How Coronavirus Affects the Brain

When we recover from colds, flus or even pneumonia, we don't often think about an aftermath punch to cognition — yet the connections have always been there. In fact, viruses such as the flu, measles, respiratory syncytial virus (RSV) and Zika have known neurological effects, as do other types of coronaviruses, including SARS and MERS. These stealthy connections are real, and we're just beginning to document the far-reaching insults that SARS-CoV-2, the virus that causes COVID-19, has on the brain. Some of the most frequent symptoms recorded have been relatively mild, such as headaches, muscle pain and dizziness. But reports of encephalopathy, or altered brain function, in nearly a third of patients — with an increased risk of severe illness and death as a result — surprised the researchers. They were also surprised to find that neurologic manifestations as a whole were more likely to occur in younger people, though encephalopathy was more frequent in older patients.

The COVID-19 Brain

How this virus attacks the brain and nerves still isn't totally clear, but researchers are increasingly focused on two primary mechanisms: one direct and the other indirect. In the first, the virus cloaks itself and evades detection as it travels with precious nutrients across the blood-brain barrier and into the fluid that bathes the brain and spinal cord. Once inside, the virus can inflict all sorts of damage to different parts of the brain, and we're still trying to understand this. Early reports reveal that the virus can exploit brain cells to make copies of itself and simultaneously suck up precious oxygen nearby, starving neighboring brain cells.

In the other pathway, the virus waves its arms wildly and provokes a counterattack from the body's immune system, which leads to a complex array of immunological effects. Such effects can result in inflammatory-related damage to tissues and organs, including the brain. Some combination of these two interwoven paths is a possibility, too.

"COVID is a chameleon of a disease,” says Richard Isaacson, M.D., a preventive neurologist at Weill Cornell Medicine and New York-Presbyterian Hospital, and host of the American Academy of Neurology's COVID-19 video interview series. “COVID affects people in so many different ways and can wreak havoc on just about every organ system in the body. As an infectious disease with potential vascular, inflammatory and immunologic manifestations, it can have wide-ranging neurological effects.”

Regardless of how exactly the virus harms the body, we now know that the impact of COVID-19 on the nervous system can be more significant and lasting than the transient loss of taste and smell that many of the first infected patients described. It can have devastating short- and long-term neurological complications — from delirium, depression and “temporary brain dysfunction” to headaches, brain inflammation, brain bleeds and clots, nerve damage and life-threatening meningitis in both the young and old. Reports of psychosis have also been reported, with the journal Nature detailing the symptoms of one woman in her mid-50s who saw lions and monkeys in her house and accused her husband of being an impostor. A study published by The Lancet Psychiatry revealed that nearly half of the patients who were found to have “altered mental status” were younger than 60.

Among my fellow neuroscientists, there are big questions that remain unanswered: Do these conditions — and potential brain changes — set the stage for serious long-term cognitive decline and dementia later on? And, most important, what can we do about it? These are five approaches that may offer hope.

Ryan Johnson

Maintain social connection in a physically distanced world.

My motto “connection for protection” has taken on a whole new meaning. We may not be able to kiss and hug whomever we want, but we can certainly maintain and even create new enriching interpersonal relationships, and we should make that a priority. The pandemic has caused widespread emotional distress and increased risk for psychiatric illness, though we don't know yet if conditions like depression from COVID-19 are happening directly from the infection or if there are other things going on psychologically from the illness to complicate this evolving picture. What we do know is that prolonged social isolation leads to memory loss, and that loneliness is a risk factor for cognitive decline, dementia and even death. It becomes all the more imperative to fight back against loneliness and remain socially engaged.

Tip: When asking about someone's well-being, probe more deeply and refuse to accept a generic “I'm doing fine.” Another tip, from my own life: Ask for guidance from people such as your parents. It lets them feel a degree of usefulness that can activate the mind. When you can, participate in virtual chats with friends and family. And when you can see people in person, focus on eye contact; it's more important than ever to ease the stress of masked faces. Plus, University of Chicago loneliness researcher Stephanie Cacioppo told me that the eyes, in particular, reflect more authentic emotion.

Eat for resiliency. 

There are no such things as immune boosters or superfoods, but there's lots of data behind the advantages of a Mediterranean-style diet rooted in fresh fruits and vegetables; whole grains; lean proteins, including seafood; healthy fats; and nuts and seeds. People who follow anti-inflammatory diets such as the Mediterranean regimen may additionally gain beneficial effects against infection itself.

Tip: Processed and sugary foods tend to raise inflammation levels. Try swapping out one processed, pro-inflammatory meal a day for minimally processed fare grounded in whole, fresh foods.

Move more. Exercise remains key to mental sharpness and a healthy immune system. 

Exercise can counteract the negative effects of isolation and confinement stress on immune function. We also know now that exercise improves immune responses to infections and could even help to develop better immunity with the aid of a vaccine. All of this ultimately helps protect the brain and its vulnerability in the face of infection.

Tip: Access to exercise is better than it ever was pre-pandemic, thanks to a surge in online programming. Find a corner in a room, log on to a virtual class, and get moving — no membership required. And remember, being outside is far safer than being inside, where the virus can linger longer, so find new, less crowded routes and quieter times of day to enjoy a brisk walk, run or bike ride.

Boost immunity through sound sleep.

Our sleeping habits have changed throughout the pandemic because of shifts in our routines. But now is not the time to lose sleep. It's your (free) secret weapon to refresh and replenish tissues and cells — among them, those of the brain and immune system. It also rinses away waste and debris in the brain that can otherwise foment disease, and it strengthens your memories. After a good night's sleep, you wake up with a smarter body and a sharper mind, better able to deal with the day's stressors.

Tip: I used to take at least 30 minutes to wind down before bedtime, but these days I've bumped up relaxing presleep activities (no more screens) to at least an hour. Harvard University psychologist and dream researcher Deirdre Barrett says it's helpful to keep a dream journal as we go through this pandemic. “You'll notice patterns in your dreams over time that you might not get just from thinking about each individual dream,” she told me. Try to prevent anxiety-ridden COVID-19 dreams by actively planning out what you want to dream about before you fall asleep.

Simon & Schuster

Everyone's life has changed over the past year, and no one welcomed this pandemic. But this situation, however challenging, does allow us the opportunity to engage in new habits and new ways of thinking that can make us more resilient to illness and mental decline. Michael Stephen, M.D., is not letting fear get in his way; during his recovery from COVID-19, he finished authoring a beautiful book about the lungs, called Breath Taking, and he's back on the battlefield to coordinate care, save more lives and help us bring an end to the pandemic. Like me, he's betting on a sharp(er) future.

Ward off anxiety and fears by learning something new, to distract from the negative news.

Distance learning is not just for kids! For less than the cost of a pizza a month, you can be a student of dance taught by Misty Copeland, of writing taught by David Sedaris or of tennis taught by Serena Williams. Finding this sort of purpose-driven activity activates the brain in protective ways.

Tip: You can up the challenge of learning something new by teaching a class yourself. Some educational platforms allow anyone — no teaching degree or formal credentials required — to share their expertise and interests with the world, anything from sign language to survival skills to the stock market.

Neurosurgeon Sanjay Gupta is CNN's chief medical correspondent. His new book Keep Sharp: Build a Better Brain at Any Age, will be in bookstores on January 5.