Stroke Symptoms

A stroke occurs when blood flow to the brain is interrupted. Stroke symptoms occur almost immediately, as oxygen deprivation damages the brain and kills brain cells. Over 700,000 Americans experience a stroke every year. For approximately 160,000 of these people, strokes are fatal.

Stroke Risk Factors

Improved treatment and control of stroke risk factors such as hypertension and high cholesterol have helped lower the incidence of stroke deaths since the 1980s. However, thirty percent of strokes still result in death.

Stroke Symptoms Strike Suddenly

Stroke symptoms begin almost as soon as blood flow to the brain is obstructed. Time is of the essence when stroke symptoms develop. The longer blood flow is obstructed, the greater the damage stroke does to the brain. Call 911 immediately: stroke treatment that begins within the first hours saves lives and minimizes brain damage.

Dementia and Stroke

The suddenness of stroke symptoms differentiates the disease from dementia or brain tumors. Dementia is a progressive disease. While dementia may share some symptoms with stroke, dementia symptoms develop slowly.

Stroke symptoms present very quickly.

Common Stroke Symptoms: Headaches and Dizziness

Stroke symptoms such as headaches and dizziness may indicate a number of conditions other than stroke. It is often the speed of symptom development that indicates stroke. People experiencing strokes may not notice symptoms themselves: the stroke may make them appear dazed, “spaced-out,” or confused.

Common stroke symptoms include sudden:

  • difficulty speaking
  • dizziness
  • headache
  • hearing difficulty
  • paralysis
  • vision problems
  • weakness.

Stroke survivors often describe sudden dizziness, and, in some cases, the most painful headaches of their lives. The sudden appearance of debilitating headaches should always be checked, especially if the person has no historyof migraine headache.

Types of Stroke: Ischemic and Hemorrhagic

Strokes are caused by impaired blood flow to the brain. Blood flow may be obstructed by blood clots or impaired due to blood vessel damage (resulting in blood bleeding out into the brain).

Ischemic Stroke: An ischemic stroke is caused by blood clots or other arterial obstructions. An ischemic stroke is often caused by atherosclerosis, a progressive narrowing of blood vessels that is also responsible for most cases of coronary artery disease. Ischemic stroke is the most common form of stroke, accounting for 80 percent of all strokes.

Hemorrhagic Stroke: While ischemic strokes are caused by blood clots and vessel narrowing, hemorrhagic strokes occur when blood vessels in the brain bleed. Hypertension is often to blame for hemorrhagic strokes: high blood pressure damages blood vessels and impairs blood flow. Hemorrhagic stroke accounts for about 15 percent of strokes.

Transient Ischemic Attack

A TIA (transient ischemic attack), or “mini-stroke”, occurs when blood flow is temporarily obstructed. Symptoms of a transient ischemic attack diminish within a day, and cause no permanent damage. A transient ischemic attack indicates a high risk of stroke: ten to fifteen percent of people who experience a transient ischemic attack suffer an ischemic or hemorrhagic stroke within a year of the TIA.


Mayo Foundation for Medical Education and Research. (2003). Stroke. Retrieved February 11, 2004, from 821670F1635148