Posts Tagged ‘stroke’

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.

Strokes Compounded With Aspirin Resistance

Persons who exhibit a resistance to aspirin may be more likely to have more severe, and larger, strokes than those who still respond to the drug, according to a new study.

“Eventually we may be able to identify people who are likely to be resistant to aspirin and give them higher doses or different drugs to prevent blood clots,” said lead author Mi Sun Oh, MD, of Hallym University College of Medicine in South Korea.

Prior aspirin use has been associated with lower stroke severity and decreased infarction size.

However, the effect of aspirin resistance on stroke severity has been inconclusive.

Doctors do not routinely test patients for aspirin resistance.

STUDY DETAILS

Dr. Oh and colleagues set out to evaluate the effect of aspirin resistance on initial stroke severity and infarct size measured by MRI diffusion weighted imaging (DWI) in 310 patients.

“We enrolled patients with at least 7 days of aspirin before symptom onset, evidence of ischemic stroke on DWI, and aspirin resistance checked within 24 hours of hospital admission,” he said.

A total of 86 patients (27.7%) were resistant to aspirin.

In a multivariable analysis, aspirin resistance was significantly associated with higher initial NIH Stroke Scale score.

Aspirin resistance also was a significant predictor of larger DWI infarction volumes.

The infarct size was 2.8 cc in aspirin-resistant patients compared with 1.6 cc for those who responded to aspirin.

In conclusion, Dr. Oh said: “Aspirin resistance is independently associated with increased initial stroke severity and stroke volume in acute ischemic patients.

However, we need better ways to identify people with aspirin resistance before any changes can be made.

DON’T STOP LOW-DOSE ASPIRIN YET

For now, people who are taking low-dose aspirin to prevent blood clotting and stroke should continue to do so.”

Antiplatelet agents such as aspirin reduce platelet aggregation, the formation of thrombus, and the size and frequency of thrombotic emboli.

When patients do not have adequate platelet inhibition, this may lead to larger and more severe strokes because of larger thrombus and higher rate of thrombotic emboli.

The researchers presented their results at the American Academy of Neurology’s 67th Annual Meeting in Washington, DC, April 18 to 25, 2015.

Abstract title: Aspirin Resistance is Associated with Increased Stroke Severity and Infarction Volume

Irregular Heart Rhythm in Men Associated With Exercise Intensity Over Time

Young men who undertake endurance exercise for more than 5 hours a week may increase their risk of developing an irregular heart rhythm later in life, according to the results of a new study.

“Physical activity contributes to prevention of several diseases, and in general is good for the well-being of your body and mind.

However, frequent high-intensity exercise during many years could increase the risk for atrial fibrillation (AF),” lead author Dr Nikola Drca, Department of Cardiology, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden, said in an interview.

The increase in risk is real, but quite small, he added.

The researchers presented their results online in the May 14, 2014, issue of the journal Heart.

RISK FACTOR FOR STROKE

In the Swedish study, the researchers quizzed more than 44,000 men aged 45 to 79 years about their leisure-time physical activity patterns at the ages of 15, 30, 50, and during the past year, when their average age was 60.

They tracked the participants’ heart health for an average of 12 years from 1997 onward to gauge how many developed AF, which is a known risk factor for stroke.

The men who had exercised intensively for more than 5 hours a week were 19% more likely to have developed AF later in their lives than those exercising for less than 1 hour a week.

The level of risk rose to 49% among those who did more than 5 hours of exercise a week at the age of 30, but who subsequently did less than an hour by the time they were age 60.

But those who cycled or walked briskly for an hour a day or more at age 60 were about 13% less likely to develop AF than those who did virtually no exercise at all.

MODERATION, MODERATION, MODERATION

“It seems that moderate doses of physical activity are enough to get the positive effects without acquiring the negative effects, while these benefits are lost with very high intensity and prolonged efforts,” Dr. Drca noted.

There are several possible mechanisms by which frequent endurance exercise could increase the risk for AF, he said.

These include enlargement of the left atrium, enlargement of and left ventricular hypertrophy, inflammatory changes in the left atrium, and an increase in the activity of the parasympathetic nervous system.

“In our study, the men who had the highest risk of developing atrial fibrillation were those who were very physically active when they were young, but stopped being physical active.

I think that moderate intensity regular physical activity that you continue throughout your life is the best way to maximize the benefits obtained by regular exercise while preventing undesirable effects.”

He added: “Physical inactivity and a sedentary lifestyle is a far bigger problem in the general population than excessive physical activity.

However, frequent high-intensity exercise during many years is associated with an increased risk of AF.”

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.”

Exercise May Boost Recovery of Motor Function in Stroke Patients

Aerobic exercise improves cardiorespiratory fitness in patients with stroke, and also may have a beneficial effect on their brain function as well as help them improve recovery of motor function, according to the results of a new study.

Aerobic exercise elicits a variety of positive effects in people of all ages.

Recently, researchers have found significant improvements in aerobic exercise capacity among stroke patients who underwent a structured cycling exercise program.

“The effects of aerobic exercise may serve to prime the central nervous system in individuals with stroke to create an environment optimal for neuroplasticity (the brain’s ability to reorganize itself),” Susan Linder, a research physical therapist at the Cleveland Clinic in Cleveland, told a packed poster session at the American Academy of Neurology annual meeting in Philadelphia.

“Our work in individuals with Parkinson’s disease indicates that forced exercise administered via a motor-assisted stationary bicycle results in increased cortical activation and improved motor and non-motor function when compared to voluntary exercise,” Linder said.

The precise mechanism responsible for improvements in patients with Parkinson disease is unknown, but Cleveland Clinic researchers hypothesize that aerobic exercise increases concentrations of brain-derived neurotrophic factor (BDNF), a protein released in the CNS that facilitates long-term enhancement of signals within the brain and promotes growth of dendrites, which are branched filaments in nerve cells.

“Pairing aerobic exercise with upper extremity repetitive task practice in individuals with stroke may exploit the neuroplasticity properties associated with BDNF and optimize motor learning,” said Linder.

IMPROVED MOTOR OUTCOMES

She reported the results of a study of 14 patients who had a stroke within the previous 6 to 12 months.

They were randomized into 3 groups.

One group performed a 45-minute session of aerobic exercise at a forced rate within their heart rate range on an exercise cycle, followed by 45 minutes of repetitive task practice with hands or arms.

The second group performed the same exercises but exercised at their own rate.

The third group did no aerobic exercise and performed two 45-minute sessions of upper extremity exercises.

All participants exercised 3 times a week for 8 weeks, and they were able to complete the cycling protocol with modifications for fatigue.

All were able to achieve hundreds of repetitions with repetitive task practice.

“Motor outcomes are trending in a positive direction for all groups, but the group who performed forced rate exercise displayed the most consistent improvements,” Linder said, noting that the control group had twice the amount of time doing upper extremity exercises.

“We also saw improvement in depression and quality of life in the aerobic exercise group trending toward favorable.”

Linder added, “We know that aerobic exercise can help stroke patients’ physical fitness.

Is there a neuroplasticity effect?

We hope that the byproduct of aerobic exercise is reduced amounts of rehabilitation time as well as doses that lead to better motor outcomes for stroke patients.”

The Cleveland Clinic researchers are expanding their research to include 75 patients and will add in neurological examinations.

Said Linder, “We plan to look at changes in structure of connectivity within the brain using imaging and resting MRI to see whether areas of brain regrow and improve neural connections with aerobic exercise.”

Mediterranean Diet Reduces Diabetes, Inflammation

Two new studies show the heart-healthy benefits of eating a Mediterranean diet.

One study linked the diet to a lower risk of diabetes, especially among those at high risk for cardiovascular disease.

The other study tied the eating plan to lower levels of platelets and white blood cells, 2 markers of inflammation, which has been associated with a greater risk of heart attack and stroke.

The Mediterranean diet frequently emphasizes fresh fruits and vegetables, whole grains, beans, nuts, fish, olive oil, and even a glass of red wine.the_mediterranean_diet_

Eating an anti-inflammatory, Mediterranean style diet has been shown to not only be a delicious and enjoyable way to eat, but also is wonderful for your health.

Earlier research has shown that following the traditional Mediterranean diet also is linked to weight loss, a reduced risk of heart disease and related death, and lower blood pressure and blood cholesterol levels.

Mediterranean Diet Reduces Risk of Diabetes

In the first pooled analysis of studies evaluating the possible role of the Mediterranean diet in diabetes development, adherence to this diet was associated with a 21% reduced risk of diabetes compared with the control dietary groups.

The likelihood of developing diabetes was almost 27% less in those at high risk for cardiovascular disease than in controls.

“Adherence to the Mediterranean diet may prevent the development of diabetes irrespective of age, sex, race, or culture,” said lead investigator Demosthenes Panagiotakos, PhD, professor at Harokopio University, Athens, Greece.

“This diet has a beneficial effect, even in high risk groups, and speaks to the fact that it is never too late to start eating a healthy diet.”

Dr. Panagiotakos and colleagues systematically reviewed 19 original research studies that followed more than 162,000 participants for an average of 5.5 years.

These studies spanned European and non-European populations, which is important because most of the published studies have been European-based and there has been some question of possible confounding factors in these regions, including genetics, the environment, lifestyle, and lower stress levels.

Dr. Panagiotakos said he believes the Mediterranean diet lowers the risk of diabetes by helping guard against obesity.

He presented his study on March 27, 2014 at the American College of Cardiology’s 63rd Annual Scientific Session in Washington, DC.

Mediterranean Diet Lowers Inflammation

To understand whether a Mediterranean diet might favorably influence platelet and white blood cell levels, Italian researchers conducted an analysis of the eating habits of nearly 15,000 healthy Italian men and women aged 35 years or older as part of a large epidemiological study.

The investigators observed that consumption of the Mediterranean diet was directly related to lower levels of platelets and white blood cells, which in turn correlated to lower levels of inflammation.

Those who strictly followed a traditional Mediterranean diet were less likely to belong to study cohorts with relatively high platelet counts and were more likely to belong to cohorts with relatively low white blood cell counts.

“Because the study included healthy participants, the lower levels of platelets and white blood cells in those who were more strictly consuming a Mediterranean diet indicate that this eating plan could account for substantial changes within normal ranges of variability,” said lead author Marialaura Bonaccio, PhD.

“This is an important finding that has implications for how these anti-inflammatory markers are tracked among the general population.”

Dr Bonaccio is with the Department of Epidemiology and Prevention at the IRCCS Istituto Neurologico Mediterraneo NEUROMED in Italy.

The results of her study were published online in the March 31, 2014 issue of Blood.