Agnosia

Article By:

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

Last reviewed:February 2021

DOI:https://doi.org/10.1036/1097-8542.015000

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• Agnosia, published May 2019:Download PDF Get Adobe Acrobat Reader

Any disorder of recognition. Agnosia is a rare neurological condition in which an individual fails to recognize and identify persons or objects (see illustration). Typically, agnosia is the result of damage to specific areas of the brain. Historically, agnosias were named by Sigmund Freud in 1891 to denote disturbances in the ability to recognize and name objects. Usually, the misrecognition involves one sensory modality, with primary sensation in that modality intact, and the ability to name the item after its presentation via another sensory modality; for example, the agnostic patient cannot identify a bell by sight, but can recognize it by its sound or touch. Brenda Milner and Hans-Lukas Teuber in 1968 defined agnosia as a "normal percept . . . stripped of its meaning." Oliver Sacks described a patient who failed to recognize his wife's face, mistaking it for a hat. See also: Brain; Nervous system (vertebrate); Neurobiology; Sensation

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