Posts Tagged strokes
“Silent Strokes” Different than TIAs, Experts Say
If you are an older American with no major health problems, chances are about one in 10 that you have had a stroke and did not know it, according to a report in the medical journal Stroke.
It was probably not severe enough to cause recognizable symptoms, such as vision problems, facial weakness, or trouble walking, but it was still a blockage of a brain artery, and it reduced your thinking powers just a bit.
That estimate comes from a new study of 2,040 people, average age 62, in the long-running Framingham Offspring Study.
Magnetic resonance imaging (MRI) scans showed that 10.7 percent of them had experienced what study author Dr. Sudha Seshadri, at Boston University, calls “a silent brain infarct.”
It is the cerebral equivalent of what physicians call a myocardial infarct – blockage of a blood vessel that causes damage to heart tissue. In the case of a silent stroke, the blockage and the damage occurs in the brain, without symptoms.
TIA Has Symptoms, Silent Stroke May Not
A silent stroke is different from a transient ischemic attack (TIA), a momentary loss of brain function, says Dr. Seshadri. A TIA causes some symptoms, while a silent stroke, by definition, does not.
But both are warning signs to pay attention to the well-known risk factors for stroke, such as cholesterol levels, blood pressure, obesity, and smoking.
The incidence found in the Framingham Offspring study “was within the ballpark of what prior studies have suggested,” notes Dr. Seshadri.
“But this was a group of people who were younger than in most of the prior studies,” she says. “The fact that one in 10 persons had silent attacks that had subtle side effects on the brain is something we should be concerned about and should address.”
The effects of a silent brain infarct show up on an MRI scan as “small lesions in various parts of the brain,” says Dr. Seshadri. “We can’t tell from that whether they had a symptomatic attack.”
And the MRI scans give no clues as to when the silent stroke occurred.
Testing showed that “on average, compared to age-matched controls, those with lesions do have subtle signs, such as loss of flexibility of talk,” she says.
Address Risks Through Lifestyle Changes
The incidence seen in the study did not startle Dr. Claudette Brooks, at West Virginia University Health Sciences Center.
“When I look for the cause of headaches and similar problems, it doesn’t surprise me when I see these lesions, and other colleagues tell me they see them,” says Dr. Brooks.
An even higher rate of silent strokes might be expected in a study of African Americans, she notes.
“They have a higher incidence of hypertension [high blood pressure], atherosclerosis, and hyperlipidemia [excess blood fat],” says Dr. Brooks.
Nothing special needs to be done to reduce the risk of silent stroke, both physicians say.
“I wouldn’t recommend that people rush out to have an MRI,” says Dr. Seshadri. “It’s up to the medical and public health community to emphasize the importance of controlling risk factors.”
“The whole thing boils down to modifying risk factors,” explains Dr. Brooks. “If you don’t have risk factors such as high cholesterol, obesity, and diabetes, try to keep yourself out of the group that does. If you do, modify them by keeping blood pressure and cholesterol down, things like that.”
Always consult your physician for more information.
Online Resources
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National Heart, Lung, and Blood Institute (NHLBI)
National Institute of Neurological Disorders and Stroke
Stroke – Prevalence and Correlates of Silent Cerebral Infarcts in the Framingham Offspring Study
Add comment September 9, 2008
