agnosia

The inability to comprehend familiar objects that are being perceived by the sense organs. This may be a partial or total inability to attach meaning to the input from one or more of the five senses. For example, in visual agnosia, the individual takes in all the normal light sensations in the visual field but cannot decipher or process this information to recognize or interpret what is being seen. This condition is often the result of brain damage, especially to the cortex, often the result of stroke.