Brain fog in COVID-19 and Lyme disease patients

man with COVID-19 and brain fog

COVID-19 patients report having brain fog, as do patients with Lyme disease. Brain fog can be a common symptom following an infection, Marie Grill, a neurologist at the Mayo Clinic tells Wired magazine. There are several theories regarding the cause of brain fog, including immune dysfunction, a reaction to a cocktail of medications, changes in blood flow to the brain, and post-traumatic stress.


Lyme disease patients often describe suffering from brain fog. So do COVID-19 patients. Sara Harrison wrote about COVID-19 brain fog in the online journal Wired.

What are examples of COVID-19 brain fog?

Dr. Aluko Hope from Montefiore Hospital in New York City described what he has learned from listening to COVID-19 patients. “About a third of his patients say they can’t recall telephone numbers they used to know, or that they struggle to remember the right word, feeling like it’s on the tip of their tongue but just out of reach. They can’t remember where their keys are, what basic traffic rules are.”

Dr. Adam Kaplan, a neuropsychiatrist at Johns Hopkins University, adds “This mental fuzziness, often referred to as ‘brain fog,’ has become one of a number of reported COVID-19 recovery symptoms.”

“They say their brains work more slowly,” explains Kaplan. “They can’t pick up information in conversation as easily as they used to, and they struggle with short-term memory: They’ll walk to the kitchen, for instance, and forget what they were looking for. Multitasking is impossible. It takes them longer to get things done, and they often feel confused and overwhelmed. Some patients struggle to return to work or to school.”

What are the causes of COVID-19 brain fog?

The causes of brain fog in COVID-19 have yet to be identified. But scientists believe contributing factors may include nerve damage, anxiety, depression, post-traumatic stress, changes in blood flow to the brain, or effects from a cocktail of drugs used to sedate patients while ventilated. However, brain fog occurs in patients who have not been hospitalized.

Another explanation focuses on the body’s immune response to the virus. “Something about that activation of the immune system is potentially causing worse cognitive function,” says Joanna Hellmuth, a neurologist at the UC San Francisco Memory and Aging Center. “It might be that prolonged immune activation after COVID is creating these cognitive changes.”

Brain fog often follows infections

“We do have experience with this,” says Marie Grill, a neurologist at the Mayo Clinic, as she points out that brain fog often follows other infections like Lyme disease, Epstein-Barr (better known as “mono”), and other types of herpes viruses. “A lot of us are not surprised at all to be encountering this, because we have seen it so many times.”

What is the future for individuals with COVID-19 brain fog?

”Scientists don’t know how long these cognitive changes will last in COVID-19 patients, nor if they will have a lasting effect on brain function,” says Hellmuth.

How can doctors tell the difference between COVID-19 fog and Lyme fog?

The article in Wired did not address this all-important question.

  1. Sara Harrison. Confused About Covid Brain Fog? Doctors Have Questions, Too. Wired. November 6, 2020.

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