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Prosopagnosia (Greek; prosop, face + agnosia, lack of knowledge) is a brain disorder that results in people being unable to recognize faces by looking at them. Prosopagnosiacs aren't blind in the traditional sense of the word, their ability to see and recognize objects other than faces is often normal. Instead, the very specific part of the brain -- the anterior region of the right fusiform gyrus for you neuroscience geeks out there -- which is responsible for recognizing and categorizing faces is broken down. This disorder doesn't affect other kinds of recognition either; a prosopagnosiac can still tell who people are by their voice, hair, clothing, walking gait, etc. Prosopagnosia can be congenital, caused by the person's genetics and present from birth, or acquired, caused by an injury or stroke to the right fusiform gyrus.

Interestingly, the disability seems to only effect conscious access to identification information about the face. For instance, prosopagnosiacs show a strong electrodermal response to well known faces, a weaker response to faces they've seen before in the laboratory, and no response at all to new faces. This finding has been confirmed by EEG/ERP work, and also in a study that measured reaction time to faces. In other words, on some level of mental processing every face is recognized as such, that recognition just doesn't trigger any other memory processing or categorization as a known face.

Since people with prosopagnosia cannot recognize faces, they also sometimes cannot recognize the emotional cues communicated by facial expression. One figure I read (not cited, so don't ask) said that emotional communication during speech was 60% facial, 30% in prosody, and 10% by what words were actually spoken. Regardless of the actual figures, a great deal of emotional context is unavailable to these prosopagnosiacs, making it hard to understand how people feel and how to appropriately react to them. A congenital prosopagnosiac has never seen the emotional content in others' faces and thus doesn't know to transmit emotional information through his or her own expression, making emotional communication with others difficult.

Related problems are Capgras' and Cotard's syndromes, in which the facial recognition works perfectly, but the emotional content is cut off. Whereas prosopagnosiacs can't recognize others but can still have feelings for them, the Capgras' sufferer has no problem recognizing people, he just can't attach any emotional significance to that recognition.

PROSOPAGNOSIA

For 80 years I lived with a mental disorder of which I was unaware until I bought a copy of The Oxford Reference to the Mind with a book voucher present. I suddenly found myself reading a description of myself.

From childhood I resented going to parties. On my first invitation to a street birthday party I asked Mum if I could take a book to read. Mum thought I was joking until I came out with my favourite book under my arm. I have always felt uneasy among groups as I could never identify friends. I suffered frequent embarrassment as I could not know if I had previously met people who obviously knew me.

Prosopagnosia, also known as Faceblindness is a deficit of the mind which prevents one from registering the image of people's faces for future recognition. Most people on seeing someone approaching will see an image of a face as opposed to a "thing". The image is sent to the fusiform gyrus, a part of the cortex in the left temple where the image is compared with a "file" of known faces. If the face is identified, motor neurons arrange a smile and outstretched hand to acknowledge recognition. Meanwhile, another "file" is searched to give the brain subjects for conversation, (recollection of last meeting, health of wife, members of family, &c.).

I have watched people walking towards me and giving me a quick glance before looking away. I estimate that within 1/50 second my face image has been examined and rejected as unknown. This extraordinary speed of mental activity is probably the fastest work called on by the mind.

Faceblindness is a misnomer as I can see eyes, noses and mouths the same as others but cannot recognise differences from one to another. I would prefer "facial amnesia" as a more accurate term. Prosopagnosia is not malignant, contagious, painful nor life threatening to sufferers nor to their acquaintenances. It therefore does not attract research grants.

Nevertheless, for sufferers it is very embarrassing. I can identify family members and a small circle of close friends. When I go to the butchers I greet Garry, who has his name outside, and wears a blue apron. But if I met Garry in Myers (Melbourne Department store), I would walk past him without acknowledging him. I repeat this snubbing of friends daily. When I walk in my local shopping strip I wear a half smile, ready for someone to identify me first. When they stop for a chat I have to desperately scan for a reference that I can respond to. Many are already aware of my problem as I have described the symptoms to them.

I was outside the chemists (pharmacists, drug store) talking to a couple who were aware of my trouble when a chap walked past us and called out, "Hi Ken!" and I replied, "Hi!" My friend asked who he was and laughed out loud when I replied, "I've never seen him before in my life!" I then walked into the chemists. I was followed by the man, who said "Hi Ken. I'm Daryl!" I immediately knew he was a regular visitor to our house when my wife was typing notes for him for the Neighborhood Watch group we shared in common! He had heard my reply and the loud laugh outside.

When we go to see a movie it always worries me if there are more than three characters as I cannot identify any more. We recently saw a movie called "Lantana" which seemed to consist of three couples who recklessly jumped in and out of each other's partners bed. This means there were 9 possibilities of sharing a bed with someone different (assuming the men avoided hopping into bed with another man). I kept whispering to my wife "Is he the man who was in bed with the blonde (or brunette)?" and similar questions throughout the performance. It was a strain for her to follow the plot with me whispering and was not too good for nearby patrons either. You can see how I used to enjoy Mickey Mouse and Donald Duck with their well defined faces.

I am certain that there are many who, like me are unaware of their condition. There is a support group website, FACEBLIND@MAELSTROM.STJOHNS.COM. I suggest if you recognise this deficit in yourself, you contact this group who will be sympathetic and supportive. I also would be pleased to hear from any other Australian who may recognise themselves here. Write to me here and tell me about it Ken Green aka Caligital.

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