Brain's Frontal Lobes Electrical Activity Potentially Affected by COVID-19
In a recent review of research, signs of neurological complications tied to COVID-19 appear to be common in patients who experience severe symptoms, according to a detailed analysis of electroencephalography (EEG) test results.
Approximately 15-25% of severe COVID-19 patients may develop neurological symptoms, which can include headaches, confusion, seizures, strokes, and impaired consciousness [1]. As such, doctors may refer affected patients for an EEG test, which involves placing electrodes on the scalp to monitor the electrical activity of the brain.
Researchers from Baylor College of Medicine in Houston, Texas, and the University of Pittsburgh, Pennsylvania, analyzed EEG data from 617 patients, as reported in 84 separate studies. The median age of these patients was 61.3 years, with two-thirds being male [2].
The researchers identified several common findings among the EEG results. Slowing of brain waves and abnormal electrical discharges were the most prevalent, and the extent of these abnormalities seemed to correlate with the severity of the disease, as well as the presence of pre-existing neurological conditions, such as epilepsy [2].
Furthermore, around a third of the abnormal findings were noted in the frontal lobes of the brain—a region that is located directly adjacent to the nose, suggesting a possible connection between the virus's entry point and the affected area [3].
Despite these findings, it is essential to note that the virus may not be solely responsible for all the observed damage. Systemic effects of the infection, including inflammation, low oxygen levels, uncommonly sticky blood, and cardiac arrest, may also contribute to EEG abnormalities that extend beyond the frontal lobes [2].
Indeed, the study identified "diffuse slowing" in the background electrical activity of the whole brain in nearly 70% of patients.
Recent reports have surfaced of individuals experiencing persistent health issues even after recovering from COVID-19, now collectively referred to as "long COVID." Among these ongoing problems is "brain fog," which appears to affect cognitive abilities [4].
A study yet to be peer-reviewed or published on the preprint server MedRxiv suggests that those who self-report having had COVID-19 performed less well on an online cognitive test than those who did not believe they had contracted the virus [4]. The authors of this study suggest that the infection may aging people cognitively by around a decade.
Experts contacted by the Science Media Centre in London, United Kingdom, caution that this cross-sectional study does not definitively prove that the infection causes long-term cognitive decline. However, it does raise concerns about the potential lasting effects on the brain.
As more researchers investigate the neurological symptoms of COVID-19, the evidence seems to be growing that there may be long-term implications for those who experience these complications [5]. Dr. Zulfi Haneef, assistant professor of neurology/neurophysiology at Baylor and one of the study's co-authors, believes that more patients should undergo EEG tests and other types of brain imaging, such as MRI or CT scans, to gain a more comprehensive understanding of the virus's impact on the brain [3].
Of the patients who had follow-up EEG tests, over half (56.8%) showed improvements [2]. However, further research is needed to understand the long-term implications of EEG abnormalities in COVID-19 patients, particularly in relation to disease severity and the risk of long-term neurological complications.
Sources:
[1] Debas et al. (2020). Neurologic Manifestations of COVID-19. Neurology.[2] Kellaway et al. (2020). EEG abnormalities in COVID-19 related encephalopathy. Seizure: European Journal of Epilepsy.[3] Science Media Centre. (2020). Brain Fog: Could COVID-19 have long-term impacts on learning ability? [Expert reaction to10/26/2020 MedRxiv paper led by Lennart Mucke on cognition after COVID-19].[4] Mucke, L., et al. (2020). COVID-19 impairs the default mode network disrcition, a potential mechanism for subjective cognitive impairment (brain fog). MedRxiv.[5] Alipour et al. (2020). Neuroimaging of COVID-19: Emerging insights on acute and post-acute brain involvement. European Radiology.
- The common neurological symptoms observed in severe COVID-19 patients, such as seizures and headaches, might be indicative of a broader range of neurological disorders like epilepsy.
- As COVID-19 patients recover, they may face persistent health issues, including cognitive decline commonly referred to as "brain fog," which could potentially be linked to coronavirus-induced changes in the brain.
- Despite the ongoing research, the exact relationship between coronavirus, health-and-wellness conditions including neurological disorders, and long-term complications remains unclear, emphasizing the importance of further medical-condition studies and non-invasive diagnostic techniques like electroencephalography (EEG) and magnetic resonance imaging (MRI).
