Every year, about 700,000 new and recurring strokes occur in the US:  28% of strokes are fatal; 50-70% of survivors will have a mild disability and will improve; 15-30% of survivors will be severely disabled even years after a stroke; and 20% require institutionalization during the first three months after the stroke.   

A stroke, or brain attack, is a serious medical emergency that requires clinical care by a health care professional.  The majority of strokes are ischemic stroke, which is any damage to the brain caused by lack of blood flow in brain blood vessels or in major arteries leading to the brain and results in temporary or permanent loss of one or more normal functions of the brain.  The remaining twenty percent, called a hemorrhagic stroke, is due to bleeding into the brain causing damage. 

Millions of brain cells die each minute a stroke is untreated.  For every minute's delay, the brain loses: 1.9 million neurons; 14 billion synapses; 7.5 miles of myelinated fibers.  If a stroke runs its full course - an estimated 10 hours on average - the brain loses: 1.2 billion neurons; 8.3 trillion synapses; 4,470 miles of myelinated fibers.      

"Stroke is a highly treatable disease but, unfortunately, the time in which physicians can effectively reverse a stroke is short," said author Jeffrey L. Saver, M.D., professor of neurology at the University of California, Los Angeles.   "Precious tissue is lost every second.  Patients need to get to the hospital at the first sign a stroke is occurring."

In volume, Saver estimates that a pea-sized piece of brain dies for every 12 minutes that treatment is delayed, and brain tissue the size of 1.5 ping-pong balls is irretrievably lost if a typical stroke runs its course without treatment.

The fact is that prevention is the key when it comes to stroke.  The immediate response to experiencing or witnessing any of the stroke symptoms listed below is to call 9-1-1 and be asked to be taken to a hospital or emergency room that specializes in stroke treatment.  Yet, less than half of stroke victims arrive at a hospital within two hours of the start of symptoms, when therapy is most effective, a report found.  Thus, the longer a person ignores symptoms or delays treatment, the more likely the brain damage will be irreversible. 

The most common warning signs of a stroke are:

• sudden weakness or numbness in the face, arms, or legs, especially on one side of the body
• sudden confusion, or difficulty speaking or understanding speech
• sudden vision problems, such as blurry vision or a partial or complete loss of vision in one or both eyes
• sudden dizziness, trouble walking, or loss of balance and coordination
• sudden severe headache with no known cause.

Any bystander can identify these symptoms but asking 3 simple questions.  Less common but still important symptoms include sudden nausea, vomiting, brief loss of consciousness, or decreased consciousness, such as fainting and convulsions.  And sometimes, people experience a transient ischemic attack (TIA), also called a "mini-stroke," which also requires prompt medical evaluation, notes the American Stroke Association.

The major risk factors for stroke are high blood pressure, pre-existing heart disease, atrial fibrillation (a very common heart rhythm abnormality), high blood cholesterol levels, diabetes, tobacco use, alcohol use, physical inactivity and obesity," said Jonathan Neyer, an epidemiologist with the CDC's Division for Heart Disease and Stroke Prevention.  Fortunately, it is possible for people to be aware of their stroke risk and take steps to address the risk factors they can control through lifestyle changes, dietary changes and medication to help prevent a stroke from happening.  Factors you can't control are age, gender, race, family history of stroke and heart disease, and a prior stroke or TIA.    

Related Story: 3 Simple Steps to Recognizing a Stroke