Brain damage real from 'silent stroke'

February 16, 2001
Web posted at: 1:21 p.m. EST (1821 GMT)

From Rhonda Rowland
CNN Medical Correspondent

(CNN) -- Eleven million Americans will have strokes this year. But they won't know it.

"There are 20 silent strokes occurring in this country each year for every single symptomatic stroke that's occurring," said Dr. Jeffrey Saver, a neurologist at the University of California-Los Angeles Stroke Center. "I think that a lot of physicians and patients and families are going to be surprised by the numbers."

Previous studies had suggested that silent strokes were quite common, but research conducted by Saver and his colleagues (funded by the National Institutes of Health and the American Heart Association) put a concrete number on the incidence of silent stroke. He called the figure "shocking and dramatic."

"This is a major disease that's affecting our population," Saver said. We need to do everything possible to have people avoid stroke by changing their lifestyle and following the principles that we already know about and by doing more research to prevent this devastating disease."

A silent stroke is just that -- a stroke that causes real brain damage, but does not exhibit the classic symptoms of stroke such as vision changes, speech problems and paralysis or weakness in one side.

	VIDEO
CNN's Rhonda Rowland explains the new findings on silent strokes Play video (QuickTime, Real or Windows Media)

"That means that the injury occurred in a relatively unimportant brain area," said Saver.

But it doesn't mean the damage is any less important. Such injury can add up over time, leading to cognitive impairments, failing memory, difficulty walking and, eventually, dementia.

Researchers admit they still have much to learn about silent strokes.

Because they don't exhibit symptoms, silent strokes are only detected when a patient undergoes a brain scan, said Dr. Michael DeGeorgia of the Cleveland Clinic.

"The question that really comes up is should every patient get a brain scan, now that we know millions of patients -- millions of people -- have silent strokes," said DeGeorgia. "Should that become a routine test? I don't think we're there yet."

Doctors do know the same factors that put people at risk for a symptomatic stroke -- family history of the disease, diabetes, high blood pressure -- put people at risk of a silent stroke. They say eating a healthy diet, exercising and cutting out smoking can help protect from both kinds of stroke.

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University of California-Los Angeles
American Heart Association
Centers for Disease Control and Prevention: Stroke information

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