For some people who’ve survived a coronavirus infection, certain symptoms persist even after the virus itself dies off. Since spring 2020, patients around the world have reported a persistent post-COVID “brain fog” — difficulty thinking, remembering, and sustaining attention — even though physical and cognitive examinations reveal no obvious signs of impairment.
Despite a lack of consensus on the causes of brain fog, clinical experts agree it’s a genuine phenomenon — now termed “post-acute COVID-19 sequelae” or “long COVID.” It’s attracted coverage in magazines like Science, discussion at Harvard Medical School, and peer-reviewed studies in medical journals. What’s more, some clinicians say they’ve already found effective treatments.
Here, we’ll take a closer look at the knowns and unknowns of brain fog, and discover which treatments may offer hope for those who suffer from this mysterious illness.
What is COVID-19 brain fog?
A high percentage of COVID survivors have reported strikingly similar symptoms: a tendency to forget names, numbers, and even ordinary words, along with trouble planning ahead, switching attention, and following trains of thought. Many patients also describe a frustrating mental “fuzziness,” similar to the feeling of a drowsy antihistamine like Benadryl — except all day, every day, for months on end.
While scientists haven’t yet reached a consensus about the physical causes of brain fog, many have pointed out that these aftereffects aren’t unique to COVID. “I’m not sure that what we’re seeing post-COVID is different” from problems that often follow other respiratory illnesses, says Faith Gunning, a neuropsychologist at Weill Cornell Medicine (WCM). Even if the virus doesn’t directly cause brain damage, symptoms like inflammation and lack of oxygen definitely can.
Another possibility is that headaches and body aches, which persist long-term in many COVID survivors, may prevent restful sleep — preventing the brain from fully “recharging” each night. “How can you think clearly if you’re feeling fatigued and your body is aching?” says Andrew Budson, a cognitive behavioral neurologist at Harvard Medical School. “How can you concentrate if you were up half the night with a headache?”
How prevalent is post-COVID brain fog?
Several large-scale studies have found that a significant percentage of COVID survivors experience long-COVID brain fog — while studies on smaller patient populations hint that the numbers may be even higher than we’ve realized.
One study by the US Centers for Disease Control and Prevention, conducted among 274 COVID patients from March to June 2020, found that 35 percent experienced fatigue, while 20 percent reported a feeling of mental confusion. An even larger study, conducted on 1,733 patients in Wuhan, China, found that 76 percent experienced fatigue, 26 percent had sleep difficulties, and 23 percent suffered from depression — up to six months after their infection.
However, a more recent study on 57 patients found that, among those who had a clinical history of neurological problems, a full 81 percent reported post-COVID problems with planning, organization and multitasking. While this was a small study, it suggests that the prevalence of brain fog may be significantly higher among people with existing neurological issues.
What treatments do clinicians recommend?
Since doctors differ on the exact causes of brain fog, the range of recommended treatments runs the full gamut from aerobic exercise, to the Mediterranean diet, to abstinence from alcohol, to playing brain-boosting video games. These are all healthy practices, and they certainly won’t do a post-COVID patient any harm. At the same time, clinical evidence for their effectiveness against brain fog remains anecdotal at best.
However, one form of treatment has delivered clinically measurable improvements by targeting the heart and circulatory system. Working from the hypothesis that COVID has a cardiovascular cause, a team of researchers at the University of the Pacific used external counterpulsation therapy (ECP) to successfully treat a 38-year-old woman suffering from post-COVID brain fog. After just one week of ECP this post-COVID patient reported measurable improvements in memory and focus. Following a subsequent four weeks of the hour-long treatment, her mental health and fitness had returned to pre-COVID levels. While these results are preliminary, they hint that ECP may be one promising non-invasive treatment option.
What is ECP?
External Counterpulsation (ECP) is a clinically proven therapy that’s been used for more than 20 years to safely treat a wide range of heart disease symptoms. ECP is typically used in the treatment of chronic stable angina that’s been unresponsive to other treatment options. It’s also used in healthy patients to help improve vasodilation, increase the maximum volume of oxygen in the body (VO₂ max), and enhance blood flow. Several studies have linked improved VO₂max scores with improved physical endurance and brain health. However, the U.S. Food and Drug Administration (FDA) has not approved the use of ECP for COVID-related brain fog.
As the statistics on brain fog symptoms demonstrate, this illness merits ongoing clinical study. In fact, the numbers suggest that self-reported cases may represent just the tip of the iceberg. If so, then as doctors gain a clearer understanding of the syndrome’s underlying physical causes, treatments like ECP may soon be another possible option for some patients whose symptoms are unresponsive to other therapies.