Cerebrovascular disease, including stroke, is the second leading cause of death and a major cause of long-term disability in Western societies. Several studies have shown that the known risk factors for cardiovascular disease -- diabetes, elevated cholesterol, and hypertension -- are also associated with stroke, which may in turn increase the risk for dementia and Alzheimer's disease. However, it remains unclear whether stroke is directly related to cognitive decline -- increasing problems with thinking, learning, and memory -- in patients without dementia or cognitive impairment.
A recent report helps answer that question. The latest news-making study comes from Christiane Reitz, M.D., and her colleagues at Columbia University in New York, who examined the relationship between stroke and memory in patients without dementia or cognitive impairment. Their study appeared in the Archives of Neurology. The goal of the study was to determine whether people who have had a stroke are more vulnerable to worsening memory as they age. The results were affirmative.
People who have had strokes are more likely to develop memory problems, and they experience a more rapid decline. The study’s authors also found that stroke increases the risk of developing Alzheimer's disease. Men were especially vulnerable to these effects.
A stroke occurs when a blood vessel that supplies the brain with oxygen and nutrients either bursts or becomes clogged by a clot or some other particle. Nerve cells in the affected area begin to die within minutes. This same process occurs in a heart attack, which is why strokes are now being referred to as "brain attacks.”
However, not all strokes are so dramatic. Many people experience so-called "partial strokes” -- the clinical term is "transient ischemic attack,” or TIA -- in which a clot blocks a blood vessel, but only temporarily (for less than 24 hours). Like the blockage itself, the TIA symptoms can disappear in a few minutes. There are also "silent strokes,” which occur when very small vessels in the brain are blocked or when a stroke occurs in a seemingly unimportant part of the brain. Even though silent strokes don’t cause the noticeable classic stroke symptoms such as vision changes, speech problems, paralysis, or weakness in one side, they do cause the death of brain cells.
Given that more than 700,000 strokes occur in the United States every year, the implications of the Columbia study are significant. An earlier report from some of the same researchers at Columbia found that the risk of Alzheimer"s disease or dementia was highest when the survivor of a stroke also had some other form of cardiovascular disease, such as high blood pressure or diabetes. Two other major studies have reported that suffering a stroke can double your chances of developing dementia.
For more Alerts and Special Reports on Stroke, please visit the Hypertension and Stroke Topic page.
