People who feel dizzy when they stand up may have higher risk of dementia

August 6, 2020

Science Daily/American Academy of Neurology

Some people who feel dizzy or lightheaded when they stand up may have an increased risk of developing dementia years later, according to a new study published in Neurology®, the medical journal of the American Academy of Neurology. The condition, called orthostatic hypotension, occurs when people experience a sudden drop in blood pressure when they stand up.

The study found the link with dementia only in people who have a drop in their systolic blood pressure, not in people with only a drop in their diastolic blood pressure or their blood pressure overall.

Systolic is the first, or top, number in a blood pressure reading and systolic orthostatic hypotension was defined as a drop of at least 15 mmHg after standing from a sitting position.

"People's blood pressure when they move from sitting to standing should be monitored," said study author Laure Rouch, Pharm.D., Ph.D., of the University of California, San Francisco. "It's possible that controlling these blood pressure drops could be a promising way to help preserve people's thinking and memory skills as they age."

The study involved 2,131 people who were an average age of 73 and did not have dementia when they enrolled. Their blood pressure readings were taken at the start of the study and then one, three and five years later. A total of 15% had orthostatic hypotension, 9% had systolic orthostatic hypotension and 6% had diastolic orthostatic hypotension.

Over the next 12 years, the participants were evaluated to see if anyone developed dementia. A total of 462 people, or 22%, did develop the disease.

The people with systolic orthostatic hypotension were nearly 40% more likely to develop dementia than those who did not have the condition. Fifty of the 192 with systolic orthostatic hypotension, or 26%, developed dementia, compared to 412 of the 1,939 people without it, or 21%. When researchers adjusted for other factors that could affect dementia risk, such as diabetes, smoking and alcohol use, those with systolic orthostatic hypotension were 37% more likely to develop dementia.

The researchers also found that people whose sitting-to-standing systolic blood pressure readings changed the most from visit to visit were more likely to develop dementia years later than people whose readings were more stable.

The people were divided into three groups based on how much their readings changed over time. A total of 24% of people in the group with the most fluctuation in systolic readings later developed dementia, compared to 19% of the people in the group with the least fluctuation. When researchers adjusted for other factors affecting dementia risk, those in the highest group were 35% more likely to develop dementia than those in the lowest group.

Rouch noted that the study is observational and does not show cause and effect. It only shows an association between the blood pressure readings and the development of dementia. Another limitation of the study was that the diagnosis of dementia was made without distinction between Alzheimer's disease and vascular dementia.

The study was funded by the National Institute on Aging.

https://www.sciencedaily.com/releases/2020/08/200806203658.htm

Sport and memory go hand in hand

September 23, 2020

Science Daily/Université de Genève

If sport is good for the body, it also seems to be good for the brain. By evaluating memory performance following a sport session, neuroscientists from the University of Geneva (UNIGE) demonstrate that an intensive physical exercise session as short as 15 minutes on a bicycle improves memory, including the acquisition of new motor skills. How? Through the action of endocanabinoids, molecules known to increase synaptic plasticity. This study, to be read in the journal Scientific Reports, highlights the virtues of sport for both health and education. School programmes and strategies aimed at reducing the effects of neurodegeneration on memory could indeed benefit from it.

Very often, right after a sporting exercise -- especially endurance such as running or cycling -- one feels physical and psychological well-being. This feeling is due to endocannabinoids, small molecules produced by the body during physical exertion. "They circulate in the blood and easily cross the blood-brain barrier. They then bind to specialise cellular receptors and trigger this feeling of euphoria. In addition, these same molecules bind to receptors in the hippocampus, the main brain structure for memory processing," says Kinga Igloi, lecturer in the laboratory of Professor Sophie Schwartz, at UNIGE Faculty of Medicine's Department of Basic Neurosciences, who led this work. "But what is the link between sport and memory? This is what we wanted to understand," she continues.

Intense effort is more effective 

To test the effect of sport on motor learning, scientists asked a group of 15 young and healthy men, who were not athletes, to take a memory test under three conditions of physical exercise: after 30 minutes of moderate cycling, after 15 minutes of intensive cycling (defined as 80% of their maximum heart rate), or after a period of rest. "The exercise was as follows: a screen showed four points placed next to each other. Each time one of the dots briefly changed into a star, the participant had to press the corresponding button as quickly as possible," explains Blanca Marin Bosch, researcher in the same laboratory. "It followed a predefined and repeated sequence in order to precisely evaluate how movements were learnt. This is very similar to what we do when, for example, we learn to type on a keyboard as quickly as possible. After an intensive sports session, the performance was much better."

In addition to the results of the memory tests, the scientists observed changes in the activation of brain structures with functional MRI and performed blood tests to measure endocannabinoid levels. The different analyses concur: the faster individuals are, the more they activate their hippocampus (the brain area of memory) and the caudate nucleus (a brain structure involved in motor processes). Moreover, their endocannabinoid levels follow the same curve: the higher the level after intense physical effort, the more the brain is activated and the better the brain's performance. "These molecules are involved in synaptic plasticity, i.e. the way in which neurons are connected to each other, and thus may act on long-term potentiation, the mechanism for optimal consolidation of memory," says Blanca Marin Bosch.

Improving school learning or preventing Alzheimer's disease 

In a previous study, the research team had already shown the positive effect of sport on another type of memory, associative memory. However, contrary to what is shown here, they had observed that a sport session of moderate intensity produced better results. It therefore shows that, as not all forms of memory use the same brain mechanisms, not all sports intensities have the same effects. It should be noted that in all cases, physical exercise improves memory more than inaction.

By providing precise neuroscientific data, these studies make it possible to envisage new strategies for improving or preserving memory. "Sports activity can be an easy to implement, minimally invasive and inexpensive intervention. For example, would it be useful to schedule a sports activity at the end of a school morning to consolidate memory and improve learning?"

Improving academic learning or preventing Alzheimer's disease 

In a previous study, the research team had already shown the positive effect of sport on another type of memory, associative memory. But, contrary to what is shown here, they had observed that a sport session of moderate intensity, not high intensity, produced better results. Thus, just as not all forms of memory use the same brain mechanisms, not all sports intensities have the same effects. It should be noted that in all cases, physical exercise improves memory more than inaction.

By providing precise neuroscientific data, these studies make it possible to envisage new strategies for improving or preserving memory. "Sports activity can be an easy to implement, minimally invasive and inexpensive intervention. Would it be useful, for example, to plan a moment of sport at the end of a school morning to consolidate school learning," Kinga Igloi wonders, who, with her colleagues at Sophie Schwartz's laboratory, aims to achieve such practical objectives.

Neuroscientists are currently pursuing their work by studying memory disorders, and in particular by studying populations at high risk of developing Alzheimer's disease. "Some people as young as 25 years of age may experience subtle memory deficits characterised by overactivation of the hippocampus. We want to evaluate the extent to which sports practice could help compensate for these early deficits that are precursors to Alzheimer's disease.," conclude the authors.

https://www.sciencedaily.com/releases/2020/09/200923124616.htm

Risk gene for Alzheimer's has early effects on the brain

September 15, 2020

Science Daily/DZNE - German Center for Neurodegenerative Diseases

A genetic predisposition to late-onset Alzheimer's disease affects how the brains of young adults cope with certain memory tasks. Researchers from the German Center for Neurodegenerative Diseases (DZNE) and the Ruhr-Universität Bochum report on this in the scientific journal Current Biology. Their findings are based on studies with magnetic resonance imaging in individuals at the age of about 20 years. The scientists suspect that the observed effects could be related to very early disease processes.

The causes for Alzheimer's in old age are only poorly understood. It is believed that the disease is caused by an unfavorable interaction of lifestyle, external factors and genetic risks. The greatest genetic risk factor for late-onset Alzheimer's disease stems from inherited mutations affecting "Apolipoprotein E" (ApoE), a protein relevant for fat metabolism and neurons. Three variants of the ApoE gene are known. The most common form is associated with an average risk for Alzheimer's. One of the two rarer variants stands for an increased risk, and the other for a reduced risk.

"We were interested in finding out whether and how the different gene variants affect brain function. That is why we examined the brains of young adults in the scanner while they had to solve a task that challenged their memory," explained Dr. Hweeling Lee, who led the current study at the DZNE in Bonn.

Distinguishing similar events

The group of study participants comprised of 82 young men and women. They were on average 20 years old, and all of them were university students considered to be cognitively healthy. According to their genotype for ApoE, 33 of them had an average, 34 an increased and 15 a reduced risk of developing Alzheimer's disease at a late age. During the study in the brain scanner, all individuals were presented with more than 150 successive images displayed on a monitor. These were everyday objects such as a hammer, a pineapple or a cat. Some pictures were repeated after a while, but sometimes the position of the displayed objects on the screen had changed. The study participants had to identify whether an object was "new" or had been shown before -- and if so, whether its position had shifted.

"We tested the ability to distinguish similar events from one another. This is called pattern separation," said Hweeling Lee. "In everyday life, for example, it's a matter of remembering whether a key has been placed in the left or right drawer of a dresser, or where the car was parked in a parking garage. We simulated such situations in a simplified way by changing the position of the depicted objects."

High-resolution through modern technology

Simultaneously to this experiment, the brain activity of the volunteers was recorded using a technique called "functional magnetic resonance imaging." Focus was on the hippocampus, an area only a few cubic centimeters in size, which can be found once in each brain hemisphere. The hippocampus is considered the switchboard of memory. It also belongs to those sections of the brain in which first damages occur in Alzheimer's disease.

When measuring brain activity, the scanner was able to show its full potential: It was an "ultra-high field tomograph" with a magnetic field strength of seven Tesla. Such devices can achieve a better resolution than brain scanners usually used in medical examinations. This enabled the researchers to record brain activity in various sub-fields of the hippocampus with high precision. "Up to now, there were no comparable studies with such level of detail in ApoE genotyped participants. This is a unique feature of our research," said Hweeling Lee.

No differences in memory performance

There were no differences between the three groups of subjects with regard to their ability for pattern separation. "All study participants performed similarly well in the memory test. It did not matter whether they had an increased, reduced or average risk for Alzheimer's disease. Such results are certainly to be expected in young healthy people," said Nikolai Axmacher, Professor of Neuropsychology at the Ruhr-Universität Bochum, who was also involved in the current study. "However, there were differences in brain activity. The different groups of study participants activated the various subfields of the hippocampus in different ways and to varying degrees. Their brains thus reacted differently to the memory task. In fact, we saw differences in brain activation not only between people with average and increased risk, but also between individuals with average and reduced risk."

At present, it is uncertain whether these effects are significant for developing Alzheimer's in old age. "Our findings might be related to very early disease processes. Determining this is a task for future studies and could help to devise biomarkers for the early diagnosis of dementia," said Hweeling Lee. "In any case, it is remarkable that a genetic predisposition for Alzheimer's disease is already reflected in the brain at young adulthood."

https://www.sciencedaily.com/releases/2020/09/200915110001.htm

Green light therapy shown to reduce migraine frequency, intensity

September 10, 2020

Science Daily/University of Arizona Health Sciences

New research from the University of Arizona Health Sciences found that people who suffer from migraine may benefit from green light therapy, which was shown to reduce the frequency and intensity of headaches and improve patient quality of life.

According to the Migraine Research Foundation, migraine is the third most prevalent illness in the world, affecting 39 million people in the United States and 1 billion worldwide.

"This is the first clinical study to evaluate green light exposure as a potential preventive therapy for patients with migraine, " said Mohab Ibrahim, MD, PhD, lead author of the study, an associate professor in the UArizona College of Medicine -- Tucson's Department of Anesthesiology, Pharmacology, and Neurosurgery and director of the Chronic Pain Management Clinic. "As a physician, this is really exciting. Now I have another tool in my toolbox to treat one of the most difficult neurological conditions -- migraine."

Overall, green light exposure reduced the number of headache days per month by an average of about 60%. A majority of study participants -- 86% of episodic migraine patients and 63% of chronic migraine patients -- reported a more than 50% reduction in headache days per month. Episodic migraine is characterized by up to 14 headache days per month, while chronic migraine is 15 or more headache days per month.

"The overall average benefit was statistically significant. Most of the people were extremely happy," Dr. Ibrahim said of the participants, who were given light strips and instructions to follow while completing the study at home. "One of the ways we measured participant satisfaction was, when we enrolled people, we told them they would have to return the light at the end of the study. But when it came to the end of the study, we offered them the option to keep the light, and 28 out of the 29 decided to keep the light."

Dr. Ibrahim and co-author Amol Patwardhan, MD, PhD, who are affiliated with the UArizona Health Sciences Comprehensive Pain and Addiction Center, have been studying the effects of green light exposure for several years. This initial clinical study included 29 people, all of whom experience episodic or chronic migraine and failed multiple traditional therapies, such as oral medications and Botox injections.

"Despite recent advances, the treatment of migraine headaches is still a challenge," said Dr. Patwardhan, an associate professor and the vice chair of research in the Department of Anesthesiology. "The use of a nonpharmacological therapy such as green light can be of tremendous help to a variety of patients that either do not want to be on medications or do not respond to them. The beauty of this approach is the lack of associated side effects. If at all, it appears to improve sleep and other quality of life measures."

During the study, patients were exposed to white light for one to two hours a day for 10 weeks. After a two-week break, they were exposed to green light for 10 weeks. They completed regular surveys and questionnaires to track the number of headaches they experienced and the intensity of those headaches, as well as quality of life measurements such as the ability to fall and stay asleep or to perform work.

Using a numeric pain scale of 0 to 10, participants noted that green light exposure resulted in a 60% reduction in pain, from 8 to 3.2. Green light therapy also shortened the duration of headaches, and it improved participants' ability to fall and stay asleep, perform chores, exercise, and work.

None of the study participants reported any side effects of green light exposure.

"In this trial, we treated green light as a drug," Dr. Ibrahim said. "It's not any green light. It has to be the right intensity, the right frequency, the right exposure time and the right exposure methods. Just like with medications, there is a sweet spot with light."

Dr. Ibrahim has been contacted by physicians from as far away as Europe, Africa and Asia, all asking for the green light parameters and schematic design for their own patients.

"As you can imagine, LED light is cheap," he said. "Especially in places where resources are not that available and people have to think twice before they spend their money, when you offer something affordable, it's a good option to try."

The paper, "Evaluation of green light exposure on headache frequency and quality of life in migraine patients: A preliminary one-way cross-over clinical trial," was published online by Cephalalgia, the journal of the International Headache Society.

"These are great findings, but this is where the story begins," Dr. Ibrahim said. "As a scientist, I am really interested in how this works because if I understand the mechanism, then I can utilize it for other conditions. I can use it as a tool to manipulate the biological systems to achieve as much as we can."

https://www.sciencedaily.com/releases/2020/09/200910090016.htm

Which foods do you eat together? How you combine them may raise dementia risk

Study finds 'food networks' centered on processed meats, starches may raise risk

April 22, 2020

Science Daily/American Academy of Neurology

t's no secret that a healthy diet may benefit the brain. However, it may not only be what foods you eat, but what foods you eat together that may be associated with your risk of dementia, according to a new study published in the April 22, 2020, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study looked at "food networks" and found that people whose diets consisted mostly of highly processed meats, starchy foods like potatoes, and snacks like cookies and cakes, were more likely to have dementia years later compared to people who ate a wider variety of healthy foods.

"There is a complex inter-connectedness of foods in a person's diet, and it is important to understand how these different connections, or food networks, may affect the brain because diet could be a promising way to prevent dementia," said study author Cécilia Samieri, PhD, of the University of Bordeaux in France. "A number of studies have shown that eating a healthier diet, for example a diet rich in green leafy vegetables, berries, nuts, whole grains and fish, may lower a person's risk of dementia. Many of those studies focused on quantity and frequency of foods. Our study went one step further to look at food networks and found important differences in the ways in which food items were co-consumed in people who went on to develop dementia and those who did not."

The study involved 209 people with an average age of 78 who had dementia and 418 people, matched for age, sex and educational level, who did not have dementia.

Participants had completed a food questionnaire five years previously describing what types of food they ate over the year, and how frequently, from less than once a month to more than four times a day. They also had medical checkups every two to three years. Researchers used the data from the food questionnaire to compare what foods were often eaten together by the patients with and without dementia.

Researchers found while there were few differences in the amount of individual foods that people ate, overall food groups or networks differed substantially between people who had dementia and those who did not have dementia.

"Processed meats were a 'hub' in the food networks of people with dementia," said Samieri. "People who developed dementia were more likely to combine highly processed meats such as sausages, cured meats and patés with starchy foods like potatoes, alcohol, and snacks like cookies and cakes. This may suggest that frequency with which processed meat is combined with other unhealthy foods, rather than average quantity, may be important for dementia risk. For example, people with dementia were more likely, when they ate processed meat, to accompany it with potatoes and people without dementia were more likely to accompany meat with more diverse foods, including fruit and vegetables and seafood."

Overall, people who did not have dementia were more likely to have a lot of diversity in their diet, demonstrated by many small food networks that usually included healthier foods, such as fruit and vegetables, seafood, poultry or meats.

"We found that more diversity in diet, and greater inclusion of a variety of healthy foods, is related to less dementia," said Samieri. "In fact, we found differences in food networks that could be seen years before people with dementia were diagnosed. Our findings suggest that studying diet by looking at food networks may help untangle the complexity of diet and biology in health and disease."

One limitation of the study was that participants completed a food questionnaire that relied on their ability to accurately recall diet rather than having researchers monitor their diets. Another limitation was that diets were only recorded once, years before the onset of dementia, so any changes in diet over time were unknown.

https://www.sciencedaily.com/releases/2020/04/200422214038.htm

Meditation goes digital in new clinical trial

Individualized program improves attention and memory in healthy young adults

June 3, 2019

Science Daily/University of California - San Francisco

Scientists at UC San Francisco have developed a personalized digital meditation training program that significantly improved attention and memory in healthy young adults -- a group already at the peak of brain health -- in just six weeks.

The intervention, called MediTrain, utilizes a closed-loop algorithm that tailors the length of the meditation sessions to the abilities of the participants, so they are not discouraged by their initial attempts to focus attention on their breath, a time-honored meditation technique.

Scientists tested the program in a randomized, double-blind, placebo-controlled trial at UCSF with 59 participants between 18 and 35 years old. The results were published Monday, June 3, 2019, in Nature Human Behaviour.

The magnitude of the effects on attention and memory, which were unexpected for healthy young adults, were similar to what has been seen in previous studies of middle-aged adults after months of in-person training or intensive meditation retreats.

The app-based program, however, required just 20 to 30 minutes of cumulative practice each day, composed of many very short meditation periods. In the beginning, participants were prompted to pay attention to their breath for just 10 to 15 seconds at a time. As they improved over the six weeks, the application challenged them to increase the amount of time they could maintain focus, which averaged several minutes after six weeks.

"This is not like any meditation practice that exists, as far as we are aware," said senior author Adam Gazzaley, MD, PhD, professor of neurology, physiology and psychiatry and executive director of Neuroscape at UCSF. "We took an ancient experiential treatment of focused meditation, reformulated it and delivered it through a digital technology, and improved attention span in millennials, an age group that is intimately familiar with the digital world, but also faces multiple challenges to sustained attention."

MediTrain made some concessions to tradition. Before they began, participants listened to recorded meditation instructions from Jack Kornfield, PhD, a meditation teacher who co-founded Spirit Rock Meditation Center north of San Francisco, and an author on the study. Then, they used the techniques on their own, without spoken instruction and with their eyes closed.

But MediTrain had other digital features that aren't present in the traditional practice of breath meditation and that may have been the reason why it achieved such strong results over such a short period and with such a healthy population.

For one thing, it underscored the need to pay attention by requiring participants to regularly check in on how they were doing.

At the end of each brief meditation segment, participants were asked to indicate whether they had been able to pay continuous attention for the allotted time, pressing a button on the left side of an iPad screen if the answer was no, and a button on the right if the answer was yes. For those who said yes, the application adapted to a slightly longer meditation period; for those who said no, the period was shortened.

The researchers believe the participatory nature of the design was important.

"Not only do you learn how to maintain focus on your breath, but you are also required to introspect on how well you're able to do that," Gazzaley said, "We believe that's part of the active ingredient of this treatment."

MediTrain also gave everyone regular feedback, with progress reports during the training sessions, at the end of each day of training and at the end of each week.

The results were impressive. On their first day, participants could stay focused on their breath for an average of only 20 seconds. After 30 days of training, that rose to an average of six minutes.

This improvement, in turn, conferred better performance on other, much more complicated tasks that scientists use to assess sustained attention and working memory. Not only did the MediTrain participants perform more consistently on attention tests than the placebo group, the scientists also found a correlation between how long participants were able to focus on their breath and how consistently they performed on these tests. The MediTrain group also performed better than the placebo group on a test of working memory, measured after the intervention.

"We thought it was a long shot to see these types of improvements in a group this young and healthy," said David Ziegler, PhD, director of multimodal biosensing in the technology division at UCSF's Neuroscape, and the first author of the paper. "But it speaks to the power of the method."

Using electroencephalography (EEG) to record brain activity in a subset of the participants in each group, the researchers identified parts of the brain, particularly in the front, that altered their activity as participants learned to stabilize their attention with meditation training.

According to Ziegler, "These frontal brain areas, which are important for controlling attention, showed greater moment-to-moment consistency in their activity after the meditation training." They are also known to strengthen their activity when other areas of the brain called the "default mode network," that are associated with distracted thinking and self-preoccupation, get weaker. Deactivation in the default mode network is also associated with better performance on tasks that require focused attention.

The researchers said that MediTrain, which has been patented by the University of California, holds promise for a younger generation that is accustomed to digital devices but faces multiple challenges to sustained attention from heavy use of media and technology.

The breath meditation -- a seemingly simple, yet quite demanding task -- worked as well in cultivating sustained attention as other more intellectually and physically challenging training programs that have been developed at Neuroscape, a translational neuroscience center at UCSF engaged in technology creation and scientific research to better assess and optimize brain function for all people.

Its very simplicity may fill a particular need created by the frenetic pace of today's world.

"Many of us struggle with challenges to our attention, which seem to be exacerbated by modern technology," Gazzaley said. "What we've done here is flip this story around by creating and studying a digital delivery system that makes cognitive benefits of traditional focused attention meditation more personalized, accessible and deliverable."

https://www.sciencedaily.com/releases/2019/06/190603124705.htm

Largest brain study of 62,454 scans identifies drivers of brain aging

Schizophrenia, cannabis use, and alcohol abuse are just several disorders that are related to accelerated brain aging

August 21, 2018

Science Daily/IOS Press

In the largest known brain imaging study, scientists from Amen Clinics (Costa Mesa, CA), Google, John's Hopkins University, University of California, Los Angeles and the University of California, San Francisco evaluated 62,454 brain SPECT (single photon emission computed tomography) scans of more than 30,000 individuals from 9 months old to 105 years of age to investigate factors that accelerate brain aging. SPECT tomography) evaluates regional cerebral blood flow in the brain that is reduced in various disorders.

Lead author, psychiatrist Daniel G. Amen, MD, founder of Amen Clinics, commented, "Based on one of the largest brain imaging studies ever done, we can now track common disorders and behaviors that prematurely age the brain. Better treatment of these disorders can slow or even halt the process of brain aging. The cannabis abuse finding was especially important, as our culture is starting to see marijuana as an innocuous substance. This study should give us pause about it."

The current study used brain SPECT imaging to determine aging trajectories in the brain and which common brain disorders predict abnormally accelerated aging. It examined these functional neuroimaging scans from a large multi-site psychiatric clinic from patients who had many different psychiatric disorders, including bipolar disorder, schizophrenia and attention deficit hyperactivity disorder (ADHD).

Researchers studied 128 brain regions to predict the chronological age of the patient. Older age predicted from the scan compared to the actual chronological age was interpreted as accelerated aging. The study found that a number of brain disorders and behaviors predicted accelerated aging, especially schizophrenia, which showed an average of 4 years of premature aging, cannabis abuse (2.8 years of accelerated aging), bipolar disorder (1.6 years accelerated aging), ADHD (1.4 years accelerated aging) and alcohol abuse (0.6 years accelerated aging). Interestingly, the researchers did not observe accelerated aging in depression and aging, which they hypothesize may be due to different types of brain patterns for these disorders.

Commenting on the study, George Perry, PhD, Chief Scientist at the Brain Health Consortium from the University of Texas at San Antonio, said, "This is one of the first population-based imaging studies, and these large studies are essential to answer how to maintain brain structure and function during aging. The effect of modifiable and non-modifiable factors of brain aging will further guide advice to maintain cognitive function."

Co-investigator Sachit Egan, Google Inc. (Mountain View, CA), said, "This paper represents an important step forward in our understanding of how the brain operates throughout the lifespan. The results indicate that we can predict an individual's age based on patterns of cerebral blood flow. Additionally, groundwork has been laid to further explore how common psychiatric disorders can influence healthy patterns of cerebral blood flow."

https://www.sciencedaily.com/releases/2018/08/180821112010.htm

Sleep deprivation accelerates Alzheimer's brain damage

January 24, 2019

Science Daily/Washington University School of Medicine

A study in mice and people shows that sleep deprivation causes tau levels to rise and tau tangles to spread through the brain. Tau tangles are associated with Alzheimer's disease and brain damage.

Poor sleep has long been linked with Alzheimer's disease, but researchers have understood little about how sleep disruptions drive the disease.

Now, studying mice and people, researchers at Washington University School of Medicine in St. Louis have found that sleep deprivation increases levels of the key Alzheimer's protein tau. And, in follow-up studies in the mice, the research team has shown that sleeplessness accelerates the spread through the brain of toxic clumps of tau - a harbinger of brain damage and decisive step along the path to dementia.

These findings, published online Jan. 24 in the journal Science, indicate that lack of sleep alone helps drive the disease, and suggests that good sleep habits may help preserve brain health.

"The interesting thing about this study is that it suggests that real-life factors such as sleep might affect how fast the disease spreads through the brain," said senior author David Holtzman, MD, the Andrew B. and Gretchen P. Jones Professor and head of the Department of Neurology. "We've known that sleep problems and Alzheimer's are associated in part via a different Alzheimer's protein -- amyloid beta -- but this study shows that sleep disruption causes the damaging protein tau to increase rapidly and to spread over time."

Tau is normally found in the brain -- even in healthy people -- but under certain conditions it can clump together into tangles that injure nearby tissue and presage cognitive decline. Recent research at the School of Medicine has shown that tau is high in older people who sleep poorly. But it wasn't clear whether lack of sleep was directly forcing tau levels upward, or if the two were associated in some other way. To find out, Holtzman and colleagues including first authors Jerrah Holth, PhD, a staff scientist, and Sarah Fritschi, PhD, a former postdoctoral scholar in Holtzman's lab, measured tau levels in mice and people with normal and disrupted sleep.

Mice are nocturnal creatures. The researchers found that tau levels in the fluid surrounding brain cells were about twice as high at night, when the animals were more awake and active, than during the day, when the mice dozed more frequently. Disturbing the mice's rest during the day caused daytime tau levels to double.

Much the same effect was seen in people. Brendan Lucey, MD, an assistant professor of neurology, obtained cerebrospinal fluid -- which bathes the brain and spinal cord -- from eight people after a normal night of sleep and again after they were kept awake all night. A sleepless night caused tau levels to rise by about 50 percent, the researchers discovered.

Staying up all night makes people stressed and cranky and likely to sleep in the next chance they get. While it's hard to judge the moods of mice, they, too, rebounded from a sleepless day by sleeping more later. To rule out the possibility that stress or behavioral changes accounted for the changes in tau levels, Fritschi created genetically modified mice that could be kept awake for hours at a time by injecting them with a harmless compound. When the compound wears off, the mice return to their normal sleep-wake cycle -- without any signs of stress or apparent desire for extra sleep.

Using these mice, the researchers found that staying awake for prolonged periods causes tau levels to rise. Altogether, the findings suggest that tau is routinely released during waking hours by the normal business of thinking and doing, and then this release is decreased during sleep allowing tau to be cleared away. Sleep deprivation interrupts this cycle, allowing tau to build up and making it more likely that the protein will start accumulating into harmful tangles.

In people with Alzheimer's disease, tau tangles tend to emerge in parts of the brain important for memory -- the hippocampus and entorhinal cortex -- and then spread to other brain regions. As tau tangles mushroom and more areas become affected, people increasingly struggle to think clearly.

To study whether the spread of tau tangles is affected by sleep, the researchers seeded the hippocampi of mice with tiny clumps of tau and then kept the animals awake for long periods each day. A separate group of mice also was injected with tau tangles but was allowed to sleep whenever they liked. After four weeks, tau tangles had spread further in the sleep-deprived mice than their rested counterparts. Notably, the new tangles appeared in the same areas of the brain affected in people with Alzheimer's.

"Getting a good night's sleep is something we should all try to do," Holtzman said. "Our brains need time to recover from the stresses of the day. We don't know yet whether getting adequate sleep as people age will protect against Alzheimer's disease. But it can't hurt, and this and other data suggest that it may even help delay and slow down the disease process if it has begun."

The researchers also found that disrupted sleep increased release of synuclein protein, a hallmark of Parkinson's disease. People with Parkinson's -- like those with Alzheimer's -- often have sleep problems.

https://www.sciencedaily.com/releases/2019/01/190124141536.htm

Exercise may lessen fall risk for older adults with Alzheimer's

Study indicates exercise may decrease risk of falling for older adults who have Alzheimer's disease and mental health challenges

October 29, 2018

Science Daily/American Geriatrics Society

A research team decided to explore whether exercise could reduce the risk of falling among community-dwelling people with Alzheimer's Disease who also had neuropsychiatric symptoms.

Alzheimer's disease (AD) is a brain disease that causes changes that kill brain cells. AD is a type of dementia, which causes memory loss and problems with thinking and making decisions. People with AD and other forms of dementia have difficulties performing the daily activities others might consider routine.

Dementia takes a toll on those who live with it -- and it also places a burden on caregivers. Along with problems connected to memory, language, and decision-making, dementia can cause neuropsychiatric symptoms, such as depression, anxiety, changes in mood, increased irritability, and changes in personality and behavior. People who have AD/dementia also have twice the risk for falls compared to people without dementia. About 60 percent of older adults with dementia fall each year.

Researchers suggest that having neuropsychiatric symptoms might predict whether an older person with AD/dementia is more likely to have a fall. We also know that exercise can reduce the number of falls in older adults with dementia. However, we don't know very much about how neuropsychiatric symptoms may increase the risk of falls, and we know even less about how exercise may reduce the risk of falls for people with dementia and neuropsychiatric symptoms. A research team decided to explore whether exercise could reduce the risk of falling among community-dwelling people with AD who also had neuropsychiatric symptoms.

To learn more, the researchers reviewed a study that investigated the effects of an exercise program for older adults with AD (the FINALEX trial). The study included a range of people living with different stages of AD/dementia and with neuropsychiatric symptoms. Their findings were published in the Journal of the American Geriatrics Society.

The original FINALEX study examined and compared older adults who had home- or group-based exercise training with people who didn't exercise but who received regular care. The researchers learned that the people who exercised had a lower risk for falls than those who didn't exercise. There was also a higher risk for falls among those who had lower scores on psychological tests and who didn't exercise.

This study revealed that people with AD/dementia and neuropsychiatric symptoms such as depression and anxiety have a higher risk for falls. Exercise can reduce the risk of falling for older adults with these symptoms. Further studies are needed to confirm these results.

https://www.sciencedaily.com/releases/2018/10/181029135235.htm

Stress can impair memory, reduce brain size in middle age

October 25, 2018

Science Daily/University of Texas Health Science Center at San Antonio

Stress may be causing impaired memory and brain shrinkage in middle-age adults, even before symptoms of Alzheimer's or other dementia begin, according to a new study.

Adults in their 40s and 50s with higher levels of cortisol -- a hormone linked to stress -- performed worse on memory and other cognitive tasks than peers of the same age with average cortisol levels, research found. Higher cortisol in the blood also was associated with smaller brain volumes, according to the study, published Oct. 24 in Neurology, the medical journal of the American Academy of Neurology.

"In our quest to understand cognitive aging, one of the factors attracting significant interest and concern is the increasing stress of modern life," said study senior author Sudha Seshadri, M.D., professor of neurology at UT Health San Antonio and founding director of the university's Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases. "One of the things we know in animals is that stress can lead to cognitive decline. In this study, higher morning cortisol levels in a large sample of people were associated with worse brain structure and cognition."

The cognitive data are from 2,231 participants in the Framingham Heart Study, for which Dr. Seshadri is a senior investigator; 2,018 participants also underwent magnetic resonance imaging (MRI) to measure brain volume. The team included Framingham collaborators at Harvard Medical School; the National Heart, Lung, and Blood Institute; Boston University School of Medicine; the University of California, Davis, at Sacramento; and UT Health San Antonio.

Blood serum cortisol, which varies in level throughout the day, was measured in early morning (between 7:30 and 9 a.m.) in each fasting participant. The study featured a relatively young sample of male and female participants (mean age 48.5).

"Cortisol affects many different functions, so it is important to fully investigate how high levels of the hormone may affect the brain," said study lead author Justin B. Echouffo-Tcheugui, M.D., Ph.D., of Harvard Medical School. "While other studies have examined cortisol and memory, we believe our large, community-based study is the first to explore, in middle-aged people, fasting blood cortisol levels and brain volume, as well as memory and thinking skills."

Memory loss and brain shrinkage were found in the study's middle-age participants before the onset of any symptoms, Dr. Echouffo-Tcheugui noted. He said it is important for physicians to counsel people with higher cortisol levels on ways to reduce stress, such as getting enough sleep and engaging in moderate exercise.

"The faster pace of life today probably means more stress, and when we are stressed, cortisol levels increase because that is our fight-or-flight response," Dr. Seshadri said. "When we are afraid, when we are threatened in any way, our cortisol levels go up. This study adds to the prevailing wisdom that it's never too early to be mindful of reducing stress."

Findings were adjusted for factors including age, sex, smoking and body mass index. The team asked whether having APOE4, a genetic risk factor for cardiovascular disease and Alzheimer's disease, might be associated with higher cortisol level. This did not prove to be the case.

https://www.sciencedaily.com/releases/2018/10/181025084043.htm

Memory 'brainwaves' look the same in sleep and wakefulness

October 9, 2018

Science Daily/University of Birmingham

Identical brain mechanisms are responsible for triggering memory in both sleep and wakefulness, new research has shown.

The study sheds new light on the processes used by the brain to 'reactivate' memories during sleep, consolidating them so they can be retrieved later.

Although the importance of sleep in stabilising memories is a well-established concept, the neural mechanisms underlying this are still poorly understood.

In this study, published in Cell Reports, scientists have been able to show for the first time in humans that distinctive neural patterns in the brain which are triggered when remembering specific memories while awake, reappear during subsequent sleep.

The findings provide further evidence of the beneficial effects of sleep on memory formation.

Gaining a more sophisticated understanding of these mechanisms also enhances our understanding of how memories are formed. This could ultimately help scientists unravel the foundations of memory disorders such as Alzheimer's and lead to the development of memory boosting interventions.

Working in partnership with researchers at the Donders Institute, in Holland, the team used a technique called Targeted Memory Reactivation, which is known to enhance memory. In the experiment, previously learned information -- in this case foreign vocabulary -- is played back to a person while asleep.

Using electroencephalography, the brain signals of the study participants were recorded while learning and remembering the foreign vocabulary before sleep.

Subsequently, the researchers recorded the distinct neural pathways activated as the sleeping volunteers' brains reacted to hearing the words they had learned.

Comparing neural signals fired by the brain in each state, the researchers were able to show clear similarities in brain activity.

Dr Thomas Schreiner, of the University of Birmingham's School of Psychology, who led the research, says: "Although sleep and wakefulness might seem to have little in common, this study shows that brain activity in each of these states might be more similar than we previously thought. The neural activity we recorded provides further evidence for how important sleep is to memory and, ultimately, for our well-being."

"If we can better understand how memory really works, this could lead to new approaches for the treatment of memory disorders, such as Alzheimer's disease."

Dr Tobias Staudigl, of the Donders Institute, is co-lead author of the study. He said: "Understanding how memories are reactivated in different states also provides insight into how these memories could be altered -- which might for example be interesting in therapeutic settings."

The team are planning a follow-on study, devising ways to investigate spontaneous memory activation during sleep. Using advanced machine learning techniques, the researchers can record and interpret neural patterns in the brain, identifying where memories are activated without the need for an external prompt.

https://www.sciencedaily.com/releases/2018/10/181009115003.htm

How sleep deprivation hinders memory

October 2, 2018

Science Daily/Michigan State University

Researchers have conducted the largest experimentally controlled study on sleep deprivation to date, revealing just how detrimental operating without sleep can be in everything from bakers adding too much salt to cookies to surgeons botching surgeries.

While sleep deprivation research isn't new, the level at which distractions hinder sleep-deprived persons' memories and challenge them from successfully completing tasks was not clear until MSU's team quantified the impact.

"If you look at mistakes and accidents in surgery, public transportation and even operating nuclear power plants, lack of sleep is one of the primary reasons for human error," said Kimberly Fenn, associate professor of psychology and director of the MSU Sleep and Learning Lab. "There are many people in critical professions who are sleep-deprived. Research has found that nearly one-quarter of the people with procedure-heavy jobs have fallen asleep on the job."

Published in the Journal of Experimental Psychology: General, Fenn's research is unlike previous studies because of its focus on sleep deprivation's impact on completing tasks. These tasks, Fenn explained, involve following directions and include multiple steps.

Some basic errors, such as adding salt twice to a recipe, might not be so serious. However, some of the world's greatest human-caused catastrophes -- like Chernobyl, the Exxon Valdez oil spill and the Challenger explosion -- along with daily train and car accidents have sleep deprivation at least partially to blame, she said.

Fenn hopes that her lab's findings will shed light on how critical sleep is to completing any task, be it large or small.

"Every day, approximately 11 sponges are left inside of patients who have undergone surgery. That's 4,000 potentially dire missteps each year and an example of a procedural task gone terribly wrong that can result from sleep deprivation," Fenn said. "Our research suggests that sleep-deprived people shouldn't perform tasks in which they are interrupted -- or, only perform them for short periods."

To test sleep deprivation's impact on how people follow steps in a task, Fenn's team brought 234 people into the sleep lab at 10 p.m. That night, all of the participants worked on a sequence-based procedure that involved following a series of tasks in order. Periodically, they were interrupted and had to remember where they were in the procedure before picking up again. At midnight, half of the participants went home to sleep while the other half stayed awake all night at the lab. The next morning, everyone completed the procedure once again.

What Fenn's team found was a stark jump in errors for those who were sleep-deprived.

"All participants met performance criteria in the evening, but roughly 15 percent of participants in the sleep-deprived group failed in the morning, compared to 1 percent of those who slept," Fenn said. "Furthermore, sleep-deprived participants not only showed more errors than those who slept but also showed a progressive increase in errors associated with memory as they performed the task -- an effect not observed in those who slept. This shows that the sleep-deprived group experienced a great deal of difficulty remembering where they were in the sequence during interruptions."

Memory maintenance, the research found, was the real culprit keeping the sleep-deprived from completing tasks successfully. With hindered memory maintenance, it's much more difficult to pick up a task where you left off without missteps, Fenn explained.

Fenn also explained that distractions we face every day -- whether receiving a text message or simply answering a question -- are unavoidable but especially harmful to sleep-deprived people.

"Operating with reduced cognitive capacity has wide-ranging effects," Fenn said. "Students may pull all-nighters and not retain information for their exams. More worrisome, individuals working critical jobs may put themselves and other members of society at risk because of sleep deprivation. It simply cannot be overlooked."

https://www.sciencedaily.com/releases/2018/10/181002114027.htm

Lowering blood pressure reduces risk of cognitive impairment

January 28, 2019

Science Daily/Wake Forest Baptist Medical Center

Intensive control of blood pressure in older people significantly reduced the risk of developing mild cognitive impairment (MCI), a precursor of early dementia, in a clinical trial led by scientists at Wake Forest School of Medicine, part of Wake Forest Baptist Health. However, the National Institutes of Health-supported Systolic Blood Pressure Intervention Trial (SPRINT) Memory and Cognition in Decreased Hypertension (SPRINT MIND) study did not prove that treating blood pressure to a goal of 120 mm Hg or less statistically reduced the risk of dementia. This result may have been due to too few new cases of dementia occurring in the study, the authors noted.

The results were reported in the Jan. 28 edition of the Journal of the American Medical Association.

MCI is defined as a decline in memory and thinking skills that is greater than expected with normal aging and is a risk factor for dementia. Dementia is defined as a group of symptoms associated with a decline in memory or other thinking skills severe enough to reduce a person's ability to perform everyday activities.

"As doctors treating older patients, we are encouraged to finally have a proven intervention to lower someone's risk for MCI," said the study's principal investigator, Jeff Williamson, M.D., professor of gerontology and geriatric medicine at Wake Forest School of Medicine. "In the study, we found that just three years of lowering blood pressure not only dramatically helped the heart but also helped the brain."

The objective of SPRINT MIND was to evaluate the effect of intensive blood pressure control on risk of dementia. Hypertension, which affects more than half of people over age 50 and more than 75 percent of those older than 65, has been identified as a potentially modifiable risk factor for MCI and dementia in previous observational studies.

The clinical trial, which enrolled 9361 volunteers, was conducted at 102 sites in the United States and Puerto Rico among adults 50 and older with hypertension but without diabetes or history of stroke. The participating group was 35.6 percent female, 30 percent black and 10.5 percent Hispanic and thus representative of the broader U.S. population.

Participants were randomly assigned to a systolic blood pressure goal of either less than 120 mm HG (intensive treatment) or less than 140 mm HG (standard treatment). They were then classified after five years as having no cognitive impairment, MCI or probable dementia.

"Although the study showed a 15 percent reduction in dementia in the intensively controlled group, we were disappointed that the results did not achieve statistical significance for this outcome," Williamson said. "Last week the Alzheimer's Association agreed to fund additional follow-up of SPRINT MIND participants in the hope that sufficient dementia cases will accrue, allowing for a more definitive statement on these outcomes."

SPRINT was stopped early due to the success of the trial in reducing cardiovascular disease. As a result, participants were on intensive blood pressure lowering treatment for a shorter period than originally planned. The authors concluded that the shorter time may have made it difficult to accurately determine the role of intensive blood pressure control on dementia cases.

Williamson said some caution should be exercised in interpreting the study result both because MCI was not the primary cognitive focus of the trial and because it is not clear what intensive blood pressure control may mean for the longer-term incidence of dementia. Although MCI considerably increases the risk of dementia, this progression is not inevitable and reversion to normal cognition is possible, he said.

https://www.sciencedaily.com/releases/2019/01/190128111703.htm

Brain wave device enhances memory function

October 22, 2018

Science Daily/University of California - Davis

The entrainment of theta brain waves with a commercially available device not only enhances theta wave activity, but also boosts memory performance, according to new research.

Electrical activity in the brain causes different types of brain waves that can be measured on the outside of the head. Theta waves occur at about five to six cycles per second, often associated with a brain that is actively monitoring something -- such as the brain of a rat navigating a maze.

In an earlier study, Charan Ranganath, professor of psychology, and colleagues at the Center for Neuroscience found that high levels of theta wave activity immediately before a memory task predicted better performance.

"Entrainment" devices use a combination of sound and lights to stimulate brain wave activity. The idea is that oscillating patterns in sensory inputs will be reflected in brain activity. The devices are marketed to address a range of problems such as anxiety, sleep issues, "low mood" and learning. However, there is very little published scientific evidence to support these claims.

Brooke Roberts, a postdoctoral researcher in Ranganath's lab, obtained a theta wave entrainment device and decided to test it. She had 50 volunteers either use the device for 36 minutes, or listen to 36 minutes of white noise, then do a simple memory test.

Improved memory performance

The subjects who had used the device showed both improved memory performance and enhanced theta wave activity, she found.

Roberts showed her results to Ranganath, who was intrigued but cautious and suggested new controls. They repeated the experiment with another 40 volunteers, but this time the control group received beta wave stimulations. Beta waves are a different type of brain wave pattern, occurring at about 12 to 30 cycles per second, associated with normal waking consciousness.

Once again, theta wave entrainment enhanced theta wave activity and memory performance.

Ranganath's lab also conducted a separate study using electrical stimulation to enhance theta waves. However, this actually had the opposite effect, disrupting theta wave activity, and temporarily weakened memory function.

Ranganath said he's surprised the devices work as well as they appear to do.

"What's surprising is that the device had a lasting effect on theta activity and memory performance for over half an hour after it was switched off," he said.

There is debate among neuroscientists over the function and role of these brain waves. Some researchers argue that they are simply a product of normal brain function with no particular role. Ranganath, however, thinks that they may play a role in coordinating brain regions.

"The neurons are more excitable at the peak of the wave, so when the waves of two brain regions are in sync with each other, they can talk to each other," he said.

Other authors on the paper are Alex Clarke, now at the University of Cambridge and Anglia Ruskin University, U.K.; and Richard Addante, now at California State University San Bernardino. Roberts is now a research scientist at QUASAR Inc., San Diego. The work was supported by a Guggenheim Fellowship and a Vannevar Bush Fellowship from the Office of Naval Research.

https://www.sciencedaily.com/releases/2018/10/181022172959.htm

Day-time naps help us acquire information not consciously perceived

'I'll sleep on it' proves scientifically sound advice

October 4, 2018

Science Daily/University of Bristol

The age-old adage 'I'll sleep on it' has proven to be scientifically sound advice, according to a new study which measured changes in people's brain activity and responses before and after a nap. The findings support the advice which suggests that a period of sleep may help weighing up pros and cons or gain insight before making a challenging decision.

The Medical Research Council-funded study, led by University of Bristol researchers, aimed to understand whether a short period of sleep can help us process unconscious information and how this might affect behaviour and reaction time.

The findings further reveal the benefits of a short bout of sleep on cognitive brain function and found that even during short bouts of sleep we process information that we are not consciously aware of.

While previous evidence demonstrates that sleep helps problem solving, resulting in enhanced cognition upon awaking; it was not clear whether some form of conscious mental process was required before or during sleep to aid problem solving. In this study, researchers hid information by presenting it very briefly and "masking" it -- so it was never consciously perceived -- the masked prime task. The hidden information, however, was processed at a subliminal level within the brain and the extent to which it interferes with responses to consciously perceived information was measured.

Sixteen healthy participants across a range of ages were recruited to take part in an experiment. Participants carried out two tasks -- the masked prime task and a control task where participants simply responded when they saw a red or blue square on a screen. Participants practiced the tasks and then either stayed awake or took a 90-minute nap before doing the tasks again.

Using an EEG, which records the electrical activity naturally produced in the brain, researchers measured the change in brain activity and response pre-and-post nap.

Sleep (but not wake) improved processing speed in the masked prime task -- but not in the control task -- suggesting sleep-specific improvements in processing of subconsciously presented primes.

The findings suggest that even a short bout of sleep may help improve our responses and process information. Therefore, the results here suggest a potentially sleep-dependent, task-specific enhancement of brain processing that could optimise human goal-directed behaviour.

Importantly, while it is already known that the process of acquiring knowledge and information recall, memory, is strengthened during sleep. This study suggests that information acquired during wakefulness may potentially be processed in some deeper, qualitative way during sleep

Dr LizCoulthard, Consultant Senior Lecturer in Dementia Neurology at the University of Bristol Medical School: Translational Health Sciences, said: "The findings are remarkable in that they can occur in the absence of initial intentional, conscious awareness, by processing of implicitly presented cues beneath participants' conscious awareness.

"Further research in a larger sample size is needed to compare if and how the findings differ between ages, and investigation of underlying neural mechanisms."

https://www.sciencedaily.com/releases/2018/10/181004095929.htm

More daytime sleepiness, more Alzheimer's risk?

Excessive daytime sleepiness linked with brain protein involved in memory-robbing disease

September 6, 2018

Science Daily/Johns Hopkins University Bloomberg School of Public Health

Analysis of data captured during a long-term study of aging adults shows that those who report being very sleepy during the day were nearly three times more likely than those who didn't to have brain deposits of beta amyloid, a protein that's a hallmark for Alzheimer's disease, years later.

The finding, reported Sept. 5 in the journal SLEEP, adds to a growing body of evidence that poor quality sleep could encourage this form of dementia to develop, suggesting that getting adequate nighttime sleep could be a way to help prevent Alzheimer's disease.

"Factors like diet, exercise and cognitive activity have been widely recognized as important potential targets for Alzheimer's disease prevention, but sleep hasn't quite risen to that status -- although that may well be changing," says Adam P. Spira, PhD, associate professor in the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health. Spira led the study with collaborators from the National Institute on Aging (NIA), the Bloomberg School and Johns Hopkins Medicine.

"If disturbed sleep contributes to Alzheimer's disease," he adds, "we may be able to treat patients with sleep issues to avoid these negative outcomes."

The study used data from the Baltimore Longitudinal Study of Aging (BLSA), a long-term study started by the NIA in 1958 that followed the health of thousands of volunteers as they age. As part of the study's periodic exams, volunteers filled a questionnaire between 1991 and 2000 that asked a simple yes/no question: "Do you often become drowsy or fall asleep during the daytime when you wish to be awake?" They were also asked, "Do you nap?" with response options of "daily," "1-2 times/week," "3-5 times/week," and "rarely or never."

A subgroup of BLSA volunteers also began receiving neuroimaging assessments in 1994. Starting in 2005, some of these participants received positron emission tomography (PET) scans using Pittsburgh compound B (PiB), a radioactive compound that can help identify beta-amyloid plaques in neuronal tissue. These plaques are a hallmark of Alzheimer's disease.

The researchers identified 123 volunteers who both answered the earlier questions and had a PET scan with PiB an average of nearly 16 years later. They then analyzed this data to see if there was a correlation between participants who reported daytime sleepiness or napping and whether they scored positive for beta-amyloid deposition in their brains.

Before adjusting for demographic factors that could influence daytime sleepiness, such as age, sex, education, and body-mass index, their results showed that those who reported daytime sleepiness were about three times more likely to have beta-amyloid deposition than those who didn't report daytime fatigue. After adjusting for these factors, the risk was still 2.75 times higher in those with daytime sleepiness.

The unadjusted risk for amyloid-beta deposition was about twice as high in volunteers who reported napping, but this did not reach statistical significance.

It's currently unclear why daytime sleepiness would be correlated with the deposition of beta-amyloid protein, Spira says. One possibility is that daytime sleepiness itself might somehow cause this protein to form in the brain. Based on previous research, a more likely explanation is that disturbed sleep -- due to obstructive sleep apnea, for example -- or insufficient sleep due to other factors, causes beta-amyloid plaques to form through a currently unknown mechanism, and that these sleep disturbances also cause excessive daytime sleepiness.

"However, we cannot rule out that amyloid plaques that were present at the time of sleep assessment caused the sleepiness," he added.

Animal studies in Alzheimer's disease models have shown that restricting nighttime sleep can lead to more beta-amyloid protein in the brain and spinal fluid. A handful of human studies have linked poor sleep with greater measures of beta-amyloid in neuronal tissue.

Researchers have long known that sleep disturbances are common in patients diagnosed with Alzheimer's disease -- caregiver stress from being up with patients at night is a leading reason for Alzheimer's disease patients to be placed in long-term care, Spira explains. Growing beta-amyloid plaques and related brain changes are thought to negatively affect sleep.

But this new study adds to growing evidence that poor sleep might actually contribute to Alzheimer's disease development, Spira adds. This suggests that sleep quality could be a risk factor that's modifiable by targeting disorders that affect sleep, such as obstructive sleep apnea and insomnia, as well as social- and individual-level factors, such as sleep loss due to work or binge-watching TV shows.

"There is no cure yet for Alzheimer's disease, so we have to do our best to prevent it. Even if a cure is developed, prevention strategies should be emphasized," Spira says. "Prioritizing sleep may be one way to help prevent or perhaps slow this condition."

https://www.sciencedaily.com/releases/2018/09/180906141501.htm

Measure of belly fat in older adults is linked with cognitive impairment

August 1, 2018

Science Daily/Trinity College Dublin

Data from over 5,000 adults over the age of 60 indicates that as waist:hip ratio increases, so does cognitive impairment. The findings have significant implications as the global prevalence of dementia is predicted to increase from 24.3 million in 2001 to 81.1 million by 2040.

Previous studies have found that people who are overweight do not perform as well on tests of memory and visuospatial ability compared to those who are normal weight. However, it is not well known if this is true in older adults. This is of concern within Ireland, as over half of the over 50s population is classified as being centrally obese, with only 16% of men and 26% of women reported to have a BMI (body mass index) within the normal range.

The researchers used data from the Trinity Ulster Department of Agriculture (TUDA) ageing cohort study comprising, which is a cross-border collaborative research project gathering data from thousands of elderly adults in Northern Ireland and Ireland.

The researchers found that a higher waist:hip ratio was associated with reduced cognitive function. This could be explained by an increased secretion of inflammatory markers by belly fat, which has been previously associated with a higher risk of impaired cognition. On the contrary, body mass index (BMI) was found to protect cognitive function. BMI is a crude measure of body fat and cannot differentiate between fat and fat-free mass (muscle), thus it is proposed that the fat-free mass component is likely to be the protective factor.

To the best of the authors' knowledge, this is one of the largest studies of older adults to report these findings. Given the high prevalence of overweight and obesity in the older population and the economic and social burden of cognitive dysfunction, the results suggest that reducing obesity and exposure to obeso-genic risk factors could offer a cost-effective public health strategy for the prevention of cognitive decline.

Clinical Associate Professor in Medical Gerontology at Trinity, Conal Cunningham, is the senior author of the study. He said: "While we have known for some time that obesity is associated with negative health consequences our study adds to emerging evidence suggesting that obesity and where we deposit our excess weight could influence our brain health. This has significant public health implications."

https://www.sciencedaily.com/releases/2018/08/180801115257.htm

Overnight brain stimulation improves memory

Non-invasive technique enhances memory storage without disturbing sleep

July 23, 2018

Science Daily/Society for Neuroscience

New research in humans demonstrates the potential to improve memory with a non-invasive brain stimulation technique delivered during sleep. The results come from a project that aims to better understand the process of memory consolidation, which could translate into improved memory function in both healthy and patient populations.

The transfer of memories from the hippocampus to the neocortex for long-term storage is thought to be enabled by synchronization of these parts of the brain during sleep. Nicholas Ketz, Praveen Pilly, and colleagues at University of New Mexico sought to enhance this natural process of overnight reactivation or neural replay to improve memory with a closed-loop transcranial alternating current stimulation system matching the phase and frequency of ongoing slow-wave oscillations during sleep.

Participants were trained and tested on a realistic visual discrimination task in which they had to detect potentially threatening hidden objects and people such as explosive devices and enemy snipers. The researchers found that when participants received stimulation during overnight visits to their sleep laboratory, they showed improved performance in detecting targets in similar but novel situations the next day compared to when they did not receive the stimulation, suggesting an integration of recent experience into a more robust and general memory.

Overnight memory changes correlated with stimulation-induced neural changes, which could be used to optimize stimulation in future applications.

These findings provide a method for enhancing memory consolidation without disturbing sleep.

https://www.sciencedaily.com/releases/2018/07/180723142907.htm

Treating dementia with the healing waves of sound

Ultrasound applied to brain could help treat patients with dementia

July 20, 2018

Science Daily/Tohoku University

Ultrasound waves applied to the whole brain improve cognitive dysfunction in mice with conditions simulating vascular dementia and Alzheimer's disease. It is possible that this type of therapy may also benefit humans.

The team, led by cardiologist Hiroaki Shimokawa, found that applying low-intensity pulsed ultrasound (LIPUS) to the whole brain of the mice improved blood vessel formation and nerve cell regeneration without having obvious side effects.

"The LIPUS therapy is a non-invasive physiotherapy that could apply to high-risk elderly patients without the need for surgery or anaesthesia, and could be used repeatedly," says Shimokawa.

Dementia affects about 50 million people worldwide, with 10 million new cases occurring every year. But there are currently no curative treatments available for vascular dementia or Alzheimer's disease, the most common causes of dementia. Also, the cells lining the brain's blood vessels are tightly packed, forming a blood-brain barrier that prevents large molecules from crossing into the brain tissue. This limits the types of drugs and cell therapies that could be made available to treat dementia.

Shimokawa and his team had conducted previous studies showing that LIPUS improved blood vessel formation in pigs with myocardial ischemia, a condition where there is reduced blood flow to the heart. Other studies have reported that LIPUS increases the production of proteins involved in nerve cell survival and growth, in addition to a role in promoting nerve regeneration. Focusing LIPUS treatment on a region in the brain called the hippocampus, which is involved in memory, has also been found to improve dementia in mice, but the details of how it does this need to be more fully investigated.

The Tohoku University team wanted to find out if whole-brain rather than focused LIPUS is effective in treating mouse models of dementia, and if it was, what was happening at the molecular levels to achieve this.

They found that cognitive impairment markedly improved in mice with conditions similar to vascular dementia and Alzheimer's disease when LIPUS was applied to the whole brain three times a day for 20 minutes each time. The mice with vascular dementia received the treatment on the first, third and fifth days following a surgical procedure that limited the brain's blood supply. The mice with a condition simulating Alzheimer's disease in humans received 11 LIPUS treatments over a period of three months.

At the molecular level, genes related to the cells lining blood vessels were turned on. Also, there was increased expression of an enzyme involved in blood vessel formation and a protein involved in nerve cell survival and growth.

The researchers conclude that their study, recently published in the journal Brain Stimulation, provides the first experimental evidence that whole-brain LIPUS therapy markedly improves cognitive dysfunctions without serious side effects by enhancing specific cells related to dementia's pathology.

The first clinical trials to evaluate the effectiveness and safety of the LIPUS treatment are already underway.

https://www.sciencedaily.com/releases/2018/07/180720092507.htm

Sugar improves memory in over-60s, helping them work smarter

July 18, 2018

Science Daily/University of Warwick

Sugar improves memory in older adults -- and makes them more motivated to perform difficult tasks at full capacity -- according to new research.

Led by PhD student Konstantinos Mantantzis, Professor Elizabeth Maylor and Dr Friederike Schlaghecken in Warwick's Department of Psychology, the study found that increasing blood sugar levels not only improves memory and performance, but makes older adults feel happier during a task.

The researchers gave young (aged 18-27) and older (aged 65-82) participants a drink containing a small amount of glucose, and got them to perform various memory tasks. Other participants were given a placebo -- a drink containing artificial sweetener.

The researchers measured participants' levels of engagement with the task, their memory score, mood, and their own perception of effort.

They found that increasing energy through a glucose drink can help both young and older adults to try harder compared to those who had the artificial sweetener. For young adults, that's where it ended, though: glucose did not improve either their mood or their memory performance.

However, older adults who had a glucose drink showed significantly better memory and more positive mood compared to older adults who consumed the artificial sweetener.

Moreover, although objective measures of task engagement showed that older adults in the glucose group put more effort into the task than those who consumed the artificial sweetener, their own self-reports showed that they did not feel as if they had tried any harder.

The authors concluded that short-term energy availability in the form of raised blood sugar levels could be an important factor in older adults' motivation to perform a task at their highest capacity.

Heightened motivation, in turn, could explain the fact that increased blood sugar levels also increase older adults' sense of self-confidence, decrease self-perceptions of effort, and improve mood. However, more research is needed to disentangle these factors in order to fully understand how energy availability affects cognitive engagement, and to develop clear dietary guidelines for older adults.

Konstantinos Mantantzis, a PhD student from the University of Warwick's Department of Psychology, commented:

"Over the years, studies have shown that actively engaging with difficult cognitive tasks is a prerequisite for the maintenance of cognitive health in older age. Therefore, the implications of uncovering the mechanisms that determine older adults' levels of engagement cannot be understated."

Dr Friederike Schlaghecken, from the University of Warwick's Department of Psychology, commented:

"Our results bring us a step closer to understanding what motivates older adults to exert effort and finding ways of increasing their willingness to try hard even if a task seems impossible to perform."

https://www.sciencedaily.com/releases/2018/07/180718104747.htm