Silent Stroke Tied to Memory Loss

What if a stroke (brain attack) occurred and you didn’t even know it? Though this may seem odd, it is possible for someone to experience symptoms but not a full-blown stroke—a “silent stroke.”

During a silent stroke, a blood clot blocks blood flow to part of the brain, causing brain cells in that area to malfunction and die. These neurological events damage a smaller area of the brain, which often doesn’t affect movement or speech — the more obvious signs of a traditional brain attack. So a patient may not notice a silent stroke and won’t know it happened until a physician diagnoses it with a magnetic resonance imaging (MRI) or a computerized tomography (CT) scan of the brain.

Research recently published in the journal Neurology demonstrated the link between silent strokes and memory problems. In the study, 23, 830 people with an average age of 64 completed stroke-symptom questionnaires at the start of the study and every six months after that, for at least two years. Researchers also tested study participants’ memory and thinking skills yearly. During the study, 30 percent of the participants experienced stroke-like symptoms, but did not suffer a brain attack. These people were more likely to develop memory and thinking problems than those without symptoms.

Moreover, the study showed that Caucasians with symptoms of a brain attack were twice as likely to develop cognitive problems (11 percent) as Caucasians who did not have stroke symptoms (5 percent). African-Americans who had stroke symptoms were nearly 70 percent as likely to develop thinking problems (16 percent) as African-Americans who did not show stroke symptoms (about 10 percent).

The noticeable difference in the findings with Caucasians and African-Americans might be related to the fact that African-Americans have a higher incidence of symptomatic strokes and larger strokes compared to Caucasians. This is largely due to African-Americans having a higher prevalence of pre-disposing risk factors such as diabetes, hypertension (high blood pressure), high cholesterol and obesity.

The Neurology study highlights the importance of doctors’ asking patients about stroke-like symptoms that may be related to a possible history of silent strokes. This is especially significant in people with risk factors of stroke, in which cases a physician can start therapies that can decrease the risk of memory problems–and more importantly, the chance of a life-threatening stroke.

This post was written by Rafael Ortiz, MD, director of neuro-endovascular surgery and stroke at Lenox Hill Hospital.  

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