Thursday, December 20, 2018
Head impacts, changes in eye function in high school football players
Head impacts in youth sports, even when they don't cause symptoms of concussion, are a public health concern because these so-called subconcussive head impacts may result in long-term neurological issues if they are sustained repeatedly. This study looked at changes in measurements of near point of convergence (NPC), which is the distance from your eyes to where both eyes can focus without double vision, in 12 high school football players at 14 different times during a season. The NPC measurement matters because it has been shown to detect damage to neurons before symptoms appear. The frequency and magnitude of head impacts from all practices and games also were measured. Study findings suggest NPC values worsened with subconcussive head impacts, and that impaired NPC didn't rapidly recover. However, NPC values began to return to normal in midseason while players continued to incur head impacts, suggesting the system controlling eye movements may develop tolerance to recurrent subconcussive head impacts. The findings of this study may not be generalized because of its small size.
How calorie content makes you rethink food choices
Hold the fries!
Credit: Photo courtesy of Pixabay
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The study is the first of its kind to examine how your brain makes food choices when calorie information is presented. The results are timely given that earlier this year, certain food chain establishments had to comply with the U.S. Food & Drug Administration's menu labeling law requiring the disclosure of calorie information on menus and menu boards. In addition, according to the Centers for Disease Control and Prevention, obesity affected nearly 40 percent of U.S. adults in 2015-16.
"Our findings suggest that calorie-labeling may alter responses in the brain's reward system when considering food options. Moreover, we believe that nutritional interventions are likely to be more successful if they take into account the motivation of the consumer, including whether or not they diet," says first author Andrea Courtney, who was a graduate student in the department of psychological and brain sciences at Dartmouth at the time of the study and is currently a postdoctoral student at the Stanford Social Neuroscience Lab at Stanford University.
For the study conducted at Dartmouth, 42 undergraduate students (ages 18 to 22) viewed 180 food images without calorie information followed by images with calorie information and were asked to rate their desire to eat the food while in a functional magnetic resonance imaging scanner (fMRI). The images were obtained from either the food pics database or popular, fast food restaurant websites that post calorie information. The 22 dieters and 20 non-dieters viewed the same set of images, including foods such as a cheeseburger, a side of French fries or a slice of cherry cheesecake. On a scale from 1 to 4 (1 = not at all, 4 = very much), they indicated how likely they would be to eat the food in the dining hall.
While dieters and non-dieters alike rated calorie-labeled foods as less appetizing, this effect was strongest among dieters. Further, the researchers analyzed responses in two brain regions that motivate eating behavior: the nucleus accumbens (NAcc) and the orbitofrontal cortex (OFC). Although all participants showed a decrease in activation in these areas when calorie information was present, dieters showed more similar activation patterns in the left OFC for calorie-labeled and unlabeled foods. This finding suggests that dieters may consider calorie information even when it isn't explicitly present and builds on previous research suggesting that the presence of health cues can lead to healthier food decisions.
"In order to motivate people to make healthier food choices, policy changes are needed that incorporate not only nutritional information, including calorie content, but also a public education component, which reinforces the long-term benefits of a healthy diet," added senior author Kristina Rapuano, who was a graduate student in the department of psychological and brain sciences at Dartmouth at the time of the study and is currently a postdoctoral student at the Fundamentals of the Adolescent Brain Lab at Yale University.
Wednesday, December 19, 2018
In just 6 months, exercise may help those with thinking problems
Getting the heart pumping with aerobic exercise, like walking or cycling for 35 minutes three times a week, may improve thinking skills in older adults with cognitive impairments, according to a study published in the December 19, 2018, online issue of Neurology®, the medical journal of the American Academy of Neurology. After six months of exercise, study participants' scores on thinking tests improved by the equivalent of reversing nearly nine years of aging.
The study looked at people who had cognitive impairments without dementia, which is defined as having difficulty concentrating, making decisions, or remembering, but not severe enough to be diagnosed with dementia.
The study found that exercise improved thinking skills called executive function. Executive function is a person's ability to regulate their own behavior, pay attention, organize and achieve goals. The study found no improvement in memory.
"The results are encouraging in that in just six months, by adding regular exercise to their lives, people who have cognitive impairments without dementia may improve their ability to plan and complete certain cognitive tasks," said study author James A. Blumenthal, PhD, of Duke University Medical Center in Durham, N.C.
The study involved 160 people with an average age of 65 and risk factors for heart disease, such as hypertension, who did not have dementia but reported problems with thinking skills. All participants were identified as having cognitive impairments without dementia and were sedentary at the start of the study.
Researchers examined the effects of both exercise and diet, specifically the Dietary Approaches to Stop Hypertension (DASH) diet, which is a low sodium, high fiber diet rich in fruits and vegetables, beans, nuts, low fat dairy products, whole grains, and lean meats. The DASH diet was designed specifically for individuals with high blood pressure.
Participants were randomly assigned to one of four groups: aerobic exercise alone; DASH diet alone; both aerobic exercise and the DASH diet; or health education, which consisted of educational phone calls once every one or two weeks. People assigned to the exercise groups exercised three times a week for 45 minutes each session which included 10 minutes of warm-up exercises and 35 minutes of aerobic exercise, such as walking, jogging, or cycling on a stationary bicycle.
At both the beginning and end of the six-month study, researchers evaluated participants' thinking and memory abilities with standardized cognitive testing, cardiorespiratory fitness with treadmill stress testing, and heart disease risk factors with screenings for blood pressure, blood glucose and lipids. They also used questionnaires and food diaries to measure how closely the participants followed the DASH diet.
Researchers found that participants who exercised showed significant improvements in thinking skills when compared to those who did not exercise. Those who took part in both the exercise and diet had average scores of nearly 47 points on the overall tests of executive thinking skills, compared to an average score of about 42 points for those with exercise and diet alone and about 38 points for those who just received health education. There was no improvement in participants who only consumed the DASH diet, although those who exercised and consumed the DASH diet had greater improvements compared to health education controls.
To illustrate, Blumenthal explained that at the start of the study, the participants had average scores for select subtests of executive function for people who were age 93, which was 28 years older than their actual chronological age. After six months, participants who exercised and followed the DASH diet saw their average executive function scores correspond with people who were age 84, a nine-year improvement. For those who received only health education, their performance on executive function tests worsened by a half year from their scores at the start of the study.
Although this may suggest added benefit of the DASH diet when combined with exercise, Blumenthal says a limitation of the study was that the number of participants was relatively small and these findings should be interpreted with caution.
"More research is still needed with larger samples, over longer periods of time to examine whether improvements to thinking abilities continue and if those improvements may be best achieved through multiple lifestyle approaches like exercise and diet," Blumenthal said.
Alcoholic beverages are migraine triggers
Additionally, more than 25 percent of migraine patients who had stopped consuming or never consumed alcoholic beverages did so because of presumed trigger effects. Wine, especially red wine (77.8 percent of participants), was recognized as the most common trigger among the alcoholic beverages; however, red wine consistently led to an attack in only 8.8 percent of participants. Time of onset was rapid (less than three hours) in one third of patients, and almost 90 percent of patients had an onset in under 10 hours independent of the type of alcoholic beverage consumed.
The authors noted that it can be debated if alcohol is a factual or a presumed trigger. Additional studies are needed to unravel this relationship.
"Alcohol-triggered migraine occurs rapid after intake of alcoholic beverages, suggesting a different mechanism than a normal hangover," said senior author Dr. Gisela Terwindt, of the Leiden University Medical Center, in the Netherlands.
Mind-body exercises may improve cognitive function as adults age
The Journal of the American Geriatrics Society analysis included 32 randomized controlled trials with 3,624 older adults with or without cognitive impairment.
The investigators noted that mind-body exercise, as a therapy that combines mental concentration, breathing control, and body movement, is beneficial for improving flexibility and mental health, but no previous studies have evaluated the effects of all major forms of mind-body exercise in a single work.
Dancing may help older women maintain the ability to perform daily tasks
The prospective study enrolled 1,003 community-dwelling older Japanese women without ADL disability at the start. In the baseline survey, all participants were asked whether or not they participated in any of 16 exercise types through a face-to-face interview. ADL disability during eight years of follow-up was defined as dependence in at least one ADL task (walking, eating, bathing, dressing, or toileting).
ADL disability was noted in 130 participants (13 percent) during follow-up. After adjusting for confounders, participation in dancing, compared with non-participation, was associated with a 73 percent significantly lower likelihood for developing ADL disability. There were no significant associations between other exercise types and ADL disability.
"Although it is unclear why dancing alone reduced the risk of ADL disability, dancing requires not only balance, strength, and endurance ability, but also cognitive ability: adaptability and concentration to move according to the music and partner, artistry for graceful and fluid motion, and memory for choreography," said lead author Dr. Yosuke Osuka, of the Tokyo Metropolitan Institute of Gerontology." We think that these various elements may contribute to the superiority of dancing in maintaining a higher ADL capacity."
Study links nutrients in blood to better brain connectivity, cognition in older adults Univ
A new study links higher levels of several key nutrients in the blood with more efficient brain connectivity and performance on cognitive tests in older adults.
The study, reported in the journal NeuroImage, looked at 32 key nutrients in the Mediterranean diet, which previous research has shown is associated with better brain function in aging. It included 116 healthy adults 65-75 years of age.
"We wanted to investigate whether diet and nutrition predict cognitive performance in healthy older adults," said University of Illinois postdoctoral researcher Christopher Zwilling, who led the study with U. of I. psychology professor Aron Barbey in the Beckman Institute for Advanced Science and Technology.
The analysis linked specific patterns of a handful of nutrient biomarkers in the blood to better brain health and cognition. The nutrient patterns included omega-3 fatty acids, which are abundant in fish, walnuts and Brussels sprouts; omega-6 fatty acids, found in flaxseed, pumpkin seeds, pine nuts and pistachios; lycopene, a vivid red pigment in tomatoes, watermelon and a few other fruits and vegetables; alpha- and beta-carotenoids, which give sweet potatoes and carrots their characteristic orange color; and vitamins B and D.
The researchers relied on some of the most rigorous methods available for examining nutrient intake and brain health, Barbey said. Rather than asking participants to answer food-intake surveys, which require the accurate recall of what and how much participants ate, the team looked for patterns of nutrient "biomarkers" in the blood. The team also used functional magnetic resonance imaging to carefully evaluate the efficiency with which various brain networks performed.
"The basic question we were asking was whether diet and nutrition are associated with healthy brain aging," Barbey said. "And instead of inferring brain health from a cognitive test, we directly examined the brain using high-resolution brain imaging."
Functional MRIs can indicate the efficiency of individual brain networks, he said.
"Efficiency has to do with how information is communicated within the network," Barbey said. "We looked at 'local efficiency' - how well information is shared within a spatially confined set of brain regions - and also 'global efficiency,' which reflects how many steps are required to transfer information from any one region to any other region in the network.
"If your network is more efficiently configured, then it should be easier, on average, to access relevant information and the task should take you less time," he said.
Participants also completed several cognitive tests.
The analysis found a robust link between higher levels of several nutrient biomarkers in the blood and enhanced performance on specific cognitive tests. These nutrients, which appeared to work synergistically, included omega-3 and omega-6 fatty acids, carotenoids, lycopene, riboflavin, folate, vitamin B12 and vitamin D.
The analysis also revealed that a pattern of omega-3s, omega-6s and carotene was linked to better functional brain network efficiency.
Different nutrient patterns appeared to moderate the efficiency in different brain networks. For example, higher levels of omega-3 fatty acids paralleled the positive relationship between a healthy frontoparietal network and general intelligence. The frontoparietal network supports the ability to focus attention and engage in goal-directed behavior.
"Our study suggests that diet and nutrition moderate the association between network efficiency and cognitive performance," Barbey said. "This means that the strength of the association between functional brain network efficiency and cognitive performance is associated with the level of the nutrients."
To test the stability of the nutrient-biomarker patterns over time, the researchers invited 40 participants back for a second analysis roughly two years after the first tests. Similar nutrient patterns persisted in this subset of the original group.
"Because we're investigating how groups of nutrients work together, we're getting a more accurate snapshot of how the body processes these nutrients and how they can impact the brain and cognitive health," Zwilling said. "Of course, future studies are needed to affirm and extend these results."
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