Coronavirus and long-haul “brain fog” similar to that reported in post-concussion syndrome

Initial data from cognitive testing

Much like lingering symptoms of concussion, a condition know as post-concussion syndrome or PCS, patients who are covid-recovered are starting to complain of “brain fog” weeks even months after recovering from the virus. Patients with PSC often describe having problems with mental endurance, decreased processing speed and efficiency that leave them feeling “in a fog”. So too are patients who have been through the coronavirus, even those who have had minor symptoms and over half who have never been hospitalized with severe virus. In fact, the most sick, those who spent time on a ventilator actually faired the best in a recent study from Italy.

The patients with severe COVID-19 experienced multidimensional functional deficits in mobility, cognition, speech, and swallowing which were pervasive at the time of admission to rehabilitation.

Michael Sefton

Stages of Coronavirus Infection
Stage I Damage to nervous system was initially thought to be limited to the epithelial cells in the nose and mouth – hence the loss of smell (41 %) and taste (55 %). These were individuals who may have experienced slight flu-like symptoms or may have thought they had a bad cold. Most were not tested for coronavirus in the first wave in early 2020 (JAMA Head & Neck 2020).

Stage II As the virus triggers an inflammatory response it can lead to the formation of clots anywhere in the body which can cause pulmonary emboli and strokes. In this pulmonary phase the immune system becomes strongly affected by infection and leads to primarily respiratory symptoms such as persistent cough, shortness of breath, and low oxygen levels. It has been observed that at this point patients can fail very quickly.

Stage III There is a huge viral load that results in an explosive inflammatory response called a cytokine storm. This impacts all body systems including lungs and heart. It can damage blood-brain barrier allowing inflammatory cells and perhaps viral particles to enter the brain – which can lead to seizures, confusion, coma, encephalopathy. Essentially this is a runaway immune response.

As I have described in the Word Press Human Behavior blog people are reporting feeling cloudy and unfocused describing it as brain fog. I have heard the same description from people who are referred for concussion management as well following unresolved symptoms of concussion. Remember concussions do not require that the patient be rendered unconscious by the injury. Even mild traumatic force from a fall can leave someone in a foggy state for weeks. Recovery from second or third concussions are never the same. Similarly the cognitive effects of the coronavirus can be debilitating to 30-50% of cases. Here in the US there have been 32 million cases of coronavirus so the means as much as 16 million people may have some form of cognitive deficiency due to their infection. What does this mean for those of us offering treatment for cognitive-behavioral problems in general?

Like PCS, the virus impacts broad cognitive systems like attention, memory, and problem solving. Physical symptoms include shortness of breath, fatigue, and limited endurance. Whether it is a professional, elite student athlete or a salesman injured in a car crash there is an experience of stigma associated with the invisible injury of concussion and PCS. The emotional impact of this marginalizes patients often leaving them feeling alone and frustrated. This isolation and loss is shared by long-haul covid recovered patients.

Experience shows most long-haulers tend to fall into the high risk category, such as those with chronic respiratory disease such as COPD or multiple conditions including diabetes mellitus and obesity. But there is a growing percentage of people who were otherwise healthy before they became infected and are suffering with the same negative cognitive impact (Ferrucci, 2021).
Ferrucci reported on a small sample of cases that were hospitalized but not in an ICU. These finding were subjectively reported 4-5 months following their diagnoses.

31.6% reported cognitive decline
50% moderate to severe increased fatiguability
26.7% moderate to severe increased forgetfulness & lack of concentration
23.3% moderate to severe increased time to perform tasks such as reading/writing
20% moderate to severe difficulties in new learning 
16% depressed mood
42.1% processing speed deficits

Formal neuropsychological testing revealed cognitive deficits in the following areas using the Repeatable Battery for the Assessment of Neuropsychological Status. Data reported below are from a small sample hospitalized in Milan, Italy.
26.3% delayed verbal recall
10.5% immediate verbal recall
18.4% impaired visual L-T memory
15.8% visual S-T memory
7.9% semantic verbal fluency deficits

As part of our review, in anticipation of questions we might get at the recent webinar, colleague Lauren Guenon and I learned that aggressive treatment is needed to assure that the patients who are returning to work are properly prepared. Recent peer reviews suggest having restorative physical and cognitive therapy 3-4 times per week. It is not clear yet whether Medicare will permit this intensity of service foe those recovering from coronavirus. Heading back to work too early can create set backs. We have also seen reported set backs that describe a return of respiratory symptoms and other signs of an errant and unpredictable inflammatory response. A gradual transition back to work is essential to insure a successful return to work. I usually prescribe a 3-4 week transition and make an effort to work with employers so they understand the importance of a staged work re-entry. I have not had an employer refuse a transition plan and most have offered their assistance returning the employee to service.


Ferrucci, R et al. (2021) Brain Sci. 2021, 11, 235.

Amjad H. Roth DL, Samus QM, Yasar S, Wolff JL. (2016) Potentially unsafe activities and living conditions of older adults with dementia. Journal Am Geriatric Soc. 64(6):1223-1232

Budson, A. (2020) B.U.Medical School — https://www.health.harvard.edu/blog/author/abudson

Gallagher, M, et al. (2020) The Impact of Covid-19 Experiences and Associated Stress on Anxiety, Depression, and Functional Impairment in American Adults. Cognitive Therapy and Research. https://doi.org/10.1007/s10608-020-10143-y.https://doi.org/10.1007/s10608-020-10143-y. Springer Science.

Goodman-Casanova JM, et al. (2020) Telehealth home support during Covid-19 confinement for community-dwelling older adults with mild cognitive impairment or mild dementia: survey study. Journal Med Internet Res. 22(5):e19434.

Sefton, M (2021) Long-haul symptoms of Coronavirus. Blog post https://msefton.blog/2021/06/26/long-haul-cognitive-effects-of-covid-19-in-those-who-have-recovered/ Taken 6/27/2021

Heneka et al. (2020) Alzheimer’s Research & Therapy. Long and Short-term Cognitive Impact of Coronavirus. 12:69 https://doi.org/10.1186/s13195-020-00640-3

Lawton, MP, Brody, EM. (1969). Assessment of older people: self-maintaining and instrumental activities of daily living. Gerontologist. 9(3): 179-186.

Author: Michael Sefton, Ph.D.

Director of Neuropsychology at Whittier Rehabiltation Hospital in Massachusetts. I am a consultant at the Direct Decision Institute Inc. it is a practice in Worcester, Massachusetts that provides training and behavioral health assessment for Law Enforcement agencies across New England. Leo F. Polizoti, Ph.D. is the founder and has worked in police psychology for over 40 years. He is a police consulting psychologist in Worcester, MA who has taught nationally at conferences around the country including for the Society of Police and Criminal Psychology. Also a member of the Direct Decision Institute is Dr. Michael Sefton who is a licensed psychologist provider who specializes in Neuropsychology, risk assessment, and pre-employment psychological assessment. Dr. Sefton is a Licensed Psychologist Provider in Massachusetts

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