Imagine if every time you saw a face, it appeared distorted. Well, for those who suffer from a very rare condition known as prosopometamorphopsia (PMO), which makes facial features appear distorted, that’s the reality.
As the Dartmouth-based prosopometamorphopsia website explains, “‘Prosopo’ comes from the Greek word for face ‘prosopon,’ while ‘metamorphopsia’ refers to perceptual distortions.” Specific symptoms vary from case to case and can affect the shape, size, color and position of facial features. The duration of PMO also varies: “it can last days, weeks or even years.”
A new Dartmouth study published in the “Clinical Imaging” section of The lancet reports a unique case of a patient with PMO. The research is the first to provide accurate, photorealistic visualizations of the facial distortions experienced by a person with PMO.
The patient, a 58-year-old man with PMO, sees undistorted faces when viewed on a screen and on paper, but sees distorted faces that appear “demonic” when viewed in person. However, in most cases of PMO distortions are seen in all contexts, so his case is especially rare and he presented a unique opportunity to accurately represent his distortions.
For the study, researchers took a photograph of a person’s face. They then showed the patient the photograph on a computer screen while looking at the same person’s real face. The researchers obtained real-time feedback from the patient about how the face on the screen and the real face in front of him differed, while modifying the photograph using computer software to match the patient’s perceived distortions.
“In other studies of the disease, patients with PMO cannot assess how accurately a visualization of their distortions represents what they see because the visualization itself also represents a face, so patients will also perceive distortions in it,” he says. lead author Antônio Mello, a doctoral student in Dartmouth’s Department of Psychology and Brain Sciences. In contrast, this patient does not see distortions on a screen. This means that the researchers were able to modify the face in the photograph and the patient could accurately compare how similar the perception of his real face was to the manipulated photograph. “Throughout the process, we were able to visualize the patient’s real-time perception of facial distortions,” Mello says.
In their research with other PMO cases, the co-authors say that some of their PMO participants consulted health professionals who wanted to help them, but were diagnosed with another health condition, not PMO.
“We have heard from several people with PMO that psychiatrists have diagnosed them with schizophrenia and prescribed antipsychotics, when their condition is a problem with the visual system,” says senior author Brad Duchaine, professor of psychology and brain sciences and principal investigator of the Laboratory. of Social Perception at Dartmouth.
“And it’s not uncommon for people who have PMO not to tell others about their problem with facial perception because they fear that others will think the distortions are a sign of a psychiatric disorder,” Duchaine says. “It’s a problem that people often don’t understand.”
Through their article, the researchers hope to increase public awareness of what PMO is.