What is a Silent Stroke?

When people think of stroke, they often visualize a dramatic incident where a person suddenly shows major signs of brain impairment like dizziness or inability to properly move and speak. A very different picture is created with the term silent stroke. When one of these occurs, it may not even be noticed, or, as it has been suggested, small, less dramatic symptoms are simply dismissed.

Stroke occurs when oxygen rich blood fails to supply all the tissues of the brain. This can be due to a blood clot reaching the brain (ischemic) and cutting off blood flow. Blood accumulation in the head may also cut off blood flow supply (hemorrhagic). Symptoms of strokes can be very profound, and may immediately be noticed. In addition to early symptoms, the longer the blood flow is restricted, the more brain cells will die from oxygen loss. This can result in huge changes to function in a number of parts of the brain.

In some circumstances, silent stroke, which is most often the ischemic type, occurs, where symptoms do not present as dramatic, and where area of brain damage doesn’t have much to do with obvious function. Research in this area has certainly shown that a silent stroke causes brain damage, which may have a cumulative effect. Add to this the increased statistical risk for additional strokes, and these “silent” episodes are still very dangerous.

There has been evidence to suggest that perhaps the silent stroke is not fully voiceless. Some people do recall symptoms while strokes occurred like sudden confusion, loss of coordination, very bad headache, or dizziness. Yet when these symptoms disappear quickly, people may ignore their importance and not get to the doctor: a vital step in follow-up treatment and preventative care. Other people don’t have any symptoms and thus don’t know they should see a doctor. Evidence of silent stroke and the brain damage it causes can be visualized with magnetic resonance imaging (MRI), making diagnosis fairly easy, when and if a person realizes they may have had a stroke.

There has been some move to recommend use of MRI as a preventative or standard diagnostic of silent stroke. This does not always meet with favor due to the expense of these scans. Yet doctors supporting routine brain screening, point to statistics suggesting that older people may have a 7% or greater risk of stroke with few symptoms.

While this matter is weighed, it is always important to take stroke seriously. Folks at highest risk include those who smoke, who have high blood pressure, or who have history of blood clots, or atherosclerosis. Those with history of strokes or transient ischemic attacks (mini-strokes) in the past are at increased risk too. A person with these risk factors, especially several of them, should discuss ways to diagnose silent stroke with a doctor. People are also advised to see medical help if symptoms occur at all, even if they quickly fade.