Silent Strokes Linked to Memory Loss

June 4, 2012

About a quarter of older adults may suffer from so-called silent strokes, small areas of damaged brain cells that may contribute to memory loss, a symptom typical of Alzheimer’s disease and other forms of dementia. Taking measures to prevent strokes may help to keep the brain healthy and ward off memory problems in old age.

Those are the findings of a study funded by the National Institutes of Health and published in the journal Neurology. Researchers from the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain at Columbia University Medical Center in New York examined 658 men and women, aged 65 and older, none of whom had a history of serious memory problems or dementia. All were given MRI brain scans to visualize the memory centers of the brain, as well as extensive tests of memory and thinking skills to look for memory problems.

They found that 174, or about 25 percent, of the seniors had evidence of silent strokes, which do not cause obvious symptoms like paralysis or speech problems, but which do appear to lead to subtle deficits in memory. There was no correlation between a shrinking brain, a feature of Alzheimer’s disease, and memory problems. Shrinkage or thinning of the brain, particularly in key memory centers like the hippocampus has been linked to Alzheimer’s in other studies.

“The new aspect of this study of memory loss in the elderly is that it examines silent strokes and shrinkage simultaneously,” study author Dr. Adam Brickman of Columbia. “Since silent strokes and the volume of the hippocampus appeared to be associated with memory loss separately in our study, our results also support stroke prevention as a means for staving off memory problems.”

Other studies have shown that people who are at risk for having a stroke are also at increased risk for memory and thinking problems as they age, even if they have never had a stroke. The findings add to a growing body of evidence that maintaining heart and cardiovascular health is critical for brain health over the long haul too.

Strokes are very common and affect more than 700,000 Americans each year; the numbers may be considerably higher due to silent strokes. They occur when blood vessels that supply the brain rupture or become blocked. A stroke can cause a host of cognitive disabilities, including effects on memory, speech and language, and everyday problem solving. But even without suffering an obvious stroke, as this and other studies show, taking steps to lower stroke risk are critical for maintaining cognitive health.

Taking steps to lower stroke risk may be important in keeping the mind sharp and include:

*Keep blood pressure under control. High blood pressure raises the risk of stroke by two- to four-fold. Get blood pressure checked regularly, and if it is high, you and your doctor can develop a plan to lower it with medications and lifestyle measures. Losing weight, cutting down on salt, eating fruits and vegetables to increase potassium in your diet.

*Quit smoking. Smokers have an increased risk of stroke and Alzheimer’s disease.

*Lower cholesterol. High levels of “bad” LDL ( low-density lipoprotein) cholesterol are linked to a higher risk of stroke.

*Get regular exercise and maintain a healthy weight. Obesity and inactivity have been linked to high blood pressure, diabetes and strokes. They are also linked to an increased risk of Alzheimer’s disease.

By ALZinfo.org. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer’s Research  at The Rockefeller University

Source: Neurology, January 3, 2012. National Institute of Neurological Disorders and Stroke.


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