Editor’s Note: Dr. Holly Andersen is dual board certified in Internal Medicine and Cardiology, is a Fellow of the American College of Cardiology and the American College of Sports Medicine and is an assistant professor of medicine at the Weill Cornell Medical Center. Dr. Andersen has been selected as one of America’s "Best Doctors" every year by Castle Connolly since 2001, and in 2008 was named by the Consumers’ Research Council of America as one of "America’s Top Cardiologists."

The idea of having a stroke is frightening. I have seen a hundred strokes, but I knew I was getting older when I walked into a hospital room last year, saw one of my patients lying in her hospital bed drooling, unable to speak or move her right side, and I thought, "I hope this doesn’t happen to me." This woman had been an impeccably dressed, exquisitely charming, eloquent professor of art history, and now — she couldn’t utter an intelligible word.

A stroke occurs when part of the brain has its oxygen or blood supply cut off. This part of the brain begins to malfunction and will die unless its blood supply is restored. A "TIA" or "transient ischemic attack" is a ministroke. It usually lasts only a few minutes, and causes no permanent damage. A TIA is an important warning sign that a person is at risk for a more dangerous and debilitating stroke, perhaps an impending one. Almost one-third of those with a TIA will have an acute stroke in the future; half of these occur within a year. If symptoms last longer than 24 hours or cause lasting brain damage, it’s considered a stroke. The most common type of stroke is an “ischemic” stroke, which involves a blockage of a blood vessel – usually from a blood clot or piece of atherosclerotic plaque that broke off a blood vessel upstream. The other main type of stroke is a “hemorrhagic” stroke, which occurs from bleeding into the brain.

A Gallup survey found that 97 percent of people over age 50 did not recognize the warning signs of a stroke. Everyone, especially those at increased risk, should know them and what to do if they occur. Symptoms for both TIA and stroke include: sudden word slurring, garbled speech or incorrect word selection, difficulty understanding others, trouble seeing in one or both eyes, numbness or weakness on one side of the face or in an arm or leg, dizziness, difficulty walking or loss of balance or coordination.

If you think you are experiencing symptoms of a TIA or stroke, seek immediate attention. This is a medical emergency; every seconds counts. Do not waste time calling your doctor — get to an emergency room. Prompt evaluation and treatment may help prevent or abruptly halt the damaging effects of a stroke, but treatment usually needs to begin within 60 minutes to prevent brain-cell death. Know ahead of time which local hospital specializes in treating acute stroke. Many hospitals now have “stroke teams” on call to the emergency room to quickly make a diagnosis and begin treatment. A clot-dissolving drug, such as tPA (tissue plasminogen activator), can be given in attempts to restore blood flow, or specially trained interventionalists can feed small catheters up through blood vessels into the brain and attempt to suck out the blockage.

My patient had experienced a very brief episode of slurred speech on the morning of her stroke. She was frightened, but was embarrassed, so she tried to cover it up. I wondered — had she acted sooner — if we could have prevented this.