A Rare Visual Disorder Twists Faces Out of Shape

It’s not uncommon for Veronica Smith to be looking at her partner’s face when suddenly she sees his features changing—his eyes moving closer together and then farther apart, his jawline getting wider and narrower, and his skin moving and shimmering. Smith, age 32, has experienced this phenomenon when looking at faces since she was four or five years old, and while it’s intermittent when she’s viewing another person’s face, it’s more constant when she views her own.

“I almost always experience it when I look at my own face in the mirror, which makes it really hard to get ready because I’ll think that I look weird,” Smith explains. “I can more easily tell that I’m experiencing distortions when I’m looking at other people because I know what they look like.”

Smith has a rare condition called prosopometamorphopsia (PMO), in which faces appear distorted in shape, texture, position or color. (PMO is related to Alice in Wonderland syndrome, or AIWS, which distorts the size perception of objects or one’s own body.) PMO has fascinated many scientists. The late neurologist and writer Oliver Sacks co-wrote a paper on the condition that was published in 2014, the year before he died. Brad Duchaine, a professor of psychological and brain sciences at Dartmouth College, explains that some people with it see distortions that affect the whole face (bilateral PMO) while others see only the left or right half of a face as distorted (hemi-PMO).

“Not surprisingly, people with PMO find the distortions extremely distressing. Over the last century, approximately 75 cases have been reported in the literature. However, little is known about the condition because cases with face distortions have usually been documented by neurologists who don’t have expertise in visual neuroscience or the time to study the cases in depth,” Duchaine says.

A simulation of what someone with PMO may see when looking at a face. Credit: Antonio Vitor Reis Goncalves Mello/Social Perception Lab at Dartmouth College (CC BY-NC 4.0)

For 25 years Duchaine’s work has focused on prosopagnosia (face blindness), but after co-authoring a study on hemi-PMO that was published in 2020, Duchaine shifted much of his lab’s work to PMO. In 2021 he launched a website dedicated to the condition, and to date, 60 people have contacted him describing their PMO symptoms. Duchaine and his team are conducting case studies on many of them, including Smith, to better understand their distortions, which can provide insight into how the typical face-processing system works.

Jan Dirk Blom, a professor of clinical psychopathology at Leiden University in the Netherlands, who co-authored the 2014 paper with Sacks, says the study of PMO is important because it could turn up clues about those parts of the brain that play a role in the representation of faces. Also, because the majority of health professionals either have not heard of PMO or don’t understand it, Blom says, people who seek help for the condition may be misdiagnosed or receive unnecessary or misdirected treatment. “Patients correctly diagnosed with PMO are in dire need of speaking to others with this condition in order to share experiences and feel less isolated and alien,” Blom says. In 2021 he co-authored a review entitled “A Century of Prosopometamorphopsia Studies.”

Many with PMO, such as Smith, see facial features morph and change. Others see faces or features that droop or twist, skin that looks like tree bark, features that turn into geometric shapes or one face that is superimposed on numerous people. In some cases, faces can even appear demonic. One man who woke up with PMO a few years ago told Duchaine he thought he had gone to hell.

Smith, who has always had migraine headaches, says that this year the frequency and intensity of the distortions increased, along with the frequency of her migraine attacks. So far Duchaine’s research has not revealed one specific cause of PMO, and he expects there are a variety of causes but says he wouldn’t be surprised if 25 percent of the people with PMO who contact him have migraine-related distortions.

Just as there is no one identifiable cause, there is also not one proved treatment. Psychoactive drugs such as SSRIs have been tried without much impact.

“Distortions often resolve on their own in people who have not had them for long. As a result, in cases like that, it’s hard to know whether newly prescribed meds contributed to the resolution of the distortions,” Duchaine says.

Blom explains that in clinical practice, tests—at the very least, a brain magnetic resonance imaging (MRI) scan, an electroencephalogram (EEG) and bloodwork—are run in an attempt to establish the underlying neurobiological disorder. “Depending on what we find—for example, epilepsy, a brain infarction, a cerebral cyst, etcetera—we apply practice-based guidelines for treatment purposes,” Blom says. “In other words, there is not one specific type of drug that we consider effective for all cases of PMO. Hopefully one day we will be able to develop evidence-based guidelines, but I expect that these will also involve a differentiation of clinical cases of PMO into types with certain underlying disorders and that treatment protocols will be aimed at treating those.”

In April Duchaine co-authored a review that uses PMO to address fundamental theoretical questions about face representations. These include whether awareness of faces and decisions about them depend on the same representations or different ones, the nature of facial symmetry and how each half of the face is separately represented in the visual system. The review also includes 18 open questions that illustrate the considerable amount left to learn about PMO and its potential to advance the understanding of face perception.

Of the 51 cases of PMO reviewed in the study, structural brain scans were available for 48 people, and lesions on visual regions of the brain were present in 44 of those individuals.

“If you look in the literature, it’s almost entirely people who suffered brain damage. But I think that might be because that’s who’s showing up in neurological clinics, whereas we’re hearing from people through the Internet, and very few of them are aware of any brain damage that coincided with the onset of their distortions,” Duchaine explains.

Of the 60 people with PMO who have contacted Duchaine, only a handful can point to an event likely to have brought on their distortions. He says there are two possibilities for the discrepancy. Either many of the participants have lesions that will be revealed by scans, or there are many individuals with PMO who do not have lesions, and Duchaine has been able to find them because his research is not limited to people who have had neurological events. (Smith’s brain scan revealed no abnormalities.)

Duchaine suspects that a few of the cases, including that of Smith and a teenager whose mother recalls that he had problems with faces at an early age, represent a variant of PMO that results from problems with the development of face perception mechanisms.

Though his research is ongoing (the latest findings are due to be published in the next year), Duchaine and his team have discovered that distortions in a substantial number of cases can be modulated by manipulating the appearances of faces. They have attempted to modulate distortions in a small number of cases and have found four people whose distortions are influenced by color—including Smith, whose distortions are less severe when she wears orange-tinted glasses—and several cases in which the presence of eyeglasses on the face being observed reduces or eliminates distortions.

Duchaine says the fact that 60 people have contacted him in nearly three years indicates that the condition may not be as rare as once believed. He hopes that publicizing his work will bring even more people with PMO to his website so they can be included in his research and perhaps find some relief.

“They’re out there,” he says.