Apperceptive Agnosia (also Known As Visual Space Agnosia)
Apperceptive agnosia (also known as visual space agnosia) is characterized by a failure to perceive objects due to improper functioning of the occipito-temporal area of the brain. The occipito-temporal lobe is located in the left hemisphere of the brain near the back of the head. Sufferers of apperceptive agnosia have trouble drawing or copying pictures of objects which suggests that they are having trouble in perceiving the object. They have difficulty distinguishing between different stimuli. Frequently color, texture, and size are used as clues to identify what an object is.
For example, a person with apperceptive agnosia may use the texture, shape, and smell of a melon to identify it because they don't have the ability to simply look at the object and identify it as a melon. Apperceptive agnosia is caused by brain damage (such as stroke or brain injury) but there is no specific area of the brain that when damaged results in developing this specific agnosia. Different sufferers do not have brain damage in the same area but damage near the occipital lobe is correlated with apperceptive agnosia.