Miércoles 5 de Septiembre de 2007, Ip nº 206

Does being bilingual help delay the onset of Alzheimer's disease?
Por Judy Foreman

It may, according to recent research by psychologist Ellen Bialystok, a scientist at York University and the Rotman Research Institute of Baycrest Hospital in Toronto.

Three years ago, Bialystok's team showed that people who had been bilingual all their lives did better at paying attention and doing the kind of intellectual tasks that the prefrontal cortex of the brain (directly behind the forehead) is responsible for: planning, being able to tune out distractions, and making judgments.

That led Bialystok to wonder whether bilingualism might protect against Alzheimer's disease. Bilingualism has been shown to boost the power of the prefrontal cortex because, in order to speak one language, the speaker must activity inhibit, or tune out, the other language.

In a study published February in the journal Neuropsychologia, she looked at the hospital records of people who had visited Baycrest's memory clinic, two-thirds of whom had Alzheimer's and one-third, other kinds of dementia.

Roughly half were "perfect bilinguals," she said, meaning that they had been speaking at least two languages every day for 50 years or more, typically English plus Polish, Russian or Yiddish. The rest were monolingual.

"What we found is that all else being equal -- education, occupational skills, marital status, money, etc." -- the age of onset of dementia was on average 71 for the monolinguals and 75 for the bilinguals, she said. "That difference is huge," she said. "The neurologist on the team was astonished."

It doesn't appear that learning a second language in midlife carries the same benefit. Bialystok is studying that now, and so far, is finding "that there is a much diminished effect for later bilinguals."

  20/08/2007. Boston.com.