A case study, published in the journal Current Biology, describes a very rare medical condition of a patient who makes the faces of the beholder appear as “half-loose”. Despite the perfect sight, in fact, the described subject is not able to see people’s faces without being visually distorted.
Known as hemi-prosopometamorphopsia (hemi-PMO) it is a condition recorded only 25 times in medical history and is caused by some form of brain damage. For the patient in this case study, simply dubbed AD by the researchers, the condition was the result of an injury in the splenium region of the brain, the terminal part of the corpus callosum, an area associated with sight.
This disorder has rarely been studied as it often wears off over time. To better understand the strange condition, the researchers showed the study subject a series of images of faces and other objects in different planes, with different angles and different perspectives. The results showed that he was able to see inanimate objects correctly, but faces were almost always distorted despite being rotated and turned.
The faces appeared as “fused” in the regions that you can see at the bottom of the news. “Whenever we see a face, the brain adjusts our representation of that face so that its size, point of view and orientation match those stored in memory, just like the facial recognition systems used by Facebook and Google.“says study co-author Brad Duchaine, principal investigator of the Social Perception Lab at Dartmouth College.
As this disorder often fades over time, we can only wish AD a speedy recovery.