Prosopagnosia, also known as face blindness, is a neurological disorder that affects a person’s ability to recognize faces. Individuals with prosopagnosia may have difficulty recognizing familiar faces, including those of friends, family members, and coworkers, and may even have difficulty recognizing their own face.
Prosopagnosia can be congenital, meaning it is present from birth, or acquired, resulting from brain damage or injury. In some cases, it may be a symptom of another underlying neurological condition, such as autism or Alzheimer’s disease.
There is no known cure for prosopagnosia, but individuals with the condition can learn to rely on other cues, such as voice, hairstyle, or clothing, to identify people. Some may also use compensatory strategies, such as associating people with distinct physical characteristics or using other contextual clues to identify individuals.
Prosopagnosia can be a challenging condition, impacting social interactions, communication, and even employment. However, with support and accommodations, individuals with prosopagnosia can lead fulfilling lives. Treatment options may include cognitive behavioral therapy, as well as assistive technology or accommodations in educational and work settings.
There is a link between brain inflammation and prosopagnosia.
Prosopagnosia can occur as a result of damage to the brain’s fusiform gyrus, a region that plays a crucial role in facial recognition. Inflammation in the brain, whether due to infection or autoimmune conditions, can cause damage to the fusiform gyrus and other regions of the brain, leading to prosopagnosia.
For example, encephalitis, an inflammation of the brain typically caused by a viral infection, can damage the brain’s fusiform gyrus and result in prosopagnosia. Similarly, autoimmune conditions such as lupus or multiple sclerosis can cause inflammation in the brain and lead to damage in the fusiform gyrus.
In addition, some studies have suggested that brain inflammation may play a role in the development of acquired prosopagnosia in individuals without any history of brain injury. In these cases, the inflammation may be caused by a viral infection, autoimmune condition, or other factors.
It’s important to note that not all cases of prosopagnosia are caused by brain inflammation. Congenital prosopagnosia, for example, is believed to be a developmental disorder that is present from birth and not related to inflammation or brain damage.
Original Research: Open access.
“Persistent prosopagnosia following COVID-19” by Marie-Luise Kieseler et al. Cortex
Prosopagnosia is defined as the inability to recognize known and new faces. It is also known as facial/visual agnosia.
Bodamer first used the word prosopagnosia in 1947 in a landmark paper that described the cases of two patients with face recognition deficits.
COVID-19 can produce long-term neurological impairments such as loss of smell and taste (Mao & Jin, 2020), memory problems and brain fog (Davis et al., 2021), verbal memory deficits, difficulty processing spoken language, and visuospatial memory problems (Ferrucci et al., 2021).
Problems with visual perception were mentioned in Mao and Jin (2020), and Graham et al. (2021) reported that 18.4% of their participants suffered from problems with visual long-term memory but no previous studies have shown severe, selective effects to visual processing caused by COVID-19.
Consistent with her difficulties with face recognition in daily life, Annie performed poorly on all four tests. Her normal scores on face identity perception and face detection tasks indicate that her difficulties with faces specifically involve face memory processes. In contrast to her face deficits, Annie shows no impairment with object recognition.
She also does not show other cognitive impairments or significant general memory problems. Her intact face perception abilities indicate that Annie suffers from an associative form of prosopagnosia and brings up the question of whether her identity processing deficits are multimodal.
Annie’s normal voice recognition performance, however, demonstrates that her person identity recognition impairments are not multimodal but are instead limited to the visual domain. Like a substantial proportion of cases with acquired prosopagnosia (Schmidt, 2015), Annie experiences difficulty navigating familiar environments.
The co-occurrence of prosopagnosia and navigational difficulties likely arises due to the proximity of brain regions critical for scene and face processing (Corrow et al, 2016). Overall, due to the dissociations between Annie’s face memory deficits but intact object and scene processing, the results indicate that Annie’s visual recognition deficits are face specific.
While Annie’s neuropsychological impairments could be the consequence of an independent problem that co-occurred at the roughly same time as her COVID-19 infection, we believe it is much more likely that Annie’s prosopagnosia and navigational deficits were caused by COVID-19 or long COVID/PASC because of the close temporal link between the onset of her problems and her COVID-19 infection.
To investigate whether other people who had COVID-19 also experience perceptual and specific cognitive deficits, we asked individuals who have had symptoms for more than 84 days (PASC group) as well as those who had recovered from COVID-19 (control group) to respond to a survey. In this survey, participants self-reported on their abilities to perform a variety of tasks before and after their COVID-19 infection.
While the control group of fully recovered participants did not show significant differences between before and after, participants in the PASC group reported significant decreases in their ability to perform several tasks including identifying people and objects, voice recognition, memorizing phone numbers, and reading comprehension.
A substantial proportion of survey respondents also reported difficulty navigating their environment after their COVID-19 infection. Davis et al. (2021) asked a question about navigation in a survey of participants with PASC/long COVID and found that 20% of the participants reported difficulty finding their way home.
We found that 32.9% of our participants in the PASC group report getting lost when traveling after COVID-19 as opposed to 9.6% prior to their COVID-19 illness, and 45.6% find familiar streets unfamiliar after COVID-19 compared to 7.4% before contracting COVID-19.
Brain fog, also referred to as mental fatigue, is one of the most common symptoms in people with long COVID (Graham et al, 2021; Komaroff & Bateman, 2021; Goërtz et al., 2020). Brain fog is characterized by the inability to concentrate, memory problems (Ross, Medow, Row & Stewart, 2013), and not being able to process multiple inputs (Callan, Lads, Husain, Pattinson & Greenhalgh, 2022).
Given these effects, we considered the role that brain fog might play in Annie’s deficits with faces and navigation and in the changes in the ratings of our survey respondents. In Annie’s case, it is unlikely that brain fog caused her impairment with face identity recognition because she achieved normal scores in object recognition tests and voice identity recognition tests that are matched to the face tests in task demands and difficulty.
As for the survey respondents, brain fog seems likely to play a role in the difficulties the participants in the PASC group are describing. However, brain fog seems an unlikely explanation for the reductions in color perception reported by 32.1% of participants in the survey.
These changes suggest that Annie may be one of many people with long COVID/PASC who have sustained damage to the visual system. Consistent with this view, studies measuring the co-occurrence of chronic fatigue syndrome (CFS) and face processing difficulties did not find significant differences between groups of participants with and without chronic fatigue syndrome (Cope et al., 1995, review on CFS and cognitive dysfunctions: Teodoro, Edwards, & Isaacs, 2018).
Previous studies of the long-term effects of COVID-19 have reported deficits in memory, attention, and concentration that substantially impair everyday functioning (Davis et al., 2021). Here we report that, in addition to the well-known broad impairments, COVID-19 sometimes causes severe selective impairments like prosopagnosia.
Survey data we collected from individuals with PASC/long COVID also showed that perceptual and cognitive deficits following COVID-19 were present in a substantial proportion of the respondents, though none report having acquired prosopagnosia.
Our findings suggest that there are a substantial number of individuals with PASC/long COVID who are experiencing selective visual deficits and indicate that future work should aim to understand the nature of these deficits and whether interventions can be developed that reduce their impact.
