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Study details rare visual condition of facial distortion

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A recent case study published in The Lancet details a single patient diagnosed with prosopometamorphopsia (PMO), a neurological disorder of visual perception in which faces appear distorted in shape, texture, position, or color.

I’m not going to lie… haven’t heard of this before.

You and me both. First reported in 1947, PMO is a condition so rare that only 81 cases have been recorded, according to a 2021 report.

Of those, an estimated 50% have claimed the condition affects the whole face (referred to as “full-face PMO”), while the other side notes only seeing distortion on one side of the face (dubbed “hemi-PMO”).

Tell me more.

The condition is characterized by altering a person’s perceptions of people’s facial features in a manner that causes them to appear drooping, swelling, discolored, stretched, or out of position.

While the type of distortion varies on a case-by-case basis, “generally faces will have more prominent eyes and mouths, features will look stretched or squashed, or in the wrong place,” as one report stated.

How long does it last?

It depends on the patient. The condition can reportedly last anywhere from a few days or weeks (as with most cases, apparently), but may also extend to years.

OK, now talk about this case study.

The 58-year-old male patient presented with a 31-month history of seeing “peoples’ faces as distorted and, in his words, appearing ‘demonic,’” according to investigators.

Of note, he reportedly experienced a significant head injury at aged 43 that led to hospitalization, and had potential carbon monoxide poisoning at aged 55, just 3 months before his PMO symptoms began.

Per the patient, this distortion appeared as “severely stretched features of the face, with deep grooves on the forehead, cheeks, and chin,” and pointed ears on the side.

Picture this: Think Spock, the Vulcan science officer of the USS Enterprise in Star Trek, he told CNN.

Interesting visual… could he still recognize people?

Yes. Despite this distortion, the patient reported being able to recognize who these people were.

“It’s like staring at demons,” he added. “Imagine waking up one morning and suddenly everybody in the world looks like a creature in a horror movie.”

Interestingly: He reported seeing no distortions when looking at objects (ie: houses or cars).

How did investigators conduct this study?

They captured a photograph of a person’s face, then presented it to the patient on a computer screen while he also looked at the actual face of the same person.

Then, the researchers recorded the patient’s real-time feedback on the differences between his viewing of the face in-person vs 2D computer-generated image. Based on his responses, they adjust the digital photograph to match the distorted visual he described of the person. 

So what did they find?

The patient’s distorted viewing of a person (face-to-face) did not extend to his viewing of them on the computer screen.

According to the study’s lead author Antônio Mello, a PhD student from Dartmouth's Department of Psychological and Brain Sciences, this differs from previous PMO studies.

"In other studies of the condition,” he stated, “patients with PMO are unable to assess how accurately a visualization of their distortions represents what they see because the visualization itself also depicts a face, so the patients will perceive distortions on it too.”


Investigators were able to actually see the patient’s real-time perception of his visual distortions on people and vice versa, with the patient seeing how his perceptions matched up with reality.

So how common is this PMO diagnosis?

Per the authors, other PMO cases have included patients who were previously (and mistakenly) diagnosed with other health conditions, such as schizophrenia. These patients were put on antipsychotics when their condition was actually a problem with the visual systems, according to Brad Duchaine, senior author of the study.

Duchaine, a professor of psychological and brain sciences and principal investigator of the Social Perception Lab at Dartmouth College, noted that it’s not uncommon for people who have PMO to not tell others about their problem with face perception “because they fear others will think the distortions are a sign of a psychiatric disorder.”

Is there any treatment available?

Researchers have learned that the condition’s distorted imaging may be linked to an area of the brain called the “fusiform gyrus (FG),” which is responsible for face perception, object recognition, and reading.

Testing is currently underway at Dartmouth to manipulate light colors (with red intensifying distortions and green removing them, in some cases).

A potential alternative therapy being investigated includes showing PMO patients “completely symmetrical faces, which appears to reduce distortion,” CNN reported.

Anything else?

Other reports of treatments include migraine medications, anti-epileptic medications, and surgery to remove tumors.

And what do the researchers hope to gain from this research?

With limited research and knowledge of PMO, investigators hope to increase public awareness of this condition.
In fact, they have launched a dedicated website for the neurological disorder, which includes a call-out to individuals experiencing face distortions or similar symptoms to participate in their ongoing research.

*Featured image courtesy of The Lancet