cognitive decline

Exercise offers protection against Alzheimer's

July 16, 2019

Science Daily/Massachusetts General Hospital

Higher levels of daily physical activity may protect against the cognitive decline and neurodegeneration (brain tissue loss) from Alzheimer's disease (AD) that alters the lives of many older people, researchers from Massachusetts General Hospital (MGH) have found. In a paper in JAMA Neurology, the team also reported that lowering vascular risk factors may offer additional protection against Alzheimer's and delay progression of the devastating disease. The findings from this study will be presented at the Alzheimer's Association International Conference (AAIC) in Los Angeles by the first author of the study, Jennifer Rabin, PhD, now at the University of Toronto, Sunnybrook Research Institute.

 

"One of the most striking findings from our study was that greater physical activity not only appeared to have positive effects on slowing cognitive decline, but also on slowing the rate of brain tissue loss over time in normal people who had high levels of amyloid plaque in the brain," says Jasmeer Chhatwal, MD, PhD of the MGH Department of Neurology, and corresponding author of the study. The report suggests that physical activity might reduce b-amyloid (Ab)-related cortical thinning and preserve gray matter structure in regions of the brain that have been implicated in episodic memory loss and Alzheimer's-related neurodegeneration.

 

The pathophysiological process of AD begins decades before clinical symptoms emerge and is characterized by early accumulation of b-amyloid protein. The MGH study is among the first to demonstrate the protective effects of physical activity and vascular risk management in the "preclinical stage" of Alzheimer's disease, while there is an opportunity to intervene prior to the onset of substantial neuronal loss and clinical impairment. "Because there are currently no disease-modifying therapies for Alzheimer's disease, there is a critical need to identify potential risk-altering factors that might delay progression of the disease," says Chhatwal.

 

The Harvard Aging Brain Study at MGH assessed physical activity in its participants -- 182 normal older adults, including those with elevated b-amyloid who were judged at high-risk of cognitive decline -- through hip-mounted pedometers which counted the number of steps walked during the course of the day.

 

"Beneficial effects were seen at even modest levels of physical activity, but were most prominent at around 8,900 steps, which is only slightly less than the 10,000 many of us strive to achieve daily," notes co-author Reisa Sperling, MD, director of the Center for Alzheimer's Research and Treatment, Brigham and Women's Hospital and Massachusetts General Hospital and co-principal investigator of the Harvard Aging Brain Study.

 

Interventional approaches that target vascular risk factors along with physical exercise have added beneficial properties, she adds, since both operate independently. Vascular risk factors measured by the researchers were drawn from the Framingham Cardiovascular Disease Risk Score Calculator, and include age, sex, weight, smoking/non-smoking, blood pressure, and whether people are on treatment for hypertension.

 

Through ongoing studies MGH is working to characterize other forms of physical activity and lifestyle changes that may help retard the progress of Alzheimer's disease. "Beta amyloid and tau protein build-up certainly set the stage for cognitive impairment in later age, but we shouldn't forget that there are steps we can take now to reduce the risk going forward -- even in people with build-up of these proteins," says Chhatwal. "Alzheimer's disease and the emergence of cognitive decline is multifactorial and demands a multifactorial approach if we hope to change its trajectory."

https://www.sciencedaily.com/releases/2019/07/190716193543.htm

'Stressors' in middle age linked to cognitive decline in older women

August 5, 2019

Science Daily/Johns Hopkins Medicine

A new analysis of data on more than 900 Baltimore adults by Johns Hopkins Medicine researchers has linked stressful life experiences among middle-aged women -- but not men -- to greater memory decline in later life.

 

The researchers say their findings add to evidence that stress hormones play an uneven gender role in brain health, and align with well-documented higher rates of Alzheimer's disease in women than men.

 

Although the researchers caution their study was designed to show associations among phenomena, and not determine cause and effect, they say that if future studies demonstrate that stress response does factor into the cause of dementia, then strategies designed to combat or moderate the body's chemical reactions to stress may prevent or delay onset of cognitive decline.

 

The findings are published in the July issue of the International Journal of Geriatric Psychiatry.

 

According to the Alzheimer's Association, 1 in 6 women over age 60 will get Alzheimer's disease, compared with 1 in 11 men. There currently are no proven treatments that prevent or halt progression of the disease.

 

"We can't get rid of stressors, but we might adjust the way we respond to stress, and have a real effect on brain function as we age," says Cynthia Munro, Ph.D., associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. "And although our study did not show the same association for men, it sheds further light on the effects of stress response on the brain with potential application to both men and women," she adds.

 

Munro says prior research by other investigators shows that the effect of age on the stress response is three times greater in women than in men. Separately, other research has shown that stressful life experiences can result in temporary memory and cognitive problems.

 

To further explore whether stressful life experiences can be linked to developing long-term memory problems in women especially, Munro and her team used data collected on 909 Baltimore residents for the National Institute of Mental Health Epidemiologic Catchment Area study. That study recruited participants from 1981 to 1983 from five cities in the U.S. to determine the prevalence of psychiatric disorders.

 

Some 63% of the participants were women and 60% were white. Participants were an average age of 47 during their mid-life check-in in the 90s.

 

After enrollment, participants returned to trial sites for interviews and checkups three additional times: once in 1982, once between 1993 and 1996, and once between 2003 and 2004.

 

During the third visit, participants were asked if they experienced a traumatic event in the past year such as combat, rape, a mugging, some other physical attack, watching someone else attacked or killed, receiving a threat, or living through a natural disaster. Some 22% of men and 23% of women reported at least one traumatic event within the past year before their visit.

 

They also were asked about stressful life experiences such as a marriage, divorce, death of a loved one, job loss, severe injury or sickness, a child moving out, retirement, or birth of a child. About 47% of men and 50% of women reported having at least one stressful life experience in the year before their visit.

 

At the third and fourth visits, the researchers tested the participants using a standardized learning and memory test developed by Iowa researchers. The test included having participants recall 20 words spoken aloud by the testers immediately after they heard them, and again 20 minutes later.

 

At the third visit, participants could recall on average eight words immediately and six words later. Participants also had to identify the words spoken to them among a written list of 40 words. During the third visit, participants correctly identified on average 15 words. By the fourth visit, participants recalled an average of seven words immediately, six words after a delay, and correctly recognized almost 14 words.

 

The researchers measured any decreases in performance on the tests between the third and fourth visits, and then compared those decreases with participants' reports of stressful life experiences or traumatic events to see if there was an association.

 

Munro's team found that having a greater number of stressful life experiences over the last year in midlife in women was linked to a greater decline in recalling words later and recognizing those words. Women who experienced no stressful life experiences within the past year at the third visit were able to remember on average 0.5 fewer words when given the same memory test at the fourth visit. Women with one or more stressful life experiences, however, recalled on average one fewer word at the fourth visit than they had at the third visit. The ability to recognize words declined by an average of 1.7 words for women with at least one stressor at the third visit compared with a 1.2-word decline for women without stressors at midlife.

 

They didn't see the same trend in women who had traumatic events. Munro says that this finding suggests that ongoing stress, such as that experienced during a divorce, may have more of a negative impact on brain functioning than distinct traumatic events. This makes sense, Munro believes, because what we call "chronic stress" can impair the body's ability to respond to stress in a healthy manner.

 

The researchers did not see an association in men between a drop in word recall or recognition and experiencing either stressful life experiences or traumatic events in midlife.

 

Stress much earlier in life also wasn't predictive of cognitive decline later in either men or women.

 

"A normal stress response causes a temporary increase in stress hormones like cortisol, and when it's over, levels return to baseline and you recover. But with repeated stress, or with enhanced sensitivity to stress, your body mounts an increased and sustained hormone response that takes longer to recover," says Munro. "We know if stress hormone levels increase and remain high, this isn't good for the brain's hippocampus -- the seat of memory."

 

The researchers say that stress reduction hasn't gotten a whole lot of attention compared with other factors that may contribute to dementia or Alzheimer's, and that it might be worth exploring stress management techniques as a way to delay or prevent disease.

 

Munro adds that there are medications being developed to combat how our brains handle stress, and that these may be used in conjunction with other behavioral stress coping techniques to reduce the impact of stress on aging minds.

https://www.sciencedaily.com/releases/2019/08/190805101144.htm

Chronic inflammation in middle age may lead to thinking and memory problems later

February 13, 2019

Science Daily/American Academy of Neurology

People who have chronic inflammation in middle-age may develop problems with thinking and memory in the decades leading up to old age.

 

There are two kinds of inflammation. Acute inflammation happens when the body's immune response jumps into action to fight off infection or an injury. It is localized, short-term and part of a healthy immune system. Chronic inflammation is not considered healthy. It is a low-grade inflammation that lingers for months or even years throughout the body. It can be caused by autoimmune disorders like rheumatoid arthritis or multiple sclerosis, physical stress or other causes. Symptoms of chronic inflammation include joint pain or stiffness, digestive problems and fatigue.

 

Ways to reduce chronic inflammation include getting regular exercise, following an anti-inflammatory heart healthy diet, and getting enough sleep.

 

"Chronic inflammation is tough on the body, and can damage joints, internal organs, tissue and cells," said study author Keenan A. Walker, PhD, of Johns Hopkins University in Baltimore, Md. "It can also lead to heart disease, stroke and cancer. While other studies have looked at chronic inflammation and its effects on the brain in older people, our large study investigated chronic inflammation beginning in middle age and showed that it may contribute to cognitive decline in the decades leading up to old age."

 

As part of the Atherosclerosis Risk in Communities (ARIC) Study, researchers followed 12,336 people with an average age of 57 for approximately 20 years. Researchers took blood samples from participants at the start of the study, measuring four biomarkers of inflammation: fibrinogen, white blood cell count, von Willebrand factor, and factor VIII. They created a composite inflammation score for the four biomarkers. Three years later, researchers measured C-reactive protein, another blood biomarker of inflammation. Participants were divided into four groups based on their composite inflammation scores and C-reactive protein levels.

 

Participants' thinking and memory skills were tested at the beginning of the study, six to nine years later, and at the end of the study.

 

Researchers found the group with the highest levels of inflammation biomarkers had an 8-percent steeper decline in thinking and memory skills over the course of the study than the group with the lowest levels of inflammation biomarkers. The group with the highest C-reactive protein levels had a 12-percent steeper decline in thinking and memory skills than the group with the lowest levels. These results were derived after researchers adjusted for other factors that could affect thinking and memory skills, such as education, heart disease and high blood pressure. Further analyses revealed that inflammation-associated declines in thinking were most prominent in areas of memory, compared to other aspects of thinking such as language and executive functioning.

 

"Overall, the additional change in thinking and memory skills associated with chronic inflammation was modest, but it was greater than what has been seen previously associated with high blood pressure in middle age," Walker said.

 

"Many of the processes that can lead to a decline in thinking and memory skills are believed to begin in middle age, and it is in middle age that they may also be most responsive to intervention," said Walker. "Our results show that chronic inflammation may be an important target for intervention. However, it's also possible that chronic inflammation is not a cause and instead a marker of, or even a response to, neurodegenerative brain diseases that can lead to cognitive decline."

 

A limitation of the study was that participants with higher levels of chronic inflammation at the start of the study were more likely to drop out or die before the final follow-up visit, so surviving participants may not be representative of the general population.

 

Future studies could include more frequent assessments of thinking and memory skills. They could also examine a larger variety of inflammation markers in the blood.

https://www.sciencedaily.com/releases/2019/02/190213160535.htm

With age comes hearing loss and a greater risk of cognitive decline

But study suggests higher education might counter effects of milder hearing impairment

February 12, 2019

Science Daily/University of California - San Diego

In a new study, researchers report that hearing impairment is associated with accelerated cognitive decline with age, though the impact of mild hearing loss may be lessened by higher education

 

Hearing impairment is a common consequence of advancing age. Almost three-quarters of U.S. adults age 70 and older suffer from some degree of hearing loss. One unanswered question has been to what degree hearing impairment intersects with and influences age-related cognitive decline.

 

In a new study, researchers at University of California San Diego School of Medicine report that hearing impairment is associated with accelerated cognitive decline with age, though the impact of mild hearing loss may be lessened by higher education.

 

The findings are published in the February 12, 2019 issue of the Journal of Gerontology: Series A Medical Sciences.

 

A team of scientists, led by senior author Linda K. McEvoy, PhD, professor in the departments of Radiology and Family Medicine and Public Health, tracked 1,164 participants (mean age 73.5 years, 64 percent women) in the longitudinal Rancho Bernardo Study of Healthy Aging for up to 24 years. All had undergone assessments for hearing acuity and cognitive function between the years 1992 to 1996 and had up to five subsequent cognitive assessments at approximately four-year intervals. None used a hearing aid.

 

The researchers found that almost half of the participants had mild hearing impairment, with 16.8 percent suffering moderate-to-severe hearing loss. Those with more serious hearing impairment showed worse performance at the initial visit on a pair of commonly used cognitive assessment tests: the Mini-Mental State Exam (MMSE) and the Trail-Making Test, Part B. Hearing impairment was associated with greater decline in performance on these tests over time, both for those with mild hearing impairment and those with more severe hearing impairment.

 

However, the association of mild hearing impairment with rate of cognitive decline was modified by education. Mild hearing impairment was associated with steeper decline among study participants without a college education, but not among those with higher education. Moderate-to-severe hearing impairment was associated with steeper MMSE decline regardless of education level.

 

"We surmise that higher education may provide sufficient cognitive reserve to counter the effects of mild hearing loss, but not enough to overcome effects of more severe hearing impairment," said McEvoy.

 

Degree of social engagement did not affect the association of hearing impairment with cognitive decline. "This was a somewhat unexpected finding" said first author Ali Alattar. "Others have postulated that cognitive deficits related to hearing impairment may arise from social isolation, but in our study, participants who had hearing impairment were as socially engaged as those without hearing loss."

 

The findings, said the authors, emphasize the need for physicians to be aware that older patients with hearing impairments are at greater risk for cognitive decline. They also emphasized the importance of preventing hearing loss at all ages, since hearing impairment is rarely reversible. One important way to protect hearing, they said, is to minimize loud noise exposure since this is the largest modifiable risk factor for hearing impairment.

https://www.sciencedaily.com/releases/2019/02/190212134802.htm

 

Memory complaints and cognitive decline: Data from the GuidAge study

A memory complaint, also called Subjective Cognitive Decline (SCD), is a subjective disorder that appears to be relatively common, especially in elderly persons

November 13, 2017

Science Daily/IOS Press

A memory complaint, also called Subjective Cognitive Decline (SCD), is a subjective disorder that appears to be relatively common, especially in elderly persons. The reports of its prevalence in various populations range from approximately 10% to as high as 88%, although it is generally thought that the prevalence of everyday memory problems lie within the range of 25% to 50%.

 

The McNair and Kahn Scale or Cognitive Difficulties Scale was employed to define and characterize cognitive complaints in the GuidAge study, involving a population of more than 2800 individuals aged 70 years or older having voluntarily complained of memory problems to their general practitioner (GPs). It contains items that are related to difficulties in attention, concentration, orientation, memory, praxis, domestic activities and errands, facial recognition, task efficiency, and name finding.

 

The results of the GuidAge study suggest that the assessment of cognitive complaint voluntarily reported to primary-care physicians, by the McNair and Kahn scale can predict a decline in cognitive performance, as 5 items out of 20 were statistically significant.

 

These 5 items are:

·      item 1, "I hardly remember usual phone numbers",

·      item 5, "I forget appointment, dates, where I store things",

·      item 6, "I forget to call people back when they called me",

·      item 10, "I forget the day of the week",

·      item 13, "I need to have people repeat instructions several times."

 

Thanks to this short scale GPs, in clinical practice, can identify which patients with memory complaints should be referred to a memory center to assess cognitive functions.

https://www.sciencedaily.com/releases/2017/11/171113095443.htm

Older adults with too much salt in diet and too little exercise at greater risk of cognitive decline

August 23, 2011

Science Daily/Baycrest Centre for Geriatric Care

Older adults who lead sedentary lifestyles and consume a lot of sodium in their diet may be putting themselves at risk for more than just heart disease. A new study has found evidence that high-salt diets coupled with low physical activity can be detrimental to cognitive health in older adults.

 

"The results of our study showed that a diet high in sodium, combined with little exercise, was especially detrimental to the cognitive performance of older adults," said Dr. Fiocco. "But the good news is that sedentary older adults showed no cognitive decline over the three years that we followed them if they had low sodium intake."

 

"These data are especially relevant as we know that munching on high-salt processed snacks when engaged in sedentary activities, such as watching TV or playing in front of the computer, is a frequent pastime for many adults," said Dr. Carol Greenwood, a senior author on the study and internationally-renowned scientist in the field of nutrition and cognitive function in late life.

http://www.sciencedaily.com/releases/2011/08/110822111737.htm

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