What is a silent stroke?

What is a silent stroke?

The brain is a complex organ responsible for controlling many different bodily functions. When working at optimal capacity, the brain is a wonder to behold. When illness or trauma affects the brain, various parts of the body may not work as they should.

One of the more devastating things that can affect the brain is stroke. The term stroke describes a sudden stoppage of blood from reaching the brain. Harvard Medical School states that if a large number of brain cells are starved of blood supply, they can die. With their demise, a person’s memory and ability to speak and move can be compromised.

While many strokes come on suddenly, certain factors may indicate a person is at risk. Such factors may include prior heart attacks, genetics, high blood pressure, smoking or a prior stroke. However, in a particular type of stroke — a “silent stroke” — symptoms are far more subtle and difficult to spot.

Silent cerebral infarction, often referred to as SCI or “silent stroke,” is a brain injury likely caused by a blood clot interrupting blood flow to the brain, according to the American Stroke Association. Silent strokes increase risk for other strokes and can be a sign of progressive brain damage. A silent stroke is typically only noticed as a side component of an MRI of the brain. Many times, patients do not recall having a stroke and never felt any symptoms. Silent strokes should not be mistaken for ministrokes. A mini-stroke is a brief but discrete and memorable event, with symptoms appearing for a few minutes or a few hours.

“Approximately 25 percent of people younger than 80 have one silent cerebral infarction,” said Dr. Sanjeeva Onteddu, vascular neurologist at the University of Arkansas for Medical Sciences.

“The prevalence of silent cerebrovascular disease exceeds, by far, the prevalence of symptomatic stroke. It has been estimated that for every symptomatic stroke, there are about 10 silent brain infarctions,” he said.

Onteddu is also the state coordinator for the AR SAVES program. AR SAVES, which stands for Arkansas Stroke Assistance through Virtual Emergency Support, has 48 partner sites throughout the state, including Unity Health in Searcy. Each site is equipped with telemedicine technology, offers training for personnel, support for dedicated tele-stroke nurse facilitators and ongoing continuing education.

Silent strokes are common and can have serious consequences, according to a study on silent stroke titled “Functional and Cognitive Consequences of Silent Stroke Discovered Using Brain Magnetic Resonance Imaging in an Elderly Population” and published in the Journal of American Geriatrics Society.

Almost 50 percent of studied silent strokes affected frontal circuit components of the brain, such as the frontal cortex, basal ganglia and thalamus. Lesions in these brain structures compromised executive functions and were related to vascular dementia. Another study showed associations between silent stroke and visual-field deficits, weakness in walking on heels, history of memory loss, migraines and lower scores in cognitive-function tests.

“Strokes have a high inheritable component, although the genetic basis for this inheritability is not well understood,” Onteddu said, adding that there also are rare genetic disorders that can cause strokes.

The “silent” part of a silent stroke also refers to the areas of the brain that the stroke affects. Experts at Harvard Medical School explain that, during a silent stroke, an interruption in blood flow destroys areas of cells in a part of the brain that is “silent,” meaning that it doesn’t control any vital functions. Researchers say that, over time, the damage from silent strokes can accumulate, leading to more and more problems with memory. Collectively, silent strokes become silent no longer.

There are certain ways to reduce the risk of any type of stroke. These include:

• Managing high blood pressure and high cholesterol levels;

• Quitting smoking;

• Reducing the risk of diabetes and effectively treat the condition if it is present;

• Losing weight to prevent obesity;

• Exercising; and

• Taking a drug that prevents blood clots. “Primary prevention of cardiovascular risk factors is more important than secondary prevention, which are done for prevention of additional strokes or heart attacks,” Onteddu said.

Silent strokes largely go unrecognized but can lead to significant brain injury. Getting the facts can help men and women reduce their risk for silent stroke.