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.
Cognitive disorder
Although Alzheimer's disease accounts for the majority of cases of neurocognitive disorders, there are various medical conditions that affect mental functions such as memory, thinking, and the ability to reason, including frontotemporal degeneration, Huntington’s disease, Lewy body disease, traumatic brain injury (TBI), Parkinson’s disease, prion disease, and dementia/neurocognitive issues due to HIV infection.
Neurocognitive disorders are diagnosed as mild and major based on the severity of their symptoms. While anxiety disorders, mood disorders, and psychotic disorders can also have an effect on cognitive and memory functions, the DSM-IV-TR does not consider these cognitive disorders, because loss of cognitive function is not the primary (causal) symptom. Additionally, developmental disorders such as Autism spectrum disorder are typically developed at birth or early in life as opposed to the acquired nature of neurocognitive disorders.