Ability to balance on one leg may reflect brain health, stroke risk
December 18, 2014
Science Daily/American Heart Association
Struggling to stand on one leg for less than 20 seconds was linked to an increased risk for stroke, small blood vessel damage in the brain, and reduced cognitive function in otherwise healthy people, a study has shown. One-legged standing time may be a simple test used to measure early signs of abnormalities in the brain associated with cognitive decline, cerebral small vessel disease and stroke.
"Our study found that the ability to balance on one leg is an important test for brain health," said Yasuharu Tabara, Ph.D., lead study author and associate professor at the Center for Genomic Medicine at Kyoto University Graduate School of Medicine in Kyoto, Japan. "Individuals showing poor balance on one leg should receive increased attention, as this may indicate an increased risk for brain disease and cognitive decline."
Researchers found that the inability to balance on one leg for longer than 20 seconds was associated with cerebral small vessel disease, namely small infarctions without symptoms such as lacunar infarction and microbleeds. They noted that:
• 34.5 percent of those with more than two lacunar infarction lesions had trouble balancing.
• 16 percent of those with one lacunar infarction lesion had trouble balancing.
• 30 percent of those with more than two microbleed lesions had trouble balancing.
• 15.3 percent one microbleed lesion had trouble balancing.
Overall, those with cerebral diseases were older, had high blood pressure and had thicker carotid arteries than those who did not have cerebral small vessel disease. However, after adjustment for these covariates, people with more microbleeds and lacunar infarctions in the brain had shorter one-legged standing times. Short one-legged standing times were also independently linked with lower cognitive scores.
Although previous studies have examined the connection between gait and physical abilities and the risk of stroke, this is among the first study to closely examine how long a person can stand on one leg as an indication of their overall brain health.
"One-leg standing time is a simple measure of postural instability and might be a consequence of the presence of brain abnormalities," said Tabara.
Small vessel disease occurs due to microangiopathy of arterioles in the brain, making these arteries less flexible, which can interfere with blood flow. Small vessel disease typically increases with age. Loss of motor coordination, including balance, as well as cognitive impairment has been suggested to represent subclinical brain damage. Tabara and colleagues also found a strong link between struggling to stand on one leg and increased age, with marked shorter one-leg standing time in patients age 60 and over.
Although the study did not assess participants' histories of falling or physical fitness issues, such as how fast they could walk or any gait abnormalities, Tabara said the one-leg standing test is an easy way to determine if there are early signs of being at risk for a stroke and cognitive impairment and whether these patients need additional evaluation.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/12/141218210013.htm
Can Certain Herbs Stave Off Alzheimer's Disease?
November 15, 2013
Science Daily/Saint Louis University
Enhanced extracts made from special antioxidants in spearmint and rosemary improve learning and memory, a study in an animal model at Saint Louis University found.
We found that these proprietary compounds reduce deficits caused by mild cognitive impairment, which can be a precursor to Alzheimer's disease," said Susan Farr, Ph.D., research professor geriatrics at Saint Louis University School of Medicine.
Farr added, "This probably means eating spearmint and rosemary is good for you. However, our experiments were in an animal model and I don't know how much -- or if any amount -- of these herbs people would have to consume for learning and memory to improve. In other words, I'm not suggesting that people chew more gum at this point."
She found that the higher dose rosemary extract compound was the most powerful in improving memory and learning in three tested behaviors. The lower dose rosemary extract improved memory in two of the behavioral tests, as did the compound made from spearmint extract.
Further, there were signs of reduced oxidative stress, which is considered a hallmark of age-related decline, in the part of the brain that controls learning and memory.
"Our research suggests these extracts made from herbs might have beneficial effects on altering the course of age-associated cognitive decline," Farr said. "It's worth additional study."
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2013/11/131115111524.htm
Can poor sleep lead to dementia?
December 10, 2014
Science Daily/American Academy of Neurology (AAN)
People who have sleep apnea or spend less time in deep sleep may be more likely to have changes in the brain that are associated with dementia, according to a new study. The study found that people who don’t have as much oxygen in their blood during sleep, which occurs with sleep apnea and conditions such as emphysema, are more likely to have tiny abnormalities in brain tissue, called micro infarcts, than people with higher levels of oxygen in the blood.
The study found that people who don’t have as much oxygen in their blood during sleep, which occurs with sleep apnea and conditions such as emphysema, are more likely to have tiny abnormalities in brain tissue, called micro infarcts, than people with higher levels of oxygen in the blood. These abnormalities are associated with the development of dementia.
In addition, people who spent less time in deep sleep, called slow wave sleep, were more likely to have loss of brain cells than people who spent more time in slow wave sleep. Slow wave sleep is important in processing new memories and remembering facts. People tend to spend less time in slow wave sleep as they age. Loss of brain cells is also associated with Alzheimer’s disease and dementia.
Previous studies have also shown a link between sleep stages and dementia. For this study, the participants were again divided into four groups based on the percentage of the night spent in slow wave sleep. Of the 37 men who spent the least time in slow wave sleep, 17 had brain cell loss, compared to seven of the 38 men who spent the most time in slow wave sleep.
The results remained the same after adjusting for factors such as smoking and body mass index and after excluding participants who had died early in the follow-up period and those who had low scores on cognitive tests at the beginning of the study.
“These findings suggest that low blood oxygen levels and reduced slow wave sleep may contribute to the processes that lead to cognitive decline and dementia,” said study author Rebecca P. Gelber, MD, DrPH, of the VA Pacific Islands Health Care System and the Pacific Health Research and Education Institute in Honolulu, Hawaii. “More research is needed to determine how slow wave sleep may play a restorative role in brain function and whether preventing low blood oxygen levels may reduce the risk of dementia.”
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2014/12/141210162103.htm
Exercise with a physiotherapist helps people with depression
June 12, 2015
Science Daily/University of Gothenburg
Exercise has a positive effect on depression. A researcher evaluated exercise as add-on therapy to medicating with antidepressants. The experiments showed that people who participated in exercise aimed at increasing their physical fitness clearly improved their mental health compared with the control group.
In a study at the Sahlgrenska Academy, the researcher evaluated exercise as add-on therapy to medicating with antidepressants. The study divided 62 individuals with diagnosed clinical depression into three groups, in which two participated in two different types of exercise with a physiotherapist twice a week for 10 weeks while the third, the control group, did not participate in systematic exercise.
Person-centered approach
The exercise in the study was based on a person-centered approach, where the exercises were adapted to the participant's needs, expectations and previous experiences.
The experiments showed that people who participated in exercise aimed at increasing their physical fitness clearly improved their mental health compared with the control group.
Reduced depressive symptoms
Even participants who were coached in basal body awareness reduced their depressive symptoms, although not as significantly.
"In our follow-up interviews for the study, participants spoke about how they felt alive again and became more active. One woman expressed this to mean that the workout "kick starts my body and helps me get the strength to crawl out of this cocoon that I am in," reports Ph.D. student Louise Danielsson, who reviews the studies in her dissertation.
More social contacts
The studies show that the participants who exercised felt that they had the strength to do more at home and engaged in more social contacts.
But it is not so easy to simply start exercising. The participants described how their depression created a resistance to leaving the house and this makes it difficult have the mental energy to desire to be physically active. Several participants stressed the importance the support they received the physiotherapist, and that exercising together with other participants constituted a meaningful connection.
Importance of design and context
The dissertation's results supports previous research on the antidepressant effects of exercise and highlights the importance of the design and context of the exercise, as well as the opportunities for professional support.
"Our results show that exercise can be used within primary care with the rehabilitation of people with depression," concludes Louise Danielsson.
The dissertation "Moved by movement: a person-centered approach to physical therapy in the treatment of major depression" was defended at a public defense of the dissertation on 2 June.
Science Daily/SOURCE :http://www.sciencedaily.com/releases/2015/06/150612091327.htm
Brain's Stress Circuits Undergo Profound Learning Early in Life
Apr. 7, 2013 —
Science Daily/University of California – Berkeley
https://www.sciencedaily.com/images/2013/04/130416204546_1_540x360.jpg
Brain cells called astrocytes (pink) appear to be key players in the response to acute stress. Stress hormones stimulate astrocytes to release fibroblast growth factor 2 (green), which in turn lead to new neurons (blue).
Credit: Image by Daniela Kaufer & Liz Kirby
Overworked and stressed out? Look on the bright side. Some stress is good for you.
"You always think about stress as a really bad thing, but it's not," said Daniela Kaufer, associate professor of integrative biology at the University of California, Berkeley. "Some amounts of stress are good to push you just to the level of optimal alertness, behavioral and cognitive performance."
New research by Kaufer and UC Berkeley post-doctoral fellow Elizabeth Kirby has uncovered exactly how acute stress -- short-lived, not chronic -- primes the brain for improved performance.
In studies on rats, they found that significant, but brief stressful events caused stem cells in their brains to proliferate into new nerve cells that, when mature two weeks later, improved the rats' mental performance.
"I think intermittent stressful events are probably what keeps the brain more alert, and you perform better when you are alert," she said.
Kaufer, Kirby and their colleagues in UC Berkeley's Helen Wills Neuroscience Institute describe their results in a paper published April 16 in the new open access online journal eLife.
The UC Berkeley researchers' findings, "in general, reinforce the notion that stress hormones help an animal adapt -- after all, remembering the place where something stressful happened is beneficial to deal with future situations in the same place," said Bruce McEwen, head of the Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology at The Rockefeller University, who was not involved in the study.
Kaufer is especially interested in how both acute and chronic stress affect memory, and since the brain's hippocampus is critical to memory, she and her colleagues focused on the effects of stress on neural stem cells in the hippocampus of the adult rat brain. Neural stem cells are a sort of generic or progenitor brain cell that, depending on chemical triggers, can mature into neurons, astrocytes or other cells in the brain. The dentate gyrus of the hippocampus is one of only two areas in the brain that generate new brain cells in adults, and is highly sensitive to glucocorticoid stress hormones, Kaufer said.
Much research has demonstrated that chronic stress elevates levels of glucocorticoid stress hormones, which suppresses the production of new neurons in the hippocampus, impairing memory. This is in addition to the effect that chronically elevated levels of stress hormones have on the entire body, such as increasing the risk of chronic obesity, heart disease and depression.
Less is known about the effects of acute stress, Kaufer said, and studies have been conflicting.
To clear up the confusion, Kirby subjected rats to what, to them, is acute but short-lived stress -- immobilization in their cages for a few hours. This led to stress hormone (corticosterone) levels as high as those from chronic stress, though for only a few hours. The stress doubled the proliferation of new brain cells in the hippocampus, specifically in the dorsal dentate gyrus.
Kirby discovered that the stressed rats performed better on a memory test two weeks after the stressful event, but not two days after the event. Using special cell labeling techniques, the researchers established that the new nerve cells triggered by the acute stress were the same ones involved in learning new tasks two weeks later.
"In terms of survival, the nerve cell proliferation doesn't help you immediately after the stress, because it takes time for the cells to become mature, functioning neurons," Kaufer said. "But in the natural environment, where acute stress happens on a regular basis, it will keep the animal more alert, more attuned to the environment and to what actually is a threat or not a threat."
They also found that nerve cell proliferation after acute stress was triggered by the release of a protein, fibroblast growth factor 2 (FGF2), by astrocytes -- brain cells formerly thought of as support cells, but that now appear to play a more critical role in regulating neurons.
"The FGF2 involvement is interesting, because FGF2 deficiency is associated with depressive-like behaviors in animals and is linked to depression in humans," McEwen said.
Kaufer noted that exposure to acute, intense stress can sometimes be harmful, leading, for example, to post-traumatic stress disorder. Further research could help to identify the factors that determine whether a response to stress is good or bad.
"I think the ultimate message is an optimistic one," she concluded. "Stress can be something that makes you better, but it is a question of how much, how long and how you interpret or perceive it."
The eLife paper was coauthored by UC Berkeley colleagues Sandra E Muroy, Wayne G. Sun and David Covarrubias of the Department of Molecular and Cell Biology; Megan J. Leong of the Helen Wills Neuroscience Institute; and Laurel A. Barchas of the Department of Integrative Biology. Kirby is now a post-doctoral fellow at Stanford University.
Kaufer's research was funded by a BRAINS (Biobehavioral Research Awards for Innovative New Scientists) award from the National Institute of Mental Health of the National Institutes of Health (R01 MH087495) and the National Alliance for Research on Schizophrenia and Depression. Kirby was supported by fellowships from the California Institute for Regenerative Medicine and the U.S. Department of Defense.
http://www.sciencedaily.com/releases/2013/04/130407133314.htm
Patients with insomnia have altered activity in specific brain regions
Science Daily/University of Pittsburgh Medical Center (UPMC)
Specific brain regions, including those involved in awareness of self and tendency to ruminate, show altered activity in patients with insomnia when compared to good sleepers, according to a new study.
In what is the largest study of its kind on insomnia, a research group led by Daniel Buysse M.D., professor of psychiatry and clinical and translational science, and the UPMC Professor of Sleep Medicine, University of Pittsburgh School of Medicine, identified ...
Jet lag treatment? Blast of thin air can reset circadian clocks
October 20, 2016
Science Daily/Cell Press
We might not think of our circadian clock until we are jetlagged, but scientists continue to puzzle over what drives our biological timepiece. Now, a study has found that variations in surrounding oxygen levels can reset circadian clocks of mice. If confirmed in humans, the research could help inform how airlines moderate cabin air pressure.
Presently, light, food, and temperature are the best known cues that can influence circadian rhythms. But lead author Gad Asher, a senior scientist at the Weizmann Institute of Science in Rehovot, Israel, and his colleagues, including postdoctoral fellows Yaarit Adamovich and Benjamin Ladeuix, wondered if oxygen might also cue circadian rhythms since oxygen absorption in animals varies alongside meals and changing temperatures.
In the paper, the researchers show that changing the concentration of oxygen in cells by just 3%, twice a day, will synchronize mouse cells to a circadian rhythm. They suspected HIF1α was the link between oxygen and the circadian clock because HIF1α plays both a role in oxygen homeostasis in cells. They found that cells with low HIF1α levels won't synchronize in response to oxygen variations.
"It was extremely exciting to see that even small changes in oxygen levels were sufficient to efficiently reset the circadian clock," says Asher. "The study actually raises a lot of important questions; although we show that clock reset by oxygen is dependent on HIF1α, we did not yet fully identify how HIF1α integrates within the core clock circuitry."
The researchers further explored oxygen's effect on circadian rhythms with jetlag experiments. Just like humans, mice are prone to jetlag after a sudden shift in daylight hours. Mice were first left to eat, sleep and run on their wheels in air-controlled environments. Altering oxygen levels alone did not change their circadian rhythms but once mice experienced a 6-hour jump ahead in daylight hours, varying oxygen levels could help them adapt their eating, sleeping and running habits to the new time faster. They also saw that a small drop in oxygen levels 12 hours before the 6-hour daylight shift, or 2 hours afterwards, put the mice back on their circadian schedules faster and this too was dependent on HIF1α levels.
Presently, commercial airliners pressurize cabins to the same air density of a city 6,000-8,000 feet above sea level. This low-pressure saves wear and tear on the airplane, but enough passengers suffer from airsickness in response to this drop in oxygen levels that some airlines are considering ways to increase the pressure on flights. In fact, Boeing designed its new 787 Dreamliner so that it can be pressurized to the equivalent of lower altitudes for this reason. But in light of these findings, the researchers noted passengers may feel better with higher pressurized cabins during flights, but may also lose a potential advantage of recovering from jetlag. And in light of the effects of lower oxygen levels, the researchers now want to see what higher oxygen levels may do to the circadian clock.
"We are very looking forward to seeing the outcome of these experiments -- it will be interesting both from basic science and also from a practical standpoint," said Asher. "I believe passengers might be more enthusiastic to inhale oxygen-enriched air to alleviate jetlag in contrast to low oxygen."
Understanding how oxygen influences the circadian clock goes beyond jetlag. Cardiovascular disease, COPD, shift work sleep disorder, and other common health problems can result in tissues with low oxygen levels. "We show that oxygen works in mammals, specifically rodents, but it will be interesting to test whether oxygen can reset the clock of bacteria, plants, flies and additional organisms," says Asher.
https://www.sciencedaily.com/releases/2016/10/161020142746.htm