A stroke, also known as a cerebrovascular accident (CVA), is a type of brain injury caused by a lack of blood flow to the brain. This can be due to a ruptured blood vessel or a blood clot blocking a vessel. Strokes are the third leading cause of death in developed countries, and a major cause of disability in people over 50 years old. About 50% of strokes are preceded by transient ischemic attacks (TIA), which are temporary episodes of brain dysfunction caused by a lack of blood flow to the brain. Symptoms of a TIA can include dizziness, blindness in one eye, confusion, double vision, and ataxia, depending on the part of the brain affected. TIAs are important indicators of an impending stroke. In Chinese medicine, a stroke is known as a wind-stroke and is classified into four types based on the depth and severity of the injury. These types include wind penetrating the collaterals, wind penetrating the channels, wind penetrating the yang organs, and wind penetrating the yin organs. Symptoms may include weakness or numbness on one side of the body, facial paralysis, difficulty swallowing, confusion, and loss of consciousness. Treatment for a wind-stroke typically involves herbal medicines and acupuncture.