apperceptive agnosia

n. A subtype of visual agnosia. During the 19th century Lissauer proposed a distinction between apperceptive and associative visual agnosia. This distinction remained somehow unnoticed until the second half of the 20th century, when it was integrated in the contemporary interpretations of visual agnosias. According to Lissauer, visual recognition supposes two different processes: (1) the process of perceptual recognition of the sensory impression and (2) the process of associating this perception with previously stored perceptual information. Apperceptive agnosia is characterized by a fundamental defect in visual perception, resulting in an inability to recognize differences between two similar objects and mentally reconstruct the visual shapes. Conversely, in associative agnosia the patient can recognize shapes but cannot interpret them. Patients with associative agnosia can match similar pictures and even copy them but cannot relate the shapes with the objects. It is supposed that apperceptive visual agnosia most often is observed in cases of right hemisphere lesions, whereas associative visual agnosia is associated with left hemisphere pathology.    - AA
▶ See also AGNOSIA