As yet, there isn’t enough data on whether the omicron variant, which tends to cause less severe COVID-19 than the delta variant, can have lasting aftereffects. But public health experts feel there may be reason for concern. One common and especially troublesome issue with long COVID is cognitive impairment, or brain fog. Other symptoms of long COVID include exhaustion, shortness of breath, headaches, sleep problems, coughing, lightheadedness, and changes in taste and smell, according to the Centers for Disease Control and Prevention (CDC). Cognitive slowing and mood problems after a person is infected with the coronavirus seem to be much more prevalent than with most other viral infections, says Serena Spudich, MD, a professor of neurology at the Yale University School of Medicine in New Haven, Connecticut, who has treated patients at Yale’s neuroCOVID-19 clinic. One person who experienced this kind of brain fog is Fiona Lowenstein, a New York City–based TV producer and writer, who developed a case of COVID-19 in March 2020 that was severe enough to require hospitalization. The ongoing issues she experienced led Lowenstein to cofound the COVID-19 support group Body Politic, which now has close to 11,000 members. Lowenstein describes a range of short-term memory issues that wreaked havoc on daily life: walking to the cabinet to get detergent while doing laundry and then forgetting why, or staring at the computer trying to write, sometimes not recalling the topic, and other times grasping for the proper word. Others on Body Politic similarly complain that the brain fog affects their work, with some struggling to stay productive and others leaving their jobs because they find it impossible to function.
Many People Seem to Be Affected
Experts are starting to get a handle on how widespread brain fog is — and the figures are startling. In a survey published in July 2021 in The Lancet’s EClinical Medicine, involving 3,762 people with confirmed or suspected COVID-19, a full 85 percent reported brain fog — which the authors define as poor attention, problem-solving, and decision-making. Only a small portion of those (10 percent) were previously hospitalized with severe COVID-19. Hospitalization, however, was a key factor in large-scale U.K. study published in the same issue of EClinical Medicine. When researchers analyzed the results of an intelligence test given to over 81,000 people, they found that participants who had recovered from COVID-19 underperformed compared with their peers who’d never had COVID-19. The level of underperformance correlated with severity of illness, with those who had been ventilated in the hospital showing the greatest shortfalls in cognition. In a study published in July 2021 in the Journal of the Neurological Sciences that only looked at people hospitalized for COVID-19, a full half of patients reported impaired thinking and diminished ability to carry out daily activities six months after being discharged. While it is well known that older adults can be susceptible to cognitive impairment after critical illness, research suggests that, with COVID-19, younger patients are also at risk. In a study reported in the October 2021 issue of JAMA Network Open, investigators tested neurological function in a relatively young group of patients (age 38 to 59) several months after being treated for COVID-19 in outpatient, ER, or hospital settings and found that as many as 24 percent continued to experience some sort of cognitive difficulties, including problems with memory, multitasking, processing speed, and focusing.
Why the Brain May Fog
The reasons for brain fog are not yet clear. Dr. Spudich believes the most likely cause relates to inflammation created by the body’s immune response rather than to the virus itself. She says an overactive immune response, in which the body starts making self-attacking antibodies (called autoantibodies), is thought to be responsible for other symptoms of COVID-19, including the breathing problems that often land patients in the hospital. Spudich points to other viral infections, such as HIV/AIDS, in which an out-of-control immune system can in some cases inflame the brain, leading to mental lapses. If an immune response is to blame for brain fog, it may be that inflammation in the body becomes so widespread that it reaches the brain. Or it could be that immune cells “are going into the brain to chase a little virus there,” Spudich says, noting that all this is currently conjecture. There is some research to back up the theory, however. A study published in the March 2021 issue of the journal Brain, Behavior, and Immunity found autoantibodies in the cerebrospinal fluid (the clear liquid that surrounds the brain and spinal cord) of COVID-19 patients with neurological symptoms. Of course, it’s possible the virus itself somehow gets into the brain, perhaps by traveling through the top part of the nose or by infecting cells known to cross the blood-brain barrier. But so far, research has not demonstrated this as a major factor. In one study by New York’s Columbia University, published in Brain in September 2021, for example, no evidence of coronavirus RNA or proteins was found in samples of the brain cells of 41 people who had died of COVID-19. Patients may then be referred for cognitive rehabilitation (aka cog rehab). “Cognitive rehabilitation is like physical therapy, but it’s for the brain,” explains Jennifer Wethe, PhD, a neuropsychologist who codirects the concussion program at Mayo Clinic Arizona and is an assistant professor of psychology at the Mayo Clinic School of Medicine in Scottsdale. The first steps are written and oral tests, typically conducted by a neuropsychologist, to identify the specific problem areas. Rehab would then focus on strategies to improve certain functions, like concentration or memory, as well as techniques to compensate for brain fog, Dr. Wethe says. For example, if you’re having issues with memory, a therapist could help you create a reliable system for recording, organizing, and retrieving information. “At a minimum, a memory support system should include a calendar for recording appointments and scheduled activities, a to-do list, and a place for notes, ideally on a smartphone so everything is all in one convenient place,” Wethe says. Many times, the problem is not actually memory but “working memory” or concentration, which is essentially the amount of information you are able to process at one time, Wethe notes. Other aftereffects of COVID-19, including headaches, fatigue, pain, and sleep disturbances, can act as additional drains on working memory, she adds. When concentration is a concern, a therapist will work with you on developing compensation strategies. For example, if your job requires multitasking, such as doing desk work while also answering the phone, Wethe recommends developing a way to mark your place in the current task before you pick up the phone. “This makes it more likely that you will be able to quickly pick up where you left off after attending to the phone call,” she says. Cognitive rehabilitation has a long track record of success with traumatic brain injuries, strokes, and concussion, Wethe says. Many different healthcare professionals are trained in this type of therapy, including psychotherapists, speech-language pathologists, physical therapists, neurofeedback practitioners, and occupational therapists.
Where to Get Treatment for Brain Fog
Many hospitals have cognitive rehab programs, even if they’re not specifically geared to long COVID patients. Treatment for brain fog is also available at many long COVID clinics. These centers, which are cropping up at an increasing number of hospitals, include Mount Sinai Center for Post-COVID Care in New York City, UT Health Austin Post-COVID-19 Program in Austin, Texas, and Memorial Primary Care Long Haulers Clinic in Hollywood, Florida. You can find a list on the website of the patient support group Survivor Corps. Cog rehab generally requires one to several sessions a week for a couple of months or more. Treatment for brain trauma and stroke is typically covered by insurance but whether insurers will foot the bill for post-COVID complications is an open question. There is some evidence that playing games like CogMed, Lumosity, and Brain HQ on your computer or phone may also improve cognition. These can be a great supplement to working with a cognitive rehabilitation therapist or coach, Wethe says.
Brain Fog Might Clear on Its Own
Doctors can’t predict how long post-COVID brain fog will persist, but Spudich thinks in many cases the fog may disperse on its own. “We have seen that though many patients have symptoms that linger for months, the severity of the problems that people experience almost invariably declines over time,” she says. Research is underway to track people’s symptoms over time, as well as to identify the biological causes of these brain symptoms, Spudich adds. One point of hope comes from the National Institutes of Health (NIH), which has begun an initiative called Researching COVID to Enhance Recovery (RECOVER). RECOVER will maintain a large database of information about people in various sates of recovery from COVID-19, as well as fund major studies to better understand long COVID symptoms, including brain fog. “As we learn more, we may find therapies we can give to people to help them improve even faster,” says Spudich.
