Silent cerebral infarction (SCI), more commonly referred to as 'silent stroke' is a brain lesion that is found incidentally on imaging of the brain in otherwise healthy subjects who have not reported symptoms consistent with stroke. SCI is often a herald of more severe strokes that exhibit symptoms or lead to progressive brain damage. According to a study published online in the journal Stroke, approximately 10% of apparently healthy middle-aged adults have experienced SCIs.

Investigators from Boston University evaluated 2040 people with an average age of 62 years who underwent magnetic resonance imaging (MRI) of the brain in 2001 and were free of the neurologic disturbances associated with clinical stroke. Of these study subjects, 10.7% had evidence of SCI on MRI. The estimated prevalence of SCI in this study is comparable to previous estimates, which range between 5.8% and 17.7%. The study subjects were also assessed using the Framingham Stroke Risk Profile, which predicts the 10-year probability of stroke. The investigators reported that the risk factors associated with clinical stroke were high blood pressure, elevated homocysteine (an amino acid) levels, and carotid artery disease. Cholesterol levels, cardiovascular disease, and cigarette smoking did not seem to affect the risk for SCI.

The findings reported in this study underscore the importance of blood pressure control, in terms of mitigating the risk not only for heart disease, but also for stroke.