One of the more common and distressing symptoms of post COVID syndrome (PCS) is brain fog. Even after relatively mild cases, patients report cognitive deficits such as short term memory problems, trouble concentrating, difficulty making decisions, confusion, mental fatigue and trouble retrieving words. Brain fog after COVID-19 can be incredibly frustrating. Two new studies confirm the phenomenon is real, with objective measures in addition to subjective suffering.
Brain Fog After COVID Can Last a Long Time:
Many people who have had COVID-19 complain of brain fog following the infection. New research published in Nature Medicine confirms that serious cases of COVID can lead to cognitive impairment up to a year later (Nature Medicine, Sept. 23, 2024).
Not all people hospitalized with severe COVID-19 ended up with neurological complications. However, those who did responded to cognitive tests as if they were 20 years older than their chronological age. They also had high levels of proteins indicative of brain injury. MRI data also showed that some areas of the brain had shrunk.
The researchers point out that COVID-19 is not simply a lung infection. Some of the most severely affected patients have brain complications that can be persistent.
Brain Function Suffers Following Infection:
Researchers at the University of Texas also published research on brain fog after COVID (Scientific Reports, Sept. 27, 2024). They report that a brain imaging study showed a reduction in connectivity between regions of the brain. These disruptions in normal connections between the cortex and lower brain structures are associated with less efficient brain function. This was also associated with subjective reports of brain fog and fatigue.
The researchers conclude that even mild to moderate cases of COVID-19 can alter patterns of information processing and effective information flow. The growing awareness that viral infections can have long-lasting neurological impacts could change the understanding of cognitive impairment associated with aging.
What It’s Like to Develop Brain Fog After COVID:
Researchers have reported physical changes in the brain that can be measured in spinal fluid. One reader describes the disturbing experience of developing cognitive complications after COVID.
Q. I had COVID in January and quarantined myself for ten days after testing positive at the local urgent care center. My doctor prescribed a short-term antibiotic and a steroid.
The obvious symptoms (slight fever, fatigue, cough, etc.) were mild and didn’t last long. I thought I was out of the woods, but I have noticed increasing confusion, distraction and forgetfulness. This is very disturbing to me.
At this point, I have not contacted any doctors about these changes after COVID. Do you have any suggestions to reverse these symptoms?
A. We are surprised that your doctor prescribed an antibiotic for this viral infection. Moreover, we are sorry that you seem to have developed long COVID. Even people who experience a mild case sometimes end up with symptoms that last for months or longer.
Young or middle-aged people as well as seniors may have cognitive complaints as part of their long-lasting problems. In addition to severe fatigue, patients have described brain fog with impaired attention, memory and executive function (JAMA Network Open, Oct. 22, 2021).
You are not the only one to report this. Janice also developed brain fog after COVID:
“I had persistent brain fog for 4 weeks after contracting the Omicron COVID -19 virus in December. It was very difficult to concentrate and comprehend when communicating with others. This made it difficult to work, since I am a 4th grade teacher! I am feeling feel better with the brain fog subsiding. However, I still have it.”
Jackie’s story shows how hard it is to know if it’s COVID or just getting older:
“I have had distorted sense smell/taste since I had COVID-19 in June of 2020. I have a neurological sensation along my gum line that comes and goes.
“In conversation, I have found myself grasping for a word and have been startled by my loss of memory, particularly visual memory. I have always been great at names and faces…until now. However, it is hard to know whether this is something that comes with the aging process or not.
“I am 69 years old. If these folks having memory problems after contracting COVID are young, I really feel for them.”
Patty describes what it was like for her:
“I had COVID in March of 2020. No testing was available at that time for COVID, short of being admitted to the hospital with severe disease. My case was relatively mild, but I experienced terrible brain fog. I could not concentrate well enough to organize a simple budget and pay a few bills. It was not a complex task at all, but I could not hold thoughts in my head long enough to make sure I was not making mistakes.
“After six months, I still had a noticeable lack of my previous ability to think. At that time, I had an outbreak of cold sores/fever blisters and my primary care doc prescribed an anti-viral, Valtrex for the cold sores specifically. Coincidentally, after two rounds of the medication, I noticed I was able to think far better that in the past six months. I can’t say the Valtrex helped the problem, but that was the only change I made at the time. My thought at the time was that both cold sores and COVID were viral diseases.”
We wish there were a proven treatment against long COVID. We did interview Dr. Bruce Patterson about the research his company, IncellDx, Inc. has been doing. You can listen to the interview and find links to his publications at this link:
Show 1273: Finding Ways to Manage Long COVID
Some people who were infected with SARS-CoV-2 continue to suffer symptoms for months afterwards. How can they manage long COVID?
How Common Is Brain Fog After COVID?
Earlier research suggested that brain fog can be a terrible problem. A small study published in the American Journal of Physical Medicine & Rehabilitation (Jan. 2022) reports some startling stats. The authors report that 156 patients completed their survey a median of 351 days after catching COVID-19. Two-thirds reported brain fog! That is extremely worrisome.
The researchers describe brain fog after COVID:
“This observational study of a cohort of patients with PACS [Post-acute COVID-19 Syndrome] reported that COVID-19–related symptoms are persistent for at least 2 mos, and often longer than 12 mos, with fatigue, brain fog, sleep disturbance, dizziness, dyspnea, memory loss, and palpitations being identified as the most common.
“The presence of cognitive dysfunction in more than half (63%) of patients, in combination with reduced usual activities and self-care scores on the EQ-5D-5L, highlights that patients with PACS may have a reduced ability to participate in society.”
Another study published in NeuroRehabilitation (June 16, 2021) reported that 47% of the patients presenting with long COVID experienced “cognitive impairment” and 33% had “neurological sequelae.”
Research published in the Annals of Clinical and Translational Neurology (May, 2021) offered this grim statistic about brain fog after COVID:
“This is a prospective study of the first 100 consecutive patients (50 SARS-CoV-2 laboratory-positive (SARS-CoV-2+ ) and 50 laboratory-negative (SARS-CoV-2- ) individuals) presenting to our Neuro-Covid-19 clinic between May and November 2020.
“The main neurologic manifestations were: “brain fog” (81%), headache (68%), numbness/tingling (60%), dysgeusia [distorted taste] (59%), anosmia [loss of smell] (55%), and myalgias (55%)…
“Interpretation: Non-hospitalized Covid-19 ‘long haulers’ experience prominent and persistent ‘brain fog’ and fatigue that affect their cognition and quality of life.”
Brain Fog After COVID?
We do not yet know how many people will develop brain fog after COVID. Even if it is “only” 20% to 30%, that could equal millions of people in the US alone.
As I write this, the total number of COVID cases in the US is over 80 million. Do the math. Worldwide, the number of cases is over 480 million. If “only” 20% develop brain fog, that could total nearly 100 million people with some kind of cognitive impairment.
Physical Changes in the Brain:
Doctors like “hard” evidence before they believe stuff. Researchers at the University of California, San Francisco looked for a biological marker among patients suffering from brain fog after COVID.
They found changes in the cerebrospinal fluid among individuals with new cognitive symptoms (Annals of Clinical and Translational Neurology, Jan. 19, 2022). People without cognitive dysfunction did not demonstrate these biological markers in their spinal fluid. The investigators believe that the biomarkers indicate brain inflammation.
There is also evidence of brain shrinkage after people catch SARS-CoV-2 (Nature, March 7, 2022). You can read about this research at this link. It is this kind of “hard” evidence that will convince health professionals that something is really happening inside the brains of COVID patients. Unfortunately, it won’t tell them what to do about it.
Final Words About Brain Fog After COVID:
Here’s the good news: We don’t know how long brain fog after COVID will last.
Here’s the bad news: We don’t know how long brain fog after COVID will last.
Individual experience with this disturbing phenomenon undoubtedly vary. We are disappointed that the most recent research suggests it could take years for recovery. And some people may never completely recover. We suspect it could a long time before we will get accurate answers to these crucial questions.
There may also be other symptoms besides brain fog after COVID. Research published in Science (Jan. 20, 2022) reports many other symptoms including depression, headache, stroke, confusion and even psychosis. We hope investigators make this a priority. Perhaps we will also glean insight into the impact of viral infections on conditions like Alzheimer’s disease. Read about this intriguing line of research at this link.
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