NEW YORK – Ms Kristin Kramer woke up early on a Tuesday morning 10 years ago because one of her dogs needed to go out. Then a couple of odd things happened.

When she tried to call her other dog, “I couldn’t speak”, she said. As she walked downstairs to let them into the yard, “I noticed my right hand wasn’t working”.

But she went back to bed, “which was totally stupid”, said the 54-year-old office manager in Indiana state. “It didn’t register that something major was happening” especially because, reawakening an hour later, “I was perfectly fine”.

So, she “just kind of blew it off” and went to work.

It is a common response to the neurological symptoms that signal a transient ischaemic attack (TIA) or mini stroke. At least 240,000 Americans experience one each year, with the incidence increasing sharply with age.

Because the symptoms disappear quickly, usually within minutes, people do not seek immediate treatment, putting them at high risk for a bigger stroke.

Ms Kramer felt some arm tingling over the next couple of days and saw her doctor, who found nothing alarming on a CT scan. But then she started “jumbling” her words and finally had a relative drive her to an emergency room (ER).

By then, she could not sign her name. After undergoing magnetic resonance imaging (MRI), she recalled, her doctor came in and said: “You’ve had a small stroke.”

Did those early-morning aberrations constitute a TIA? Might an emergency call and an earlier start on anti-clotting drugs have prevented her stroke? “We don’t know,” Ms Kramer said.

She is doing well now, but faced with such symptoms again, “I would seek medical attention”.

Now, a large epidemiological study by researchers at the University of Alabama at Birmingham, published in JAMA Neurology, points to another reason to take TIAs seriously. Ov...