Women may be more likely than men to suffer certain "non-traditional" symptoms of stroke, a new study suggests.

Strokes occur when blood flow to the brain is disrupted, usually by a clot blocking an artery. Among the main warning signs are sudden numbness or weakness in the face, arm or leg, especially on one side of the body; trouble speaking or seeing in one or both eyes; and sudden dizziness or coordination and balance problems.

The new study included 461 stroke patients with about an equal number of men and women. The majority of women had at least one of these traditional symptoms. However, more than half also had one or more non-traditional symptom — most often a sudden change in mental status, such as disorientation or confusion.

Compared with men, women were 42 percent more likely to suffer a non-traditional symptom.

The findings, published in the American Heart Association journal Stroke, echo those of studies that have found sex differences in heart attack symptoms. During a heart attack, women are more likely than their male counterparts to have shortness of breath, nausea and vomiting, and pain in the back or jaw, for example.

The full significance of the sex differences in stroke symptoms is not yet clear, however, according to Dr. Lynda D. Lisabeth and her colleagues at the University of Michigan Medical School in Ann Arbor.

Past studies have found that women are less likely than men to receive a stroke therapy called tissue plasminogen activator, or tPA. The drug dissolves clots and restores blood flow to the brain, but it must be given within a few hours of stroke onset. If less-typical symptoms are causing delayed diagnosis in some women, that might help explain the tPA gap, according to Lisabeth's team.

However, they say, more studies are needed to show whether that is, in fact, the case.

It is also unclear whether women should be told to be on the lookout for non-traditional stroke symptoms — which, besides confusion and disorientation, include pain in the face or one side of the body; lightheadedness; possible neurological symptoms such as nausea and general body weakness; and non-neurological symptoms such as chest pain and shortness of breath.

Adding those symptoms to the list of traditional stroke symptoms may confuse people and make stroke recognition overly complex, Lisabeth and her colleagues write.

In addition, women rarely suffered a non-traditional symptom in isolation — with 3 percent to 4 percent reporting only atypical symptoms.

That, the researchers write, suggests that most female stroke sufferers will have at least one of the traditional warning signs.