Images generated by photographic computer software are the first to depict accurate images of facial distortions experienced by patients with prosopometamorphopsia (PMO), a rare visual disorder that is often mistaken for mental illness.
PMO is a rare, often misdiagnosed, visual disorder in which human faces appear distorted in shape, texture, position, or color. Most patients with PMO see these distorted facial features all the time, whether they are looking at a face in person, on a screen, or paper.
Unlike most cases of PMO, the patient reported seeing the distortions only when encountering someone in person but not on a screen or on paper.
This allowed researchers to use editing software to create an image on a computer screen that matched the patient’s distorted view.
“This new information should help healthcare professionals grasp the intensity of facial distortions experienced by people with PMO,” study investigator Brad Duchaine, PhD, professor, Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, told this news organization.
“A substantial number of people we have worked with have been misdiagnosed, often with schizophrenia or some sort of psychotic episode, and some have been put on antipsychotics despite the fact they’ve just had some little tweak in their visual system,” he added.
The report was published online on March 23 in The Lancet.
Prevalence Underestimated?
Although fewer than 100 cases of PMO have been reported in the literature, Dr. Duchaine said this is likely an underestimate. Based on a response to a website his team created to recruit affected patients, he said he believes “there are far more cases out there that we realize.”
PMO might be caused by a neurologic event that leads to a lesion in the right temporal lobe, near areas of facial processing, but in many cases, the cause is unclear.
PMO can occur in the context of head trauma, as well as cerebral infarction, epilepsy, migraine, and hallucinogen-persisting perception disorder, researchers noted. The condition can also manifest without detectable structural brain changes.
“We’re hearing from a lot of people through our website who haven’t had, or aren’t aware of having had, a neurologic event that coincided with the onset of face distortions,” Dr. Duchaine noted.
The patient in this study had a significant head injury at age 43 that led to hospitalization. He was exposed to high levels of carbon monoxide about 4 months before his symptoms began, but it’s not clear if the PMO and the incident are related.
He was not prescribed any medications and reported no history of illicit substance use.
The patient also had a history of bipolar affective disorder and posttraumatic stress disorder. His visions of distorted faces were not accompanied by delusional beliefs about the people he encountered, the investigators reported.
Neuropsychological tests were normal, and there were no deficits of visual acuity or color vision. Computer-based face perception tests indicated mild impairment in recognition of facial identity but normal recognition of facial expression.
The patient did not typically see distortions when looking at objects, such as a coffee mug or computer. However, said Dr. Duchaine, “if you get enough text together, the text will start to swirl for him.”