Connecting More Dots: Brain Shrinkage and Covid-19

Spoiler alert: Houston, we have a problem.

Biobanks are repositories for human tissue and other test samples. There are a number of them around the world, with the content of each specific to the mission or focus of that particular facility.(1)

One of the ten largest is in UK. This Biobank holds brain scan information donated by 45,000 British individuals. What’s important about this database is that the information was collected prior to the Covid pandemic.

British researchers were able to obtain updated brain scans (MRIs) from 785 of the original contributors, including 401 who are known to have been infected with Covid-19. This allows them to compare before-and-after scans as well as compare those infected with those not infected. We can see any brain changes among those infected with Covid, and compare those changes with the impact of normal aging among the uninfected.

The post-infection MRIs were collected approximately 4.5 months after the diagnosis of infection. That’s a relatively short time in which to detect brain damage from the virus, but it was long enough as it turns out.

Among those requiring hospitalization from the virus and those with less severe illness, the virus affected areas of the brain responsible for emotions, decision making, and the creation and retention of memories.

Compared with the control group, the infected group showed greater tissue loss in specific regions of the cerebral cortex, the wrinkled outer surface of the brain. One region, called the orbitofrontal cortex, sits just above the eye sockets, receives signals from brain areas involved in sensation, emotion and memory and plays an important role in decision-making. The other, known as the parahippocampal gyrus, surrounds the hippocampus, a seahorse-shaped structure in the middle of the brain that’s important for encoding new memories. 

. . . the infected group also showed a greater reduction in overall brain size than the control group.

The brain loss is significantly in excess of what is normal in adults. In addition, those infected with Covid had lower scores on cognitive tests assessing attention and decision-making than did their uninfected peers.

Finally, and no surprise here, researchers detected damage to the brain area that processes smell information collected by cells in the nose. Since that’s already been identified as a direct access path for the virus to travel to the brain, that damage fits with what we already know.

Note that a separate report links Long Covid symptoms to damage by the virus to the vagus nerve. That nerve connects the brain to the heart, lungs and digestive system, and controls heart rate, speech, sweating, and the gag reflex.

Between the brain and vagus nerve, think about driving in rush hour traffic. What could possibly go wrong?

About the dots . . .

We’re talking about impairment of decision making by Covid. Other sources have identified a substantial increase in traffic accidents during the pandemic. Are these issues related? A better question might be, why aren’t they?

In the absence of any tools for countering brain shrinkage, we have to consider this damage as permanent. Is the damage done, or will it continue to increase over time? How fast is mental deterioration going to be? That’s something we cannot know yet, unless someone has a time machine.

Since we have reason to believe that the virus remains in the body after symptoms disappear, are we looking at a large population who will need nursing home care at a much earlier age?

If you think you might have had Covid, or you have friends or family members who did, you need to be attentive to signs of unusual moods or behaviors that might signal this damage. You also need to think about how you want to deal with these problems. To paraphrase President Eisenhower, plans are useless, but planning is everything.

The future may be sooner than you thought.


Now imagine the patient with dark hair and 20 years younger.


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