What is a Stroke?
A stroke happens when something disrupts blood flow to an area of the brain. The extent of stroke damage depends on how much brain tissue is affected and how quickly the stroke is treated. Strokes can cause long-lasting disability or even death.
The most common type of stroke, an ischemic stroke, occurs when a blockage clogs an artery, starving the brain of oxygen and vital nutrients. A hemorrhagic stroke happens when an artery ruptures and blood spills into the brain.
When blood flow to the brain is suddenly disrupted, oxygen-starved tissue rapidly begins to die. Sudden confusion, visual disturbances, dizziness, an unusual headache, numbness, or weakness—especially on one side of the body—can signal the onset of a stroke.
An ischemic stroke is the most common stroke. A blood clot blocks an artery, starving the brain of oxygen and vital nutrients. Often the clogged artery is already narrowed by fatty deposits. A blood clot can also travel to the brain from another part of the body. If the blood supply is interrupted for more than a few minutes, the brain can suffer lasting injury.
Hemorrhagic (bleeding) strokes
Intracerebral hemorrhage is bleeding within the brain from a broken blood vessel; the immediate damaging effects of bleeding in the brain range from movement and speech problems to paralysis.
Subarachnoid hemorrhage occurs when blood from a damaged blood vessel accumulates at the surface of the brain. When this happens, blood spills into the space between the brain and the skull.
Only about 15% of people return to an independent lifestyle after a bleeding stroke, and more than a third die within a month.
People are at risk for pneumonia, blood clots, and other severe complications for several weeks after a bleeding stroke.
Symptoms of Stroke
Warning signs of a stroke include:
- Sudden, severe, otherwise unexplainable headache
- Sudden numbness or weakness in the face or limbs, often on only one side of the body
- Sudden speech difficulties (speaking or understanding)
- Sudden confusion
- Sudden vision problems
- Sudden dizziness or problems with balance, coordination, or walking
What Causes a Stroke?
A stroke is typically a quickly developing event caused by a wide range of underlying conditions. It’s very difficult to predict when a stroke will occur or prevent it from happening once the conditions are in place.
However, it is possible to identify factors that put an individual at increased risk of having a stroke. Ischemic and hemorrhagic strokes have some risk factors in common, and some are unique to each type of stroke.
Risk factors for an ischemic stroke
- Age 40 or over
- Heart disease
- High blood pressure (hypertension)
- High blood cholesterol levels
- Illegal drug use
- Recent childbirth
- Previous mini-stroke or transient ischemic attack (TIA)
- Inactive lifestyle and lack of exercise
- Current or past history of blood clots
- Family history of cardiac disease and/or stroke
Risk factors for hemorrhagic stroke
- High blood pressure (hypertension)
- Heavy alcohol use
- Advanced age
- Illegal drug use (primarily cocaine and “crystal meth”)
- Anticoagulant medications
- Bleeding disorders
- Deformities in blood vessels
- Aneurysm (a weakening in the lining of the blood vessel)
Is a Stroke Hereditary?
Scientists have looked for a connection between strokes and genes passed from parent to child, but so far, no definitive genetic association has been found. However, many of the underlying conditions that cause strokes may be inherited or more common in people with a family history.
People at risk for a stroke often have a family history of:
- High blood pressure
- High levels of cholesterol, especially “bad” cholesterol or LDL
- High triglyceride values
- Inherited bleeding disorders
- Sickle cell disease
- Blockage in the neck or brain arteries
- An arteriovenous malformation (AVM), a tangle of abnormal blood vessels in the brain
How is a Stroke Detected?
Brief episodes of numbness, weakness, or vision loss are urgent warning signs of a stroke. A transient ischemic attack (TIA)—a “mini-stroke”—often precedes a more serious cardiovascular event.
The acronym FAST is a reminder to take symptoms seriously. Each letter in the word stands for one of the things to watch for if a stroke is suspected:
Face: Sudden weakness or drooping of the face and/or visual problems
Arm: Sudden weakness or numbness of one or both arms
Speech: Difficulty speaking and/or slurred or speech
Time: Time saves the brain. The sooner treatment begins, the better the chances are for recovery. Dial 9-1-1 to call an ambulance right away.
How is a Stroke Diagnosed?
Doctors rely on imaging tests to diagnose strokes. If tests show that someone is having a stroke, doctors must quickly determine the exact cause. Scans of the brain and blood vessels that supply the brain with blood are vital to diagnosing stroke. High-resolution imaging allows a doctor to see the area of the brain affected by the stroke. Specialized tests can confirm whether the stroke is ischemic (caused by a blood clot) or hemorrhagic (caused by bleeding in or around the brain).
The following tests are routinely used to diagnose a stroke:
- A computed tomography (CT) scan for suspected hemorrhagic (bleeding) stroke
- Magnetic resonance imaging (MRI) scan
- Lumbar puncture or spinal tap for suspected subarachnoid hemorrhage. A small sample of cerebrospinal fluid is removed through a needle and examined to see if it contains blood.
- MRI angiography to map blood flow to the brain
- Because a hemorrhagic stroke involves bleeding, doctors test the ability of the blood to clot. Certain medications raise the risk of stroke.
- Blood tests
- Electrocardiogram (EKG)
- Chest X-ray
- Ultrasound testing of the arteries in the neck (carotid Doppler) or of the heart (echocardiogram)
PLEASE CONSULT A PHYSICIAN FOR MORE INFORMATION.
How is a Stroke Treated?
A stroke is a medical emergency that requires immediate medical attention. The faster someone reaches the hospital after the stroke begins, the better the chances of recovery.
When a blood clot blocks an artery, doctors quickly restore blood flow to the brain. Treatment procedures for an ischemic stroke include:
Clot-retrieval devices can be used up to 24 hours after symptoms begin. Minimally invasive procedures offer new hope for acute stroke patients with blood clots in the brain’s blood vessels. Doctors insert a spaghetti-thin tube (catheter) into an artery in the groin and move it up through the body to an artery in the brain. The doctor then threads the clot-retrieval device up through the catheter, snags the clot, and removes it.
Clot-busting (thrombolytic) drugs can be delivered directly to the blockage to dissolve the blockage. The most common medication is tissue plasminogen activator (tPA). Drugs to dissolve a clot must be given as soon as possible (The Golden Hour) after the onset of symptoms. The window of time for clot-busting drug delivery is, at most, four and a half hours.
Early treatment of a “bleeding” stroke can repair bleeding blood vessels. Weakened blood vessels are at greater risk of developing aneurysms that can burst and lead to a bleeding stroke.
- Aneurysms can be repaired by placing a surgical clip or coil to stop the bleeding.
- A tiny metal mesh tube (stent) can be placed in the blood vessel.
- Medications are used to lower the pressure within the skull.
- Patients may be connected to a mechanical ventilator to help them breathe.
- Surgery may be needed to prevent a hemorrhage from reoccurring.
How does a Stroke Progress?
If left untreated, stroke can be deadly. One in four patients dies during the first several days or weeks following a stroke. Even if a stroke is treated successfully and the patient survives, complications can develop, and sometimes these complications may be permanent.
Common complications of stroke include:
- Blood clots or deep vein thrombosis (DVT)
- Chronic headaches
- Speech difficulties
- Muscle pain or tightness
- Sleep disruptions
- Memory problems
How is a Stroke Prevented?
While strokes are difficult to predict, high blood pressure (hypertension) serves as a warning sign of blockage within the body’s network of blood vessels. High blood pressure is the most common risk factor for a hemorrhagic stroke.
If you have high blood pressure, high blood pressure, or other conditions that increase the risk of stroke, it is vital that you follow your doctor’s instructions for the treatment of these conditions (s).
- Take blood pressure medication as prescribed by your doctor.
- Control cholesterol levels with statin medications.
- Take anticoagulant drug therapy to prevent dangerous clotting.
- Make heart-healthy lifestyle changes, like eating a diet low in animal fat, losing weight, exercising, and quitting smoking.
- Treat type 2 diabetes. The disease more than doubles the risk of stroke.
- Drink only moderately. Excessive alcohol consumption dramatically increases the risk of having a stroke, particularly in women.
- Follow a healthy sleep routine. Sleep disorders are associated with an increased risk of stroke.
Stroke Caregiver Tips
Tips to help a loved one:
- Create a safe, comfortable environment for your loved one. It’s normal for someone to be confused and frightened after a stroke. The more you can put them at ease, the better. Install assistive devices, including ramps, handrails, and shower seats, if your loved one has mobility problems.
- Encourage speech-language, occupational, or physical therapy. Find a doctor who specializes in rehabilitation, and be an advocate for your loved one’s continued treatment and rehabilitation.
- Understand the difficulty of accepting disability and brain injury, and be prepared for frustration.
Stroke Brain Science
The brain is the most blood-hungry organ in the body, with a constant need for oxygen and other nutrients delivered through the bloodstream. When starved of blood, the fragile brain is vulnerable to damage ranging from speech difficulties to paralysis. One in four patients dies from their stroke during the first several days or weeks.
Blockages in the arteries of the neck are the leading preventable cause of a stroke. When the arteries become clogged with a buildup of plaque-causing a “swishing” sound in the ears, a specialist’s treatment can prevent a stroke and restore blood flow to the brain.
Brain scientists are currently investigating what happens when blood rushes back into the brain after an ischemic stroke. Even after removing the clot, the brain releases a flood of inflammatory chemicals that damage the brain. New approaches aim to create a drug that could target the stroke site to stop immune cells from attacking vital brain tissue.
Title: Virtual Reality in Stroke Rehabilitation
Stage: Not Yet Recruiting
Principal investigator: Peggy Comer, LRT
Wake Forest University Health Sciences
In this pilot study, the objective is to determine if there is an increase in MoCA (Montreal Cognitive Assessment), MFRT (Modified Functional Reach Test), and FMA-UA (Fugl-Meyer Assessment Upper Extremity) scores of participants who receive the VR intervention in addition to traditional inpatient rehabilitation standard of care (experimental group) versus participants who receive the conventional standard of care (control group).
Title: Stroke Rehabilitation Using Brain-Computer Interface (BCI) Technology
Principal investigator: Vivek Prabhakaran, MD, PhD
University of Wisconsin
Ongoing research (NCT02098265) suggests that noninvasive EEG driven Brain-Computer Interface (BCI) systems hold the potential for facilitating recovery in the chronic phase after stroke by synchronizing central or brain activity with peripheral movements and thereby harnessing brain plasticity.
The specific aims of this study are:
Aim 1: To investigate the efficacy of active FES vs. passive FES, as determined by changes in behavioral measures. The investigators hypothesize that motor function improvements will be significantly more significant using active FES therapy than passive FES therapy.
Aim 2: To investigate the relationship between brain functional activation patterns and behavior changes induced by active vs. passive FES intervention. The investigators hypothesize that changes caused by active FES (as measured by brain fMRI and EEG measures) will show more significant adaptive brain reorganization changes (i.e., brain changes that correlate with improved outcomes) than those induced by the passive FES.
Aim 3: To investigate the relationship between brain white matter integrity and behavior changes induced by active vs. passive FES intervention. The investigators hypothesize that changes caused by active FES (as measured by brain DTI measures) will show more significant adaptive brain reorganization changes (i.e., brain changes that correlate with improved outcomes) than those induced by the passive FES.
Title: A Pilot Study of a Strategy and Computer-based Intervention to Enhance Daily Cognitive Functioning After Stroke
Principal investigator: Abhishek Jaywant, PhD
Weill Medical College of Cornell University
New York, NY
This is an initial pilot study to test feasibility, participant engagement and satisfaction, and clinical and neurobiological target engagement of a behavioral treatment called “ASCEND” that combines computer-based cognitive training and coaching of cognitive strategies to improve daily cognitive functioning in individuals with stroke.