An Analysis of Agnosia

Abstract

An attempt is made to analyze the significance of the disturbances of function called "agnostic," such as visual agnosia, auditory agnosia, finger agnosia and so on. Gnosis involves perception, here defined as the qualitative experience of a conscious individual, occurring as a result of the unconscious reception, selection and integration of sensory stimuli. Perception demands spontaneous action on the part of the perceiving individual, necessitating,(perhaps at unconscious levels) the abstraction of sensory patterns and subsequently their recognition if they recur. The perceiving individual endows sensations with spatial, temporal and directional qualities. For this performance, an active judgment of sensory relationships is essential. It is suggested that agnosia is due to defective ability to judge specific sensory relationships, which is a psychologic disorder. Patients suffering from one variety of agnosia may overcome the disability with the aid of additional sensory information of another category, allowing them to accomplish the judgment of sensory relationships. The physiologic components of the relevant sensation are often impaired in patients suffering from agnosia but as a rule only to an extent insufficient to account for the total disability. A distinction is drawn between agnosia and dementia. It is suggested that the varieties of agnosia to which a complicated terminology has been applied should be regarded aspects of defective perception, all essentially caused by the inability of the individual to compare and contrast sensory relationships.