What Are the Different Types of Stroke?

Brain science has revealed that stroke and depression are closely linked. One large study (funded by the National Institutes of Health) found that people with depression are far more likely to suffer a stroke. In fact, high levels of depressive symptoms increased stroke risk by 73 percent, while moderate symptoms raised the risk by 25 percent.

Other studies show that at least two-thirds of stroke victims develop depression. People who have strokes in the left front part of the brain seem to be at increased risk, for reasons that are not yet clear. Post-stroke depression can severely interfere with recovery, and triples the risk of dying in the years immediately following a stroke.

Despite its prevalence, depression following stroke is not often recognized or properly treated. Believing that depression is a normal reaction to suffering a stroke could prevent people from seeking and getting help.

Stroke is a medical emergency; if you notice any of the warning signs of stroke, you should get immediate medical attention. For some people with ischemic stroke, a "clot-busting" drug (called t-PA), can limit the secondary brain damage following a stroke—but only if it is administered within three hours of the stroke's onset.

Many strokes can be prevented. Primary risk factors that can be managed with lifestyle modifications include

Smoking
Excessive alcohol use
Diabetes
High blood pressure
Obesity
Inactivity
Some people may also inherit a vulnerability to stroke, which means you are at greater risk if you have a relative who has a stroke.

Good news: Antidepressants—especially those that act on the brain chemical serotonin—can greatly improve symptoms of post-stroke depression. Many experts believe that treating depression symptoms will speed stroke recovery, and studies are underway to determine which therapies are best.

Also, advances in our understanding of how the brain functions and repairs itself following injury have improved stroke recovery. A number of studies are investigating which rehabilitation strategies work best in which people. Beginning rehabilitation immediately seems to be critical to helping stroke victims recover lost function.


In addition to two types of stroke—ischemic, which accounts for about three-quarters of strokes, and hemorrhagic—many people are also diagnosed as having "mini strokes." These three terms are described below:

Ischemic stroke: Results from a blockage or narrowing of a blood vessel due to plaque build-up or a blood clot. The carotid artery (the main vessel carrying blood to the brain) is most commonly affected.
Hemorrhagic stroke:
Subarachnoid hemorrhage occurs when an aneurysm (a weak spot in a blood vessel that fills with blood) bursts, causing bleeding on the outer edge of the brain.
Intracerebral hemorrhage, which happens deep in the brain, results when blood leaks from a tear in a blood vessel.
"Mini strokes" (TIAs): People who have "mini-strokes" (also called transient ischemic attacks or TIAs) are at greatly increased risk for suffering a major stroke. Treatment with blood thinners, such as aspirin or heparin, may reduce this risk.

Stroke

A stroke, or "brain attack," occurs when blood flow to the brain is interrupted, cutting off the essential nutrients and oxygen that brain cells need to survive.

Within a few minutes of a stroke, brain cells start to die, setting off a cascade of damage to nearby and interconnected cells. Swelling and toxins released by dying nerve cells may broaden the area of damage.

Strokes can cause a number of changes in mental and physical functions, depending on where in the brain damage has occurred. These changes can include paralysis of muscles in the face and in the limbs, and speech impairment or the inability to speak; they may be evident only on one side of the body.

New Research in Parkinson's Disease

Gene therapy—which uses the brain's own systems for cell growth to fight brain illnesses—is a promising area of brain research. The idea is to introduce properly functioning genes that can help make up for abilities lost through disease or injury.

Scientists hope that this approach may be used to treat many movement disorders (like PD) and other neurodegenerative diseases (like Alzheimer's), which are caused by the ongoing loss of nerve cells in certain areas of the brain.

Researchers have already had some success using gene therapy in animal testing (using models of PD) to help restore lost dopamine-producing cells. In animals, the therapy has helped keep nerve cells alive.

This type of treatment is now being investigated in people. But experts point out that gene therapy is still far from perfect. Much more research is necessary make it safer and more effective.

However, many scientists believe these early PD experiments will open the door to a wider use of gene therapy. For example, it could possibly be used in treating ALS—also known as Lou Gehrig's disease—and Huntington's disease.

Treating Parkinson's Disease

There is no cure for PD, but many patients don't require treatment for several years after they are diagnosed. When their symptoms do become severe, their doctors may prescribe drugs that help replace dopamine.

Other approaches to treating severe PD include:

Pallidotomy—a type of brain surgery that can effectively reduce symptoms in many people

Deep-brain stimulation—a procedure in which a pacemaker-like device is placed in the brain to reduce tremors.