Apperceptive agnosia
Each patient that suffers from apperceptive agnosia does not have brain damage in exactly the same area. However, brain damage in proximity to the occipital lobe is largely correlated with the patterns of deficit seen in apperceptive agnosics. For example, patient JB suffered extensive damage to the parietal-occipital areas to the left cerebral hemisphere leading to his deficit in the ability to name distinguish between structurally similar object.
Recognition memory
Damage to the temporal lobes can also result in visual agnosia, a deficit in which patients are unable to properly recognize objects, either due to a perceptive deficit, or a deficit in semantic memory. In the process of object recognition, visual information from the occipital lobes (such as lines, movement, colour etc.) must at some point be actively interpreted by the brain and attributed meaning. This is commonly referred to in terms of the ventral, or "what" pathway, which leads to the temporal lobes. People with visual agnosia are often able to identify features of an object (it is small, cylindrical, has a handle etc.), but are unable to recognize the object as a whole (a tea cup). This has been termed specifically as integrative agnosia.