Also known as face blindness or facial agnosia, Prosopagnosia is a neurological disorder characterized by the inability to recognize faces. The term comes from the Greek words for “face” and “lack of knowledge”. Depending upon the degree of impairment, some people with prosopagnosia may only have difficulty recognizing a familiar face; others will be unable to discriminate between unknown faces, while still others may not even be able to distinguish a face as being different from an object. Some people with the disorder are unable to recognize their own face (auto-prosopagnosia). For the vast majority, the problem is not so much about detecting a face; they can see eyes, noses and mouths as clearly as anyone else. It’s about recognizing the same set of features when seeing them again. Many people also report deficits in other aspects of face processing, such as judging age or gender, recognizing certain emotional expressions, or following the direction of a person’s eye gaze.

Prosopagnosia is not related to memory dysfunction, memory loss, impaired vision, or learning disabilities. Prosopagnosia is thought to be the result of abnormalities, damage, or impairment in the right fusiform gyrus, a fold in the brain that appears to coordinate the neural systems that control facial perception and memory.

The condition has traditionally been studied in individuals who acquire the disorder following neurological damage (typically from stroke or head injury). However, it has recently become clear that many more people suffer from prosopagnosia without experiencing neurological damage. This form of the disorder is commonly referred to as “developmental” or “congenital” prosopagnosia, and these individuals simply fail to develop normal face processing abilities despite normal intellectual and perceptual functions. Developmental prosopagnosics have suffered from the face recognition impairment for most of their lives, perhaps since birth. Recent evidence suggests there may be a genetic contribution to developmental prosopagnosia, and several case studies report at least one first-degree relative who also suffers from the face recognition impairment.

Some degree of prosopagnosia is often present in children with autism and Asperger’s syndrome, and may be the cause of their impaired social development. The condition has also been studied in people with Schizophrenia.

Dr. Anthony C. Ruocco recently published his study about prosopagnosia in individuals with Borderline Personality Disorder in Personality Disorders: Theory, Research and Treatment. They found that their facial recognition is intact, but it is their emotion recognition that is specifically biased in one direction or the other

Dr. Thomas Grüter of the Institute of Human Genetics in Münster, believes that that the condition affects about 1 in 50 people: more than 5 million in the U.S. alone.

There is no formal treatment for prosopagnosia.