This shows a distorted face.
"Through the process, we were able to visualize the patient's real-time perception of the face distortions," says Mello. Credit: Neuroscience News

Devil in the Details: The Visual World of Prosopometamorphopsia

Summary: Researchers conducted a pioneering study on prosopometamorphopsia (PMO), a rare condition where individuals perceive facial features as distorted. The study details the unique case of a 58-year-old male who experiences facial distortions exclusively in person, not when viewing images on screens or paper, allowing researchers to create accurate visualizations of his perceptions.

This novel approach offers insight into PMO, challenging previous diagnostic practices and aiming to enhance understanding and recognition of the condition, which has often been misdiagnosed as a psychiatric disorder due to a lack of awareness.

Key Facts:

  1. Unique Case of PMO: Unlike typical PMO cases, the patient’s condition allows him to perceive faces without distortion on digital screens and printed photos, enabling researchers to accurately depict his real-time facial distortions.
  2. Methodology: By comparing the patient’s feedback on a real face versus its modified image on a screen, researchers successfully visualized the specific distortions he perceives, a breakthrough in understanding PMO.
  3. Diagnostic Challenges: The study highlights the misdiagnosis of PMO as psychiatric conditions such as schizophrenia, underscoring the need for greater awareness and understanding among health professionals.

Source: Dartmouth College

Imagine if every time you saw a face, it appeared distorted. Well, for those who have a very rare condition known as prosopometamorphopsia (PMO), which causes facial features to appear distorted, that is reality.

As the Dartmouth-based website about prosopometamorphopsia 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 for days, weeks, or even years.”

A new Dartmouth study published in the “Clinical Pictures” section of The Lancet reports on a unique case of a patient with PMO. The research is the first to provide accurate and photorealistic visualizations of the facial distortions experienced by an individual with PMO.

The patient, a 58-year-old male with PMO, sees faces without any distortions when they are viewed on a screen and on paper, but he sees distorted faces that appear “demonic” when viewed in-person.

Most PMO cases however, see distortions in all contexts, so his case is especially rare and presented a unique opportunity to accurately depict his distortions.

For the study, the researchers took a photograph of a person’s face. Then, they showed the patient the photograph on a computer screen while he looked at the real face of the same person.

The researchers obtained real-time feedback from the patient on how the face on the screen and the real face in front of him differed, as they modified the photograph using computer software to match the distortions perceived by the patient.

“In other studies of the condition, 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,” says lead author Antônio Mello, a PhD student in the Department of Psychological and Brain Sciences at Dartmouth. In contrast, this patient doesn’t see distortions on a screen.

This shows distored faces.
Computer-generated images of the distortions of a male face (top) and female face (bottom), as perceived by the patient in the study. Credit: A. Mello et al.

This means that the researchers were able to modify the face in the photograph, and the patient could accurately compare how similar his perception of the real face was to the manipulated photograph.

“Through the process, we were able to visualize the patient’s real-time perception of the face distortions,” says Mello.

In their research with other PMO cases, the co-authors state that some of their PMO participants have seen health professionals who wanted to help but diagnosed them with another health condition, not PMO.

“We’ve heard from multiple people with PMO that they have been diagnosed by psychiatrists as having schizophrenia and put on anti-psychotics, when their condition is a problem with the visual system,” says senior author Brad Duchaine, a professor of psychological and brain sciences and principal investigator of the Social Perception Lab at Dartmouth.

“And 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,” says Duchaine. “It’s a problem that people often don’t understand.”

Through their paper, the researchers hope to increase public awareness of what PMO is. For more information about PMO, visit the prosopometamorphopsia website.

About this prosopometamorphopsia and visual neuroscience research news

Author: Amy Olson
Source: Dartmouth College
Contact: Amy Olson – Dartmouth College
Image: The top image is credited to Neuroscience News. The image in the post is credited to A. Mello et al.

Original Research: The findings will be published in The Lancet

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  1. However, having some ideas i want to debate, I would like to propose to you, considering the functions of the hippocampus and research on anomalies or lesions of it and the link to various personality disorders, if the possibility of a coding function possessed by the hippocampus in the sense of information acquisition, encoding and storage has been considered. An anomaly in the protocol or in the encoding process can lead to data corruption. Also, given that the hippocampus is involved in emotional processing, anxiety and avoidance behaviors, has it been considered that the condition is generated by a visual transposition of basic survival and avoidance processes of some perceived potential dangers? (all 75 documented cases show that people perceive distorted faces as frightening or scary and none as beautiful or more pleasant than they really are)


    Interesting Ideas about Prosopometamorphopsia and the Hippocampus

    Your ideas about the hippocampus and its potential role in prosopometamorphopsia are interesting and raise some valid points for further exploration. Here’s a breakdown of your thoughts and some insights:

    1. Hippocampal Coding Function and Data Corruption:

    • The hippocampus is indeed crucial for memory formation. It helps encode information and consolidate it into long-term memory.

    • The concept of “data corruption” during encoding in the hippocampus related to prosopometamorphopsia is an intriguing theory. While not mainstream, it could be a potential avenue for future research.

    • However, current research on prosopometamorphopsia primarily focuses on areas of the brain involved in visual processing and face recognition.

    2. Hippocampus, Emotions, and Fear Response:

    • You’re right, the hippocampus plays a role in emotional processing, including anxiety and avoidance behaviors.

    • The idea of distorted faces triggering a fear response due to a “visual transposition” is a novel concept.

    • The fact that all documented cases report distorted faces as scary could support this theory. However, more research is needed to explore the connection between the hippocampus and fear-based distortions in facial perception.


    • Your ideas offer a fresh perspective on understanding prosopometamorphopsia.

    • While the current understanding focuses on visual processing areas, the role of the hippocampus in memory and emotional processing shouldn’t be entirely disregarded.

    • Further research is needed to explore these connections and see if they hold merit.

    Additional Points:

    • The limited number of documented cases (around 75) makes it challenging to draw definitive conclusions.

    • More studies investigating the specific brain activity patterns during prosopometamorphopsia episodes could shed light on the underlying mechanisms.

    Remember, these are just ideas to consider. If you’re interested in learning more about ongoing research in this area, you can search for scientific articles on prosopometamorphopsia and the hippocampus.


    .But do you agree, considering your knowledge of computer science, that in fact a sensor or a camera captures the information or captures the image, but a codec actually turns it into a file because otherwise it is uninterpretable or nonsensical for a human?


    Yes, I agree with the analogy between encoding information in the brain and encoding files on a computer. There are significant similarities:

    1. Capture of Information:

    • A sensor/camera captures light and converts it into electrical signals.

    • Our eyes capture light and convert it into neural signals.

    2. Transformation of Information:

    • A codec converts electrical signals into digital data (files).

    • The brain transforms neural signals into interpretable information.

    3. Storage of Information:

    • Files are stored on hard drives.

    • Memories are stored in neural networks in the brain.

    4. Interpretation of Information:

    • A computer program interprets data from files.

    • The brain interprets information from memories.

    The analogy has limits:

    • The brain is much more complex than a computer.

    • The processes in the brain are not fully understood.

    Still, the analogy remains valuable:

    • Helps to understand how the brain processes information.

    • Provides a framework for exploring cognitive functions.


    The similarity between encoding information in the brain and encoding files on a computer is a useful analogy. It helps us better understand the complexity of cognitive processes and the important role of the brain in transforming stimuli into meaningful information

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