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Post: COVID-19 and the Brain: Infection Mechanisms, Electroencephalographic Findings and Clinical Implications

COVID-19 and the Brain: Infection Mechanisms, Electroencephalographic Findings and Clinical Implications

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The term long-COVID refers to a wide array of psychological impacts arising from infection with the Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2). The virus has been reported to attack the nervous system directly, with nondirect impacts to organs and systems, such as elevated inflammation, blood pressure, and immune responses also damaging the brain. The electroencephalogram (EEG) has been used to image these insults and provides a valuable tool to guide understanding of infection mechanisms and, consequentially, therapeutic intervention. Due to the high likelihood of neurological complications, neurofeedback and other forms of neuromodulation may be particularly well suited to help long-COVID patients recover. However, clinicians providing neuromodulation interventions should be aware of, and take adequate steps to minimize, risks to themselves and others in providing face-to-face services. This review seeks to provide mental health professionals with an overview of the impacts of COVID-19 upon the nervous system, details current EEG findings, and outlines possibly relevant neurofeedback and neuromodulation interventions.

Although COVID-19 was first described as a disease-causing respiratory illness affecting the lungs, veins, and arteries, it is now recognized to have a far wider reach in the human body (Ni et al., 2020). As indicated in Figure 1, the virus can infect and damage multiple organs including the heart, kidneys, liver, intestines, muscles, and skin (Ni et al., 2020). It has also been implicated in disorders of both the brain (Bodro et al., 2021; Satarker & Nampoothiri, 2020) and the mind (Hampshire et al., 2021; Marshall, 2020).

Severe Acute Respiratory Coronavirus 2 (SARSCoV-2), the virus that causes the Coronavirus disease of 2019 (COVID-19), is increasingly associated with neurological and psychological impacts. Many people affected have reported the loss of smell, headaches, dizziness, anxiety, movement difficulties, inattention, and cognitive difficulties (Hampshire et al., 2021). In a minority of cases, disorientation, confusion (Bodro et al., 2021; Satarker & Nampoothiri, 2020), and psychosis can occur (Marshall, 2020).However, regardless of the severity of psychological symptoms, pathological processes can occur in the brain as a result of COVID-19 infection. The virus can invade the nervous system directly, damaging brain cells (encephalopathy, encephalitis, endotheliitis, and myelitis) and can be implicated in conditions such as epilepsy, stroke, and brain hemorrhage (Bodro et al., 2021). The virus also can cause psychological symptoms by nondirect mechanisms including COVID-19 Can Infect Multiple Organs in the Body.excessive inflammation, insufficient oxygen levels, organ failures, toxicity, and blood clotting produced by the virus (Panariello et al., 2020; Satarker & Nampoothiri, 2020). In part, these neurological impacts contribute to the virus being so deadly, especially the stronger and more infectious Delta variant (Davis et al., 2021; Farinholt et al., 2021; Roy et al., 2021). COVID-19 can infect anyone, but as the pandemic goes on it is becoming increasingly clear there are certain groups more at risk of serious outcomes from contracting it. From the outset, older individuals and those with preexisting health conditions were considered the most vulnerable (Australian Department of Health, 2021). Now it is becoming clear that individuals with preexisting mental health conditions are more likely to be hospitalized or die as a result of being infected by COVID-19 (Ceban et al., 2021). However, for those lucky enough to survive, the legacy of infection can leave lasting physical and mental challenges.

These longstanding mental health challenges are being referred to as “long-COVID,” which has been described as brain fog, memory issues, perceptual fuzziness, fatigue, a lack of clarity, and confusion (Hampshire et al., 2021). Long-COVID has been reported in 84.1% of individuals who were ventilated, 12.2% of those hospitalized, 9.2% of those requiring assistance at home, 5.8% requiring no assistance, and 3.8% without respiratory symptoms (Hampshire et al., 2021). This is approximately 24.4% of individuals who return positive biological test results for COVID-19 (Hampshire et al., 2021). While these figures are from one study, it is reasonable to assume a substantial number of individuals may present with long-COVID given the World Health Organization figures indicate there are 194,080,019 confirmed cases globally as of late July 2021 (World Health Organization, 2021). In previous coronavirus outbreaks, neurological symptoms were seen in 0.04% of those infected with Severe Acute Respiratory Syndrome 1, and 0.2% of those infected with Middle East Respiratory Syndrome (Marshall, 2020). Using these figures as an estimate and current WHO case estimates, approximately 7,763,200 to 38,816,003 people may have impacts on their nervous systems as a result of COVID-19. If we assume 24.4% of the 194,080,019 global COVID-19 cases will have long-COVID symptoms, this is approximately 46,579,204 individuals. These numbers suggest there will be a substantive mental health burden from the pandemic that mental health professionals will need to understand and find ways of addressing to help impacted individuals. 

The question of how COVID-19 impacts the brain and mind is still being investigated, but several possible mechanisms have emerged (Ni et al., 2020; Satarker & Nampoothiri, 2020).