Stroke

A stroke, also known as a cerebrovascular accident (CVA), is a sudden interruption of continuous blood flow to the brain and constitutes a medical emergency. A stroke occurs when a blood vessel in the brain becomes blocked or narrows or when a blood vessel bursts and spills blood into the brain. Similar to a heart attack, a stroke requires immediate medical attention.

Some brain cells die due to a lack of essential oxygen and nutrients. Other brain cells die as a result of sudden bleeding in or around the brain. Some brain cells die rapidly, while many remain in a compromised or weakened state for several hours. A stroke can result in permanent brain damage within minutes to hours.

With a stroke, “time is brain,” meaning that the sooner treatment begins, the better. Recognizing the signs of a stroke and calling 911 immediately can help save a family member, neighbor or friend. With prompt treatment, brain cells can be preserved, and the damage can be significantly reduced and even reversed.

Strokes result from blocked blood flow to the brain (ischemic stroke) or sudden bleeding in the brain (hemorrhagic stroke). Various factors increase the risk of stroke, many of which can be modified to help prevent a stroke or a recurrence.

Ischemic strokes are typically caused by plaque or a blood clot that obstructs blood flow to the brain. When plaque accumulates on the inner walls of the arteries, it can result in a condition known as atherosclerosis. Plaque hardens and narrows the arteries, limiting blood flow to tissues and organs. Plaque can accumulate in any artery in the body, including those in the brain and neck. Carotid artery disease occurs when plaque builds up in the carotid arteries of the neck that supply blood to the brain. It is a common cause of ischemic stroke.

Plaque in an artery can also rupture. Blood platelets adhere to the site of the plaque damage and aggregate to form blood clots, which can partially or completely obstruct an artery.

A blood clot that forms in one part of the body can break loose and travel to the brain. This type of ischemic stroke is known as an embolic stroke. Certain heart and blood conditions, such as atrial fibrillation and sickle cell disease, can cause blood clots that lead to a stroke.

Chronic (long-term) inflammation contributes to ischemic strokes. Researchers continue to strive to fully understand this phenomenon. However, it is known that inflammation can damage blood vessels and contribute to atherosclerosis. Furthermore, ischemic strokes can result in inflammation that further harms brain cells.

A transient ischemic attack (TIA) is caused by a blockage in the brain, similar to an ischemic stroke. However, the blockage dissolves before any damage occurs to the brain. It usually lasts less than an hour, but can be intermittent. Ultimately, it may advance to a full stroke. A TIA is also referred to as a mini-stroke.

Sudden bleeding can lead to a hemorrhagic stroke. This occurs when an artery in or on the surface of the brain ruptures. The blood that leaks out causes the brain to swell, which increases pressure and can damage brain cells.

Certain conditions increase the likelihood of bleeding in the blood vessels of the brain:

• An aneurysm: a balloon-like bulge in an artery that can stretch and rupture
• Arteriovenous malformations (AVMs): tangles of poorly formed arteries and veins that can break open in the brain
• High blood pressure: puts pressure on the inside walls of the arteries. This pressure makes the arteries more likely to break open, especially when weakened by an aneurysm or AVM.

Each year, nearly 800,000 Americans suffer a stroke, with about 600,000 being first-time incidents. Once a person experiences their first stroke, the risk of having another stroke increases. The likelihood of a recurrent stroke is highest immediately following the initial stroke and decreases over time. Approximately 25% of individuals who recover from their first stroke will experience another stroke within five years, and about 3% of stroke patients will have a subsequent stroke within 30 days of their first one. Overall, one-third of recurrent strokes occur within two years of the initial stroke.

Stroke occurs across all age groups, genders and races in every country. It can even happen before birth when the developing infant is still in the womb, which is a common cause of cerebral palsy.

Some risk factors for stroke affect only females. These include pregnancy, childbirth and menopause. These factors are linked to hormonal changes that influence females at different life stages. In females of childbearing age, the risk of stroke is relatively low, with an annual incidence of one in 10,000. However, studies have demonstrated that pregnancy triples that risk.

Several factors contribute to the increased risk of stroke during pregnancy:

• The activity of blood-clotting proteins is naturally more significant during pregnancy, increasing the chances of stroke for the mother. Sometimes, clots form in the brain’s large draining veins, which can lead to headaches or seizures.
• Pregnancy-related stroke is more likely to occur in females who experience certain complications, such as infections or preeclampsia (high blood pressure with fluid retention), or who have other risk factors for stroke, such as high blood pressure or diabetes.
• Most strokes occur during the postpartum period—the first few weeks after delivery. These strokes may be caused by a drop in blood volume or by the rapid hormonal changes that follow childbirth.

Just as hormonal changes during pregnancy and childbirth are linked to an increased risk of stroke, changes in hormones at the end of childbearing years—during menopause—can similarly elevate the risk of stroke. While hormone replacement therapy (HRT) may alleviate some menopause symptoms, research indicates that HRT increases the risk of stroke.

Understanding the risk factors and addressing them may help prevent a stroke. Generally, stroke risk factors fall into two categories: unmodifiable and modifiable.

• Unmodifiable risk factors: those that can’t be changed or controlled, including age, gender, race or ethnicity and family history
• Modifiable risk factors and medical conditions: those that can be changed or controlled with medical care, including high blood pressure, high cholesterol and smoking.

Making lifestyle changes can lower a person’s risk of stroke. It is essential for individuals to avoid stopping their medications without first consulting and receiving approval from their healthcare provider. Stopping medications without medical guidance can lead to a stroke. The following are considered modifiable risk factors in preventing stroke:

• High blood pressure: Hypertension, or high blood pressure, is the leading risk factor for stroke. For individuals with high blood pressure, the risk of stroke before age 80 is two to four times greater than for those without it. Hypertension contributes to the development of atherosclerosis and damages blood vessels. Atherosclerosis is the main cause of narrowed blood vessels, which can lead to both heart attacks and strokes. Early treatment is crucial. Regular blood pressure checks are important. Controlling blood pressure can lower a person’s risk of stroke and may prevent strokes and heart attacks. Maintaining healthy blood pressure may also lessen the risk of other disorders later in life, including dementia and cognitive decline. Antihypertensive medications work by relaxing blood vessels or reducing blood volume.
• Atrial fibrillation: The atria are the chambers that receive blood entering the heart. In atrial fibrillation, the two upper chambers of the heart no longer beat effectively; instead, the muscular walls exhibit a fine wiggling motion known as fibrillation. Consequently, the atria fail to push blood into the heart’s two lower chambers. This results in blood stagnation in the atria and the formation of blood clots, which can dislodge and travel to the brain, causing an ischemic stroke. Atrial fibrillation is the most common type of heart arrhythmia, impacting over 9% of individuals over age 65. Medications known as blood thinners (e.g. warfarin or direct thrombin inhibitors) have been proven to significantly reduce stroke risk in people with atrial fibrillation. Surgical and endovascular procedures can sometimes prevent recurrent atrial fibrillation or can be utilized to seal the part of the atria most likely to generate clots. Individuals under age 60 with atrial fibrillation and no additional risk factors may be prescribed aspirin.
• Cholesterol levels: Many people do not realize that high cholesterol contributes to the risk of stroke. Cholesterol, a waxy, fatty substance produced by the liver, is vital for the body. It aids in producing hormones such as vitamin D and is an essential component of the membranes surrounding cells. There are two types of cholesterol: high-density lipoprotein (HDL), commonly known as “good” cholesterol, and low-density lipoprotein (LDL), usually referred to as “bad” cholesterol. Most cholesterol in the body is LDL. Excessive LDL can cause cholesterol to accumulate in blood vessels, leading to stenosis and atherosclerosis. This excess plaque obstructs blood vessels and can contribute to the formation of blood clots. Cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood. Ideally, a person’s LDL level should be less than 130 mg/dL. LDL levels between 130 and 159 mg/dL indicate that a person may face a slightly higher risk for atherosclerosis, heart disease and stroke. A score over 160 mg/dL places a person at significant risk for a heart attack or stroke. Certain levels of HDL are beneficial and help prevent a stroke. Currently, an HDL score higher than 35 mg/dL is considered good. Low HDL levels (lower than 35 mg/dL) increase the risk for heart disease and stroke. Genetics may also play a role in high cholesterol levels. Hyperlipidemia (abnormally high levels of fatty substances known as lipids) and hypercholesterolemia (excess cholesterol in the bloodstream) are inherited conditions that can lead to high cholesterol. A healthy diet and regular exercise are the best ways to lower total cholesterol levels. In some cases, doctors may prescribe cholesterol-lowering medications such as statin drugs. Statins significantly lower stroke risk in most individuals with high cholesterol.
• Diabetes: Diabetes can damage blood vessels in the brain and increase a person’s risk of stroke. In diabetes, glucose (blood sugar) is not efficiently transported from the blood to the body’s cells. As a result, it accumulates in the blood, harming the blood vessels and tissues that carry fluids (including blood) throughout the body. High blood pressure is prevalent among people with diabetes and contributes significantly to their increased stroke risk. The most significant modifiable risk factor for diabetes is obesity. The rise in obesity and diabetes in the U.S. is believed to be responsible for the recent decline in the decades-long progress of reducing stroke and heart attack incidences. Medications to control blood pressure and diabetes, dietary changes and weight loss can lower an individual’s stroke risk. If blood glucose levels are elevated at the time of a stroke, brain damage is typically more severe and extensive than when blood glucose levels are closer to normal. However, a recent clinical trial did not find any benefits from the aggressive use of insulin to manage blood pressure in acute ischemic stroke. Controlling blood sugar does seem to decrease the risk of recurrent stroke.
• Smoking: Smoking alone (without other risk factors) nearly doubles a person’s risk of ischemic strokes. It promotes atherosclerosis and aneurysm formation while stimulating the production of blood clotting factors. The risk of stroke decreases significantly two years after quitting; by five years, it drops further, approaching levels similar to those of nonsmokers. Additionally, smoking heightens the risk of rupture and subarachnoid hemorrhage in individuals with cerebral aneurysms.
• Obesity: A medical condition characterized by excessive body fat, obesity is linked to three additional stroke risk factors: high blood pressure, diabetes and heart disease. It is a significant risk factor for stroke. Although no studies have specifically examined the impact of moderate exercise or weight loss on stroke risk, both strategies generally help lower high blood pressure and enhance heart health. Always consult with a physician before beginning any exercise program.
• Head and neck injuries: Head injuries or traumatic brain injuries (TBIs) can cause bleeding in the brain, potentially resulting in damage similar to that of a hemorrhagic stroke. A neck injury, particularly one involving spontaneous tearing of the arteries due to sudden and severe neck extension, neck rotation or pressure on the artery, can also contribute to the risk of stroke, especially in young adults. Activities such as neck calisthenics, “bottoms-up” drinking, extending the neck backward over a sink while getting hair washed in salons and improperly performed chiropractic manipulation of the neck can strain the arteries and may lead to a stroke.
• Drug abuse: Drug abuse significantly heightens the risk of stroke. Both short- and long-term use of addictive substances such as cocaine and amphetamines can harm blood vessel walls, leading them to rupture and bleed into the brain (hemorrhagic stroke). Additionally, these and other drugs can constrict the brain’s blood vessels and impede blood flow, resulting in an ischemic stroke. Intravenous (through a vein) use of drugs like heroin poses a substantial risk of heart valve infection, which may trigger a stroke. The likelihood of a drug-related stroke escalates with each use of the substance, particularly when other risk factors are present.

Strokes can be prevented. Making lifestyle changes and obtaining regular medical and prenatal care can help prevent strokes and significantly reduce the risk of other disorders such as dementia, heart disease and diabetes.

Stroke warning signs are indicators that the body exhibits when the brain isn’t receiving enough oxygen. The crucial aspect of recognizing stroke symptoms is that they occur suddenly.

Individuals who experience a stroke may not realize what is happening or might mistakenly choose to disregard the symptoms, believing the issue will resolve itself. Even when they recognize a problem, they may not be able to seek emergency assistance on their own. Those nearby might also be unaware of what is taking place, but they may sense that something is wrong.

Call 911 immediately if one or more of the following symptoms occur:

• Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
• Sudden confusion, difficulty speaking or understanding
• Sudden loss of vision or trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden, unusually severe headache with no known cause

Less commonly, individuals experiencing a stroke may exhibit disorientation or memory loss, as well as nausea, dizziness or vomiting.

Sometimes, warning symptoms may last only a few moments before disappearing. These signs could indicate that someone is experiencing a minor stroke or a transient ischemic attack (TIA).

Doctors use various tools to diagnose a stroke quickly and accurately. The initial step is a neurological examination, which is an observational evaluation of the nervous system. When someone suspected of having a stroke arrives at a hospital, a healthcare professional, typically a doctor or nurse, will conduct a thorough assessment of the individual’s signs and symptoms. They will also inquire about when the symptoms began. Given the significance of early treatment, the assessment may even commence in the ambulance.

One test that helps doctors assess the severity of a stroke is the standardized National Institutes of Health (NIH) Stroke Scale, developed through research funded by the National Institute of Neurological Disorders and Stroke (NINDS). Healthcare professionals use the NIH Stroke Scale to evaluate neurological function and deficits by asking the individual to answer questions and perform various physical and mental tests. This checklist of questions and tasks rates a person’s level of alertness, ability to communicate and capability to perform simple movements. Other scales that may be used include the Glasgow Coma Scale, the Modified Rankin Scale and the Barthel Index. These scales can sensitively assess disabilities resulting from a stroke.

Healthcare professionals also use various brain imaging techniques to assess stroke risk, diagnose stroke, identify its type (as well as the extent and precise location of damage) and evaluate individuals for clinical studies and optimal treatment. These imaging tests include:

• Computed tomography (CT): uses X-rays and a computer to generate cross-sectional images of organs, bones and tissues. A plain CT scan of the head and brain is the most commonly used imaging procedure to rule out bleeding. Doctors must determine whether there is any bleeding in the brain before administering certain medications, such as thrombolytic therapy or t-PA (tissue plasminogen activator), which might increase bleeding and worsen a hemorrhagic stroke. With the injection of a standard contrast agent (a dye), the CT scan can reveal the large blood vessels supplying the brain and assess whether there is a blockage. The injection of the contrast agent can also be used to create maps of brain blood perfusion that distinguish viable tissue from already damaged tissue. A NINDS-funded study recently demonstrated that this technique, known as perfusion imaging, can identify patients who will benefit from procedures to remove a clot from the large vessels, even many hours after stroke onset.
• Magnetic resonance imaging (MRI): uses magnetic fields and radio waves to create three-dimensional, detailed computerized images of bone structures, organs, nerves and tissues, including brain tissue. One consequence of ischemic stroke is the stagnation of water movement through cells in injured brain tissue. Diffusion-weighted imaging (DWI), a specialized type of MRI, assesses the movement of water within brain tissue. DWI can detect an ischemic stroke before it becomes visible on a non-contrast CT scan and is particularly valuable for identifying small areas of dead tissue caused by loss of blood supply. The use of a contrast agent enables doctors to visualize maps of brain blood perfusion, highlighting brain regions that have not yet been damaged and may still be salvaged. In a recent NINDS-funded clinical trial, perfusion imaging demonstrated the ability to identify patients who could benefit from clot-removal procedures even many hours after stroke onset.
• Catheter-based angiography: used to identify blockages in arteries or veins. A catheter is inserted into the arteries supplying the brain, and a dye is injected to reveal the site of blockage in an ischemic stroke or to detect stenosis or vascular malformations, such as an aneurysm or arteriovenous malformation, that put a person at risk for a stroke. Procedures to remove a clot from large arteries are also performed using devices that can be inserted via catheters into the arteries, with their placement guided by catheter-based angiography.
• Other tools include ultrasound for imaging atherosclerosis in the carotid artery and Doppler ultrasound to measure blood velocity in large blood vessels. Additionally, blood tests of the clotting system, an electrocardiogram (ECG)—a display of the heart’s electrical activity and rhythm, a Holter monitor (which measures the ECG over days to identify episodes of atrial fibrillation) or a cardiac ultrasound searching for clots in the heart or other cardiac abnormalities will be used to identify abnormalities that may have contributed to the stroke.

Although MRI and CT scans are equally accurate in detecting the presence of hemorrhage (bleeding), MRI offers a more precise and earlier diagnosis of ischemic strokes, particularly for smaller strokes and transient ischemic attacks (TIAs). Additionally, MRIs can be more sensitive than CTs in identifying other neurological disorders that may mimic stroke symptoms. However, MRIs are not suitable for individuals with certain types of metallic or electronic implants, such as pacemakers.

A stroke can cause permanent damage within minutes to hours. Calling 911 immediately and getting to the hospital in an ambulance can support stroke treatment and recovery.

Treatment following a stroke generally falls into three therapeutic approaches:

1. Emergency medical or surgical care, given immediately after a stroke, to minimize the extent of injury
2. Treatment to prevent a second or recurrent stroke
3. Rehabilitation to improve disabilities that result from a stroke

Treatment for ischemic stroke or a TIA may involve medications and medical procedures. Treatment for hemorrhagic stroke focuses on identifying and controlling the source of bleeding. Significant advancements in acute stroke therapy have been achieved, particularly with stenting and devices designed to remove clots and restore blood flow in brain arteries.

Medications
Medication or drug therapy is the most common treatment for ischemic strokes. The most effective types of drugs for preventing or treating acute (occurring in the past few hours) ischemic strokes are antithrombotics (blood-thinning medicines that include antiplatelet agents and anticoagulants) and thrombolytics (drugs that break up and dissolve existing clots). Another group of medications—called neuroprotectants—protects the brain from secondary injury caused by strokes. Although there are no approved neuroprotectants for use in the event of a stroke, many medicines have been and are being tested in clinical trials.

Ischemic strokes can be treated by restoring blood flow to the brain before damage becomes irreversible. This can be achieved using intravenous thrombolytic drugs, which dissolve the blood clot obstructing circulation to the brain, or by inserting a catheter into the blocked artery and removing the obstruction. In all cases, a person requires immediate medical attention once stroke symptoms begin to ensure evaluation and treatment as quickly as possible to preserve as much brain tissue as feasible.

The body produces thrombolytic proteins, some of which have been developed into drugs. Decades ago, NINDS-funded research discovered that a thrombolytic drug known as t-PA can be effective if a person receives it intravenously within three hours after stroke symptoms begin. Study results indicated that individuals who were given intravenous t-PA were 30% more likely to experience minimal or no disability three months after treatment. This led to the first treatment approved by the U.S. Food and Drug Administration (FDA) for acute ischemic strokes. Since thrombolytic drugs can increase bleeding, t-PA should be used only after the doctor is certain that the person has suffered an ischemic stroke and not a hemorrhagic stroke. In more recent studies, scientists have identified conditions under which individuals may benefit from t-PA beyond the three-hour window after stroke symptoms begin. Most clinicians now treat within a five-hour window.

Additional NINDS-Funded Studies with Key Findings
Researchers have long sought to determine whether there are benefits to administering antiplatelet drugs or anticoagulants during an ischemic stroke, in addition to t-PA, or instead of t-PA for individuals who are not eligible to receive it. One NINDS-sponsored trial—Trial of Org 10172 in Acute Stroke Treatment (TOAST)—aimed to assess whether strokes could be treated with a formulation of the anticoagulant heparin known as Org 10172, which was less likely to cause bleeding. The study found that the drug offered no significant benefit. However, scientists established a set of guidelines—called the TOAST criteria—for defining various types of ischemic strokes. These guidelines are now widely utilized in other studies.

For many years, aspirin and warfarin have been used to prevent strokes in individuals with atrial fibrillation, the most common heart condition that leads to strokes. Researchers have sought to definitively determine whether a daily regimen of aspirin or warfarin could benefit those at risk for ischemic strokes. Two NINDS studies indicated that daily warfarin is most effective for individuals with atrial fibrillation who are over 65 or possess additional risk factors. Results also showed that daily aspirin provides sufficient protection against stroke for individuals under 60 with atrial fibrillation.

Two other NINDS-sponsored trials compared the effectiveness of daily warfarin and aspirin in people who did not have atrial fibrillation but had experienced a prior stroke, thus putting them at risk for another stroke. Both trials concluded that aspirin is as effective as warfarin in reducing stroke risk in individuals without atrial fibrillation. A trial is currently underway to assess whether anticoagulation with a direct thrombin inhibitor is more effective than antiplatelet therapy in preventing recurrent strokes in individuals suspected of having atrial dysfunction.

Surgical & Endovascular Procedures
Brain blood vessels can be accessed by inserting catheters into large arteries in the leg and threading them through to the brain blood vessels. This forms the basis of catheter angiography, and it is also used to treat vascular abnormalities that can cause strokes. Surgery can also be employed to prevent or treat some types of strokes or to repair damage to the blood vessels, as well as to address malformations in and around the brain.

Carotid Endarterectomy
Carotid endarterectomy involves the surgical removal of plaque that obstructs the carotid artery, thereby widening it. The carotid arteries in the neck are the primary suppliers of blood to the brain.

NINDS sponsored large clinical trials to test the effectiveness of carotid endarterectomy. These trials showed that it is safe and highly effective in preventing strokes in people with carotid-associated TIAs, and somewhat effective for preventing strokes in most asymptomatic individuals with more than 50% stenosis (narrowing of the carotid arteries). A NINDS-funded trial is currently underway to examine the effectiveness of carotid endarterectomy in patients without symptoms of a TIA or stroke who are taking aggressive stroke prevention medications.

Stenting
Stenting involves inserting a catheter with a wire into the diseased artery and passing a tube-shaped device made of mesh-like material over the wire. The stent is compressed until it is threaded into position, and then it is expanded to widen the artery and flatten the obstructing atherosclerotic plaque.

In the Carotid Revascularization vs. Stenting Trial (CREST), funded by NINDS, scientists compared endarterectomy with stenting. The findings indicated that the overall safety and effectiveness of the two procedures were essentially the same, providing equal benefits for both females and males, as well as for individuals who had previously suffered a stroke and those who had not. However, the study revealed that older adults generally had better outcomes with surgery, while younger individuals fared better with stenting.

In another NINDS study involving stenting, scientists compared the effectiveness of medical treatment plus stenting to medical treatment alone for preventing recurrent strokes in people with severe stenosis of an intracranial artery. Results showed that aggressive medical treatment alone is more effective for preventing a second or recurrent stroke, and that stenting the intracranial artery increased a person’s postoperative risk of developing a stroke or significant bleeding from complications of the procedure.

Clot Removal
Although t-PA is the only medically proven treatment to dissolve clots in patients with large arteries blocked by significant obstructions, the drug often fails to reopen the vessel in time. To achieve reperfusion (normal blood flow) in these patients, specially trained neurointerventionalists thread a catheter (a thin, flexible tube) through the artery to the blockage site and use various devices to open the artery. These include applying suction to vacuum out the clot. A corkscrew-like device can be extended from the tip of a catheter to grasp and extract the clot. Numerous large clinical studies conducted recently have demonstrated the advantages of stent-like devices in retrieving clots and restoring blood flow in individuals with large vessel occlusions (large clots in blood vessels), which can lead to severe strokes. Severe strokes are those that may result in a lifelong loss of independent functions and are often triggered by blood clots that suddenly obstruct one of the major arteries providing blood to the brain. A NINDS-funded trial showed that perfusion brain imaging using MRI or CT can identify some patients with large artery occlusion who may benefit from clot retrieval up to 24 hours after a stroke.

Recent advances in endovascular thrombectomy present new opportunities to explore neuroprotective agents that could extend the time window for restoring blood flow to the brain, safeguarding surrounding tissue and enhancing long-term functional outcomes. Studies planned through the NIH Stroke Preclinical Assessment Network will assess whether an add-on intervention can improve outcomes compared to blood flow restoration alone, paving the way for clinical trials involving the most promising neuroprotective therapies.

Treatments for Hemorrhagic Stroke
Treating hemorrhagic stroke involves identifying the source of the blood leak and controlling it. Hemorrhagic strokes worsen with thrombolytic medications, making it essential to determine the primary stroke type before initiating emergency treatment.

One of the body’s most intricate networks of blood vessels supplies the brain with nourishment. A blockage or rupture in one of these blood vessels can happen in any area of the brain. Because each area is responsible for different functions, the effects of a stroke can range from mild to severe disabilities based on the type, severity and location of the stroke. The symptoms may be either temporary or permanent.

For example, the brainstem controls vital functions such as breathing, blood pressure and heartbeat while connecting the brain to the rest of the body. A stroke in the brainstem can be fatal or leave someone in a “locked-in” state in which they are paralyzed, cannot speak and can only move their eyes up and down.

• Problems with muscle movement (motor sensory impairment): A common after-effect of a stroke is weakness (paresis) or paralysis (plegia). This paralysis or weakness may affect one or more limbs, such as an arm, a leg or the entire side of the body and face. Movement issues can arise from damage to the part of the brain that controls balance and coordination. A person who has experienced a stroke might struggle with even the simplest daily activities, such as walking, dressing, eating and using the bathroom. Some individuals who have had a stroke may also have difficulty swallowing, known as dysphagia.
• Problems with cognition, thinking or memory: A stroke may lead to difficulties with thinking, awareness, attention, learning, judgment or memory. Some individuals who have had a stroke experience a “neglect” syndrome, meaning they are unaware of one side of their body (usually the left side) or one side of their visual field, and they do not recognize this issue. A person who has had a stroke may be oblivious to their surroundings or unaware of the cognitive, emotional and/or behavioral challenges that arise from the stroke. Some individuals will face a permanent decline in cognitive function, known as vascular cognitive impairment (VCI). In its most severe form, this includes vascular dementia; however, it also refers to a gradual decrease in mental function resulting from multiple strokes occurring over time, some of which may be silent (without noticeable symptoms). VCI appears to primarily impact the brain’s executive function—the capacity to plan activities ranging from getting dressed in the morning to managing medications and finances or negotiating a business deal. Managing risk factors can help lower the likelihood of VCI and dementia.
• Problems with speaking or understanding speech: People who have had a stroke often experience difficulties in speaking or comprehending language. These issues are frequently accompanied by challenges in reading and writing. For most individuals, language difficulties stem from damage to the left hemisphere of the brain, and severe damage can lead to a complete inability to speak or understand (aphasia). Slurred speech caused by weakness or lack of coordination of the muscles involved in speaking is termed dysarthria and is a physical rather than a language problem. Dysarthria can arise from any weakness or lack of coordination of the speech muscles and may result from damage to either side of the brain. It is often linked to difficulties in swallowing (dysphagia).
• Problems with emotion: People who have had a stroke may find it challenging to control their emotions or may express inappropriate feelings in certain situations. Post-stroke depression, which commonly affects individuals after a stroke, is a serious medical condition that can hinder recovery and rehabilitation and may even result in suicide. Post-stroke depression can be treated with antidepressant medications and psychotherapy.
• Problems with pain and sensation: After a stroke, individuals may experience pain, uncomfortable numbness or unusual sensations. These sensations can stem from various factors, including damage to the sensory regions of the brain, stiff joints, spastic muscles or an affected limb. A rare type of pain associated with a stroke is known as central stroke pain or central pain syndrome (CPS). CPS arises from damage to a part of the brain called the thalamus, which plays a role in sensory perception and movement. The pain consists of a variety of sensations, such as heat and cold, burning, tingling, numbness, sharp stabbing and persistent aching pain. It is most intense in the areas affected by the stroke, which may include the face, extremities or trunk on one side of the body. Movement and changes in temperature, particularly exposure to cold, can exacerbate the pain. Unfortunately, since most pain medications provide little relief from these sensations, there are very few treatment options or therapies available for managing CPS.

Rehabilitation is essential for stroke recovery. Strokes are the leading cause of severe adult disability in the U.S. and worldwide, yet most stroke survivors experience some recovery of function. Ongoing research in this field has led to several potential approaches and therapies aimed at helping individuals rehabilitate after a stroke.

• Physical therapy serves as the primary form of rehabilitation for many stroke survivors. Its goal is to assist individuals in relearning basic motor skills, including walking, sitting, standing, lying down and transitioning between movements. To achieve this, physical therapists employ various training techniques and exercises aimed at restoring movement, balance and coordination. In one NINDS-supported stroke rehabilitation study, researchers compared at-home physical therapy with a locomotor training program that incorporated treadmill walking with body weight support, followed by additional walking practice. The Locomotor Experience Applied Post-Stroke (LEAPS) trial revealed that stroke patients who participated in at-home physical therapy showed improvements in walking abilities comparable to those who underwent the locomotor training program. Furthermore, study investigators discovered that patients continued to make progress for up to a year after the stroke, challenging the conventional belief that recovery primarily occurs early and generally concludes within six months.
• Occupational therapy assists individuals in relearning the skills necessary to carry out daily activities, such as eating, drinking and swallowing, dressing, bathing, cooking, reading, writing and using the toilet. This form of therapy also includes exercise and training. Occupational therapists can suggest modifications to the home or workplace to support individuals in resuming an independent or semi-independent lifestyle.
• Speech therapy helps stroke survivors relearn language and speaking skills or acquire alternative forms of communication. It is suitable for individuals who have no cognitive or thinking difficulties but struggle with understanding speech or written language or producing speech. Additionally, speech therapy helps individuals develop coping strategies to manage the frustration of being unable to communicate effectively. With time and patience, speech therapy can enable a stroke survivor to regain some, and occasionally all, of their language and speaking abilities.
• Vocational therapy helps individuals return to the workforce. Approximately one-fourth of all strokes occur in people aged 45 to 65, making reemployment a major concern for many in this age group. This process may involve relearning the complex skills previously used in their jobs or acquiring new skills for different positions. Vocational therapists assist individuals with lasting disabilities in identifying their job skills and strengths and help them seek new employment opportunities if needed.
• Psychological or psychiatric therapy can help many individuals as they recover from a stroke. Depression, anxiety, frustration and anger are common challenges faced by stroke survivors. Therapy, in conjunction with medication, can alleviate some of the mental and emotional difficulties that arise from a stroke. Additionally, it can be beneficial for family members to seek psychological support for themselves as well.
• The FDA has approved the Neurolutions Upper Extremity Rehabilitation System for individuals aged 18 and older who have upper-arm disabilities and are undergoing stroke rehabilitation, aiming to increase their range of motion and grasping ability. This brain-computer interface employs noninvasive electroencephalography electrodes to record brain activity, which is then transmitted wirelessly to a tablet for analysis of the intended muscle movement. A signal is subsequently sent to a wireless electronic hand brace that facilitates the movement of the person’s hand.
• The FDA approved the Vivistim® Paired VNS™ System (vagus nerve stimulation), which is intended to be used alongside stroke rehabilitation to assist individuals with moderate to severe upper limb and extremity motor impairments caused by chronic ischemic strokes. This system electrically stimulates the vagus nerve, which extends from the brain to the abdomen, to enhance upper limb and extremity motor function as well as an individual’s capacity to move their arms and hands.

Consider getting involved in a clinical trial to help clinicians and scientists learn more about strokes and related disorders. Clinical research relies on human volunteers to assist researchers in understanding a disorder and finding improved methods for safely detecting, treating or preventing disease.

All types of volunteers—those who are healthy or may have an illness or disease—of various ages, sexes, races and ethnicities are needed to ensure that study results apply to as many people as possible and that treatments will be safe and effective for everyone who uses them.