COVID-19 may interfere with electrical functioning in the frontal regions of the human brain.
Approximately 15-25% of severe COVID-19 patients may experience neurological symptoms such as headaches, confusion, delirium, impaired consciousness, seizures, and strokes, according to available data. These individuals may undergo EEG tests, which involve placing electrodes on the scalp to monitor brain activity, to investigate neurological symptoms further.
Researchers from Baylor College of Medicine and the University of Pittsburgh analyzed EEG results from 617 patients, reported in 84 different studies, to understand how COVID-19 affects the brain. They found that the most common EEG findings were slowing of brain waves and abnormal electrical discharges. The extent of these abnormalities correlated with the disease's severity and whether patients had preexisting neurological conditions, such as epilepsy.
The study, published in the journal Seizure: European Journal of Epilepsy, found around a third of the EEG abnormalities were in the frontal lobes of the brain. Dr. Zulfi Haneef, assistant professor of neurology/neurophysiology at Baylor, suggests that this could be due to the virus's most likely entry point being the nose, which is located near the frontal lobe. Haneef also suggests that EEG tests, as well as other brain imaging techniques such as MRI or CT scans, should be used more frequently to examine the frontal lobe in COVID-19 patients.
The researchers also noted that while the virus may not be directly responsible for all the damage, systemic effects of the infection, such as inflammation, low oxygen levels, unusually "sticky" blood, and cardiac arrest, may play a role in EEG abnormalities that extend beyond the frontal lobes.
The study also identified "diffuse slowing" in the background electrical activity of the whole brain in almost 70% of patients. Some people who have recovered from COVID-19 report ongoing health problems, labeled "long COVID," among which is "brain fog." A recent study found that individuals who claim to have had COVID-19 performed less well on an online cognitive test than those who did not believe they had contracted the virus. This study highlights concerns about lasting effects on the brain, but does not directly link the infection to long-term cognitive decline.
On a positive note, 56.8% of those who had follow-up EEG tests showed improvements. However, the researchers noted several limitations in their analysis, including lack of access to raw data and potential skewing of results due to doctors performing disproportionately more EEGs on patients with neurological symptoms and giving anti-seizure medications to many patients who they suspected were having seizures.
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In summary, research connecting COVID-19 to EEG abnormalities, especially in the frontal lobe, is evolving and mainly demonstrates associations rather than clear causal mechanisms. While there is evidence of neurocognitive and psychiatric sequelae after COVID-19, direct correlation between COVID-19 and localized EEG abnormalities in the frontal lobe remains limited. Most reports of EEG abnormalities in COVID-19 relate to generalized encephalopathy or seizures rather than focal frontal lobe findings.
- The study published in Seizure: European Journal of Epilepsy found that approximately one-third of EEG abnormalities in COVID-19 patients were located in the frontal lobes of the brain, suggesting the virus's entry point near the frontal lobe could be a factor.
- Researchers analyzing EEG results from COVID-19 patients have identified 'diffuse slowing' in the background electrical activity of the whole brain in almost 70% of cases, raising concerns about potential long-term cognitive effects, known as "brain fog," among those who have recovered from the virus.
- Even though the extent of COVID-19's impact on the brain is still evolving, discussing neurocognitive and psychiatric effects after recovery, direct correlation between the infection and localized EEG abnormalities in the frontal lobe remains limited, according to the bulk of the current research.
