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What you need to know about silent strokes

Blog
01/15/26
Most strokes are “silent.” That is, they happen without the person knowing. But they can lead to subtle losses of function. And they're a sign that a person is at risk of another stroke.

A stroke happens when a blood vessel in the brain gets blocked by a clot or ruptures. It can have a sudden, sometimes obvious onset. If a person notices stroke symptoms, they should get emergency medical help immediately.

There’s an acronym to help people remember the symptoms of stroke. It’s called F.A.S.T.

  • Face: One part of the face is drooping.
  • Arms: It is suddenly difficult to lift one or both arms over the head.
  • Speech: The person has slurred speech.
  • Time: Getting emergency help as soon as possible can help improve the person’s chances of recovery.

But sometimes, there are no apparent symptoms.

A silent stroke is a stroke that people don’t realize has happened. Experts estimate that for every stroke that’s detected, 10 more go undetected.

Identifying when a silent stroke has happened is important not just to help the person recover and rehabilitate, but also to help them avoid another stroke in the future. Having a stroke increases a person’s risk of having another one.

Silent stroke causes

A stroke is when a blood vessel in the brain becomes blocked (usually due to a blood clot) or bursts. This cuts off the blood supply to a specific area of the brain, causing the brain cells in that area to die.

The person experiencing a stroke loses the capacities controlled by the affected part of the brain. They may experience issues with speech, memory, vision or movement.

When blood can’t get to an area of the brain and causes tissue death without symptoms, this is known as a silent stroke or silent infarct. One in four people over the age of 80 has had at least one silent stroke.

A silent stroke only affects a small area of the brain. They’re usually caused by atherosclerosis (disease of the arteries) in small blood vessels in the brain or by emboli. Emboli are small blood clots from the heart or carotid arteries that travel to the brain and block small blood vessels.

Usually, the small damaged area of the brain only partially contributes to certain functions like movement or speech. And another brain area also contributes to the functions, making the symptoms less noticeable.

Sometimes, a stroke is silent because a small blood vessel in the brain was blocked. And this area of the brain also gets its blood supply from another blood vessel, so the damaged area is very small.

Silent stroke symptoms

Can a person have a stroke and not know it? Yes. Silent strokes don’t have obvious symptoms.

However, silent strokes may result in subtle changes to how a person moves or processes things mentally. These changes may be hard to recognize can affect:

  • Vision
  • Ability to walk
  • Speech
  • Understanding language
  • Personality
  • Memory
  • Cognitive ability (thinking skills)

It’s usually hard to pin down when the symptoms started. A larger stroke will usually cause several symptoms, such as one-sided numbness and weakness in the arm and leg.

Silent stroke diagnosis

To diagnose stroke, a healthcare team will need to rule out conditions that cause similar symptoms. These can include seizures, migraine headaches and drug overdose.

Diagnostic tools physicians will use include:

  • Interviewing the person about their symptoms, medical history and family history
  • Physical examination
  • Neurological examination
  • Blood tests
  • Medical imaging, such as CT or MRI scans

A care team can identify evidence of an old stroke on an MRI, CT scan or through other types of medical imaging.

A silent stroke is usually found incidentally during imaging for other neurological symptoms or dementia.

If a person receives a diagnosis of a silent stroke, it’s important for them to work with their physician to:

  • Identify what stroke effects they may have been having, such as speech problems
  • Start therapy and/or rehab to improve the lost skills
  • Get tested for stroke risk factors
  • Get treatment for those risk factors to reduce the chance of a more serious stroke in the future

Risk factors for a stroke

Some risk factors for stroke are possible to manage, while others aren’t.

Manageable stroke risk factors include:

  • High blood pressure: It’s possible to manage blood pressure through lifestyle changes and medication.
  • Birth control that contains estrogen: Hormonal birth control may not be appropriate for people at high risk of stroke.
  • High blood sugar levels: Keeping blood sugar within a target range, especially in people with diabetes and prediabetes, can help lower stroke risk.
  • Diets high in saturated fat, trans fat and cholesterol: Following the Mediterranean or DASH diet may help lower stroke risk.
  • Lack of physical activity: Increasing physical activity of any kind helps. Speak with a physician for personalized recommendations.
  • High fat and cholesterol levels: In addition to lifestyle changes, use of statins can help lower cholesterol levels and reduce the risk of stroke.
  • Certain preexisting conditions: Those with diabetes, blood disorders, artery disease or sleep apnea may have a higher risk of stroke. It’s best to talk with a provider about ways to help lower these risks.

Unmanageable stroke risk factors include:

  • Age: Risk increases with age, but stroke can happen in people of any age.
  • Family history: Having a genetically related family member who has had a stroke, especially before the age of 65, raises your personal risk of stroke.
  • Race: Black and Hispanic people have a much higher risk of death from stroke than white people. There may be some genetic factors for this increased risk. In addition, lack of access to healthcare plays a role.
  • A history of stroke, heart attack or transient ischemic attack (TIA): These events are all linked with plaque buildup in the blood vessels, which contributes to stroke.

Treatment and rehabilitation

How physicians treat stroke depends on the type of stroke and where in the brain it happened. Again, it’s important that people with symptoms of stroke seek immediate emergency medical treatment to get the best possible outcome. A person’s rehabilitation after stroke depends on how severe their stroke was and what functions were affected by the stroke.

Over time, a person who has had a stroke, including a silent stroke, can recover some of the abilities they lost.

People who have lost physical, mental or emotional functions as a result of a stroke can benefit from rehabilitation. It’s an important way to restore the person’s ability to perform everyday activities.

Stroke rehabilitation includes various therapies designed to help people regain specific functions, depending on the functions they’ve lost. Rehabilitation professionals design personalized programs based on the person’s needs.

Takeaway

A silent stroke is a stroke that goes unnoticed, even by the person who experienced it. However, it leaves damage and may cause subtle changes in functions.

Typically, a silent stroke is found incidentally when a physician is evaluating a person for subtle neurological symptoms. If a person receives a diagnosis of a silent stroke, it’s important to manage risk factors to help prevent another one. They can also work with a physician to start therapy or rehabilitation to ease any symptoms caused by the silent stroke.

Up to 80% of strokes can be prevented with the right medical care and lifestyle changes.

It’s critical to seek emergency help at the first signs of a stroke.

A person should call 911 right away if they have the following stroke symptoms:

  • Speaking problems
  • Face drooping
  • Arm weakness
  • Vision changes
  • Weakness on one side of the body
  • Confusion
  • Slurred speech
  • Using the wrong words
  • Trouble understanding others

The neurologists at Crystal Run Healthcare are expertly trained to investigate, diagnose and treat neurological disorders, which include diseases of the brain, spinal cord, nerves and muscles. Our experienced neurologists treat a full range of neurological disorders, including Alzheimer's disease. We can diagnose a range of neurologic conditions using state-of-the-art diagnostic equipment and technology to complete testing like MRI, CT and PET, lumbar punctures (spinal taps) and more.

Neurology