Below, two neurologists discuss how to recognize the earliest signs of stroke, and how to respond effectively.

First, what is meant by the term "acute stroke"?
DARA JAMIESON, MD: "Acute stroke" refers to the process of brain damage that occurs by the minute during a stroke, or "brain attack". The patient will notice the sudden onset of neurologic symptoms. One minute the patient may be home relaxing and all of a sudden she may notice an inability to move the right side of her body, or she may experience difficulty speaking. That's an example of a patient who is having an acute stroke, and needs to recognize the symptoms immediately, get to the hospital, and get treatment immediately.

A person suffering these symptoms should call 911 immediately, and should not wait?
RALPH L. SACCO, MD: If you have these neurologic symptoms, then you need to call right away. You don't want to wait. The key for stroke treatment is to receive medical treatment in less than three hours. That's why we use the term "time is brain." The most effective therapy we have only works if you get it within three hours.

What happens once the person calls 911?
In most cities, a 911 call will prompt an ambulance to get the patient to the hospital right away. At the hospital the patient will be stabilized, and then the key is to find out what kind of stroke it is. Often, a brain scan will be done, which can tell us whether it's a bleeding stroke or an ischemic stroke. If it's an ischemic stroke -- which constitute nearly 85% of strokes -- then the patient may be a candidate for a clot-busting medicine to reduce the damage from stroke and improve outcome.

How do these clot-busting medicines work and what are they?
DARA JAMIESON, MD: The clot-busting medicines are given intravenously to people who meet certain criteria. The patient has to have significant (neurologic) deficit, be treated within three hours of the onset of the stroke symptoms, and be medically stable. The patient must have normal to only slightly elevated blood pressure and not have any history of bleeding problems.

How do the clot-busting medications work?
DARA JAMIESON, MD: They are given intravenously, and they go into the artery that is clogged and dissolve the clot, which permits normal blood flood to the brain.

Can medication reverse or minimize the damage already done by stroke?
DARA JAMIESON, MD: Studies have shown that the clot-busting drugs yield improvement at three months, not instantly, at the bedside. But it's important to understand that damage from stroke is a continuous process. The brain damage occurs in a cascade of different events that occur within brain cells, so different things may occur at different times. The faster you respond with medical care, the more likely you are to preserve brain cells.

You mentioned that 85% of patients have an ischemic attack. What about the other 15%? How are they treated if the clot-busting drugs are not an option?
RALPH L. SACCO, MD: The other 15% of stroke victims have what is called a "bleeding stroke". We have fewer treatments available for bleeding stroke. But there are things that we do to stabilize bleeding stroke victims in the hospital, to try to prevent further injury. In some cases, surgery is an option, to evacuate the blood clots.

Are bleeding strokes much more serious than ischemic attacks?
RALPH L. SACCO, MD: Yes, and there is a much greater chance of actually dying from a stroke if it's a bleeding stroke.

Is the level of damage to the brain determined by the area of the brain that is affected?
DARA JAMIESON, MD: There are certain areas of the brain that have many more functions. For instance, if you have a stroke in your brain stem or the lower part of the brain, chances are you will have a more serious outcome. That's an area of the brain that is very densely packed with cells that are regulating things in your face, such as your eyes and your speech. It's an area where cells regulate breathing and heart rate.

If you have a stroke that is in the front part of your brain, you may actually have a large stroke but have relatively small problems.

Those who have strokes on the left side of the brain will most often experience speech problems.

Is it recommended that people suffering from stroke take aspirin right away?
RALPH L. SACCO, MD: We're not sure yet. It's often done, and we know that it has at least a small effect. In studies, stroke victims who took aspirin within 48 hours of a stroke had a better outcome at six months than those who didn't. But it is small. I think the main thing really is to get medical treatment first. For example, if you had a bleeding stroke, you don't want to be taking aspirin before you call 911. Medicines, like aspirin, can be given once you receive medical treatment and the diagnosis is established.

Why do you think there is so much more public awareness about heart attack than stroke? Why are people so much less likely to seek treatment quickly after a stroke?
DARA JAMIESON, MD: One of the problems with stroke is that there is no pain. Pain is something that gets people to the emergency room because pain hurts and you want to find a way to get rid of it. But if you have transient weakness or numbness, it's pretty easy to rationalize it away.

But if you ask people what are they most scared of -- a heart attack or stroke -- most people will tell you they're most scared of having a stroke because it's going to leave them with a deficit that's going to take them away from their family, their job, and their life as they know it. It's difficult to get people to understand how important it is to recognize the warning signs and get help.