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FAQ

Source: NINDS, National Institutes of Health

What is Stroke?

A stroke occurs when the blood supply to the part of the brain is suddenly interrupted (ischemic) or when a blood vessel in the brain bursts, spilling blood into the spaces surrounding the brain cells (hemorrhagic). The symptoms of stroke are easy to spot: sudden numbness or weakness, especially on one side of the body; sudden confusion or trouble speaking or understanding speech; sudden trouble seeing in one or both eyes; sudden trouble walking; dizziness; or loss of balance or coordination. Brain cells die when they no longer receive oxygen and nutrients from the blood or when they are damaged by sudden bleeding into or around the brain. These damaged cells can linger in a compromised state for several hours. With timely treatment, these cells can be saved. Stroke is diagnosed through several techniques: a short neurological examination, blood tests, CT scans, MRI scans, Doppler ultrasound, and arteriography. Stroke seems to run in some families. Family members may have a genetic tendency for stroke or share a lifestyle that contributes to stroke. The most important risk factors for stroke are hypertension, heart disease, diabetes, and cigarette smoking. Other risks include heavy alcohol consumption, high blood cholesterol levels, illicit drug use, and genetic or congenital conditions. Some risk factors for stroke apply only to women. Primary among these are pregnancy, childbirth, and menopause.

What is aphasia?

At least one-fourth of all stroke survivors experience language impairments, involving the ability to speak, write, and understand spoken and written language. A stroke-induced injury to any of the brain's language-control centers can severely impair verbal communication. Damage to a language center located on the dominant side of the brain, known as Broca's area, causes expressive aphasia. People with this type of aphasia have difficulty conveying their thoughts through words or writing. They lose the ability to speak the words they are thinking and to put words together in coherent, grammatically correct sentences. In contrast, damage to a language center located in a rear portion of the brain, called Wernicke's area, results in receptive aphasia. People with this condition have difficulty understanding spoken or written language and often have incoherent speech. Although they can form grammatically correct sentences, their utterances are often devoid of meaning. The most severe form of aphasia, global aphasia, is caused by extensive damage to several areas involved in language function. People with global aphasia lose nearly all their linguistic abilities; they can neither understand language nor use it to convey thought. A less severe form of aphasia, called anomic or amnesic aphasia, occurs when there is only a minimal amount of brain damage; its effects are often quite subtle. People with anomic aphasia may simply selectively forget interrelated groups of words, such as the names of people or particular kinds of objects.