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Entries in Cognition (6)

Wednesday
Jan092013

Study: Bilinguals Have Faster, More Adaptive Brains When They Get Older

iStockphoto/Thinkstock(NEW YORK) -- Speaking two languages can actually help offset some effects of aging on the brain, a new study has found.

Researchers tested how long it took participants to switch from one cognitive task to another, something that’s known to take longer for older adults, said lead researcher Brian Gold, a neuroscientist at the University of Kentucky.

“It has big implications these days because our population is aging more and more,” Gold said.  “Seniors are living longer, and that’s a good thing, but it’s only a good thing to the extent that their brains are healthy.”

Gold’s team compared task-switching speeds for younger and older adults, knowing they would find slower speeds in the older population because of previous studies.  However, they found that older adults who spoke two languages were able to switch mental gears faster than those who didn’t.

But don’t go out and buy Rosetta Stone just yet.  The study only looked at life-long bilinguals, defined in the study as people who had spoken a second language daily since they were at least 10 years old.

First, Gold and his team asked 30 people, who were either bilingual or monolingual, to look at a series of colored shapes and respond with the name of each shape by pushing a button.  Then, they presented the participants with a similar series of colored shapes and asked them to respond with what colors the shapes were by pushing a button.  Finally, researchers presented participants with a series of colored shapes, but they mixed prompts for either a shape or a color to test participants’ task-switching times.

The bilingual people were able to respond faster to the shifting prompts.

Researchers then gathered 80 more people for a second experiment: 20 young bilinguals, 20 young monolinguals, 20 old bilinguals, and 20 old monolinguals.  This time, researchers used fMRI scans to monitor brain activity during the same shape- and color-identifying tasks.  Gold and his team found that bilingual people were not only able to switch tasks faster -- they had different brain activity than their monolingual peers.

“It allows a sort of window into how the brains of people who have different cognitive processing abilities and are processing the same stimuli in different ways,” said Kristina Visscher, a neurobologist at the University of Alabama School of Medicine who did not work on the study.

Visscher called bilingualism a “beautiful natural experiment,” because people grow up speaking two languages, and studies have shown that they reap certain cognitive benefits from switching between languages and determining which to respond with based on what’s going on around them.  The University of Kentucky researchers took it a step further by using brain imaging, which she said was “exciting.”

Gold said he grew up in Montreal, where he spoke French at school and English at home, prompting relatives to question whether his French language immersion would somehow hinder his ability to learn English.

“Until very recently, learning a second language in childhood was thought of as dangerous,” he said.  “Actually, it’s beneficial.”

Copyright 2013 ABC News Radio

Thursday
Jun142012

Childhood Obesity Affects Math Performance, Study Says

Fuse/Getty Images(COLUMBIA, Mo.) -- Childhood obesity affects math performance in school, along with children's social skills and well-being, according to a new study published in the journal Child Development.

Researchers from the University of Missouri analyzed data of more than 6,000 children in the Early Childhood Longitudinal Study-Kindergarten Cohort, which collected information from children starting in kindergarten and following them through the fifth grade.  At five different times, parents reported family dynamics and teachers reported on the children's social skills and emotional well-being.  Researchers tested the children on academics, and recorded their height and weight.

Kids who were obese throughout the study period performed worse on math tests in the first through fifth grades than children who were not obese.

"Obesity that persists across the elementary school years has the potential to compromise several areas of children's development, including their social and emotional well-being and academic performance," said Sara Gable, associate professor of nutrition and exercise physiology at University of Missouri and lead author of the study.

In addition to the math performance findings, obese children reportedly felt sadder, lonelier and more anxious than kids of healthier weights.  Researchers said this emotional well-being also could contribute to their poorer performances in math.

Obesity among children continues to grow in the U.S.; 17 percent, or about 12.5 million, of children and teens are obese, according to the Centers for Disease Control and Prevention. Since 1980, obesity among the youth population has nearly tripled. One in seven low-income pre-school children is obese.

While weight may indeed contribute to poor school performance, there are likely several confounding factors that also contribute to an obese child's overall well-being, experts said.

"Obesity does not prevent kids from doing math, but obesity develops in families where there may be less oversight, less education, fewer resources," said Dr. David Katz, director of the Yale Prevention Center.

"Stress has been shown to affect brain development and functioning," Dr. Jennifer Cross, a pediatrician at the Komansky Center for Children's Health at NY-Presbyterian/Weill Cornell Medical Center, wrote in an email.  "If obesity causes a child to feel chronically stressed (i.e. bullying, low self esteem, etc.), that could lead to differences in the brain."

While it is difficult to say whether obesity actually affects cognition, "we certainly can say that obesity affects everything from self-esteem to social standing to mood and even hormonal balance, so the likelihood that there would be a whole cascade of effects between weight and math test scores is very high," said Katz.

Copyright 2012 ABC News Radio

Wednesday
Jun132012

Omega-3 Fatty Acids May Not Offer Touted Brain Benefits After All

Jupiterimages/Thinkstock(LONDON) -- Despite doctors' advice that omega-3 fatty acids can prevent a decline in cognitive function, a new review of previous studies suggests that taking omega-3 supplements may not offer any brain benefits at all.

Researchers led by Emma Sydenham at the London School of Hygiene & Tropical Medicine analyzed data from three separate studies that evaluated the effects of omega-3 fatty acid supplementation on cognitive function among older people who showed no signs of dementia or other brain dysfunction.

The studies involved a total of 3,536 people and lasted between six and 40 months.

They found that subjects with normal brain function who either supplemented their diet with omega-3 fatty acids -- fats commonly found in fish and plant oils -- either in capsule form or by using supplement-containing margarine spreads, did not perform better on standardized tests than subjects who received a placebo.

"The results of the available studies show no benefit for cognitive function with [omega-3] supplementation among cognitively healthy older people," the authors wrote.  But they did add that researchers need to conduct longer studies to assess whether there are preventive benefits.

But experts not involved in the research review say there is clear evidence of the ability of omega-3s to prevent cognitive decline.

Dr. Gary Small, professor of psychiatry and biobehavioral sciences at UCLA's David Geffen School of Medicine, said that the studies the Sydenham team evaluated have major flaws.

"Other studies have found that those who ingest omega-3 fatty acids are at lower risk of developing Alzheimer's disease," said Small.

A study published in February found a link between low levels of omega-3s and a more rapid aging of the brain and greater likelihood of losing memory and abstract thinking ability.

The extent of those cognitive benefits remains under debate, however, said Dr. Samuel Gandy, a professor of Alzheimer's disease research at Mount Sinai Medical Center in New York.

"There is some evidence that omega-3s may protect from aging-associated memory impairment, but there is no consistent evidence that omega-3s delay or protect from Alzheimer's disease," he said.

While the role of omega-3 fatty acids in protecting the brain still needs to be fleshed out, the researchers who performed the study review stressed that omega-3s may offer other benefits.  While they didn't mention it specifically, helping protect against cardiovascular disease is one of them.  Eating fish, they wrote, "is recommended as part of a healthy diet."

Copyright 2012 ABC News Radio

Thursday
Apr262012

Are Berries the New Brain Food?

BananaStock/Thinkstock(BOSTON) -- Sweet and refreshing, berries are thought of as a summer treat, but new evidence suggests that eating these fruits regularly may also help preserve brain function.

Harvard researchers found that women who said they ate more blueberries and strawberries were more likely to display less-rapid cognitive deterioration as they aged.

“Our findings have significant public health implications as increasing berry intake is a fairly simple dietary modification to test cognition protection in older adults,” lead author Dr. Elizabeth Devore of Harvard Medical School said in a news release.

In the study, published Thursday in the journal Annals of Neurology, researchers analyzed data gathered by the Nurses Health Study in which participants had filled out questionnaires and described their dietary habits and other aspects of their lives every two to four years since 1980.

In 1995, cognitive, or intellectual, function was added to the questionnaire and was measured every two years.  When Devore and her colleagues examined the data, they found that participants who had recorded increased servings of blueberries and strawberries preserved their brain function to a greater degree than those who had not.  This remained true even after socioeconomic factors were taken into account. 

Moreover, the researchers found that those who had the highest berry intake over time could delay cognitive aging by up to two and a half years.

Why might this be?  One theory has to do with the fact that blueberries and strawberries are both high in compounds called anthocyanidins and flavonoids, which have powerful antioxidant properties.  The researchers believe that these two substances contribute to a delay in cognitive aging. 

Flavonoid-rich fruit juices have been found to improve short-term intellectual performance in small trials.  Anthocyanidins are a particular subclass of flavonoids, which localize in areas of learning and memory.

But don’t run to the grocery store just yet, as the study still leaves some questions.

“This is an association or correlation.  It is not proof of causality,” said Dr. Clifford Saper, a professor of neurology at Harvard Medical School.  “Also, we do not know what component of the berries may have caused a better result.  So, to say that higher intake of flavonoids appears to reduce rates of cognitive decline is just not valid.”

The study also looked only at women.  The researchers pointed out that there is little evidence to find changes in intellectual functioning related to one’s sex.  Nonetheless, experts agree that future studies should also include men.

It is also worth noting that the study was partially funded by a berry trade group and berry eaters surveyed practiced many more healthy behaviors than the non-berry eaters.

Copyright 2012 ABC News Radio

Thursday
Apr192012

Study Shows Six Years of Boxing Can Change Brain

iStockphoto/Thinkstock(CLEVELAND) -- The long term consequences of combat sport are no secret, thanks to high-profile athletes like Muhammad Ali.  But a new study suggests that six years of boxing can cause lasting changes in the brain, including shrinkage of areas involved in memory and cognition.

"We asked the question: Is there a certain degree of repetitive head trauma that the brain can tolerate, beyond which you run the risk of developing long term complications?" said study author Dr. Charles Bernick, associate director of the Cleveland Clinic's Lou Ruvo Center for Brain Health in Las Vegas.  "And if that's the case, can we detect changes in the brain before people become symptomatic?"

Bernick and colleagues followed 109 current boxers and mixed martial art fighters, using surveys to assess their fight frequencies and MRI scans to detect changes in their brains.  The more fights, the more severe the brain changes were in fighters with six or more years in the ring.  And after 12 years, the number of fights was linked to poorer performance on memory tests.

"This raises the possibility of detecting brain changes before people are symptomatic," said Bernick, who is presenting the ongoing study at the American Academy of Neurology annual meeting this week in New Orleans.  "If you wait for someone to start having symptoms and retire, you've bought the farm.  You may not be able to do too much about it."

Mounting research in boxing, football, hockey and military service suggests smaller blows can add up to major consequences, including chronic traumatic encephalopathy, a progressive brain disease with features of Alzheimer's, Parkinson's and ALS.

"It's not just the big concussions, but the chronic accumulation of smaller blows to the head," said Dr. Daryl Rosenbaum, assistant professor of sports medicine at Wake Forest University in Winston-Salem, N.C.  "We get asked all the time how many hits are too many.  We don't know the answer to that question, but studies like this will help."

Copyright 2012 ABC News Radio

Tuesday
Jan172012

Sleep Locks In Bad Memories, Emotions

Siri Stafford/Digital Vision/Thinkstock(AMHERST, Mass.) -- Sleeping after a traumatic event might lock in bad memories and emotions, a new study has found.

Researchers from the University of Massachusetts at Amherst asked more than 100 healthy adults to rate their emotional responses to a series of images, some depicting unsettling scenes. Twelve hours later, they rated the images again. The difference: Half of the subjects slept during the break; the other half did not.

"Not only did sleep protect the memory, but it also protected the emotional reaction," said Rebecca Spencer, a neuroscientist at UMass Amherst and co-author of the study that was published in the Journal of Neuroscience.

Study subjects who stayed awake for 12 hours had a weaker emotional response to the unsettling images the second time around, suggesting sleep serves to preserve and even amplify negative emotions. Their memories were also weaker than those of their well-rested counterparts, as they struggled to remember whether they had seen the images before.

"It's true that 'sleeping on it' is usually a good thing to do," said Spencer, citing evidence that sleep boosts memory and other cognitive functions. "It's just when something truly traumatic or out of the ordinary happens that you might want to stay awake."

Spencer said people often find it difficult to sleep after a traumatic event.

"This study suggests the biological response we have after trauma might actually be healthy," she said. "Perhaps letting people go through a period of insomnia before feeding them sleeping meds is actually beneficial."

While the findings may have implications for post traumatic stress disorder, Spencer emphasized that daily emotional ups and downs are not grounds for sleep deprivation.

"Just because we have a bad day doesn't mean we should stay awake," she said. "We need to maintain some memories and emotional context to know what to avoid. We do learn something from them."

Although sleep gives the body some much-needed rest, the brain stays active. Spencer used polysomnography to monitor brain activity in some sleeping subjects.

"REM sleep in particular was associated with a change in how emotional you found something," she said. "We think there are parts of the brain being activated during sleep that allow us to process those emotions more than during day."

Next, Spencer plans to study the link between sleep and memory in the context of aging. With age, the amount of time spent sleeping drops dramatically.

"We want to know if those changes actually underlie some of the cognitive and behavioral changes that occur with age," she said.

Copyright 2012 ABC News Radio







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