This very rare neurological disease gives faces a demonic appearance

This very rare neurological disease gives faces a demonic appearance

Suffering from a rare visual disorder called prosopometamorphopsia, a man sees the faces around him as distorted demons. Thanks to him, science today knows a little more about this disturbing fact.

A nightmare when he wakes up, he wakes up surrounded by “demons”

One morning in 2020, when he woke up, Victor Sharrah, 58, experienced the fear of his life: in front of him, his roommate looked at him, adorned with pointy ears, gigantic eyes and a mouth cut to the edges of the face. Same vision of horror when he leaves his house: the passers-by all have monstrous and deformed faces.

“My first thought was that I had woken up in a world of demons”, he told AFP. “I started to panic” and think that “I was going to be committed to a psychiatry” relate-t-il.

But Victor Sharrah is not under the influence of hallucinogenic substances as one might think. No, he has what we call prosopometamorphopsia, or PMO, an extremely rare disorder that visually distorts faces.

What do patients with prosopometamorphopsia see?

Prosopometamorphopsia is a very rare disorder of face perception. Patients with this condition typically see a person’s features distort when they look at them, until they resemble your worst nightmares.

The fifty-year-old, who nevertheless has perfect vision, has long been frightened by his apparitions. However, it has one advantage: it does not perceive any distortion on faces when they are seen on a screen and on paper. This allowed Dartmouth researchers to provide precise visualizations of facial distortions seen by patients thanks to his collaboration.

For the study, the volunteer was put in the presence of people and their photographs. He could thus indicate to the researchers the differences they observed between the figure on the screen and the real face in front of him. The image was modified using computer software so that it corresponded to the distortions perceived by the patient. Ultimately giving portraits resembling elves or elves… In short, inhuman creatures.

“Thanks to this process, we were able to visualize the patient’s perception of facial distortions in real time” enthused Antônio Mello of the Department of Brain Sciences and Psychology at Dartmouth.

The cause, however, remains a mystery

Fortunately, prosopometamorphopsia remains a very rare disease today. According to the authors, only 75 cases are to date listed in the scientific literature and they are not identical: the disorders can affect the shape, size, color and position of facial features, during “days, weeks, even years”specify the researchers in their press release.

As for its origin, the mystery remains. If this rare disorder generally appears after a brain injury, the diagnosis is not easy. Victor Sharrah, for example, did have a brain lesion, the result of an injury when he worked as a truck driver in 2007. But it would not be linked to his disorder, according to Antonio Mello, because MRI images located his lesion in the hippocampus, part of the brain which is “not associated with the image processing network“.

The fear of appearing crazy

On the other hand, the disorder can be confused with a mental disorder. “Many people with PMO have told us that they have been diagnosed by psychiatrists as having schizophrenia and that they had been put on antipsychotics, even though their condition was a problem of the visual system”says lead author Brad Duchaine of Dartmouth.

In fact, the authors also believe that, for fear of what they might learn, or for fear of appearing crazy, people with the condition do not talk about it, living alone in fear of their perception.

For three years, Victor Sharrah has gotten used to this world populated by demons. However, he decided to talk about it to advance science and inform other patients who could wake up, like him, in the middle of a nightmare.