What is the duration/prognosis of brain fog in individuals with post-COVID syndrome?

09 Dec 2022
Respiratory conditions
  • COVID-19
  • Post COVID
Type of resource
IPCRG COVID-19 and respiratory Q&A

What the research says:

Brain fog is one of the most common persistent symptoms among individuals with post-COVID syndrome (PCS; Junior et al 2022, Premraj et al 2022). While not a diagnostic term, patients describe a constellation of symptoms including poor concentration, confusion, slowed or fuzzy thinking, forgetfulness, lost words and mental fatigue (Jennings et al 2022; Venkataramani and Winkler 2022).

The clinical evolution of PCS-associated brain fog is variable and may emerge during the acute illness or after the acute symptoms have resolved and may resolve and relapse in the weeks and months following the acute illness (WHO 2022). While the cause remains unclear, early stage research suggests neuroinflammation in response to a viral infection may be involved (Venkataramani and Winkler 2022). The risk for the emergence of cognitive impairment following an acute COVID-19 illness remains elevated for at least 2 years following the acute illness (Taquet et al 2022). Patients with PCS may continue to experience symptoms of brain fog for more than 1 year after their acute illness (Ali et al 2022; Cristillo et al 2022). Depression has been shown as a strong predictor of persistent brain fog (Cristillo et al 2022). Early data suggests that female gender, greater neuropsychiatric symptoms, sleep disorders and rumination/indecision may be associated with worse cognitive impairment (Donata Orfei et al 2022; Sadat Mirfazeli et al 2022).

Patients with PCS require holistic rehabilitation depending on the specific constellation of ongoing symptoms they are experiencing (Greenhalgh et al 2022). There are currently no recommended treatments for cognitive impairment/brain fog in people with PCS; management is largely supportive (Jennings et al 2022). A range of activities are suggested to supporting cognition and memory including regular aerobic exercise, participation in social and cognitively stimulating activities, practicing mindfulness, eating a healthy Mediterranean-style diet (including olive oil, fruits and vegetables, nuts, beans and whole grains), avoiding alcohol and drugs (including tobacco) and maintaining a good sleep routine (Budson 2022). Other strategies such as pacing, energy conservation, use of a daily to-do list may help with day to day coping (Greenhalgh et al 2022). Pharmacotherapy for sleep disturbance may be considered for patients reporting non-restorative sleep. Stimulants have also been suggested for the treatment of cognitive impairment/brain fog in patients with fibromyalgia, chronic fatigue syndrome or cancer-related fatigue. The efficacy of these agents for COVID-19-associated cognitive impairment/brain fog has not yet been systematically evaluated.

What this means for your clinical practice:

  • Continue to follow-up and support our patients once they recover from acute COVID-19 illness of any severity, with vigilance for symptoms of cognitive impairment
  • Encourage patients to undertake self-care including pacing and energy conservation, regular aerobic exercise, participation in social and cognitively stimulating activities, practicing mindfulness, eating a healthy Mediterranean-style diet, avoiding alcohol and drugs (including tobacco), and maintaining a good sleep routine
  • Evaluate for and manage psychological issues including depression and/or anxiety
  • Consider appropriate assessment and/or referrals for persistent or emergent neurological symptoms

Authors

With grateful thanks to Dr Alan Kaplan (Chair Family Physician Airways Group of Canada) for and on behalf of the IPCRG practice driven answers review group.

Useful links and supporting references:

Ali ST, et al. Evolution of neurologic symptoms in non-hospitalized COVID-19 “long-haulers”. Ann Clin Translat Neurol 2022;9:950–61. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9268866/pdf/ACN3-9-950.pdf. Accessed November 2022.

Budson AE. What is COVID-19 brain fog – and how can you clear it? Available at: https://www.health.harvard.edu/blog/what-is-covid-19-brain-fog-and-how-can-you-clear-it-2021030822076. Accessed November 2022.

Cristillo V, et al. Predictors of “brain fog” 1 year after COVID-19 disease. Neurol Sci 2022;43:5795–7. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9361921/pdf/10072_2022_Article_6285.pdf. Accessed November 2022.

Donata Orfei M, et al. A new look on long-COVID effects: The functional brain fog syndrome. J Clin Med 2022;11:5529. Available at: https://pubmed.ncbi.nlm.nih.gov/36233392/. Accessed November 2022.

Greenhalgh T, et al. Long covid – an update for primary care. BMJ 2022;378:e072117. Available at: https://www.bmj.com/content/378/bmj-2022-072117.long. Accessed November 2022.

Jennings G, et al. Comprehensive clinical characterisation of brain fog in adults reporting long COVID symptoms. J Clin Med 2022;11:3440. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9224578/. Accessed November 2022.

Junior G, et al. Neurologic and neuropsychiatric symptoms in long-COVID 19 syndrome: a systematic review. Available at: 3273ff85-e3de-4e4c-b4dc-5f2cccc276d3.pdf (researchsquare.com). Accessed November 2022.

Premraj L, et al. Mid and long-term neurological and neuropsychiatric manifestations of post-COVID-19 syndrome: A meta-analysis. J Neurol Sci 2022;434:120162. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8798975/pdf/main.pdf. Accessed November 2022.

Sadata Mirfazeli F, et al. Chronic fatigue syndrome and cognitive deficit are associated with acute-phase neuropsychiatric manifestations of COVID-19: A 9-month follow-up study. Neurol Sci 2022;43:2231–9. Available at: https://pubmed.ncbi.nlm.nih.gov/35059902/. Accessed November 2022.

Taquet M, et al. Neurological and psychiatric risk trajectories after SARS-CoV-2 infection: an analysis of 2-year retrospective cohort studies including 1 284 437 patients. Lancet Psychiatry 2022;9;815–27. Available at: https://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(22)00260-7/fulltext. Accessed November 2022.

Venkataramani V, Winkle F. Cognitive deficits in long Covid-19. NEJM 2022;387:19. Available at: https://www.nejm.org/doi/10.1056/NEJMcibr2210069?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed. Accessed November 2022.

WHO. What is post COVID-19 condition? Available at: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/coronavirus-disease-(covid-19)-post-covid-19-condition. Accessed November 2022