Prosopometamorphopsia: discover the rare disorder that makes patients see ‘demonic’ faces

For the first time, researchers demonstrated how people with prosopometamorphopsia (PMO), a disorder that causes changes in the perception of faces, sometimes showing them with “demonic” appearances, visualizing other people’s faces.

Published in March 2024 in the magazine The Lancetand with only 75 cases reported to date, The extremely rare neurological disorder is poorly understood, despite having been the subject of several investigations, and is often confused with schizophrenia. It is characterized by changes in the patient’s visual perception, who begin to see deformed faces.

The types of distortions perceived, such as shape, size, color and texture, vary from case to case. According to reports, some sufferers see contorted and dislocated eyes and nose, while others see cartoon-like faces and there are also those who see frightening appearances.

Most patients cannot accurately evaluate an illustration of what they see because perceive distortions in their own representation. However, researchers at Dartmouth College, in the United States, discovered a PMO sufferer who only visualizes the deformations when seeing a face in person.

Distortions seen by someone with PMO

Suffering from prosopometamorphopsia for almost three years, Victor Sharrah sees demonic faces due to the condition, but only if he is face to face with someone. Taking advantage of this, the authors took photos of volunteers and displayed them on the computer, at the same time as the man viewed the real person.

Using specific software, the scientists modified the photographs based on the patient’s descriptions. The 58-year-old man visualizes elongated features in the eyes, mouth and ears, as well as distortions in the chin, cheeks and forehead. The disorder does not affect your vision when looking at objects.

“Through the process, we were able to visualize the patient’s perception of facial distortions in real time,” said Dartmouth doctoral student Antônio Mello, co-author of the study, in a statement. He further reported that the changes in Sharrah were not accompanied by delusional beliefs about the people seen.

What causes prosopometamorphopsia?

Although the causes of PMO are unknown, it is suspected to be associated with abnormalities or damage in the areas of the brain where vision processing occurs. In some cases studied, the distortions appeared after migraines, traumatic brain injuries or strokes, but in others they appeared without apparent reasons.

The volunteer for this research suffered a head injury 15 years ago, resulting in damage to the left part of the brain. Furthermore, he suffered carbon monoxide poisoning months before the changes in vision appeared, situations that may have contributed to triggering the problem.

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