Saturday, February 10, 2007

Bilingualism delays dementia?

Do bilinguals differ from monolinguals only in being bilingual? Unlikely. So the generalizations below are suspect. The effects claimed could be due to other factors associated with bilingualism -- such as higher IQ. Low IQ people would seem much less likely to develop substantial bilingualism

After school, Carlos and Carmen Nguyen shuttle between two sets of grandparents in happy bursts of English, Spanish, Tagalog and Vietnamese. Their parents love the way languages open their children's eyes to the family's heritage and to other cultures. Yet when they began their multilingual journey, they never imagined that Carlos and Carmen, now 6 and 9, also might be developing brains especially good at ignoring distractions and better able to withstand aging. "This is incredible," said the children's mother, Irene Bersola-Nguyen, a child development lecturer at California State University, Sacramento, who has been trading delighted e-mails with friends and colleagues about the latest study on the bilingual brain.

A team of Canadian researchers who studied people being treated for dementia found that those who regularly used two languages reported their first symptoms of a fading mind about four years later than those who used only one language. That work, published in February's edition of the journal Neuropsychologia, follows a 2004 study that found older bilingual people were better at paying close attention despite distractions. "Language pays off big time," said Ellen Bialystok, lead researcher on both studies and a scientist with the Baycrest Research Centre for Aging and the Brain in Toronto.

Bialystok and others cautioned that so many factors contribute to healthy aging, it would be premature to say language skills definitely delay dementia. Still, growing indications that bilingualism may deliver lifelong benefits in cognition have captured the attention of educators and researchers. "Ellen Bialystok is a pioneer in this field, and she's generating quite a buzz," said Tamar Gollan, a University of California, San Diego, psychiatry professor who studies bilingualism. "People all over the world are replicating her findings for some of her earlier work."

Few places in the United States have more at stake in understanding the bilingual brain than California, where a staggering 42 percent of people age 5 and older speak a language other than English at home. In Sacramento County, it's 29 percent. With the immigrant population and the proportion of those who are fully bilingual both expected to grow, California could be a living laboratory for examining the impact of what we gain -- and lose -- from speaking more than one language.

There are clearly losses as well as gains, said Gollan, whose own research probes the subtle deficits of bilinguals. Yet when she weighed them, she came down soundly on the side of raising her own small children with two languages.

Bialystok, who began studying bilingual kids decades ago, believes one key to their special brainpower lies in the way they must constantly decide which language to use and which to suppress. For people who use two languages daily, "every time you want to speak one language, the other language is activated" in the brain as well, she said. "That means you need a mechanism so that you're only drawing from the right pool (of words). It's going be a mechanism that works extremely fast ... while you're producing sentences. It's way below your radar for detecting what's happening." So bilinguals get far more practice than monolinguals in using the part of the brain that focuses our attention, helping us sort through conflicting information and ignore distractions. Using two languages seems to bolster rapid decision-making, multi-tasking and perhaps memory.

To measure the effect in older adults, Bialystok used one of the many psychological tests designed to confound us, because we have to respond to information with conflicting cues. It may be a picture that requires you to move your left hand, which shows up on the right side of a computer screen. Or it may be the word "green," written in red letters. In such tests, bilingual people in their 70s did noticeably better than monolingual people. With lots of practice, the one-language speakers eventually caught up.

Fergus Craik, a senior scientist at Baycrest's Rotman Research Institute who collaborates with Bialystok, said ongoing research seems to point to memory advantages. Bilingualism may bolster the kind of memory that lets us recall specific things that happened to us or recognize a person out of context, Craik said.

Both researchers suspect that bilingualism may delay dementia in the same way that other intense mental activity is believed to, whether it's playing an instrument or solving puzzles. Not everyone is convinced the "use it or lose it" strategy for maintaining a healthy brain has been proven, but it's something "we're all thinking about," said Dr. Charles DeCarli, a UC Davis neurology professor who heads the UCD Alzheimer's Disease Research Center.


Implantable pacemaker the future of weight loss?

DIETS and exercise may not be the future for weight loss. A pacemaker-like device, which blocks hunger nerves, has been successfully trialled at Adelaide's Flinders Medical Centre, with stunning results. The first person to be implanted with the device lost 20 kilograms in a year without changing her dietary habits or exercise regime. The Adelaide medical centre was one of three in the world to trial the new device, developed by EnteroMedics Inc.

Flinders' Professor of Digestive Surgery James Toouli (Toouli) said the instrument was placed under the abdominal skin and powered by parts worn outside the body. The device then intermittently blocked hunger signals carried by vagus nerves - two large cables which go from the brain to the gastrointestinal tract. "The vagus are the most important nerve that go to the digestive system," Prof Toouli said today. "These nerves control the movement of the stomach and they control some of the secretions used for digestion, and by blocking these intermittently, what it does is it slows downs the aching of the stomach so consequently people don't feel as hungry."

The theory of blocking the hunger nerves came from clinical observations from past surgery where patients had the nerves divided. "It was noted in those people if they were overweight, they actually would lose weight," Prof Toouli said. "Instead of dividing the nerves we now block them with this pacemaker-type device. "And the reason why this is better than dividing them ... is the body always recuperates if we do something permanent and those nerves do regenerate in time. "So if you can just block them intermittently but not destroy them, then the effects are most likely to last for a long time."

Flinders trialled the device on 10 people including 32-year-old Sarah Polkinghorne, who lost 20kg in a year after having her vagus nerves blocked for a total of 12 hours a day. The group was told not to alter their exercise or dietary habits. A smaller improved version of the device is now being trialled. "The idea is that this will be implantable, the whole thing," Prof Toouli said. "At the moment what we call the neuroregulator is implantable but the person has to actually apply an external device in order to send messages to the nerves. "Ultimately what we are working towards is a fully implantable thing just like a pacemaker so it would be put in and left there for a number of years with a rechargeable battery.

"These early trials are geared towards trying to work out the dosage and how often this thing needs to be turned on so that it will optimise the fully implantable device, which is still very much in a prototype stage." Prof Toouli hoped the device would be widely available in the future. "That is certainly our view," he said. "As always with these things, cost comes into it and these things have not been worked out yet, but it's really very promising."



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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