from urban or rural areas, the study authors noted.
While the study found an association between speaking two languages and mental ability, it didn't not prove cause-and-effect.