The findings were published in the Dec. 26 issue of the Journal of the American Medical Association.
The researchers found that brief neurological problems occurred in 548 of the subjects. Of those, 282 were classified as focal (suggesting a problem in a specific area of the brain), while 228 others seemed to be more of a widespread problem in the brain. The rest, 38 subjects, had incidents that fit into both categories.
Those who had focal incidents were more than twice as likely to have a stroke as the others; their risk of a stroke within three months after an incident was 3.5 percent. Patients with non-focal incidents had a 56 percent higher risk of stroke and 59 percent higher risk of senility than those who didn't experience such a problem.
"Our findings challenge the strong but unfounded conviction that non-focal [incidents] are harmless," the authors wrote.
In a commentary that accompanied the study, Dr. S. Claiborne Johnston, director of the Neurovascular Disease and Stroke Center at the University of California, San Francisco, wrote that there's too little information about how to handle patients who experience these problems: "There is no consistent evaluation, no guidelines for treatment, and no information on prognosis. This study argues that, whatever is causing these events, the prognosis justifies greater attention."
In any event, people should call 911 if they have any "new neurologic deficit," such as weakness, numbness, difficulty speaking, poor vision on one side, memory loss or a sudden headache associated with nausea and neck pain, Hillis said. Emergency care is needed for this condition "even if it only lasts for five to 10 minutes."
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