Classification Broadly,<unk>  is divided into apperceptive and associative<unk> . Apperceptive<unk>  is failure of object recognition even when the basic<unk>  functions (acuity, color, motion) and other mental processing, such as language and intelligence, are normal. The brain must correctly integrate features such as edges, light intensity, and color from sensory information to form a complete percept of an object. If a failure occurs during this process, a percept of an object is not fully formed and thus it cannot be recognized. Tasks requiring copying, matching, or drawing simple figures can distinguish the individuals with apperceptive<unk>  because they cannot perform such tasks. Associative<unk>  is an inability to identify objects even with apparent perception and knowledge of them. It involves a higher level of processing than apperceptive<unk> . Individuals with associative<unk>  can copy or match simple figures, indicating that they can perceive objects correctly. They also display the knowledge of objects when tested with tactile or verbal information. However, when tested<unk> ly, they cannot name or describe common objects. This means that there is an impairment in associating the perception of objects with the stored knowledge of them. Although<unk>  can be general, there exist many variants that impair recognition of specific types. These variants of<unk>  include prosopagnosia (inability to recognize faces), pure word blindness (inability to recognize words, often called "agnosic alexia" or "pure alexia"),<unk> s for colors (inability to differentiate colors),<unk> s for the environment (inability to recognize landmarks or difficulty with spatial layout of an environment, i.e. topographagnosia) and simultanagnosia (inability to sort out multiple objects in a<unk>  scene). Categories and subtypes of<unk>  The two main categories of<unk>  are: * Apperceptive<unk> , impaired object recognition. Individuals with apperceptive<unk>  cannot form a whole percept of<unk>  information. * Associative<unk> , impaired object identification. Individuals with associative<unk>  cannot give a meaning to a formed percept. The percept is created, but it would have no meaning for individuals who have an associative<unk> . Subtypes of associative<unk>  * Achromatopsia, an inability to distinguish different colors. * Prosopagnosia, an inability to recognize human faces. Individuals with prosopagnosia know that they are looking at faces, but cannot recognize people by the sight of their face, even people whom they know well. * Simultagnosia, an inability to recognize multiple objects in a scene, including distinct objects within a spatial layout and distinguishing between "local" objects and "global" objects, such as being able to see a tree but not the forest or vice versa. * Topographagnosia, an inability to process the spatial layout of an environment, including landmark<unk> , difficulty recognizing buildings and places; difficulty building mental maps of a location or scene; and/or an inability to discern the orientation between objects in space. * Pure alexia, an inability to read. * Orientation<unk> : an inability to judge or determine orientation of objects. * Pantomime<unk> : an inability to understand pantomimes (gestures). It appears that the inferior cortical<unk>  cortex is critical in recognizing pantomimes.
Visual agnosia
Apperceptive agnosia
Auditory agnosia
Finger agnosia
Phonagnosia
Cynanthropy
Anosognosia
Binocular dysphoria