Posts Tagged ‘cognitive decline’

Cognitive Decline Accelerates Years After Stroke

Stroke is associated with acute decline in cognitive function as well as a decline in new learning and memory, according to the first study to monitor cognitive function in a longitudinal manner before and after stroke.

About one-third of stroke patients have significant cognitive impairment within several months of the event.

In addition, silent strokes, experienced by 1 in 10 adults by their early 60s, are harbingers of both future stroke and cognitive dysfunction.

Downward Trajectory

Researchers led by Deborah A. Levine, MD, MPH, of the University of Michigan, Ann Arbor, tracked the trajectories of cognitive decline before and after incident stroke in a prospective study of 23,572 participants age 45 years or older without baseline cognitive impairment.

The participants were part of the Reasons for Geographic and Racial Differences in Stroke cohort.

Over a median follow-up of 6 years, 515 participants survived incident stroke and 23,057 remained stroke free.

All participants underwent cognitive function tests administered by telephone to assess their global cognition annually.

They also underwent a battery of cognitive tests administered twice a year.

The results show stroke was associated with acute decline in global cognition, new learning, and verbal memory.

Faster Decline in Cognition

“Participants with stroke, compared with those without stroke, demonstrated faster declines in global cognition and executive function, but not in new learning and verbal memory, compared with pre-stroke slopes,” they wrote.

Also, cognitive impairment was significantly faster post-stroke compared with pre-stroke.

As an example, the researchers note that for a 70-year-old black woman who had average values at baseline, stroke at year 3 was associated with greater incident cognitive impairment.

The absolute difference was 4% at year 3 and 12.4% at year 6.

The results suggest that stroke survivors should be monitored for years, they note.

In an accompanying editorial, Philip B. Gorelick, MD, MPH, and David Nyenhuis, PhD, from the Michigan State University College of Human Medicine, Grand Rapids, state that “acute cognitive decline was associated with incident stroke and accelerated and persisted over the approximately 6-year follow-up period.”

Tracking Pre-stroke Cognition

They note that a novel feature of the study was that it allowed for pre-stroke cognition to be tracked, allowing the researchers to acquire rates of cognitive change prior to incident stroke.

These results suggest that clinicians may have an opportunity to intervene immediately following stroke to prevent accelerated stroke-related cognitive decline.

They support screening for cognitive impairment over the long term following stroke.

Carotid Narrowing Tied to Cognitive Decline as Well as Stroke

Patients who have blockages in the carotid arteries are at risk not only for stroke but possibly for cognitive impairment as well, according to the results of a new study.

“We have fairly compelling evidence that there is a decline in cognitive function associated with blockages in the carotid arteries in asymptomatic patients (those with no symptoms),” principal investigator Brajesh Lal, MD, Professor of Vascular Surgery at the University of Maryland School of Medicine in Baltimore, said in an interview.

“No one has asked about what happens to the way the brain functions—thinks, processes information, remembers, recollects new information—when blood flow is restricted from stenosis (narrowing).”

A neuropsychologist at the University of Maryland, Moira C. Dux, PhD, presented the details of the study at the American Academy of Neurology annual meeting in Philadelphia.

NARROW CAROTIDS, WORSE MEMORY

The study involved 67 persons with asymptomatic carotid stenosis who had a 50% reduction in the diameter of the artery, and 60 persons with vascular risk factors, including diabetes mellitus, hypertension, hypercholesterolemia, and coronary artery disease, with no stenosis.

The patients underwent extensive testing for overall thinking abilities and for specific aspects of thinking, such as processing speed, learning, memory, decision making, and language.

The stenosis group performed significantly worse on the overall memory and thinking tests, as well as on tests for motor and processing speed, and learning and memory.

Language scores did not differ between the 2 groups.

“We have demonstrated, for the first time, that carotid stenosis without a neurologic deficit is not necessarily ‘asymptomatic’ and is associated with greater cognitive impairment compared to patients with similar risk factors but no stenosis,” said Dr. Lal.

TWO POTENTIAL MECHANISMS

Two potential mechanisms are restriction of blood flow caused by the stenosis and microinfarction from the release of microparticles, Dr. Lal stated.

“Microparticles could lodge in non-expressive areas of the brain, which become infarcted, and then be expressed as cognitive impairment,” he said.

“We are now looking at transcranial flow within the brain, microembolization from plaque, and microinfarction and brain injury in these patients.”

The researchers also plan to monitor these patients, average age 60 years, for at least another 2 years to assess their risk of stroke.

Every patient with carotid stenosis has significant atherosclerosis and should be receiving aspirin and statin therapy, Dr. Lal said.

“HOW HAS YOUR MEMORY BEEN?”

“With these data, I will start asking my carotid stenosis patients, how has your memory been? Do you have trouble thinking? If they have any suggestion of cognitive impairment, I will refer them to a neuropsychologist,” he said, adding “I don’t think I can recommend carotid endarterectomy yet.”

Carotid endarterectomy is a surgical procedure used to reduce the risk of stroke by correcting narrowing in the carotid arteries.

Dr. Lal has preliminary data from a previous study that show using both surgery and stenting for carotid artery stenosis leads to a net improvement in cognitive function.

“From 8 to 15 million US patients have asymptomatic carotid artery stenosis.

I anticipate a large number of follow-up studies searching for causes and the best treatment options for this newly identified morbidity associated with carotid narrowing,” Dr. Lal said.

“Once we identify the mechanism, we potentially can mount a clinical trial comparing cognitive rehabilitation versus revascularization.”

Heavy Drinking Hastens Cognitive Decline in Men

Men who are heavy drinkers show a faster cognitive decline compared with men who consume light to moderate amounts of alcohol, according to a new study.

The middle-age men who averaged 3 or more drinks per day showed faster 10-year declines in cognitive function than did lighter drinkers.

“The detrimental effect of heavy alcohol consumption on health is well documented.

This study adds a new argument against heavy drinking, showing that it is also detrimental for cognitive aging, with effects evident as early as age 55 years,” said lead author Séverine Sabia, PhD, from the Department of Epidemiology & Public Health at University College London.

“For example, heavy drinking men aged 60 years old show a decline in memory comparable to men aged 66 years old,” she noted.

The researchers published their results online on January 15, 2014 in the journal Neurology.

Lifestyle Questionnaires Assess Alcohol Consumption

Dr. Sabia and colleagues analyzed data from more than 7000 British civil servants, average age 56 years, who had agreed to complete lifestyle questionnaires and to undergo a physical examination beginning in the 1980s.

About two-thirds of the participants were men.

Alcohol consumption was assessed 3 times in the 10 years preceding the first cognitive assessment in the late 1990s.

Cognitive tests were repeated twice more in the 2000s.

The cognitive test battery included 4 tests that assessed memory and executive function.

The participants were stratified into 6 groups according to drinking status, including complete abstainers; those who stopped drinking entirely at some point during follow-up; “occasional” drinkers (their average daily alcohol consumption was not quantified); and light, moderate, and heavy regular drinkers.

Almost two-thirds of the men were light drinkers, just under 20% were moderate drinkers, and just under 10% were heavy drinkers.

The researchers used the light drinkers as the reference group to analyze drinking and cognitive decline.

Heavy Drinking = Cognitive Declines

Compared with the declines observed in the light drinkers, declines in cognitive scores were statistically higher in the heavy-drinking men but did not differ for the other groups.

The scores on 4 tests of short-term memory and executive function dropped the most in the heaviest male drinkers.

“Although we cannot completely exclude confusing effects from an unhealthy lifestyle, we did take into account fruit and vegetable consumption, physical activity, and smoking in the analyses,” said Dr. Sabia.

“The mechanisms underlying the association between alcohol consumption and cognition are complex.

The main hypothesis focuses on cerebrovascular and cardiovascular pathways, involving effects that play out over an extended period of time.

Heavy alcohol consumption is associated with higher risk of vascular disease which, in turn, may increase the risk of cognitive impairment.”

In addition, Dr. Sabia noted that “heavy alcohol consumption has detrimental short-term and long-term effects on the brain, including direct neurotoxic effects, pro-inflammatory effects, and indirect impact via cerebrovascular disease and vitamin deficiency.”

Dr. Sabia added, “Our findings are in agreement with previous studies showing that moderate alcohol consumption is probably not deleterious for cognitive outcomes, but they also show that heavy alcohol consumption in midlife is likely to be harmful for cognitive aging, at least in men.”

Healthy Behaviors Trim Dementia, Chronic Diseases

Five healthy behaviors — regular exercise; no smoking; and maintaining a low body weight, a healthy diet, and low alcohol intake — appear to reduce the risk of dementia and several chronic diseases significantly, according to a 35-year study that monitored men’s health habits.

The men who consistently engaged in 4 or 5 of these behaviors experienced a 60% reduction in dementia and cognitive decline — with exercise being the strongest mitigating factor — as well as 70% fewer instances of diabetes mellitus, heart disease, and stroke, compared with persons who engaged in none of them.

“Undoubtedly, these protective behaviors affect a host of biological mechanisms.

Separating out relationships between the 5 behaviors and the 4 disease outcomes we examined would be an enormous, and probably a rather fruitless, task.

It would not be helpful to the overall aim of promoting healthy lifestyles to dissect out and promote individual behaviors.

People should be urged to adopt a healthy lifestyle as a complete package,” said lead author Peter Elwood, DSc, MD of the Cochrane Institute of Primary Care and Public Health at Cardiff University.

Dr. Elwood and colleagues presented their results in the December 9, 2013 issue of PLoS One.

Researchers have known for some time that what is good for the heart is good for the head, Dr. Elwood pointed out, noting that the study provides more evidence that healthy living could significantly reduce the chances of developing dementia.

The Caerphilly Cohort Study recorded the healthy behaviors of 2235 men aged 45 to 59 years in Caerphilly, South Wales.

An important aim of the study was to examine the relationships among healthy lifestyles, chronic disease, and cognitive decline over a 35-year period.

The researchers also monitored changes in the take-up of healthy behaviors.

“The size of reduction in the instance of disease owing to these simple healthy steps is of enormous importance in an aging population,” said Dr. Elwood.

“What the research shows is that following a healthy lifestyle confers surprisingly large benefits to health. Healthy behaviors have a far more beneficial effect than any medical treatment or preventative procedure.”

However, Dr. Elwood pointed out, “our study showed that over 30 years health promotion had no detectable effect upon the prevalence of healthy living.”

Despite increasing knowledge of the relevance of lifestyle to health and to survival, the proportion of the adult Welsh population following all 5 healthy behaviors was, and remains, under 1%.

The prevalence of all 5 healthy behaviors is estimated to be only 3% in large, primary prevention studies in the United States.

“Clearly there is an urgent need for new strategies in health promotion to be developed and evaluated,” Dr. Elwood said.

He suggested that rather than talk to their patients about the benefits of a healthy lifestyle in rather vague terms, physicians should speak in precise, quantitative terms, saying something like: “People who live a truly active lifestyle experience 60% fewer heart attacks, 70% less diabetes, and a 60% reduction in dementia.

Furthermore, those who follow a healthy lifestyle and still get a disease or dementia get it when they are about 12 years older.”