Aphasia

Article By:

Kirshner, Howard S. Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee.

Last reviewed:February 2021

DOI:https://doi.org/10.1036/1097-8542.042700

A disorder of language acquired as a result of brain disease. Aphasia is impairment in the use of spoken or written language caused by brain disorders (see illustration) that cannot be explained by paralysis or incoordination of the articulatory organs, impairment of hearing or vision, impaired level of consciousness, or impaired motivation to communicate. Thus, aphasia strikes at a key human attribute—communication with other people. However, aphasia must be distinguished from three other conditions: motor speech disorders, developmental language disorders, and psychosis. Motor speech disorders represent abnormalities of speech articulation, caused by weakness or incoordination of the muscles of speech. Aphasia is an acquired loss of previously intact language ability, not a developmental problem, and is often called dysphasia. Psychotic disorders usually involve thought, that is, the content of language, rather than language itself. See also: Brain; Linguistics; Psycholinguistics; Psychosis; Speech; Speech disorders; Speech perception

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