sought my help. He was driving home from the gym in the early morning; even though he was quite familiar with the route, that day he felt confused and failed to halt at a stop sign. Soon he saw the flashing lights behind and pulled to the shoulder. He explained to the police officer that after suffering from COVID, his brain gets brain fog now and then and he did not see the stop sign. The officer checked his driver’ s license and after a few minutes handed over a ticket smiling,“ This ought to clear your brain fog.” The officer also warned him that his driving license would be revoked if this happened again. I was placed in a tough spot as he expected me to give him medications and cure his brain fog.
The Merriam-Webster dictionary defines brain fog as“ a usually temporary state of diminished mental capacity marked by inability to concentrate or to think or reason clearly.” According to Mir, 1 the term often refers to“ cognitive impairment including inability to concentrate and multitask and short term and long-term memory loss.” Although, brain fog has become a frequently used term after the COVID-19 pandemic as part of Long COVID, it has been around for a long time to denote cognitive problems that can occur in several conditions including cancer chemotherapy(“ chemo fog”), fibromyalgia(“ fibro fog”), SLE(“ lupus fog”), hypothyroidism, Lyme disease etc.
While the precise definition of brain fog is still elusive, the National Academies of Sciences, Engineering, and Medicine( NASEM) has finally provided a definition for Long COVID 2:“ Long Covid is an infection-associated chronic condition that occurs after SARS-CoV-2 infection and is present for at least 3 months as a continuous, relapsing and remitting or progressive disease state that affects one or more organ systems.” It is estimated that 15-20 million Americans have had long COVID, with its fatigue, cognitive dysfunction and orthostatic intolerance causing significant disability. 3 inflammation and microglial activation as well as microvascular endothelial cell dysfunction. FDG PET scan is reported to show hypoperfusion and hypometabolism predominantly in the frontal lobes. 3
Thanks to social media, brain fog is often self-diagnosed by patients. Bedside tests like the Montreal Cognitive Assessment( MoCA) can be helpful in deciding whether to order the more comprehensive neuropsychological evaluation. CT scans and MRI are often normal in patients with brain fog as the main symptom, although useful in ruling out more serious brain disorders. The treatment of brain fog is challenging due to our lack of adequate scientifically sound studies of different therapeutic measures. Cognitive behavioral therapy( CBT) and computerized cognitive training are believed to provide some benefit. Hyperbaric oxygen therapy as well as transcranial magnetic stimulation( TMS) are also deemed useful. Pharmacotherapy trials are still in infancy. A combination of guanfacine( alpha 2 A adrenoreceptor agonist) and N-acetyl cysteine( antioxidant) has been reported to be of benefit. Ultra micronized palmitoyl ethanol amide and luteolin( PEA-LUT) supplements, believed to have anti-inflammatory and neuroprotective effects, have also been found to be useful. 3
Long COVID lasts for quite varying amounts of time – will the brain fog, if associated, vary as well? The million-dollar question is whether patients with Long COVID and brain fog are at higher risk for development of dementia. One study points to an association between COVID-19 infection and new-onset dementia in older adults. 4 More research is needed by long term follow up of Long COVID patients with brain fog to provide conclusive answers. Let me close with one of my favorite quotes by Orison Swett Marden:“ There is no medicine like hope, no incentive so great, and no tonic so powerful as expectation of something tomorrow.”
References:
1
Mir MA. Brain Fog: a Narrative Review of the Most Common Mysterious Cognitive Disorder in COVID-19. Mol Neurobiol. 2024; 61( 12): 9915
2
Ely WE et al. Long Covid defined. NEJM. 2024; 391:1746
3
Tavee J. Current concepts in long COVID 19 brain fog and postural orthostatic tachycardia syndrome. Ann Allergy Asthma & Immunol 2024; 133( 50): 22
4
Shan D et al. Association between COVID-19 infection and new-onset dementia in older adults. BMC Geriatrics 2024; 24:940
Dr. Iyer practices at the Neurodiagnostic Center of Louisville and is a retired professor of neurology at the University of Louisville School of Medicine.
Dr. Iyer practices at the Neurodiagnostic Center of Louisville and is a retired professor of neurology at the University of Louisville School of Medicine.
Brain fog is a prominent symptom of Long COVID, manifesting as memory loss, impaired attention and concentration, word finding difficulties, slowed cognitive processing and executive dysfunction. The pathophysiology of brain fog continues to be speculative. The main theories include immune dysregulation leading to cytokine-mediated
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