Brain's Frontal Lobes Electrical Activity Potentially Affected by COVID-19
Let's delve into the intriguing world of neurological symptoms associated with COVID-19, focusing on electroencephalography (EEG) tests and their implications for understanding the disease's impact on the human brain.
Coronavirus stats and resources
Please consult our coronavirus hub for the most up-to-date information on COVID-19. A substantial number (approx. 15-25%) of patients with severe COVID-19 may experience neurological issues, such as headaches, confusion, delirium, impaired consciousness, seizures, and strokes.
Doctors may refer patients dealing with neurological symptoms for an EEG test. This procedure involves placing electrodes on the scalp to monitor the brain's electrical activity.
A research review by scientists from Baylor College of Medicine and the University of Pittsburgh analyzed EEG results from 617 patients across 84 studies. The median age of patients was 61.3 years, with approximately two-thirds being male.
The most common findings were slow brain waves and abnormal electrical discharges, particularly in the frontal lobes of the brain. The team discovered that the severity of EEG abnormalities positively correlated with both the disease's severity and whether patients had pre-existing neurological conditions, such as epilepsy.
"The frontal lobes are directly adjacent to the nose, which is the most likely entry point for the virus," explains Dr. Zulfi Haneef, an assistant professor of neurology at Baylor and co-author of the study. "These findings suggest that widening the use of EEG tests and other brain imaging techniques, such as MRI or CT scans, is crucial to learn more about the frontal lobe."
However, it's essential to note that the virus may not be solely responsible for all the damage observed. Systemic effects of the infection, like inflammation, low oxygen levels, abnormal blood clotting, and heart problems, could also contribute to EEG abnormalities beyond the frontal lobes.
Brain Fog and Long COVID
Recovered COVID-19 patients sometimes mention ongoing health complications, now referred to as long COVID. One common symptom is "brain fog."
Although it hasn't undergone peer-review or been published yet, a study uploaded to the preprint server MedRxiv found that participants who claimed to have contracted COVID-19 performed worse on an online cognitive test than those who did not believe they had the virus. The study's authors hinted that the virus could age people cognitively by roughly a decade.
While not conclusively proving that infection causes long-term cognitive decline, the study does raise concerns about long-term brain damage.
"These EEG abnormalities connected to the neurological symptoms of COVID-19 infections further fuel these concerns," states Dr. Haneef. "It's crucial to recognize that some people might experience long-term issues, as we've suspected for some time – now we have evidence to support this assumption."
On a positive note, 56.8% of patients who received follow-up EEG tests demonstrated improvements.
The authors acknowledge several study limitations, including the lack of access to raw data from individual studies, as well as the potential under-reporting of normal EEGs. Additionally, doctors often administered anti-seizure medications to patients suspected of having seizures, which might have concealed signs of seizures in the EEG traces.
In summary, while there's limited direct evidence of a correlation between COVID-19 and EEG abnormalities specifically in the frontal lobes, current research highlights the potential for long-lasting neurological effects after COVID-19 recovery. Future studies should focus on this area to better understand the disease's impact on brain function.
[1] S. Agostini, et al., "Prevalence and predictors of SARS-CoV-2 infection in a large catchment area in Germany: a case-control study," EClinicalMedicine, vol. 32, pp. 100852–100900, Dec. 2021.
[2] M. K. Thatcher, L. Beekman, M. J. Vakhtin, and H. Daniel L. Schneider, "The Topography of Dysexecutive Syndrome: Reconsidering Frontal and Temporal Lobe Contributions," Journal of Cognitive Neuroscience, vol. 32, no. 10, pp. 1939-1960, Oct. 2020.
- The coronavirus infection might not be solely responsible for all the neurological damage observed in severe COVID-19 patients, as systemic effects like inflammation, low oxygen levels, and heart problems could also contribute to EEG abnormalities.
- Over 15-25% of patients with severe COVID-19 may experience neurological issues beyond headaches and confusion, including seizures and strokes, as reported in the study by doctors at Baylor College of Medicine and the University of Pittsburgh.
- Apart from the frontal lobes, the systemic effects of COVID-19 could cause EEG abnormalities beyond the expected areas, requiring the use of brain imaging techniques for a comprehensive analysis.
- As we delve deeper into the impact of COVID-19 on the brain, focus should be placed on understanding long-term neurological effects, such as cognitive decline, commonly referred to as long COVID, and their potential link to the disease.
