1. Learning with music can change brain structure

    July 21, 2017 by Ashley

    From the University of Edinburgh press release:

    Using musical cues to learn a physical task significantly develops an important part of the brain, according to a new study.

    People who practiced a basic movement task to music showed increased structural connectivity between the regions of the brain that process sound and control movement.

    The findings focus on white matter pathways — the wiring that enables brain cells to communicate with each other.

    The study could have positive implications for future research into rehabilitation for patients who have lost some degree of movement control.

    Thirty right-handed volunteers were divided into two groups and charged with learning a new task involving sequences of finger movements with the non-dominant, left hand. One group learned the task with musical cues, the other group without music.

    After four weeks of practice, both groups of volunteers performed equally well at learning the sequences, researchers at the University of Edinburgh found.

    Using MRI scans, it was found that the music group showed a significant increase in structural connectivity in the white matter tract that links auditory and motor regions on the right side of the brain. The non-music group showed no change.

    Researchers hope that future study with larger numbers of participants will examine whether music can help with special kinds of motor rehabilitation programmes, such as after a stroke.

    The interdisciplinary project brought together researchers from the University of Edinburgh’s Institute for Music in Human and Social Development, Clinical Research Imaging Centre, and Centre for Clinical Brain Sciences, and from Clinical Neuropsychology, Leiden University, The Netherlands.

    The results are published in the journal Brain & Cognition.

    Dr Katie Overy, who led the research team said: “The study suggests that music makes a key difference. We have long known that music encourages people to move. This study provides the first experimental evidence that adding musical cues to learning new motor task can lead to changes in white matter structure in the brain.”


  2. Brains evolved to need exercise

    July 20, 2017 by Ashley

    From the University of Arizona press release:

    Mounting scientific evidence shows that exercise is good not only for our bodies, but for our brains. Yet, exactly why physical activity benefits the brain is not well understood.

    In a new article published in the journal Trends in Neurosciences, University of Arizona researchers suggest that the link between exercise and the brain is a product of our evolutionary history and our past as hunter-gatherers.

    UA anthropologist David Raichlen and UA psychologist Gene Alexander, who together run a research program on exercise and the brain, propose an “adaptive capacity model” for understanding, from an evolutionary neuroscience perspective, how physical activity impacts brain structure and function.

    Their argument: As humans transitioned from a relatively sedentary apelike existence to a more physically demanding hunter-gatherer lifestyle, starting around 2 million years ago, we began to engage in complex foraging tasks that were simultaneously physically and mentally demanding, and that may explain how physical activity and the brain came to be so connected.

    “We think our physiology evolved to respond to those increases in physical activity levels, and those physiological adaptations go from your bones and your muscles, apparently all the way to your brain,” said Raichlen, an associate professor in the UA School of Anthropology in the College of Social and Behavioral Sciences.

    “It’s very odd to think that moving your body should affect your brain in this way — that exercise should have some beneficial impact on brain structure and function — but if you start thinking about it from an evolutionary perspective, you can start to piece together why that system would adaptively respond to exercise challenges and stresses,” he said.

    Having this underlying understanding of the exercise-brain connection could help researchers come up with ways to enhance the benefits of exercise even further, and to develop effective interventions for age-related cognitive decline or even neurodegenerative diseases such as Alzheimer’s.

    Notably, the parts of the brain most taxed during a complex activity such as foraging — areas that play a key role in memory and executive functions such as problem solving and planning — are the same areas that seem to benefit from exercise in studies.

    “Foraging is an incredibly complex cognitive behavior,” Raichlen said. “You’re moving on a landscape, you’re using memory not only to know where to go but also to navigate your way back, you’re paying attention to your surroundings. You’re multitasking the entire time because you’re making decisions while you’re paying attention to the environment, while you are also monitoring your motor systems over complex terrain. Putting all that together creates a very complex multitasking effort.”

    The adaptive capacity model could help explain research findings such as those published by Raichlen and Alexander last year showing that runners’ brains appear to be more connected than brains of non-runners.

    The model also could help inform interventions for the cognitive decline that often accompanies aging — in a period in life when physical activity levels tend to decline as well.

    “What we’re proposing is, if you’re not sufficiently engaged in this kind of cognitively challenging aerobic activity, then this may be responsible for what we often see as healthy brain aging, where people start to show some diminished cognitive abilities,” said Alexander, a UA professor of psychology, psychiatry, neuroscience and physiological sciences. “So the natural aging process might really be part of a reduced capacity in response to not being engaged enough.”

    Reduced capacity refers to what can happen in organ systems throughout the body when they are deprived of exercise.

    “Our organ systems adapt to the stresses they undergo,” said Raichlen, an avid runner and expert on running. “For example, if you engage in exercise, your cardiovascular system has to adapt to expand capacity, be it through enlarging your heart or increasing your vasculature, and that takes energy. So if you’re not challenging it in that way — if you’re not engaging in aerobic exercise — to save energy, your body simply reduces that capacity.”

    In the case of the brain, if it is not being stressed enough it may begin to atrophy. This may be especially concerning, considering how much more sedentary humans’ lifestyles have become.

    “Our evolutionary history suggests that we are, fundamentally, cognitively engaged endurance athletes, and that if we don’t remain active we’re going to have this loss of capacity in response to that,” said Alexander, who studies brain aging and Alzheimer’s disease as a member of the UA’s Evelyn F. McKnight Brain Institute. “So there really may be a mismatch between our relatively sedentary lifestyles of today and how we evolved.”

    Alexander and Raichlen say future research should look at how different levels of exercise intensity, as well as different types of exercise, or exercise paired specifically with cognitive tasks, affect the brain.

    For example, exercising in a novel environment that poses a new mental challenge, may prove to be especially beneficial, Raichlen said.

    “Most of the research in this area puts people in a cognitively impoverished environment. They put people in a lab and have them run on a treadmill or exercise bike, and you don’t really have to do as much, so it’s possible that we’re missing something by not increasing novelty,” he said.

    Alexander and Raichlen say they hope the adaptive capacity model will help advance research on exercise and the brain.

    “This evolutionary neuroscience perspective is something that’s been generally lacking in the field,” Alexander said. “And we think this might be helpful to advance research and help develop some new specific hypotheses and ways to identify more universally effective interventions that could be helpful to everyone.”


  3. Training changes the way the brain pays attention

    July 18, 2017 by Ashley

    From the PLOS press release:

    Behavioral training changes the way attention facilitates information processing in the human brain, a study publishing on June 27 in the open access journal PLOS Biology led by Sirawaj Itthipuripat, at University of California San Diego, has found.

    After moving to a new city, driving to work on the second or third day may feel very different than it felt on the first day. Over time, drivers will feel more at ease on the road, not only because they can better remember which road signs to attend to or where to turn, but also because they will have an actual experience of doing so. This type of cognitive phenomenon applies not only for everyday-life activities like driving, but also for career-related skills that require training and expertise such as reading x-rays and excelling in sporting activities.

    The scientists monitored behavioral performance and brain activity using electroencephalography (EEG) for over 1 month in human participants performing a computer task that required them to direct their attention to a visual stimulus.

    They discovered that early in the task, attention enhanced the magnitude of sensory-evoked responses in the visual cortex. Using computational modeling, they also found that this attentional gain predicted the benefit of training observed in behavioral performance. Surprisingly, after extended training, this attentional gain disappeared, even though behavioral performance was still improved compared to before training. Their modelling experiments indicated that after extended training noise-reduction in brain activity predicted the benefit of training in behavioral performance.

    Interestingly, these findings also help reconcile contradictory results observed across studies conducted in different species. Specifically, in monkeys, previous research has demonstrated that changes in neural noise play a more dominant role than attentional gain in supporting attention-related benefits in behavioral performance. The current findings in humans suggest that this particular result from monkey studies could be due to non-human primates being highly-trained.

    According to Itthipuripat, “Most primate studies have to train subjects over many months to perform behavioral tasks that humans can conceptualize and perform well within 2-3 minutes. So, it is not surprising that many times, results obtained from humans and monkeys diverge from one another. Here we had to train human participants across many days to observe converging results across the two species. Our research, which demonstrates that attentional mechanisms could change with training, teaches us that we can’t fully understand how attention operates at the neural level without understanding how attentional mechanisms may change through a course of training. Thus, our research has important implications for understanding attentional mechanisms, as well as for generalizing results from studies using different species that often require substantially different amounts of training.”


  4. Artists and architects think differently compared to other people

    by Ashley

    From the University College London press release:

    Architects, painters and sculptors conceive of spaces in different ways from other people and from each other, finds a new study by UCL and Bangor University researchers.

    When asked to talk about images of places, painters are more likely to describe the depicted space as a two-dimensional image, while architects are more likely to focus on paths and the boundaries of the space.

    “We found that painters, sculptors and architects consistently showed signs of their profession when talking about the spaces we showed them, and all three groups had more elaborate, detailed descriptions than people in unrelated professions,” said senior author Dr Hugo Spiers (UCL Psychology & Language Sciences).

    For the study, published in Cognitive Science, the researchers brought in 16 people from each of the three professions — they all had at least eight years of experience and included Sir Anthony Gormley — alongside 16 participants without any relevant background, who acted as controls. The participants were presented with a Google Street View image, a painting of St. Peter’s Basilica, and a computer-generated surreal scene. They had to describe the environment, explain how they would explore the space, and suggest changes to the environment in the image.

    The researchers categorised elements of the responses for both qualitative and quantitative analyses using a novel technique called Cognitive Discourse Analysis, developed by one of the co-authors, Dr Thora Tenbrink (Bangor University), designed to highlight aspects of thought that underlie linguistic choices, beyond what speakers are consciously aware of.

    “By looking at language systematically we found some consistent patterns, which turned out to be quite revealing,” Dr Tenbrink said.

    The painters tended to shift between describing the scene as a 3D space or as a 2D image. Architects were more likely to describe barriers and boundaries of the space, and used more dynamic terms, while sculptors’ responses were between the two. Painters and architects also differed in how they described the furthest point of the space, as painters called it the ‘back’ and architects called it the ‘end.’ The control participants gave less elaborate responses, which the authors say went beyond just a lack of expert terminology.

    “Our study has provided evidence that your career may well change the way you think. There’s already extensive research into how culture changes cognition, but here we’ve found that even within the same culture, people of different professions differ in how they appreciate the world,” said Dr Spiers.

    “Our findings also raise the possibility that people who are already inclined to see the world as a 2D image, or who focus on the borders of a space, may be more inclined to pursue painting or architecture,” he said.

    “In their day-to-day work, artists and architects have a heightened awareness of their surroundings, which seems to have a deep influence on the way they conceive of space,” said the study’s first author, Claudia Cialone (now based at the ARC Centre of Excellence for the Dynamics of Language, Australian National University). “We hope our research will lead to further studies into the spatial cognition of other professionals, which could help devise new ways of understanding, representing and communicating space for ourselves.”


  5. Study suggests cocoa and chocolate have benefits for cognition

    July 17, 2017 by Ashley

    From the Frontiers press release:

    A balanced diet is chocolate in both hands — a phrase commonly used to justify ones chocolate snacking behavior. A phrase now shown to actually harbor some truth, as the cocoa bean is a rich source of flavanols: a class of natural compounds that has neuroprotective effects.

    In their recent review published in Frontiers in Nutrition, Italian researchers examined the available literature for the effects of acute and chronic administration of cocoa flavanols on different cognitive domains. In other words: what happens to your brain up to a few hours after you eat cocoa flavanols, and what happens when you sustain such a cocoa flavanol enriched diet for a prolonged period of time?

    Although randomized controlled trials investigating the acute effect of cocoa flavanols are sparse, most of them point towards a beneficial effect on cognitive performance. Participants showed, among others, enhancements in working memory performance and improved visual information processing after having had cocoa flavanols. And for women, eating cocoa after a night of total sleep deprivation actually counteracted the cognitive impairment (i.e. less accuracy in performing tasks) that such a night brings about. Promising results for people that suffer from chronic sleep deprivation or work shifts.

    It has to be noted though, that the effects depended on the length and mental load of the used cognitive tests to measure the effect of acute cocoa consumption. In young and healthy adults, for example, a high demanding cognitive test was required to uncover the subtle immediate behavioral effects that cocoa flavanols have on this group.

    The effects of relatively long-term ingestion of cocoa flavanols (ranging from 5 days up to 3 months) has generally been investigated in elderly individuals. It turns out that for them cognitive performance was improved by a daily intake of cocoa flavanols. Factors such as attention, processing speed, working memory, and verbal fluency were greatly affected. These effects were, however, most pronounced in older adults with a starting memory decline or other mild cognitive impairments.

    And this was exactly the most unexpected and promising result according to authors Valentina Socci and Michele Ferrara from the University of L’Aquila in Italy. “This result suggests the potential of cocoa flavanols to protect cognition in vulnerable populations over time by improving cognitive performance. If you look at the underlying mechanism, the cocoa flavanols have beneficial effects for cardiovascular health and can increase cerebral blood volume in the dentate gyrus of the hippocampus. This structure is particularly affected by aging and therefore the potential source of age-related memory decline in humans.”

    So should cocoa become a dietary supplement to improve our cognition? “Regular intake of cocoa and chocolate could indeed provide beneficial effects on cognitive functioning over time. There are, however, potential side effects of eating cocoa and chocolate. Those are generally linked to the caloric value of chocolate, some inherent chemical compounds of the cocoa plant such as caffeine and theobromine, and a variety of additives we add to chocolate such as sugar or milk.”

    Nonetheless, the scientists are the first to put their results into practice: “Dark chocolate is a rich source of flavanols. So we always eat some dark chocolate. Every day.”


  6. Adults with autism make more consistent choices

    by Ashley

    From the Association for Psychological Science press release:

    People with autism spectrum conditions (ASC) often show a reduced sensitivity to contextual information in perceptual tasks, but new research suggests that this reduced sensitivity may actually lead to more consistent choices in high-level decision-making tasks.

    The findings, published in Psychological Science, a journal of the Association for Psychological Science, indicate that individuals with ASC are less susceptible to the effects of decoy options when evaluating and choosing the “best” product among several options relative to individuals without ASC.

    “People with autism are indeed more consistent in their choices than the neurotypical population. From an economic perspective, this suggests that people with autism are more rational and less likely to be influenced by the way choices are presented,” says psychology researcher George Farmer of the University of Cambridge.

    While numerous studies have compared the performance of individuals with ASC and neurotypical individuals on a variety of low-level perceptual tasks, Farmer and University of Cambridge co-authors William J. Skylark and Simon Baron-Cohen noticed that relatively little research had examined their performance in the realm of decision making.

    People with autism are thought to focus more on detail and less on the bigger picture — this is often found in more perceptual studies, for instance by showing that people with autism are less susceptible to some visual illusions,” explains Farmer. “We wanted to know if this tendency would apply to higher-level decision-making tasks.”

    The researchers recruited 90 adults with ASC and 212 neurotypical adults to participate in an online decision-making study. The researchers used 10 product pairs and the products in each pair differed on two dimensions. Importantly, the pairs were always presented as part of a trio that included a third decoy item.

    Participants saw each pair twice — in one case, the accompanying decoy was designed to target product A; in the other case, it was designed to target product B. The participants indicated the “best” option out of the three presented.

    For example, participants might be asked to choose one of three USB drives that varied according to their capacity and their lifespan. Product A has a capacity of 32 GB and a lifespan of 20 months, while Product B has less capacity (16 GB) but a longer lifespan (36 months). The decoy, with a capacity of 28 GB and lifespan of 16 months, is objectively worse than A and should therefore be ignored.

    Participants also completed measures assessing aspects of cognitive ability and a measure that assessed traits typically associated with ASC.

    With purely rational economic decision making, the decoy items would be irrelevant and participants would make the same choice both times that products A and B were shown. If the decoys were effective, however, participants would switch their selection when the decoy changed, favoring the product targeted by the decoy in each trio. In the example above, people would be more likely to choose Product A with the decoy present than they would if there were simply comparing Product A and B.

    The data revealed that, compared with neurotypical participants, participants with ASC made more consistent choices and made fewer switches in their selections.

    In a second experiment, the researchers recruited participants from the general population, administering the same task with only those who scored in the bottom and top deciles of a validated measure of traits typically associated with autism. Their results showed an attenuated pattern similar to that seen in the first experiment: Participants who scored high on autistic traits were more likely to make consistent choices compared with low-scoring participants.

    Together, the findings indicate that individuals with ASC are less likely to show a cognitive bias that often affects their neurotypical peers.

    “[C]hoice consistency is regarded as normative in conventional economic theory, so reduced context sensitivity would provide a new demonstration that autism is not in all respects a ‘disability’,” the researchers write in their paper.

    “These findings suggest that people with autism might be less susceptible to having their choices biased by the way information is presented to them — for instance, via marketing tricks when choosing between consumer products,” Farmer adds.

    The results also indicate that the reduced sensitivity to context that is associated with ASC may extend well beyond low-level cognitive processes, shedding new light on the nature of “autistic cognition,” the researchers argue:

    “Altered preferences in a choice task involving verbally described consumer products would suggest the need for a broader characterization and integrated theorizing across levels and domains of processing,” they conclude.


  7. Alzheimer’s gene associated with failure to adapt to cognitive challenge in healthy adults

    July 15, 2017 by Ashley

    From the Society for Neuroscience press release:

    Healthy adults carrying the gene APOE4 — the strongest known genetic risk factor for Alzheimer’s disease (AD) — may struggle to adapt their brain activity to increasing cognitive demands as they get older, according to a study published in The Journal of Neuroscience. This age-related effect, which was not observed in people without the risk factor, suggests that interventions targeting cognitive decline in at-risk populations may need to begin many years before any symptoms of the disease emerge in order to be effective.

    Karen Rodrigue and colleagues assessed the performance of 31 adults (ages 20-86) with APOE4 on a distance judgment task at different levels of difficulty while measuring their brain activity. Although these at-risk participants showed similar adjustment in brain activity to the difficulty of the task as non-APOE4 carrying adults of the same age, sex, and education level, this ability declined with increasing age in the individuals with APOE4. These changes occurred in the precuneus, a part of the brain implicated in the early stages of AD, and reduced modulation of this area was associated with poorer performance on the task. These findings may help to inform the identification of individuals at increased risk of developing the disease.


  8. Study links greater muscle strength to better cognitive function in seniors

    July 13, 2017 by Ashley

    From the University of Eastern Finland press release:

    Greater muscle strength is associated with better cognitive function in aging men and women, according to a new Finnish study. The association of extensively measured upper and lower body muscle strength with cognitive function was observed, but handgrip strength was not associated with cognitive function. Cognition refers to brain functions relating to receiving, storing, processing and using information. The findings were published in European Geriatric Medicine.

    The study population comprised 338 men and women with an average age of 66 years. Their muscle strength was measured utilising handgrip strength, three lower body exercises such as leg extension, leg flexion and leg press and two upper body exercises such as chest press and seated row. Sum scores to depict lower body and upper body muscle strength were calculated separately, and cognitive function was assessed using the CERAD neuropsychological test battery with calculated total score.

    Handgrip strength is relatively easy and fast to measure, and it has been widely used as a measure of muscle strength in various studies. However, this new study could not demonstrate an association between muscle strength and cognitive function when using a model based on mere handgrip strength and age. Instead, an association between muscle strength and cognitive function was observed only when sum scores depicting upper or lower body muscle strength were included in the model.

    “The findings suggest that it may be justified to go beyond the handgrip and to include the upper and lower body when measuring muscle strength, as this may better reflect the association between muscle strength and cognition,” says Early Stage Researcher Heikki Pentikäinen, the first author of the article, who is currently preparing a PhD thesis on the topic for the University of Eastern Finland.

    Exercise is known to have various health benefits, and strength training is a way for practically everyone to increase muscle mass and enhance muscle strength. However, the association of muscle strength with various aspects of cognitive function is a relatively under-researched area. The study provided new insight into the methodology of measuring muscle strength and into the role of muscle strength in cognitive function. The study constituted part of the extensive, population-based DR’s EXTRA study, which was a four-year randomised and controlled intervention study analysing the effects of exercise and nutrition on endothelial function, atherosclerosis and cognition. The study was carried out at Kuopio Research Institute of Exercise Medicine in 2005-2011 and it involved more than 1,400 men and women living in the eastern part of Finland.


  9. Taking photos of experiences boosts visual memory, impairs auditory memory

    July 12, 2017 by Ashley

    From the Association for Psychological Science press release:

    A quick glance at any social media platform will tell you that people love taking photos of their experiences — whether they’re lying on the beach, touring a museum, or just waiting in line at the grocery store. New research shows that choosing to take photos may actually help us remember the visual details of our encounters.

    The findings are published in Psychological Science, a journal of the Association for Psychological Science.

    “Our research is novel because it shows that photo-taking itself improves memory for visual aspects of an experience but can hurt memory for nonvisual aspects, like auditory details,” the authors say.

    This research was conducted by Alixandra Barasch (New York University Stern School of Business), Kristin Diehl (USC Marshall School of Business), Jackie Silverman (The Wharton School of the University of Pennsylvania), and Gal Zauberman (Yale School of Management).

    Previous research has suggested that being able to take photographs or consult the Internet may allow us to outsource our memory, freeing up cognitive resources but potentially impairing our ability to remember.

    Barasch, Diehl, Silverman, and Zauberman hypothesized that this offloading effect may hold for factual information, but might not apply when it comes to the experiences we deliberately choose to photograph.

    “People take photos specifically to remember these experiences, whether it’s a fun dinner with friends, a sightseeing tour, or something else,” they argue.

    Of course, the reality is that most of the photos we take will probably never get a second glance. The researchers wondered: How well do we remember the experiences we photograph if we never revisit the photos? Furthermore, does taking photos affect memory for what we saw differently than for what we heard?

    In one experiment, the researchers had 294 participants tour a real-life museum exhibit of Etruscan artifacts. The participants stashed their belongings before starting the tour but some were allowed to keep a camera on them. Those with a camera could photograph anything they wanted in the exhibit and were told to take at least 10 photos. As the participants toured the exhibit, they listened to an accompanying audio guide.

    At the end of the tour, they answered multiple-choice questions asking them to identify objects they had seen or complete factual statements from the audio guide.

    The results showed that those who took photos visually recognized more of the objects compared with those who didn’t have a camera. But they also remembered less auditory information than their camera-less peers.

    These findings provided evidence that taking pictures can enhance visual memory. To test their hypotheses in a more controlled environment, the researchers designed a virtual art-gallery tour. Participants navigated through the gallery on screen as they would in real life and some were able to take pictures of what they saw on screen by clicking an on-screen button.

    Again, participants who were able to take pictures were better at recognizing what they saw and worse at remembering what they heard, compared to those who couldn’t take pictures.

    When the researchers examined visual memory for specific objects, they found that participants who were able to take pictures performed better on visual memory tasks regardless of whether the objects in question were the most or least photographed. Photo-takers even had better visual memory for aspects of the exhibit they didn’t photograph, compared with participants who weren’t able to take pictures.

    “These findings suggest that having a camera changes how people approach an experience in a fundamental way,” the authors say. “Even when people don’t take a photo of a particular object, like a sculpture, but have a camera with them and the intention to take photos, they remember that sculpture better than people who did not have a camera with them.”

    Pooling findings from all four studies, the researchers found that taking photos had a reliably positive effect on visual memory and a smaller but reliable negative effect on auditory memory.

    Even participants who thought their photos would be deleted and those who were instructed to “mentally take a photo” showed enhanced visual memory and impaired auditory memory relative to participants who couldn’t take pictures.

    Together, these experiments suggest that photographing our experiences doesn’t outsource our memory so much as it focuses it, funneling our attention toward visual aspects of our experiences and away from others.


  10. Interventions to prevent cognitive decline, dementia

    July 11, 2017 by Ashley

    From the National Academies of Sciences, Engineering, and Medicine press release:

    Cognitive training, blood pressure management for people with hypertension, and increased physical activity all show modest but inconclusive evidence that they can help prevent cognitive decline and dementia, but there is insufficient evidence to support a public health campaign encouraging their adoption, says a new report from the National Academies of Sciences, Engineering, and Medicine. Additional research is needed to further understand and gain confidence in their effectiveness, said the committee that conducted the study and wrote the report.

    “There is good cause for hope that in the next several years much more will be known about how to prevent cognitive decline and dementia, as more clinical trial results become available and more evidence emerges,” said Alan I. Leshner, chair of the committee and CEO emeritus, American Association for the Advancement of Science. “Even though clinical trials have not conclusively supported the three interventions discussed in our report, the evidence is strong enough to suggest the public should at least have access to these results to help inform their decisions about how they can invest their time and resources to maintain brain health with aging.”

    An earlier systematic review published in 2010 by the Agency for Healthcare Research and Quality (AHRQ) and an associated “state of the science” conference at the National Institutes of Health had concluded that there was insufficient evidence to make recommendations about any interventions to prevent cognitive decline and dementia. Since then, understanding of the pathological processes that result in dementia has advanced significantly, and a number of clinical trials of potential preventive interventions have been completed and published. In 2015, the National Institute on Aging (NIA) contracted with AHRQ to conduct another systematic review of the current evidence. NIA also asked the National Academies to convene an expert committee to help inform the design of the AHRQ review and then use the results to make recommendations to inform the development of public health messaging, as well as recommendations for future research. This report examines the most recent evidence on steps that can be taken to prevent, slow, or delay the onset of mild cognitive impairment and clinical Alzheimer’s-type dementia as well as steps that can delay or slow age-related cognitive decline.

    Overall, the committee determined that despite an array of advances in understanding cognitive decline and dementia, the available evidence on interventions derived from randomized controlled trials — considered the gold standard of evidence — remains relatively limited and has significant shortcomings. Based on the totality of available evidence, however, the committee concluded that three classes of interventions can be described as supported by encouraging but inconclusive evidence. These interventions are:

    cognitive training — which includes programs aimed at enhancing reasoning and problem solving, memory, and speed of processing — to delay or slow age-related cognitive decline. Such structured training exercises may or may not be computer-based. blood pressure management for people with hypertension — to prevent, delay, or slow clinical Alzheimer’s-type dementia. increased physical activity — to delay or slow age-related cognitive decline.

    Cognitive training has been the object of considerable interest and debate in both the academic and commercial sectors, particularly within the last 15 years. Good evidence shows that cognitive training can improve performance on a trained task, at least in the short term. However, debate has centered on evidence for long-term benefits and whether training in one domain, such as processing speed, yields benefits in others, such as in memory and reasoning, and if this can translate to maintaining independence in instrumental activities of daily living, such as driving and remembering to take medications. Evidence from one randomized controlled trial suggests that cognitive training delivered over time and in an interactive context can improve long-term cognitive function as well as help maintain independence in instrumental activities of daily living for adults with normal cognition. However, results from other randomized controlled trials that tested cognitive training were mixed.

    Managing blood pressure for people with hypertension, particularly during midlife — generally ages 35 to 65 years — is supported by encouraging but inconclusive evidence for preventing, delaying, and slowing clinical Alzheimer’s-type dementia, the committee said. The available evidence, together with the strong evidence for blood pressure management in preventing stroke and cardiovascular disease and the relative benefit/risk ratio of antihypertensive medications and lifestyle interventions, is sufficient to justify communication with the public regarding the use of blood pressure management, particularly during midlife, for preventing, delaying, and slowing clinical Alzheimer’s-type dementia, the report says.

    It is well-documented that physical activity has many health benefits, and some of these benefits — such as stroke prevention — are causally related to brain health. The AHRQ systematic review found that the pattern of randomized controlled trials results across different types of physical activity interventions provides an indication of the effectiveness of increased physical activity in delaying or slowing age-related cognitive decline, although these results were not consistently positive. However, several other considerations led the committee to conclude that the evidence is sufficient to justify communicating to the public that increased physical activity for delaying or slowing age-related cognitive decline is supported by encouraging but inconclusive evidence.

    None of the interventions evaluated in the AHRQ systematic review met the criteria for being supported by high-strength evidence, based on the quality of randomized controlled trials and the lack of consistently positive results across independent studies. This limitation suggests the need for additional research as well as methodological improvements in the future research. The National Institutes of Health and other interested organizations should support further research to strengthen the evidence base on cognitive training, blood pressure management, and increased physical activity, the committee said. Examples of research priorities for these three classes of interventions include evaluating the comparative effectiveness of different forms of cognitive training interventions; determining whether there are optimal blood pressure targets and approaches across different age ranges; and comparing the effects of different forms of physical activity.

    When funding research on preventing cognitive decline and dementia, the National Institutes of Health and other interested organizations should identify individuals who are at higher risk of cognitive decline and dementia; increase participation of underrepresented populations; begin more interventions at younger ages and have longer follow-up periods; use consistent cognitive outcome measures across trials to enable pooling; integrate robust cognitive outcome measures into trials with other primary purposes; include biomarkers as intermediate outcomes; and conduct large trials designed to test the effectiveness of an intervention in broad, routine clinical practices or community settings.