Brain imaging was performed on 2,000 people participating in an ongoing study from the Netherlands designed to explore the effect of aging on the brain. The average age of the study participants was 63.
Magnetic resonance imaging (MRI) revealed that 7% of the participants showed evidence of a previous unrecognized, asymptomatic stroke.
An additional 1.6% had benign brain tumors and nearly 2% had aneurysms.
Only two of the people with incidental brain findings reported symptoms that would indicate a neurological problem.
The findings are reported in the Nov. 1 issue of TheNew England Journal of Medicine.
Silent Stroke, Major Stroke
The clinical relevance of these incidental brain findings is not completely clear, but earlier studies by the same research team showed that the presence of silent strokes on brain imaging more than doubled the risk for a subsequent major stroke and dementia.
"We know that there is a relationship between asymptomatic stroke and symptomatic stroke and dementia," researcher Aad van der Lugt, MD, tells WebMD. "We now need strategies to prevent these consequences."
Stroke specialist Claudette Brooks, MD, of West Virginia University School of Medicine, tells WebMD that many so-called "silent" strokes are not silent at all.
"Many people ignore symptoms of a small stroke, or they may not associate them with a stroke," she says.
Brooks says any symptoms that might indicate a stroke should always be reported to a doctor, even if the symptom goes away.
According to the American Stroke Association, signs of a potential stroke include:
- Sudden numbness or weakness of the face, arms, or legs, especially on one side of the body.
- Sudden confusion, trouble speaking, or trouble understanding.
- Sudden trouble seeing in one or both eyes.
- Sudden trouble walking, dizziness, and loss of balance or coordination.
- Sudden, severe headache with no known cause.
More MRI, More Discovery of Brain Problems
The fact that almost 2% of the study population had asymptomatic aneurysms or benign brain tumors was more surprising to van der Lugt than the silent stroke finding.
He adds that as the use of brain imaging for diagnosis and clinical research increases, more and more clinically ambiguous brain abnormalities will be discovered.
The best course of managing these asymptomatic brain issues is not known, because it is not clear how often they lead to serious problems.
"We need studies to clarify the clinical implications of asymptomatic brain abnormalities," van der Lugt says. "And people who participate in [imaging] studies need to be made aware of the possibility of these incidental findings which may not need treatment, but could lead to a lot of anxiety."