Brain Fog After Covid

Brain Fog After Covid

Yvonne Hedeker Yvonne Hedeker
4 minute read

We now know that even mild cases of COVID-19 can cause persistent neurological problems, including confusion, headaches, dizziness, and other types of altered mental function.  Scientists are still working on the reasons behind the long-term neurological symptoms that appear related to the virus.  Some neurologists and patients describe the phenomenon as “brain fog”, which includes symptoms such as: 

Difficulty putting thoughts together
Problems with concentration
Inability to remember what happened a short time before
Trouble organizing and planning their day
Difficulty waking up in the morning
Trouble working longer hours
Suffering from insomnia and inexplicable anxiety
Ongoing mental and physical fatigue

“…these people who still don’t feel quite right afterward, but have normal brain scans,” says researcher, Rachel L Brown, in Brain, an Oxford University Journal.  

How prevalent these neurological problems are, is not yet understood. However, it is safe to say that “neurological problems are not rare for COVID-19 patients,” according to Majid Fotuhi, MD, PhD, medical director of NeuroGrow Brain Fitness and lead author of a comprehensive review of COVID-19’s published in Journal of Alzheimer’s Disease. “Our best estimate so far is that 30% to 50% of hospitalized patients have neurological issues,” he says.

A French report in August on 120 patients who had been hospitalized found that 34 percent had memory loss and 27 percent had concentration problems months later. Another survey of 3,930 members of Survivor Corps, a group of people who have connected to discuss life post Covid, more than 50% reported difficulty concentrating or focusing, said Natalie Lambert, an associate research professor at Indiana University School of Medicine, who helped lead the study. It was the fourth most common symptom out of the 101 long-term and short-term physical, neurological, and psychological conditions reported. Memory problems, dizziness or confusion were reported by a third or more respondents.

No one knows how long these symptoms can last, or even if they are permanent. Some researchers believe that the virus can specifically invade the brain, others think it’s more likely that the systemic inflammation caused by the coronavirus,  affecting many organs, including the brain and the immune system within the brain. Systemic inflammation can change the way the brain signals. These changes may be occurring even without a true infection of the brain cells. It is probable that several different disease processes at work:

Complications from intensive care: People who have been hospitalized in the ICU, for any reason, are more likely to experience long-term problems with cognition and an increased risk of anxiety and depression.

Inflammatory or immune response: In some patients, COVID-19 seems to trigger a runaway immune response that can cause problems throughout the body.

Stroke: COVID-19 has been found to cause blood clots that can travel to the brain and cause a stroke. Strokes have occurred in COVID-19 patients of all ages.

Viral infection of the brain: There have been a few accounts of the virus turning up in cerebrospinal fluid, which raises the possibility that SARS-CoV-2, the virus that causes COVID-19, may be able to directly infect brain cells. However, the theory that the virus can make its way into the cells of the brain is still being questioned.

Medical study on lingering brain fog is just beginning. Researchers are scrambling to understand just how COVID-19 is impacting the brain, so that they can develop treatment strategies to prevent neurological damage during Covid as well as help those suffering after Covid.

Experts around the world have started collaborating with the Global Consortium to Study Neurological Dysfunction in COVID-19. The effort, endorsed by the Neurocritical Care Society, is collecting data and evaluating functional and cognitive outcomes to inform treatment strategies (Frontera, J., et al., Neurocritical Care, Vol. 33, No. 1, 2020).

But physicians should not wait until all the data is in to start intervening, suggests Robert Stevens, MD, FCCM, an intensive care physician at Johns Hopkins Medicine who treats patients with critical neurological illnesses.  Existing therapies are available to treat autoimmune encephalitis, for example. “But these haven’t yet been studied specifically in COVID-19 patients.”


Brain, Journal of Neurology, Volume 143, Issue 10, October 2020

Journal of Alzheimer’s Disease, Vol. 76, No. 1, 2020

Excerpts from:


« Back to Blog