Aphasia - A type of brain damage affecting communication capabilities in the organism. This can range from the inability to construct a sentence either in voice or on paper, to the inability to recognise speech itself. This sort of damage focuses on the frontal lobe area of the brain.
Visual Neglect - This is where the information collated on one half of the brain is rejected and therefore the sufferer can only operate with one eye, because the part of the brain receiving visual information from the other eye is not functioning properly. In some cases, sufferers may only be able to paint half a painting or eat one half of a plate of food as they are unaware of the information about the other half of the environment.
Amnesia - Or retrograde amnesia, this sort of damage affects the memory, caused by degeneration / damage in the frontal lobe. Sufferers have memory blanks when relating to past experiences in their life
Agnosia - This unusual sort of brain damage is where sufferers still have the complete ability to see around them (unlike visual neglect), though cannot relate their surroundings in a quantifiable way, i.e. they fail to recognize a familiar surrounding, person or object, due to a malfunction in recalling past events involving the surrounding, person or object.