WASHINGTON —
Mastering a second language can pump up the brain in ways that  seem to delay getting Alzheimer’s disease later on, scientists say.
 
While the new research focuses mostly on the truly long-term bilingual,  scientists say even people who tackle a new language later in life stand  to gain.
 
The more proficient the person becomes, the better, but “every little  bit helps,” said Ellen Bialystok, a psychology professor at York  University in Toronto.
 
Much of the study of bilingualism has centered on babies, as scientists  wondered why simply speaking to infants in two languages allows them to  learn both in the time it takes most babies to learn one. Their brains  seem to become more flexible, better able to multitask. As they grow up,  their brains show better “executive control,” a system key to higher  functioning—as Bialystok puts it, “the most important part of your  mind.”
 
Does that mental juggling in youngsters translate into protection against cognitive decline when in older people?
 
Bialystok studied 450 Alzheimer’s patients, all of whom showed the same  degree of impairment at the time of diagnosis. Half are bilingual; they  have spoken two languages regularly for most of their lives. The rest  are monolingual.
 
The bilingual patients had Alzheimer’s symptoms and were diagnosed  between four and five years later than the patients who spoke only one  language, she told the annual meeting of the American Association for  the Advancement of Science.
 
Being bilingual does nothing to prevent Alzheimer’s disease from  striking. But once the disease does begin its silent attack, those years  of robust executive control provide a buffer so that symptoms do not  become apparent as quickly, Bialystok said.
 
“They’ve been able to cope with the disease,” she said.
 
Her work supports an earlier study from other researchers that also found a protective effect.
 
What is it about being bilingual that enhances that all-important executive control system?
 
Both languages are essentially turned on all the time, but the brain  learns to inhibit the one that is not needed, said psychology professor  Teresa Bajo of the University of Granada in Spain. That is pretty  constant activity.
 
That is not the only area. University of British Columbia psychologist  Janet Werker studies infants exposed to two languages from birth to see  why they do not confuse the two, and says bilingual babies learn very  early to pay attention better.
 
Werker tested babies in Spain who were growing up learning both Spanish  and Catalan. She showed the babies videos of women speaking languages  they’d never heard—English and French—but with the sound off. By  measuring the tots’ attention span, Werker concluded that babies could  distinguish between English and French simply by watching the speakers’  facial cues. It could have been the different lip shapes.
 
“It looks like French people are always kissing,” she joked, while the  English “th” sound evokes a distinctive lip-in-teeth shape.
 
Whatever the cues, monolingual babies could not tell the difference, Werker said Friday at the meeting.
 
But what about people who were not lucky enough to have been raised  bilingual? Scientists and educators know that it becomes far harder to  learn a new language after puberty.
 
Partly that’s because adults’ brains are so bombarded with other demands  that they do not give learning a new language the same attention that a  young child does, Bialystok said.
 
At the University of Maryland, scientists are studying how to identify  adults who would be good candidates to master a new language, and then  what types of training are best. Having a pretty strong executive  control system, like the lifelong bilinguals have, is among the good  predictive factors, said Amy Weinberg, deputy director of the  university’s Center for Advanced Study of Language.
 
But people do not have to master a new language to benefit some,  Bialystok said. Exercising your brain throughout life contributes to  what is called cognitive reserve, the overall ability to withstand the  declines of aging and disease. That is the basis of the  use-it-or-lose-it advice from aging experts who also recommend such  things as crossword puzzles to keep the brain nimble.
 
“If you start to learn at 40, 50, 60, you are certainly keeping your brain active,” she said.
 
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Science meeting: http://www.aaas.org/meetings/