The consequences of a stroke can be devastating for older adults, leading to dementia, physical disability, or death. In a recent study, researchers from Boston University present new findings about a particularly dangerous form of stroke: those that occur without symptoms. The exact prevalence of these strokes has been unclear, but the study, which appears in Stoke: the Journal of the American Heart Association, indicates that they may affect as many as 10 percent of seemingly-healthy older adults and, though they cause no observable effects, can still result in significant damage to the brain.

The study involved over 2,000 people who averaged 62 years of age and did not have any symptoms that would indicate a neurological problem. None of the subjects had a history of stroke, yet brain scans found that 10.7 percent had suffered a silent stroke at some point. These strokes corresponded to age, and the prevalence rate ranged from seven percent among those aged 30 through 49 to 15 percent in those aged 70 through 89. Silent stokes caused no symptoms, but they did leave lesions in the brain, especially in the subcortical areas. This brain damage could herald future problems, and past research has shown that individuals who have experienced silent strokes have an increased risk of future stokes and long-term dementia.

To determine risk factors, the researchers investigated a number of related health conditions. They found that, as is the case with symptomatic strokes, cardiovascular risk factors also highly influence an individual’s chances of suffering a silent stroke, particularly high blood pressure, elevated blood levels of the amino acid homocysteine, and atrial fibrillation, the most common form of abnormal heartbeat. Importantly, these risk factors can be partially prevented through lifestyle changes, and individuals who eat well, stay active, quit smoking, and cut down on alcohol consumption will have a better chance at staving off these health conditions and lowering their chances of stroke or heart disease.

Anyone who experiences symptoms of a stroke, which could include numbness, difficulty speaking, or confusion, should seek help immediately, even if the symptoms are not severe or do not last long. Early treatment is the most effective way to prevent disability or death, and we must continue to study silent strokes to better understand how they develop and how they can be treated. Future studies should focus on ways of identifying those who have had a silent stroke or who may be at risk for one, as screening methods could greatly reduce the number of adults who go untreated after suffering a stroke. With a clearer understanding of silent strokes, we may be able to help many retain their physical and mental health as they age.