Andreas Fhager, a biomedical engineer at the Chalmers University of Technology in Sweden, adjusts the Strokefinder device on a test subject's head. Gunilla Brocker hide caption

itoggle caption Gunilla Brocker

Sen. Mark Kirk, R-Ill., gets help entering the Capitol from Vice President Joe Biden (right) in January 2013, one year after suffering a stroke at age 52. Jewel Samad/AFP/Getty Images hide caption

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Aspirin has been prescribed for decades as a simple way to reduce heart disease risk, but doctors still aren't sure how it works. iStockphoto.com hide caption

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The cause of strokes in younger people remains largely a mystery. iStockphoto.com hide caption

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Insomnia, feeling isolated, and bursts of anger are symptoms of the anxiety disorder known as PTSD. iStockphoto.com hide caption

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Japanese women drink green tea during an outdoor tea ceremony in Kobe, Japan. Making the brew a daily habit may be protective against stroke. Buddhika Weerasinghe/Getty Images hide caption

itoggle caption Buddhika Weerasinghe/Getty Images

The flavonoids in coffee may have health benefits, but preventing stroke may not be one of them. iStockphoto.com hide caption

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Doctors used a type of MRI test to look at the blood vessels in the brain of a woman with dystextia. The test confirmed she was suffering from a stroke on the right side of her brain Archives of Neurology hide caption

itoggle caption Archives of Neurology

Laurel Fontaine, 16, (left) and her twin sister Heather. When Laurel was 11 years old, she suffered a stroke that destroyed 80 percent of the left side of her brain. The singing therapy helped her regain the ability to speak. Ellen Webber for NPR hide caption

itoggle caption Ellen Webber for NPR