One in Seven Strokes Occurs During Sleep, Many Go Without Clot-Busting Treatment
14 percent of all strokes occur during sleep, preventing many from
getting clot-busting treatment, according to a study published in the
print issue of Neurology, the medical journal of the American Academy
"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
Dr. Jason Mackey, of the University of Cincinnati and a member of the
American Academy of Neurology. "Imaging studies are being conducted now
to help us develop better methods to identify which people are most
likely to benefit from the treatment, even if symptoms started during
The study examined all cases of ischemic stroke in
people age 18 and older seen in hospital emergency departments in the
Greater Cincinnati/Northern Kentucky region over one year. The majority
of strokes are ischemic strokes caused by blocked blood flow in the
Of the 1,854 ischemic strokes in the study, 273,
or 14 percent, 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 compared those with wake-up
strokes to those who were awake when their stroke symptoms started.
There were no differences between the two groups in terms of sex,
whether they were married or were living with someone, and their stroke
risk factors such as high blood pressure, diabetes, smoking or high
There were minor statistically significant
differences in age and the severity of the stroke. People with wake-up
strokes were an average of 72 years old, compared to 70 for non-wake-up
strokes. Those with wake-up strokes had an average score of four on a
test of stroke severity, compared to a three for those with non-wake-up
strokes. Scores ranging from one to four indicate mild strokes.
The researchers also analyzed 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.
"This is a group of patients that should be a
focus for future studies," Mackey said. "It's likely that some of these
strokes occurred immediately prior to awakening, and people would
benefit from treatment."
For more information on the American Academy of Neurology, visit www.aan.com.