Brain cells need a constant supply of oxygen and nutrients. They are delivered by a network of blood vessels that reach every part of the brain. When something cuts off that supply, brain cells downstream begin to die. The injury that follows is called a stroke.

Most strokes strike when a blood clot becomes lodged in one of the brain's arteries, blocking blood flow. In some cases, the clot forms inside the artery, usually because a cholesterol-filled plaque inside the artery breaks open. This is called a thrombotic stroke. In other cases, a blood clot or a solid mass of debris that originates elsewhere travels to the brain, where it blocks a brain artery. This is called an embolic stroke. A third type of stroke, hemorrhagic stroke, occurs when a blood vessel in the brain bursts.

Since different areas of the brain are responsible for different functions, symptoms of stroke vary. They can be changes in sensation, movement, sight, speech, balance, and coordination. Sometimes a stroke is preceded by one or more transient ischemic attacks (TIAs). These are brief episodes of stroke-like symptoms that last for a few minutes — or possibly up to 24 hours — but that go away on their own.

If you think that you, or someone you are with, is having a stroke, call 911 right away. The sooner you call, the sooner treatment can begin — "time is brain," as emergency room doctors say. The type of treatment depends on the type of stroke that has occurred. If the brain's blood supply is restored quickly and completely, a full recovery with little or no disability is possible. The more widespread the damage, and the greater delay of treatment, the more severe and long-lasting the damage.

Recovery after a stroke depends on how well healthy areas of the brain take over duties that had been performed by the damaged brain tissue. To some extent, especially in children and young adults, recovery is possible because of the brain's ability to compensate for damage in one area by working harder in another — by relying on alternate wiring for some functions or by rewiring around the injured site. When such rewiring isn't possible, rehabilitation techniques can help the brain recover function.

Stroke Articles

Unique stroke risks in women with atrial fibrillation

Women with atrial fibrillation, a common heart-rhythm problem, are at greater risk for a stroke than men, and may need to be treated more aggressively with medicine that protects against stroke by preventing the formation of blood clots. (Locked) More »

Could a silent stroke erode your memory?

A traditional stroke can be dramatic—and devastating. As part of the brain is starved of its blood supply, cells may die and a person can lose the ability to speak, move, and remember. A "silent stroke" is far subtler and harder to spot, but researchers are finding that they can still have a significant and lasting impact on memory. The good news is that silent strokes are a preventable form of memory loss. This lifestyle tips can help you avoid a silent stroke and protect your memory. More »

Robotics help stroke survivors walk again

For people with difficulty walking after a stroke, exoskeletons hold exciting promise. These robotic, computer-controlled devices provide physical support while helping move patients' legs back and forth. (Locked) More »

Triglycerides may predict stroke

The strongest predictors of a woman's stroke risk may be triglycerides. Scientists looked at more than 900 post-menopausal women and found that those with the highest levels of triglycerides were 56% more likely to have an ischemic stroke (the type due to blood vessel blockage) as those with the lowest levels. (Locked) More »

Arm-to-arm variations in blood pressure may warrant attention

Roll up both sleeves the next time you check your blood pressure at home or have it measured by a health care provider. Why? A difference of 15 points or greater between the two arms can signal the presence of peripheral artery disease or an increased risk of having a stroke or dying from cardiovascular disease. More »

Changes to the statin label: What they really mean

The FDA has made changes to the safety label for statins in hopes of reducing the chances of having a heart attack or stroke. When the changes were announced in February 2012, it reignited a smoldering debate about the benefits and risks of statins. If you want our bottom line, here it is: the vast majority of people taking statins should continue to take them, but some additional attention to blood sugar levels is warranted. And, as with any medication, if you're taking a statin and experience side effects, you shouldn't hesitate to contact your doctor. (Locked) More »