From VOA Learning English, this is the Health Report.

　　New research suggests that speaking more than one language may delay different kinds of dementia, that is the lost of mental ability. In fact, researchers say, speaking two languages appears to be more important than the level of education in defending against dementias.

　　A study in India examined the effect of knowing more than one language in delaying the first signs of several disorders, these included Alzheimer's disease, frontotemporal dementia, vascular dementia, Lewy bodies dementia and mixed dementias. Researchers studied nearly 650 people whose average age was 66. 240 of those studied suffered from Alzheimer's, the most common form of mental decline.

　　Investigators found the dementias began about four-and-a-half years later in those who were bilingual compared to those who spoke only one language. The level of education had no effect on the age at the first sign of dementia.

　　Thomas Bak helped to organise the study. He is with the Center of Cognitive Aging at the University of Edinburgh in Scotland. He suggests that individuals who speak more than one language train their brains by moving back and forth between different words and expressions.

　　Mr Bok believes this effort improves what scientists called executive functioning or attention to tasks, this mental ability often weakens in people with dementias.

　　Researchers found there was no extra gain in speaking more than two languages. They also did not see a delay in the first signs of Lewy bodies dementia, the disorder causes patients to see or experience things that do not real exist. They can also cause sufferers to move back and forth between being wide awake and really sleeping.

　　Mr Bak says it does not appear important whether you learn a language at a young age or later in life.

　　"So it's not something you sort of say that '[if] you missed the boat when you do not do it as a baby.' It is something that is still quite useful and powerful when you do it as an adult," he said.

　　Scientists found that speaking more than one language help delay the first signs of dementias, even in those who could not read.

　　An article on the benefits of bilingualism on dementias was published this month in the journal Neurology.

　　And that is the VOA Health Report from VOA Learning English. You can read, listen and learn English with health news on our website 51voa.com. You can also watch captioned videos at the VOA Learning English channel on YouTube. I'm Milagros Ardin.