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.
Amusia
Other than their inability to hear music, which is most likely due to a genetic defect, the rest of an amusic's brain remains normal. The only effect is on the ability to tell different notes apart due to the separation of two key areas in the brain. Most sufferers of amusia describe music as unpleasant. Others simply refer to it as noise and find it annoying. This can have social implications because amusics often try to avoid music, which in many social situations is not an option. In China and other countries in which identical words have different meanings based on pitch, amusia may have a much more pronounced social and emotional impact: difficulty in speaking and understanding the language.