From time to time, we all have moments of forgetfulness, slow thoughts and poor concentration. Brain fog itself is not a medical condition, but rather a term that encompasses a range of symptoms that may be associated with conditions, such as Alzheimer’s disease, multiple sclerosis, and depression. The cognitive challenges of brain fog may highlight an underlying cause that needs to be addressed, meaning that it is often difficult to directly eliminate brain fog without treating the condition that is causing it in the first place.
The specifics of brain fog continue to riddle scientists however research has been accelerated by the reports of brain fog as a symptom of long COVID. One highly plausible idea is that rather than directly causing brain fog itself, COVID-19 exacerbates pre-existing conditions that, in turn, lead to brain fog. Studies evidencing that COVID-19 causes damage to the body as a result of a heightened immune response could suggest that it could likewise cause inflammation in the brain. If this is indeed the case, cell damage would ensue and would ultimately disrupt communication between neurons. A study which compared the medical records and brain scans of 401 individuals before and after COVID-19 found an overall decline in performance on cognitive assessments as well as damage to tissues in areas of the brain, including the hippocampus, a structure in the temporal lobe with a significant role in memory. Nonetheless, it still cannot be confirmed with full confidence whether this is the cause of brain fog.
The brain fog that is associated with COVID-19 can overlap with a range of cognitive problems which are unrelated to coronavirus. This could mean symptoms are less easy to identify and address. For example, it has recently been suggested that the reason why thinking hard makes us feel mentally drained could be due to the build of glutamate in areas of the brain. Glutamate, a neurotransmitter, is released during periods of prolonged concentration. How can we be sure whether our mental exhaustion is a mere consequence of hard thinking or a symptom of long COVID? Another occasion which aimed to further investigate cognitive decline was a study conducted by Peking University in Beijing. A correlation between worse air quality and mathematical and verbal test performances raised questions about the role of air pollution in reducing the brain’s white matter. White matter mainly consists of myelinated nerve fibers; a reduction in white matter would - similarly to brain fog - result in memory issues.
There is a seemingly long list of potential factors that make us feel mentally hazy for varying lengths of time. Brain fog could be a result of permanent structural damage to the brain yet equally, it could be a temporary symptom that will disappear on its own in most cases.
Both cognition and neurodegeneration have so many areas which are yet to be fully understood but when they are, that knowledge will have an invaluable role in improving the quality of life for so many patients.