Approximately 14% strokes occur when asleep: Study

A new study has revealed that approximately 14% of all strokes occur during sleep, preventing many from getting clot-busting treatment.

"Because the only treatment for ischemic stroke must be given within a few hours after the first symptoms begin, people who wake up with stroke symptoms often can't receive the treatment since we can't determine when the symptoms started," said study author Jason Mackey, of the University of Cincinnati and a member of the American Academy of Neurology.

The researchers examined all cases of ischemic stroke in people age 18 and older seen in hospital emergency departments. The majority of strokes are ischemic strokes caused by blocked blood flow in the brain.

Of the 1,854 ischemic strokes in the study, 273, or 14%, were "wake-up strokes," where the person woke up with stroke symptoms. By extrapolating that number to the general U.S. population, the researchers estimate that approximately 58,000 people in the United States go to the emergency department with a wake-up stroke in a year.

The researchers also analysed whether those with wake-up strokes would have been eligible for the clot-busting drug tissue plasminogen activator, or tPA, if the time of stroke onset had been available. Of the 273 wake-up strokes, at least 98 would have been eligible for treatment.

The study was recently published in the- print issue of Neurology.