A stroke, previously known medically as a cerebrovascular accident (CVA), is the rapidly developing loss of brain function(s) due to disturbance in the blood supply to the brain. This can be due to ischemia (lack of blood flow) caused by blockage (thrombosis, arterial embolism), or a hemorrhage (leakage of blood).^[1] As a result, the affected area of the brain is unable to function, leading to inability to move one or more limbs on one side of the body, inability to understand or formulate speech, or an inability to see one side of the visual field.^[2]

A stroke is a medical emergency and can cause permanent neurological damage, complications, and even death. It is the leading cause of adult disability in the United States and Europe and it is the number two cause of death worldwide.^[3] Risk factors for stroke include advanced age, hypertension (high blood pressure), previous stroke or transient ischemic attack (TIA), diabetes, high cholesterol, cigarette smoking and atrial fibrillation.^[4] High blood pressure is the most important modifiable risk factor of stroke.^[2]

A stroke is occasionally treated in a hospital with thrombolysis (also known as a "clot buster"). Post-stroke prevention may involve the administration of antiplatelet drugs such as aspirin and dipyridamole, control and reduction of hypertension, the use of statins, and in selected patients with carotid endarterectomy, the use of anticoagulants.^[2] Treatment to recover any lost function is stroke rehabilitation, involving health professions such as speech and language therapy, physical therapy and occupational therapy.