Apperceptive agnosia
Apperceptive Agnosia is the visual disorder that renders a person unable to recognize objects. It is also known as visual space agnosia. Distinction between shapes is difficult, although other aspects of vision, such as ability to see detail and colour, remain intact. Recognition of, copying and discriminating between visual stimuli, even of different shapes, is problematic. Apperceptive agnosics cannot complete an object matching task. Because they are unable to recognize even simple shapes, Apperceptive agnosia is considered a problem in the early part of the visual processing system. As contrasted with patients diagnosed Associative agnosia, whom are able to recognize simple shapes and even copy complex shapes (drawing of an anchor, for example) but are unable to recognize what an object is.
In both cases, identification of objects is entirely based on inferences made by the person based on the colour, size, social, or contextual cues.
A variant of apperceptive agnosia is the inability to recognize objects outside of their normal rotation or orientation.
See also
References
Further reading
- Fundamentals of Sensation and Perception, Michael Levine. Oxford University Press (3rd Edition). London, 2000.
- Visual Perception, Tom Cornsweet. Harcourt Publishing, London, 1970.
