Impairment in recognition of visually presented objects
Visual agnosia is an impairment in recognition of visually presented objects. It is not due to a deficit in vision (acuity, visual field, and scanning), language, memory, or intellect.[1] While cortical blindness results from lesions to primary visual cortex, visual agnosia is often due to damage to more anterior cortex such as the posterior occipital and/or temporal lobe(s) in the brain.[2] There are two types of visual agnosia: apperceptive agnosia and associative agnosia.
Recognition of visual objects occurs at two primary levels. At an apperceptive level, the features of the visual information from the retina are put together to form a perceptual representation of an object. At an associative level, the meaning of an object is attached to the perceptual representation and the object is identified.[2] If a person is unable to recognize objects because they cannot perceive correct forms of the objects, although their knowledge of the objects is intact (i.e. they do not have anomia), they have apperceptive agnosia. If a person correctly perceives the forms and has knowledge of the objects, but cannot identify the objects, they have associative agnosia.[3]
^Delvenne, Jean-François; Seron, Xavier; Coyette, Françoise; Rossion, Bruno (2004). "Evidence for perceptual deficits in associative visual (Prosop)agnosia: A single-case study". Neuropsychologia. 42 (5): 597–612. doi:10.1016/j.neuropsychologia.2003.10.008. PMID 14725798. S2CID 7681129.
^Riddoch, M. Jane; Humphreys, Glyn W. (1987). "A Case of Integrative Visual Agnosia". Brain. 110 (6): 1431–1462. doi:10.1093/brain/110.6.1431. PMID 3427396.
^Karnath, H.-O.; Ruter, J.; Mandler, A.; Himmelbach, M. (2009). "The anatomy of object recognition—Visual form agnosia caused by medial occipitotemporal stroke". The Journal of Neuroscience. 29 (18): 5854–5862. doi:10.1523/JNEUROSCI.5192-08.2009. PMC 6665227. PMID 19420252.
Visualagnosia is an impairment in recognition of visually presented objects. It is not due to a deficit in vision (acuity, visual field, and scanning)...
different subtypes: apperceptive visualagnosia and associative visualagnosia. Individuals with apperceptive visualagnosia display the ability to see contours...
Associative visualagnosia is a form of visualagnosia. It is an impairment in recognition or assigning meaning to a stimulus that is accurately perceived...
Prosopagnosia (from Greek prósōpon, meaning "face", and agnōsía, meaning "non-knowledge"), also known as face blindness, is a cognitive disorder of face...
type of agnosia where perception occurs but recognition still does not occur. When referring to apperceptive agnosia, visual and object agnosia are most...
disorder often arises after damage to the fusiform face area. Visualagnosia, or visual-form agnosia, is a brain disorder that produces an inability to recognize...
[citation needed] Eidetic memory can still occur in those with visualagnosia, who, unlike visual thinkers, may be limited in the use of visualization skills...
title of the book from the case study of one of his patients who has visualagnosia, a neurological condition that leaves him unable to recognize faces...
figures is often lost in patients with visualagnosia, the test is also employed as a method to identify visualagnosia. Some evidence suggests that the test...
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(German for "shape decomposition" or Gestalt decomposition) is a type of visualagnosia and is a psychological phenomenon where delays in recognition are observed...
that are known the cause deficits in higher-level visual processing, including visual object agnosia, prosopagnosia, topographagnosia, alexia, achromatopsia...
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one survivor with a lasting brain lesion who presented symptoms of visualagnosia, most likely caused by exposure to carbon monoxide fumes, other noxious...
perceived. The most common symptom of inferior temporal lobe damage is visualagnosia, which involves impairment in the identification of familiar objects...
Finger agnosia, first defined in 1924 by Josef Gerstmann, is the loss in the ability to distinguish, name, or recognize the fingers—not only the patient's...
agnosia if only one hand is affected) is the inability to identify an object by active touch of the hands without other sensory input, such as visual...
Auditory agnosia is a form of agnosia that manifests itself primarily in the inability to recognize or differentiate between sounds. It is not a defect...
are disorders with perturbed visual perception such as associative visualagnosia, prosopagnosia, visual amnesia, visual hypo-emotionality; but also some...
which is interrupted in patients with such conditions as blindsight and visualagnosia. Therefore, object identification and object recognition are thought...
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