What is a silent stroke?
However, some strokes don’t cause any symptoms at all. In fact, in some cases you wouldn’t even know you had one unless you had an MRI or brain scan for an unrelated reason such as headaches, trouble thinking, or dizziness, says Rohan Arora, MD, director of the Stroke Program at Northwell Health’s Long Island Jewish in Forest Hills, Queens, New York. Still, the effects of these silent strokes, known medically as silent cerebral infarctions, can add up and cause lasting brain damage and erode your memory. Silent strokes also increase your risk for having a major stroke.
Silent strokes are much more common than strokes that cause symptoms. In fact, as many as 11 million Americans may have a silent stroke each year, while 800,000 suffer traditional strokes with symptoms, according to the American Heart Association (AHA) and American Stroke Association. These strokes tend to become more common with age, and about one in four people over age 80 have had one or more, according to the AHA.
“As the name suggests, individuals who have silent strokes do not typically have or present to the doctor with stroke symptoms such as sudden drooping of face, slurred speech, balance problems, or paralysis,” says Dr. Arora.
During a silent stroke, a tiny blood clot blocks blood flow to a small area of your brain, and this small area of brain tissue dies permanently, explains Deepak L. Bhatt, MD, MPH, executive director of Interventional Cardiovascular Programs at Brigham and Women’s Hospital in Boston. Silent strokes appear as white spots on an MRI, with the spot the result of blockage-related scar tissue or tiny areas of bleeding.
Even though they are silent, these strokes still have serious and lasting consequences, Dr. Bhatt stresses. “Having silent strokes can lead to damage of the brain, and you can develop vascular dementia over the course of a decade,” he says. (Marked by decline in thinking skills, vascular dementia is the second most common cause of dementia after Alzheimer’s disease, according to the Alzheimer’s Association.) “The brain just doesn’t work as well as it once did.”
Silent strokes typically don’t have signs but sometimes there may be subtle symptoms. “If your right hand is clumsy all of a sudden, it’s probably not lack of sleep,” Dr. Bhatt explains. “If you have trouble moving your mouth or grabbing onto something, it’s never normal. It may go away and you will be relieved, but it could have been a silent stroke.”
Silent strokes are even more subtle than silent heart attacks, he adds. “When someone is told by their doctor they had a silent heart attack, they may look back and recall a time where they felt short of breath for a week.” he says. But “it is unlikely that you will have paralysis of leg or half of face and not realize it.”