Herbert Lindenberger, a retired professor of literature at Stanford University, was picking up his wife from the San Francisco airport after she took a two-week trip to visit their grandchild.
Lindenberger stood at the baggage claim carousel staring intently into each face that passed by. He could have been any one of those at the carousel, waiting for that familiar "click" in his brain when he would recognize the face of a loved one and greet her with a hug.
But for Lindenberger, that "click" of recognition never comes. It wasn't until Lindenberger's wife began waving at him that he was able to distinguish who she was.
Lindenberger has prosopagnosia, commonly known as "face blindness."
"I have a mild case, but it's bad enough," Lindenberger said. "I even failed to recognize the faces of each of my children after I hadn't seen them for several months."
Previous research of the disorder suggests that about 1 to 2 percent of the general population has the condition, which affects one's ability to recognize faces.
The condition has continued to puzzle scientists for years because brain scans of prosopagnosia patients reveal that their brain areas that are devoted to face processing are of normal size and activity level. More baffling is that those with the disorder appear to be able to recognize other objects easily.
But new research on face blindness, published in the journal Nature Neuroscience, may provide information that could help unlock the secrets of this rare disorder.
Researchers from Carnegie Mellon University in Pittsburgh compared six people with prosopagnosia to 17 people without the disorder.
According to Cibu Thomas, lead study investigator and professor in the department of psychology at Carnegie Mellon University, his team hypothesized that, though a patient can technically "see" the faces he is looking at, his brain is unable to put the various facial features together into a clear enough picture that he can recognize the person.
"We hypothesized that if there's normal activation of the parts of the brain involved in face processing, maybe the face-related information that is processed in other regions are not arriving -- there's some sort of disconnection," Thomas explained.
Using a new MRI technology that allows scientists to look at the communication pathways in the brains of patients, the researchers found that those with prosopagnosia had disruptions in the connectivity between brain areas devoted to face processing.
Currently, there are no treatment options for prosopagnosia patients beyond attempting to retrain the brain to recognize faces. However, Thomas said that patients with this condition have very little to no success in improving their ability to recognize faces through such training.
"One fundamental understanding that we have about the brain is it is quite plastic and can learn things; even people with strokes who have speech difficulty can eventually learn to speak," Thomas said. "But here is a case where it shows some amount of genetic involvement, because these patients have a lifetime experience with faces but don't ever develop the ability to recognize faces."
Facing Up to Other Disorders
The condition itself may be rare, but the findings could eventually be far-reaching. Because of the clear influence that genetic factors and brain circuitry have on the development of this condition, some experts believe that "face blindness" may be linked to other developmental disorders, such as dyslexia.
"Individuals with this condition often recognize familiar people by voice, touch, smell or other means, so patients can be trained to use other senses," said Dr. Ausim Azizi, chairperson of the department of neurology at the Temple University School of Medicine in Philadelphia. "In this respect, it is similar to dyslexia -- with impaired ability to read -- but learning can occur by listening."
Still, although these findings move us another step closer to unlocking the secrets of this and so many other developmental disorders, experts say that we do not know enough about prosopagnosia for the research to yield any clinical significance. However, experts say that this study is vitally important for future research on prosopagnosia and other developmental disorders.
"This [study] doesn't fully resolve why this [condition] occurs, as the authors correctly point out that genetic studies would need to be performed to determine who is at risk, and then studies could begin to understand why it occurs," said Dr. David Beversdorf, associate professor of psychology at the University of Missouri.
Beversdorf added that, while a treatment for the disorder may not be on the horizon just yet, the findings "help with our understanding of congenital prosopagnosia and may allow us to better understand and track the effects of potential treatments in the future."
Learning to Cope
In the absence of any treatment for prosopagnosia, Lindenberger explained his struggle to try to train himself to depend on other senses and cues to recognize people that he knows. He has even tried in the past to retrain his brain -- but with little success.
"I didn't know what was wrong with me, and lots of times I thought I must be insensitive to people, because I don't really notice things that other people notice," Lindenberger said.
Unable to improve even slightly at his ability to recognize faces, Lindenberger created various tips and tricks to overcome the daily frustration and embarrassment of his condition.
"I've learned to rely on other cues -- a person's gait, hair style, hair color, or the sound of their voice -- to string together enough clues to make an educated guess on who the person is," he said.
And even though he can't recognize faces, he has honed his memory skills.
"I have incredible memory for details of people's lives, and anything you tell me about yourself, I will remember it," Lindenberger said. "So, one thing I learned to do was when I have a bad encounter with someone and offend them by not recognizing who they are, I find a way -- once the person explains who they are -- to inject a detail from their past to ... prove to them that I do have some interest in them and am not being callous."
But, Lindenberger added, "It is always embarrassing when I hurt someone's feelings because I should know who they are, but I just can't recognize their face."
Marlene Behrmann, a co-author of the study and a professor in the department of psychology at Carnegie Mellon University, said prosopagnosia patients are commonly mislabeled as having autism or asperger's syndrome, due to the awkward nature of many of their social interactions with people whose faces they cannot recognize. But Behrmann said the condition is completely unique from autism disorders, and often patients with "face blindness" go out of their way to develop new methods of overcoming their disorder to have comfortable social interactions.
"One woman I know [with prosopagnosia] is a scientist and goes to conferences and is always known as the friendliest person at the entire conference," Behrmann said. "She greets everyone with such joviality because she doesn't want to offend anybody that she knows but doesn't recognize.
"So, these patients have strategies to overcome their condition, but hardly ever withdraw from social interaction; they try really hard to find ways around this disorder and to keep in the social mainstream."
Lindenberger's biggest hope is that this latest research will provide more publicity for this condition and help others to become more sensitive to those with "face blindness."
"I want the public to know as much as possible, so people will be tolerant of those who have the condition," he said.