Question: What Is Prosopagnosia?
Prosopagnosia is the inability to recognize the identity of familiar faces. People with prosopagnosia can tell you that a face is a face, and they can even identify each part of the face (e.g, nose, mouth, etc). However, they can’t tell you whose face they are looking at.
Prosopagnosia often results from a stroke in a very specific area at the border between the occipital and the temporal lobes of the brain.
Allan Ropper and Robert Brown, Adam's and Victor's Principles of Neurology, 8th Edition McGraw-Hill Companies Inc, United States of America, 2005, pp 417-430.