Posts Tagged ‘memory’

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.”

Obstructive Lung Disease Tied to Cognitive Impairment

If you have obstructive lung disease such as asthma, bronchitis, or chronic obstructive pulmonary disease (COPD), you may be more likely to have problems with memory and information processing.

New evidence suggests that the more diminished your airflow, the greater your impairment.

“Persons with obstructive lung disease experience cognitive impairment mainly in memory and information processing, which is partially related to impaired lung function,” said Fiona Cleutjens, MSc, of the Center of Expertise in Chronic Organ Failure in Horn, the Netherlands.

“We know from other studies that cognitive impairment may have negative consequences for daily functioning, health status, and treatment adherence.”

The researchers presented their results at the 2013 European Respiratory Society Annual Congress.

Earlier studies suggested that those with obstructive lung disease often experience problems with a range of mental processes.

But those studies looked only at global cognitive function.

The new study looked at specific cognitive functions that affect those with obstructive lung disease.

Cleutjens and colleagues conducted a large prospective cohort study of more than 500,000 Scottish, English, and Welsh persons aged 40 to 70 years that focused on genetics, environmental exposures, and lifestyle.

They identified more than 5000 men and women who had obstructive lung disease and more than 37,000 comparable people who did not have lung disease.

All completed several tests to examine cognitive performance and lung function.

Worse Scores on Memory Tests

Those with obstructive lung disease had significantly worse scores on memory tests as well as slower reaction speeds compared with those without lung disease, which is an indirect indication of the cognitive processing speed, Ms Cleutjens said.

They also scored worse on tests that reflect the capacity to understand and remember the spatial relations among objects.

They also scored significantly more poorly for all but the test of fluid intelligence, which Ms Cleutjens described as reflecting the capacity to solve problems that require logic and reasoning ability.

Those with the least severe obstructive airway disease had significantly better fluid intelligence scores than those in the intermediate group and significantly better numeric memory than those in the most impaired group.

Ms Cleutjens noted that cognitive problems associated with obstructive lung disease can be debilitating, particularly for a patient who is already dealing with the symptoms of lung disease.

She added that obstructive lung diseases such as asthma and COPD often exist alongside other conditions.

Routine Screening for Cognitive Problems

Ms Cleutjens recommended routine screening for cognitive problems in patients with obstructive lung disease and suggested that a simple screening questionnaire would be a good first step.

Then any patients showing problems could be tested further with a neurocognitive battery to determine which aspects of cognition are impaired or a physician may decide to test only those patients who report cognitive difficulties or who have other risk factors for cognitive impairment, such as vascular problems.

Medications also may affect cognitive performance.

For example, anticholinergic drugs often prescribed for obstructive lung disease are associated with memory loss in some patients.

Ms Cleutjens noted, “Clinicians and health care professionals need to be alert to the possible impact of cognitive impairment in the self-management, clinical management, and pulmonary rehabilitation of obstructive lung disease patients.”