APHASIA IS NEUROGENIC. Aphasia always results from...

APHASIA IS NEUROGENIC. Aphasia always results from some form of damage to the brain. The specific structures affected vary among cases, as do the means by which the damage may occur. Still, the underlying cause of aphasia is always neurologic. Aphasia is most often caused by stroke, but may also arise from head trauma, surgical removal of brain tissue, growth of brain tumors, or infections. APHASIA IS ACQUIRED. Aphasia is not characterized as a developmental disorder; an individual is not born with it. Rather, it is charaterized by the partial or complete loss of language function in a person who had previously developed some language ability. it is important to note that most people with aphasia retain many linguistic abilites, many experience problems of reduced efficiency of formulation and/or production, reduced access to linguistic information still stored in the brain, and reduced retention of new linguistic information, not necessarily a complete lack of ability in any given area of language processing. The term "childhood aphasia" referes to an acquired language problem in childern; it is not, by definition, applicable to children who never had language abilities to lose. (childhood aphasia is not discussed in this text.) It should be noted, though that children who have suffered neurologic incidents such as gunshot wounds, surgical removal of tumors, or even stroke, may develop a true form of "aphasia" if those incidents cause them to lose communicatin abilities they had gained earlier in life. APHASIA INVOLVES LANGUAGE PROBLEMS. Aphasia is often described as symbolic processing disorders, a multimodal problems of formulation and interprretation of linguistic symbols. In defining aphasia it is important to recognize that any or all modalities of symbolic communication may be affected: speaking, listening, reading, writing, and receptive and expressive use of sign language. Most cases involve at least some impairment in all language modalities. APHASIA IS NOT A PROBLEM OF SENSATION, MOTOR FUNCTIN, OR INTELLECT. Aphasia excludes general sensory and mental deficits. By definition, aphasia does not involve a problem of sight, touch, smell, hearing, or taste. Althought aphasia may be accompanied by any number of other deficits in perceptual acuity, its definition excludes such deficits. Further, aphasia is not a result of general intellectual deterioration, mental slowing, or psychiatric disturbance. Aphasia is also not due to motor impairment. The exclusionary charactersitics of the definition of aphasia are especially critical in the differential diagnosis of a wide array of neurogenic language, speech, cognitive, motor, and perceptual disorders.