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.
Visual agnosia
Magnetic Resonance Imaging (MRI) showed bilateral thinning of C.K.’s Occipital Lobe which resulted in associative visual agnosia. Patients that suffer from visual agnosia are unable to identify visually presented objects. They can identify these objects through other modalities such as touch but if presented visually, they are unable to. Associative Agnosic patients cannot create a detailed representation of the visual world in their brains, they can only perceive elements of whole objects. They also cannot form associations between objects or assign meaning to objects.