Facial blindness: always in the fog
Those who suffer from so-called prosopagnosia do not even recognize their relatives if they are unannounced on the doorstep. Affected people often wonder for a long time what is wrong with them
Who do I know, who have I never seen? That can hardly be answered in the case of facial blindness
Imagine walking across the street. You see people, but you cannot classify them: the faces tell you nothing. They do not know whether they are complete strangers or acquaintances. What do you do? Greetings as a precaution? But there are so many ...
What sounds like a nightmare is everyday life for people with prosopagnosia. You can't tell other people by their faces. "It becomes particularly difficult for them when they happen to meet someone in an unexpected place," says doctor Dr. Martina Grüter from Münster, who did her doctorate on the subject. "Then they are lost."
In a study of nearly 700 high school and college students, she discovered that more than two percent of the population suffer from congenital facial recognition weakness. Prosopagnosia makes life difficult for those affected: in kindergarten and school they are often seen as conspicuous. They take longer to integrate. Later they seem unfriendly because they don't say hello. They are not lacking in openness or empathy. "When you have someone in front of you, you can see how they feel," explains the doctor.
The deficit puts pressure: "Those affected must always actively memorize certain characteristics in order to be able to identify a certain person," says Grüter. For example voice, glasses, hairstyle, clothes, the way of walking, the perfume. Some can only tell their colleagues apart based on the seats in the office.
A new hairstyle disturbed
The detection system is very fragile and can always collapse, for example if someone changes hairstyle or glasses. However, if you live with this limitation from an early age, it often occurs late that you might be blind to the face.
In Germany, those affected can only find out whether the presumption is correct at a few contact points - for example from the neurologist Dr. Andreas Lüschow at the Charité in Berlin or with the neuropsychologist Professor Boris Suchan at the Ruhr University Bochum. The examinations take two to four hours. Among other things, they aim to rule out other psychiatric or neurological diseases and to identify possible visual problems.
Facial recognition studies
Many questions are asked, such as: In films, do you get confused when the actors change their looks? Neuropsychological examinations typically show that those affected can easily recognize objects such as houses, figures or animals - only faces not. It is particularly important for the diagnosis that the problems persist for life. If congenital prosopagnosia appears likely, an MRI of the brain follows in order to rule out other damage.
Such a diagnosis costs several hundred euros. Because the perception problem has not yet been recognized as a disease, the health insurance does not cover anything.
Nevertheless, both Lüschow and Suchan report that they can barely cope with inquiries from all over Germany. Lüschow would like to set up a special consultation hour at the Charité, but there is a problem with the financing. "There is a need for this," he says. Facial blindness cannot be cured or treated, "but people just want to know what is wrong with them," says Suchan. "When they have an explanation, they can handle it better. It makes them easier."
After all, those affected can now find out more online, for example at www.prosopagnosie.de from Martina Grüter and her husband Dr. Thomas Grüter, who is also researching the subject and is himself blind to the face. There are also free self-tests developed by universities on the Internet: The "Cambridge Face Memory" has to remember faces, the "Glasgow Face Matching Test" is about comparing similar faces. Both tests are a challenge even for healthy people. The experts warn against making such a self-diagnosis.
Research into innate prosopagnosia has been increasing since the turn of the millennium. A discovery made by Canadian neuroscientist Justine Sergent back in 1992 was of central importance for this: There is an area in the brain that is specifically responsible for recognizing faces. Neuroscientist Professor Nancy Kanwisher called it the Fusiform Face Area (FFA) in 1997. It's about the size of a blueberry and sits behind the right ear.
Network of memory
In the meantime, other brain areas have been found that play a role in recognizing faces and remembering the respective people. Together with the FFA, they form a network. "In the face-blind, the nerve cells in the FFA are less selective than in other people, so to speak, less sensitive to the difference in faces," explains Dr. Maximilian Riesenhuber, neuroscientist at Georgetown University in Washington.
In addition, the connection to the anterior temporal lobe is apparently impaired. There people are assigned information on appearance and character. Magnetic resonance tests show how similar the activity in FFA and anterior temporal lobe is. "If they are very different, that is an indication of a weak link."
Normally, specialized associations of neurons in the brain become active 170 milliseconds after seeing a face. In a study using MEG examinations, i.e. the measurement of magnetic activity in the brain, the neurologist Lüschow showed that this activity is significantly weaker in prosopagnostics.
Injury and Inheritance
"This suggests that people with prosopagnosia already have a deficit at an early stage of perception." The researchers interpret this result to mean that congenital prosopagnosia is an independent disease. This is also supported by the frequent occurrence in families.
Other scientists such as Riesenhuber assume that the line between the healthy and the face-blind is fluid. Little is known about the genetic causes. "It is possible that genes play a role that are also important for the binding hormone oxytocin," says neuropsychologist Suchan.
Martina Grüter showed that prosopagnosia is hereditary in her doctoral thesis published in 2004: There is a 50 percent chance that a child will become face-blind if one of the parents has the condition. Previously, prosopagnosia was only known as a result of injuries or illnesses such as stroke or epilepsy.
It is possible that there will soon be an official diagnosis for congenital prosopagnosia in the international classification system for diseases. "It is a dysfunction like red-green blindness, and it is also recognized as a disease," says Andreas Lüschow. Those affected often have massive problems.
The experts know many fates: for example, the policewoman who has been observing the same suspects for weeks, but then arrests the wrong man. The woman who does not recognize her father when he stands unannounced on the doorstep. The teacher who cannot tell the difference between her students with certainty. Some impress with creative strategies: Thomas Grüter reports on a dentist who recognizes her patients based on the position of their teeth.
Many feel better when they inform close friends and family members. You no longer have to worry about offending your favorite people, and they can take strange situations with humor.