Hanya Gaber
MISSBOBBIT / ISTOCK
He stood there frozen, unable to take one move forward. This stranger was standing ahead of him, in his own bedroom, staring right back at him. He slowly reaches out for his phone to call for help but the man reaches replicates that action and then it hits him that he's looking at his own reflection in the mirror.
This is the story of a normal day for someone who has prosopagnosia. Millions of people, including Steve Wozniak, the co-founder of Apple Co., suffer from this clinical syndrome. While some are only unable to identify others, some are unable to identify their own selves.
Prosopagnosia is a neurological condition characterized by the inability to recognize familiar faces, more widely known as “face blindness”. Facial recognition is a multi-stage process with its main stages being; image processing in the fusiform gyrus, communication with the temporal lobe and matching the memories with the processed face.
Prosopagnosia is further classified into two main groups according to etiology: developmental prosopagnosia, genetic in origin, and acquired prosopagnosia, which is further subdivided into apperceptive and associative prosopagnosia.
Patients with the developmental variant have normal intelligence and memory. Acquired prosopagnosia occurs as a result of lesions in the occipito-temporal lobe due to trauma, tumors, and intracranial hemorrhages.
It can also happen in association with other neurological disorders such as Alzheimer’s disease, and schizophrenia, though as a symptom, it is referred to as “impaired facial recognition”.
In apperceptive prosopagnosia, the patient is unable to perceive and cognitively process the faces of others; since the damage happens in the face perception part of the brain. Hence, the individual is unable to recognize both familiar and unfamiliar faces; they cannot identify sex, race (if identifiable from facial features), facial expressions or emotions.
However, they are able to associate other identifiers like voice, clothes, hairstyles, smells or gait with the memory of a familiar person. For example, in a photograph, one cannot recognize the face of their mother, but can see that the person in the picture has their mother’s blonde updo, her red blouse and hence is able to associate these features with memories of their mother and identify her.
On the other hand, patients with associative prosopagnosia are unable to associate a certain face to the individual’s profile. They have no problem perceiving a face, and previously mentioned characteristics as sex, race, ...etc, however, they cannot recall if this face belongs to someone they know, or recall associated memories.
In brief, they view anyone as a stranger. These patients might also have problems identifying people by other identifiers as clothes, hairstyles, ...etc. In a very rare type of prosopagnosia -mirror-image prosopagnosia- patients cannot even recognize their own faces in mirrors or photographs!
There are multiple tests used to diagnose prosopagnosia, each approaching the diagnosis from a different aspect. Some tests rely on the memory of familiar faces, where the patients are presented with faces of celebrities and are asked to identify them.
However, these tests are not accurate since the test requires the patients to be familiar with the celebrities beforehand; however, there are different tests for different countries that portray national celebrities to eliminate cultural gaps.
There are tests that rely on the short term memory of unfamiliar faces, as the Cambridge Face Memory Test (CFMT), where photographs of unfamiliar faces are shown to the patient. The patient is then asked to identify the face they have seen out of a group of others. This test is not accurate as well since it relies on short term memory, which is already variable between healthy individuals.
Other tests, like the Benton Facial Recognition Test, rely on the ability to recognize and match a photograph face with its corresponding photograph, that could be inverted horizontally or vertically to avoid using other aspects of recognition, or could be a picture of the same person from a different angle. (Fig. 1)
Figure 1: Benton Facial Recognition Test
Currently, there is no effective treatment for prosopagnosia and spontaneous resolution of the condition is extremely rare. The only approaches available are treatment of the cause, to prevent further deterioration of the condition, and compensatory treatments; such as verbalizing facial details to enhance facial recognition, though the latter has limited evidence and has not proven to be effective.
The following is a link to the CFME, for a better idea about how the test works. http://www.bbk.ac.uk/psychology/psychologyexperiments/experiments/facememorytest/startup.php?r=8&p=0&d=1&dn=0&g=0&m=68f7d848edeaebd6cc29371b806b3017
However, don’t worry if you don't get all the answers right. As mentioned, this is a very subjective test that relies on short term memory, which is variable. Less than 60% is only suggestive of prosopagnosia.
References:
https://www.nytimes.com/2020/10/12/health/coronavirus-monoclonal-antibodies-trump.html
https://www.sciencemag.org/news/2020/09/provocative-results-boost-hopes-antibody-treatment-covid-19
https://www.bbc.com/news/health-54120753
https://pubmed.ncbi.nlm.nih.gov/32134278/
http://apjai-journal.org/wp-content/uploads/2020/03/2.pdf
https://investor.regeneron.com/news-releases/news-release-details/regenerons-regn-cov2-antibody-cocktail-reduced-viral-levels-and
https://www.regeneron.com/covid19
https://investor.regeneron.com/news-releases/news-release-details/two-science-publications-highlight-potential-regn-cov2-anti
https://science.sciencemag.org/content/369/6506/1010
https://www.prnewswire.com/news-releases/regenerons-regn-cov2-antibody-cocktail-reduced-viral-levels-and-improved-symptoms-in-non-hospitalized-covid-19-patients-301140336.html
https://investor.regeneron.com/index.php/news-releases/news-release-details/regeneron-announces-start-regn-cov2-phase-3-covid-19-prevention
Comments