Often called mini-strokes, transient ischemic attacks (search) such as that suffered by Sen. Harry Reid can cause brief but frightening stroke-like symptoms.

The good news: These attacks do no permanent damage to the brain.

The bad news: About one-third of the people who experience a TIA will later suffer a stroke.

A TIA can serve as a warning of a potential stroke and an opportunity to take steps to prevent it, the Mayo Clinic reports.

A look at transient ischemic attacks:

Q. What is a transient ischemic attack?

A. It is a temporary disturbance in part of the brain, usually lasting only a few minutes, though symptoms can sometimes persist for a few hours.

Q. What causes it?

A. According to the National Institute of Neurological Disorders and Stroke, the cause is an interruption to the brain's blood supply. This can happen when cholesterol containing fatty deposits, or a blood clot moving from another part of the body, temporarily blocks a blood vessel.

Q. What are the symptoms?

A. Symptoms are similar to a stroke and can include weakness of the face, arm or leg; slurred or garbled speech; dizziness; sudden blindness in one or both of the eyes; or double vision.

Q. Is there any treatment?

A. A person with those symptoms needs prompt medical evaluation to determine if he is having a TIA or a stroke. A doctor may recommend drugs to increase the blood flow and reduce the blockage or even surgery to prevent the eventual stroke.

Q. Who is at risk?

A. Risk increases as people age. A family history of strokes increases the danger. Men, black people and smokers are at higher risk, as are people with high blood pressure, diabetes or heart disease.