Clinical Electroencephalography Findings and Considerations in Hospitalized Patients With Coronavirus SARS-CoV-2

Spectrum of EEG Abnormalities in COVID-19 Patients

PURPOSE

Neurologic involvement is commonly reported in coronavirus disease (COVID-19) patients. The published literature regarding the COVID-19-related neurophysiological findings, including the EEG findings, is still quite limited. The objective of this study was to evaluate the EEG findings in patients with a COVID-19 infection and look for a possible correlations and prognosis.

METHODS

This is an inpatient hospital-based retrospective observational study. All admitted COVID-19 patients undergoing an EEG study between January 1, 2020 and June 30, 2021 were included in this study. EEG was ordered by the primary intensive care physician or a neurologist taking part in the clinical care of patients.

RESULTS

Sixty-six EEG studies in 57 patients were included. Mean age was 62.2 ± 16.3 years with male predominance (65%). Encephalopathy (70%) was the most common indication for an EEG. Background EEG abnormalities were seen in most of the patients (92.4%) with severe abnormalities correlating with the prognosis of the patient. Epileptiform discharges were only seen in 7.5% of the EEGs, with majority of the discharges arising from the frontal region. Mortality reported was high (47%).

CONCLUSIONS

Nonspecific diffuse background EEG abnormalities are commonly seen in COVID-19 patients. Epileptiform discharges are less common but mostly originate from frontal region. Most of these patients also had an abnormal neuroimaging. The significance of this peculiar finding needs further research.

SIGNIFICANCE

Nonspecific background EEG changes are common in COVID-19 patients. Among epileptiform discharges, focal epileptiform discharges arising from the frontal region were common, usually associated with an abnormal neuroimaging.

New Onset Seizures in Hospitalized COVID-19 Patients; A Systematic Review and Meta-Analysis

Objective

Seizures in COVID-19 patients continue to be a common reason for consulting the neurology service in the inpatient setting. This paper assesses the frequency of new onset seizures in adult hospitalized COVID-19 patients.

Method

PubMed and EMBASE were searched, with fifteen cohort studies identified to calculate the primary outcome, which was the frequency of new onset seizures in hospitalized COVID-19 patients. An inverse variance meta-analysis of single proportions with a random effects model was applied to these cohort studies to calculate the primary outcome. Risk of bias in individual studies was assessed using the 10-item risk of bias tool for prevalence studies.

Results

The meta-analysis revealed a frequency of .71% (95% confidential interval: .32-1.25, I2 = 89%, 147/28242 patients) for acute symptomatic seizures in patients with COVID-19. For secondary outcomes, the risk of seizures in patients who had EEG completed was 8.49% (95% confidential interval: .62-24.07, I2 = 14%, 44/535 patients). Slightly less than half of patients with COVID-19 and seizures were reported to have acute imaging abnormalities (45.7%) with acute vascular insults being commonly reported. Only a small percentage of COVID-19 patients with seizures (2.8%) met the criteria for COVID-19 encephalitis as determined by the international encephalitis consortium.

Conclusion

The frequency of seizures in COVID-19 was .71% (95% confidential interval: .32-1.25). Slightly less than half of COVID-19 patients had head imaging abnormalities as a complication of COVID-19 infection. Only a small percentage of patients with seizures and COVID-19 met the criteria for COVID-19 encephalitis.

Neurocircuitry Hypothesis and Clinical Experience in Treating Neuropsychiatric Symptoms of Postacute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2

Persistent symptoms following COVID-19 infection have been termed postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection. Many of these symptoms are neuropsychiatric, such as inattention, impaired memory, and executive dysfunction; these are often colloquially termed "brain fog". These symptoms are common and often persist long after the acute phase. The pattern of these deficits combined with laboratory, neuroimaging, electroencephalographic, and neuropsychological data suggest that these symptoms may be driven by direct and indirect damage to the frontal-subcortical neural networks. Here, we review this evidence, share our clinical experience at an academic medical center, and discuss potential treatment implications. While the exact etiology remains unknown, a neurocircuit-informed understanding of postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection can help guide pharmacology, neuromodulation, and physical and psychological therapeutic approaches.

The value of EEG attenuation in the prediction of outcome in COVID-19 patients

Introduction

During the COVID-19 pandemic, electroencephalography (EEG) proved to be a useful tool to demonstrate brain involvement. Many studies reported non-reactive generalized slowing as the most frequent pattern and epileptiform activity in a minority of patients.

Objective

To investigate the prevalence of diffuse unreactive background attenuation or suppression and its correlation with outcome in a cohort of COVID-19 patients.

Methods

The EEGs recorded during the first year of the COVID-19 pandemic were retrospectively evaluated to identify the main pattern and focus on the occurrence of a low-voltage background, either attenuated (10–20 μV) or suppressed (< 10 μV). We sought a correlation between in-hospital mortality and low-voltage EEG. In a subsample of patients, biomarkers of inflammation, hypoxemia and organ failure were collected. Brain imaging was also evaluated.

Results

Among 98 EEG performed in 50 consecutive patients, diffuse unreactive slowing was the most prevalent pattern (54%), followed by unreactive attenuation or suppression pattern (26%), being the latter significantly correlated with an unfavourable outcome (p = 0.0004). Survivors showed significantly lower interleukine-6 values compared to non-survivors. Patients with attenuated EEG and non-survivors also showed lower PaO₂/FiO₂ values. Neuroradiological findings were very heterogeneous with a prevalence of lesions suggestive of a microangiopathic substrate.

Conclusions

EEG attenuation or suppression may be more frequent than previously reported and significantly associated with a poor outcome. SARS-CoV-2 infection may result in encephalopathy and reduced EEG voltage through mechanisms that are still unknown but deserve attention given its negative impact on prognosis.

Mechanisms of Entry Into the Central Nervous System by Neuroinvasive Pathogens

BACKGROUND

The literature on neurological manifestations, cerebrospinal fluid analyses, and autopsies in patients with COVID-19 continues to grow. The proposed mechanisms for neurological disease in patients with COVID-19 include indirect processes such as inflammation, microvascular injury, and hypoxic-ischemic damage. An alternate hypothesis suggests direct viral entry of SARS-CoV-2 into the brain and cerebrospinal fluid, given varying reports regarding isolation of viral components from these anatomical sites.

EVIDENCE ACQUISITION

PubMed, Google Scholar databases, and neuroanatomical textbooks were manually searched and reviewed.

RESULTS

We provide clinical concepts regarding the mechanisms of viral pathogen invasion in the central nervous system (CNS); advances in our mechanistic understanding of CNS invasion in well-known neurotropic pathogens can aid in understanding how viruses evolve strategies to enter brain parenchyma. We also present the structural components of CNS compartments that influence viral entry, focusing on hematogenous and transneuronal spread, and discuss this evidence as it relates to our understanding of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).

CONCLUSIONS

Although there is a paucity of data supporting direct viral entry of SARS-CoV-2 in humans, increasing our knowledge of the structural components of CNS compartments that block viral entry and pathways exploited by pathogens is fundamental to preparing clinicians and researchers for what to expect when a novel emerging virus with neurological symptoms establishes infection in the CNS, and how to design therapeutics to mitigate such an infection.

Non-Invasive Multimodal Neuromonitoring in Non-Critically Ill Hospitalized Adult Patients With COVID-19: A Systematic Review and Meta-Analysis

Introduction

Neurological complications are frequent in patients with coronavirus disease-2019 (COVID-19). The use of non-invasive neuromonitoring in subjects without primary brain injury but with potential neurological derangement is gaining attention outside the intensive care unit (ICU). This systematic review and meta-analysis investigates the use of non-invasive multimodal neuromonitoring of the brain in non-critically ill patients with COVID-19 outside the ICU and quantifies the prevalence of abnormal neuromonitoring findings in this population.

Methods

A structured literature search was performed in MEDLINE/PubMed, Scopus, Cochrane, and EMBASE to investigate the use of non-invasive neuromonitoring tools, including transcranial doppler (TCD); optic nerve sheath diameter (ONSD); near-infrared spectroscopy (NIRS); pupillometry; and electroencephalography (EEG) inpatients with COVID-19 outside the ICU. The proportion of non-ICU patients with CVOID-19 and a particular neurological feature at neuromonitoring at the study time was defined as prevalence.

Results

A total of 6,593 records were identified through literature searching. Twenty-one studies were finally selected, comprising 368 non-ICU patients, of whom 97 were considered for the prevalence of meta-analysis. The pooled prevalence of electroencephalographic seizures, periodic and rhythmic patterns, slow background abnormalities, and abnormal background on EEG was.17 (95% CI 0.04–0.29), 0.42 (95% CI 0.01–0.82), 0.92 (95% CI 0.83–1.01), and.95 (95% CI 0.088–1.09), respectively. No studies investigating NIRS and ONSD outside the ICU were found. The pooled prevalence for abnormal neuromonitoring findings detected using the TCD and pupillometry were incomputable due to insufficient data.

Conclusions

Neuromonitoring tools are non-invasive, less expensive, safe, and bedside available tools with a great potential for both diagnosis and monitoring of patients with COVID-19 at risk of brain derangements. However, extensive literature searching reveals that they are rarely used outside critical care settings.

Systematic Review Registration:www.crd.york.ac.uk/prospero/display_record.php?RecordID=265617, identifier: CRD42021265617.