Aphasia, << uh FAY zhuh, >> is the loss or partial loss of the ability to use and understand spoken and written language. It results from damage to the language centers of the brain. Many cases result from a stroke, which occurs when part of the brain does not receive sufficient oxygen-carrying blood. Aphasia also may result from a brain tumor, an infection, or a blow to the head.
Aphasia tends to affect all forms of communication. However, the condition may affect some types of communication more than others, depending on the location and extent of the brain injury. Most people with aphasia have difficulty reading, writing, speaking, and understanding words and sentences. Their ability to use numbers and gestures may be impaired as well.
Some types of aphasia may affect only reading or writing. People with such reading disabilities as alexia and dyslexia can see written material but cannot read it. People with agraphia cannot write even though the muscles of their fingers and hands are undamaged.
Two speech disorders, dysarthria and apraxia, are often associated with aphasia. Dysarthria results from damage to the nerves that control the muscles used for speech, such as the tongue. In patients with this disorder, speech sounds are slurred. Patients with apraxia have forgotten how to make certain sounds though they may have normal use of the speech muscles.
Some aphasia patients can regain part or most of their ability to understand language. Working with speech-language pathologists can help most patients. But if no improvement occurs within several months, complete recovery is unlikely.
