Researchers reporting June 19 in the journal Neurology said the findings emphasise the need to be vigilant when any sign of stroke occurs.
"Our study highlights the importance of discussing stroke-like symptoms with your family doctor, even if they don't last long," study author Dr Brendan Kelley, of the University of Cincinnati, said in a journal news release. "These symptoms can be a warning sign that a person is at increased risk of stroke or problems with thinking or memory."
Kelley's team's study involved nearly 24 000 people, average age 64, who completed stroke-symptom questionnaires at the start of the study and every six months after that for at least two years. Their memory and thinking skills were also tested yearly.
During the study, 30% of the participants experienced stroke-like symptoms but did not suffer a stroke. Those people were more likely to develop memory and thinking problems than those without such symptoms.
Memory and thinking problems were much more likely to occur in both whites and blacks with stroke-like symptoms (11% and 16%, respectively) than in people without such symptoms (5% and 10%).
Knowing symptoms is key
"Silent strokes that cause small areas of brain damage have been tied to memory and thinking problems, but it has been difficult to study these 'silent strokes' due to the cost and inconvenience of obtaining brain MRIs," Kelley said. "With this study, we found that a quick, seven-question test can be a cost-effective tool to help identify people at increased risk of developing dementia."
Another expert said knowing the symptoms of stroke is key.
"It is important that people who experience an inability to speak, slurred speech, weakness, double vision, dizziness or numbness on one side of the body undergo [emergency care] for treatment of stroke," said Dr Rafael Alexander Ortiz, director of Neuro-Endovascular Surgery and Stroke at Lenox Hill Hospital in New York City. He was not involved in the new study.
"Some strokes can be 'silent' or asymptomatic because of the location within the brain," Ortiz said. Health care workers should ask questions regarding a potential history of silent strokes in patients, he added, so therapies might be initiated that could "decrease the chance of memory problems and, more importantly, to decrease the chance of a life-threatening stroke."
The US National Institute of Neurological Disorders and Stroke outlines the symptoms of a stroke.