agnosias Flashcards
Apperceptive agnosia:
-can perceive elementary aspects of the stimulus (features such as lines or colours
-but can no longer integrate the info into a meaningful image;
-mostly caused by large bilateral or R-sided lesions
Object agnosia:
-Apperceptive agnosia: the inability to develop a perception of the structure of the object
Associative agnosia: is the inability to identify an object while percept is intact
Agnosia
-inability to combine individual visual impressions into complete patterns
-Damage to regions higher up the occipital lobe leads to problems in object recognition
-Inability to recognize
-Inability to draw or copy
Associative agnosia:
-the inability to recognize an object despite normal perception
-Able to copy it, but not able to identify it
-object remains meaningless; probably problems with semantic categorization);
-generally associated with L-sided lesions of the ventral stream farther up the hierarchy (temporal lobe)
Prosopagnosia
-Inability to recognize faces
-Able to recognize facial features
-Bilateral damage in a region below the calcarine fissure at the temporal junction (Fusiform gyrus)
Visuospatial agnosia
-Unable to understand the spatial relationships of objects
-Topographical disorientation: inability to recognize landmarks that indicate direction
-Linked to facial agnosia
alexia
-inability to construct whole words from separate letters
-Inability to access word memory
-Left fusiform gyrus lesions
Asomatognosia
loss of knowledge or sense of one’s own body
Anosognosia
Unawareness of one’s own illness
Finger agnosia
Unable to point to or show their fingers
Simultagnosia
Inability to see two objects
Auditory agnosia
a general inability to perceive
and identify complex sounds despite intact
hearing
Verbal auditory agnosia
-word deafness
* Can also result from subcortical damage to the auditory
tracts
