April 5, 2024 – For greater than two years, a 58-year-old man has been seeing “demonic”-looking human faces at any time when he looks at one other person.
Now, for the primary time, researchers have used computer software to display accurate depictions of the facial distortions that patients like these see on account of a rare vision disorder called prosopometamorphopsia, or PMO, which is usually mistaken for a mental illness.
PMO is a rare, often misdiagnosed vision disorder during which human faces appear distorted in shape, texture, position or color. Most patients with PMO see these distorted facial expression on a regular basis, whether or not they are taking a look at an actual person, a screen, or paper.
But the person involved this new study The study, published in March, said he only sees the distortions when he meets someone in person, not on a screen or on paper.
This allowed researchers to make use of editing software to create a picture on a pc screen that matched the patient's distorted view.
“This new information should help healthcare professionals understand the intensity of facial distortions experienced by people with PMO,” said study researcher Brad Duchaine, PhD, professor within the department of psychology and brain sciences at Dartmouth College in Hanover, NH.
“A significant number of people we worked with were misdiagnosed, often with schizophrenia or some type of psychotic episode, and some were treated with antipsychotics even though their visual system had just experienced a small improvement,” he said.
Prevalence underestimated?
Although fewer than 100 cases of PMO have been reported within the literature, Duchaine said this is probably going an underestimate. Based on a solution to a website His team was created to recruit affected patients. He believes there are “far more cases than we know.”
PMO will be brought on by a neurological event that ends in a lesion in the best temporal lobe near facial processing areas. In many cases, nonetheless, the cause is unclear.
PMO can occur within the context of head trauma, in addition to stroke, epilepsy, migraine, and hallucinogen-persistent cognitive impairment, the researchers noted. The disease may occur without noticeable structural changes within the brain.
“Through our website, we hear from many people who have not had or are unaware of a neurological event that coincided with the appearance of facial distortions,” noted Duchaine.
The patient on this study suffered a severe head injury at age 43 that resulted in hospitalization. He was exposed to high levels of carbon monoxide about 4 months before his symptoms began, but it surely shouldn't be clear whether the exposure was related to his PMO.
He was not prescribed any medication and stated that he had no history of illicit drug use.
The patient also had a history of bipolar affective disorder and posttraumatic stress disorder. Although he sees visions of distorted faces, he didn't have delusional ideas concerning the people he encountered, investigators wrote.
Neuropsychological testing was normal and there have been no problems along with his vision. Computerized facial perception tests showed slight problems in facial identity recognition, but facial features recognition was normal.
When taking a look at objects equivalent to a coffee cup or a pc, the patient often didn't notice any distortion. However, says Duchaine, “if you get enough text together, the text will start to swirl for him.”
Insightful insights
The patient described the visual facial distortions as “severely stretched facial features with deep furrows on the forehead, cheeks and chin.” Even though these faces were distorted, he could recognize the people he saw.
Since the patient didn't report distortions when viewing facial images on a screen, the researchers asked him to match what he saw when he checked out an individual's face within the room with a photograph of the identical person on a pc screen.
The patient alternately checked out the actual person, which he perceived as distorted, and on the photo on the screen, which he perceived as normal.
The researchers used real-time feedback from the patient and photo editing software to control the photo on the screen until the photo and the patient's visual perception of the person within the room matched.
“This is the first time that we actually have a visualization that we're really confident that this is what someone with PMO is experiencing,” Duchaine said. “If he were a typical PMO case, he would be looking at the face in real life and looking at the face on the screen, and the face on the screen would also be distorted.”
The researchers found that the patient's distortions are influenced by color; When he looks at faces through a red filter, the distortions are greatly increased, but when he looks at them through a green filter, the distortions are greatly reduced. He now wears green-filtering glasses in certain situations.
Duchaine hopes this case will open the eyes of doctors. “These types of vision distortions your patient is telling you about are probably real and not a sign of a broader mental illness; it is a problem limited to the visual system,” he said.