Skip to content
Back to blog
COVID Brain Fog Symptoms: Measuring Impact and Recovery
Neurological Care

COVID Brain Fog Symptoms: Measuring Impact and Recovery

Published: 25/04/2024

Written by: Creyos

Since the COVID-19 pandemic began, we’ve learned a lot about how the novel coronavirus affects the brain. Studies show that both cognitive function and mental health can be severely impacted by the virus—and that symptoms can linger for more than a year. 

Research like the COVID-19 Brain Study has helped us identify some of the long-term effects so we can learn more about the long-term effects of COVID on cognitive, neurological psychological, and physiological health. 

Many of the symptoms—especially trouble with memory and concentration—are often associated with the subjective feeling of “brain fog.” One 2023 study showed that 89% of patients diagnosed with COVID-19 reported prominent and persistent brain fog for weeks or even months after COVID infection.

There are simple and effective strategies available to help health care providers detect COVID brain fog, monitor symptoms, and assess treatment efficacy. In the aftermath of the pandemic, providers must be prepared to detect and treat these long term cognitive effects.

Below, we detail what is currently known about long COVID and brain fog, including ways healthcare providers can respond.

What Is COVID Brain Fog?

Brain fog is not a diagnosed medical condition, but the general term describes the subjective feeling characterized by problems with concentration, memory, and mental acuity. Conditions other than COVID-19 can also result in brain fog symptoms.

Symptoms of COVID Brain Fog

Sufferers of long COVID—”long haulers”, as some call themselves—can experience lingering symptoms such as fatigue, headaches, loss of smell, and disruptions to cognition like memory loss and trouble concentrating. All of these symptoms are associated with COVID-related brain fog. 

Just a few of the neurological, psychological, and physiological effects include:

  • Memory deficits

  • Trouble concentrating

  • Sleep disorders

  • Headache

  • Fatigue

  • Anxiety

  • Depression

  • Blurred vision

  • Dizziness

Especially if they have brain fog, it might be hard for patients to pinpoint what exactly feels wrong. Patients struggling with brain fog might describe fuzzy thoughts, slow thoughts, trouble making connections, inattention, a lack of mental clarity, or just feeling “spaced out”.

How Brain Fog Affects Patient Cognitive and Mental Health

Research studies using Creyos to investigate the effects of COVID-19 on specific domains of cognition have found that some of the most significant cognitive issues post-COVID centered around communication and understanding. Verbal processing (60%) and memory most often saw a negative impact, while other forms of processing—including visual processing—were also affected.

It is important to note that “brain fog” usually refers to neurologic symptoms rather than mental health symptoms, although there is considerable overlap between the two. This said, COVID has also been known to impact mental health. 

Later on, we’ll talk more about the distinction between how to detect and treat the lingering cognitive and mental health effects of COVID.

How Does COVID Brain Fog Occur? 

We’ve mentioned some common symptoms of COVID-related brain fog, including fatigue, poor concentration, poor sleep, and memory impairment. We now know that long-COVID symptoms, including those affecting brain health, can even go away and come back again later

But questions remain: why do neurological symptoms manifest so often after a COVID infection?

What COVID Does to the Brain

We’re still learning about the physiological effects of COVID on the brain. However, recent studies have reported that inflammation tends to linger in sufferers of long COVID. They also note that high levels of post-COVID fatigue are consistent with high inflammatory markers.

Because the COVID virus penetrates the blood–brain barrier, researchers theorize that COVID-related systemic inflammation likely affects the brain, especially in more severe COVID cases.

It is important to note that the effects of neuroinflammation are not always consistent. In fact, some consequences of neuroinflammation may be seen as positive, resulting in heightened immune response. On the other hand, chronic brain inflammation has been linked to increased levels of cognitive impairment.

In short, high rates of brain inflammation during COVID infection may influence long COVID brain fog—though further research is needed to investigate other potential mechanisms.

Impacts of Long COVID on Mental Health

We’ve talked about the effects of COVID on the brain, but COVID can also have significant mental health impacts in the short- and long-term. 

One study found that major depression and anxiety were reported in up to 40% of people post-COVID infection, while another study cited rates of depression and anxiety of up to 53% of COVID sufferers. Up to one-third of COVID sufferers may even show signs of PTSD post-infection.

It is not clear whether post-COVID mental distress is directly caused by the virus, or whether life changes and disruptions are stronger culprits. After all, COVID infection can also impose social and financial detriments on its sufferers, especially social isolation, financial stress, and ability to meet one’s own needs. These factors in and of themselves can contribute to higher rates of depression and anxiety.

Though depression—along with cognitive challenges—was more likely to be a chronic symptom after a COVID infection, anxiety was more likely to spontaneously resolve. In one study focusing on the neuroinflammation response seen in COVID illness, cognitive disruption and depression were frequently found together in patients recovering from the disease.

Another study using Creyos aimed to disentangle the cognitive, physical, and mental health symptoms of COVID. The new study found that the severity of cognitive symptoms was related to the severity of physical COVID symptoms, rather than mental health symptoms. It suggests that while mental health issues result from COVID, they are not the only explanation for brain fog

In short, some disruptions in mental health post-COVID may result from the virus’s physiological effects, while others may be tethered to social consequences of being sick. In any case, mental health disruptions are often connected to cognitive impairment, emphasizing the importance of symptom  identification and treatment. 

A number of mental health screening tools may help identify psychological symptoms. Check out the Perceived Stress Scale, the GAD-7 questionnaire for anxiety, and the PHQ-9 measure for depression as just a few ways to screen a patients’ mental health. All of these are available in the Creyos platform, giving doctors a centralized place to track cognitive and mental health.

How Does the Brain Recover from COVID Brain Fog?

Cognitive impairment is a symptom of many health disorders, including COVID-19. Research and treatment for any cognitive impairment—COVID-related or otherwise—is an area of significant research and has few one-size-fits-all answers. As we’ve seen, when it comes to COVID-related brain fog, we know that cognitive impairments often result from physical damage to the brain

Symptom relief and recovery tends to rely on the regeneration of nervous system neurons—something the body does on its own and is hard to encourage externally. Some studies suggest anti-inflammatory treatment as one possible way to alleviate lingering neurological symptoms of brain fog after COVID—including measures like exercise and healthy diet.

Patients struggling with brain fog after COVID may also benefit from cognitive training activities, or activities that may be beneficial to overall cognitive health.

Another major recommendation in treating COVID-related brain fog comes down to cognitive function testing which can, over time, help with identification of brain fog and make early cognitive intervention a cornerstone of post-COVID recovery. 

Cognitive testing can also help to pinpoint more precise expressions of symptoms in post-COVID brain fog sufferers. Meanwhile, recovery tracking tools can help detect impairment, monitor recovery over time, assess treatment efficacy over time by providing useful brain health data to doctors about trends in patient recovery.

No matter what the diagnosis, prognosis, and course of treatment is, talking to patients about their cognitive health is important. By making regular cognitive health check-ins part of routine health care provision, practitioners can allow patients to feel heard and understood during a difficult and scary period of their lives—and develop strong medical practices around brain health.

How Long Can COVID Brain Fog Last?

How long COVID brain fog lasts will vary from person to person. One 2023 study shows that some people’s symptoms may alleviate in a matter of months, while others continue to show lingering symptoms more than a year after being infected with COVID.

Since COVID can affect the brain in many ways (potentially through mechanisms discussed above), recovery can be a lengthy and difficult process. Some studies have found that recovery from COVID-related brain fog is often spontaneous, which can make recovery difficult to predict and understand. 

Though long COVID symptoms may resolve spontaneously within weeks, some patients may find recovery to be a frustrating months-long process. Others still may find recovery to pre-COVID cognitive ability takes years—or doesn’t happen at all. 

Patient education and counseling may be an effective tool to help set expectations about patient outcomes.

Preparing for the Long Term Impacts of COVID-19

The medical community’s understanding of COVID-19 and its effects on the population is constantly evolving. Healthcare practitioners should prepare for continued demand for their services and be in a position to address cognitive and neurological symptoms and reduce brain fog impacts.

Practitioners in the mental health space should also expect long COVID to have distinct but related effects on both mental health and cognition. With robust screening and long-term data, cognitive impairment and mental health deficits can be better understood and intervened against early and often.

Screening for the Mental and Cognitive Effects of Long COVID Brain Fog

Creyos offers a robust suite of tools that physicians can use to measure cognitive and mental health throughout the process of diagnosing, treating, and tracking COVID brain fog symptoms. Practitioners can use the platform to:

  1. Educate patients on the expected outcomes and recovery from COVID-related brain fog. Doctors can use information like the summaries and studies provided in this article to communicate with patients and set expectations. Creyos also produces immediate, data rich reports that are easy to interpret. These practices can go a long way to building trust and rapport, and encouraging patients to be active participants in their health journey.

  2. Validate subjective feelings of brain fog with objective cognitive assessments. Brain fog is a subjective experience, but cognitive assessments offer a scientifically robust means to measure the impacts of COVID-19 on elements of cognition, such as verbal processing, memory, focus, and more.

  3. Track mental health impacts with standardized questionnaires over time. While conversations with patients are important and illuminating, using standardized questionnaires can also provide a consistent framework for tracking significant changes to mental health. Done frequently, these can give healthcare providers a structured way to track the impacts of medication, lifestyle changes, and other factors.

  4. Demonstrate treatment efficacy. As we mentioned above, cognitive assessments offer objective measures on cognitive performance, which can be used to track reduction in brain fog symptoms throughout the recovery process.

In the big picture of treating long COVID and addressing the prevalence of brain fog, measurement is going to be a critical tool in healthcare providers' toolbox. Continuing to gather health data on the cognitive and mental impacts, the longevity, and the successful treatment modalities as they relate to COVID can make a significant difference in advancing our understanding and treatment of the illness.

Join thousands of healthcare professionals who receive a monthly update on the latest research and news in brain health.