'Benign' Brain Events May Signal Stroke

Study: Symptoms Like Confusion or Fainting May Be Linked to Stroke and Dementia

From the WebMD Archives

Dec. 27, 2007 -- Brief episodes of confusion, amnesia, or fainting with no easily explainable medical cause may signal an increased risk for stroke and dementia among older people, new research suggests.

Doctors often dismiss such episodes as benign occurrences, but researchers found that they were associated with a more than 50% higher risk of stroke and dementia among people age 55 and over.

"Our findings challenge the strong but unfounded conviction that [these events] are harmless," Michiel J. Bos, MD, and colleagues from the Netherlands' Erasmus Medical Center write in the Dec. 26 issue of The Journal of the American Medical Association.

Assessing Stroke Risk

Patients who have small "mini-strokes" -- with symptoms typically lasting only a few minutes -- are at increased risk for more severe strokes with serious medical consequences.

Known medically as transient ischemic attack (TIA), studies suggest that about one in 10 patients who have these transient mini-strokes will suffer a major stroke within 90 days of the event.

But diagnosing a TIA is difficult precisely because symptoms often resolve very quickly.

In the latest study, Bos and colleagues considered the role of a broader range of neurological events in major stroke risk.

These transient neurological attacks (TNAs), as the researchers termed them, were defined as events involving neurological symptoms typically lasting only a few minutes or hours and no more than 24 hours.

TIAs were labeled focal TNAs; other events -- including quickly resolving amnesia, confusion, or dizziness and fainting -- were labeled nonfocal TNAs.

The study included 6,062 residents of Holland over the age of 54 (average age of 68) with no history of stroke, heart attack, or dementia. They were followed for 12 to 15 years through December 2004.

During the observation period, 548 of the participants experienced TNAs, with 282 classified as focal, 228 as nonfocal, and 38 as mixed.

The incidence of focal and nonfocal TNAs was similar among men and women, and the frequency of the events increased with age.

Compared with study participants without TNAs, those with focal TNAs had more than twice the risk of stroke. Their risk of having a major stroke within 90 days was 3.5%.

Patients with nonfocal TNA had a 56% higher risk of stroke and a 59% higher risk of dementia than study participants without a TNA.

"Our findings suggest that nonfocal TNA are not only a risk factor for stroke, but also for dementia," Bos and colleagues concluded.


Benign or Risky?

University of San Francisco neurologist S. Claiborne Johnston, MD, PhD, tells WebMD that it is clear from the findings that doctors should not ignore transient, unexplained neurological events such as bouts of confusion, amnesia, or fainting in their older patients.

"This tells us that this grab bag of events generally thought of as benign may not be so benign after all," he tells WebMD.

"This is really a call for us to learn more about these events. Most of the time they may end up being nothing to worry about. But we need to be able to distinguish the benign ones from the non-benign ones."

In an editorial accompanying the study, Johnston called on clinicians to carefully evaluate patients with these symptoms for stroke risk.

"More needs to be done to identify the TNA patients at greatest risk, to complete evaluations, to rule out important underlying disease, and to continue to study this heterogeneous group," he writes.

WebMD Health News Reviewed by Louise Chang, MD on December 27, 2007


SOURCES: Bos, M.J. The Journal of the American Medical Association, Dec. 26, 2007; vol 298: pp 2877-2885. Michiel J. Bos, MD, MSc, Erasmus Medical Center, Rotterdam, Netherlands. S. Claiborne Johnston, MD, PhD, department of neurology, University of California, San Francisco. Kleindorfer D. Stroke, 2005; vol 36: pp 720-723.

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