Can Covid Cause "Face Blindness"?

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Are you "good" at recognizing faces? Or do you sometimes have trouble telling characters apart in a television show, or don't recognize your acquaintances if they are in a different context from the one you are used to seeing them in?

Prosopagnosia, also known as "face blindness," is the more severe end of the spectrum of this condition. People with prosopagnosia lack the ability to recognize even the faces of people most familiar to them—in extreme cases, even their own faces. A recent case study found the advent of prosopagnosia in a 28 year-old woman after a Covid infection, a woman who'd had no such facial recognition problems before. The case raises a concerning question: will we see an increase in cases of prosopagnosia over time, as more people suffer from the effects of Covid and recognize and report their symptoms? What else might it tell us about the potential neurological effects of Covid?

Covid's effects on the brain have been documented since early in the virus's existence, with loss of the sense of smell a prominent symptom for many. But less attention has been paid to Covid's potential effects on navigational abilities and facial recognition. This most recent case study, published in the journal Cortex, outlines the experience of a woman named Annie. A few weeks after contracting Covid in the spring of 2020, during which she had the typical respiratory symptomology including fever and coughing fits, she noticed that "something was off" with her perception of faces. This included her struggling to tell her father and her uncle apart, and also having the unsettling sensation that familiar voices were coming out of the faces of people that, to her, looked like strangers.

A part-time portrait artist, Annie clearly possessed substantial visual skills and the prior capacity for detailed facial perception. Prior to her Covid diagnosis, Annie reported, she was aware of no deficits in this faculty, and could typically draw a face without looking at the reference photo for 15 minutes at a time. Now, strikingly, she felt like perceiving differences in faces felt similar to trying to decode a foreign language.

Indeed, Annie's scores on four different face identity memory tests showed significant and debilitating deficits. Though she experienced brain fog and increased navigational difficulties, her overall cognitive functioning—or her visual recognition abilities for objects that weren't faces—were far less affected.

It's important to note some limitations of Annie's case, including the idea that her having had a stroke (the risk of which is increased with Covid infection) was not definitively ruled out. Also, the Covid diagnosis itself, early in the pandemic where tests were not available, was strongly suspected but not definitively proven.

As of yet, cases like Annie's appear to be rare—but this might just be because people aren't seeking treatment, or are lumping prosopagnosia symptoms into a larger category of "brain fog"—a very common complaint for those who are suffering from long Covid. But Annie's case suggests that, at least for some people, a Covid infection could be associated with the development of a very selective type of cognitive impairment.

With findings like these, and the continued association of Covid with potential long-term neurological and psychiatric effects, further research is crucial. As the world attempts to move forward past the shadow of the pandemic, more studies need to be devoted to the specific neurological conditions that could still be associated with infection, so that we can build better paths to help those people whose lives seem to be forever changed.