Approaches to understanding COVID-19 and its neurological associations

Incidence and prevalence of headache in influenza: A 2010-2021 surveillance-based study

BACKGROUND AND PURPOSE

Influenza is a common cause of acute respiratory infection, with headache being one of the symptoms included in the European Commission case definition. The prevalence of headache as a symptom of influenza remains unknown. We aimed to describe the incidence and prevalence of headache in patients with influenza.

METHODS

All consecutive patients who met the definition criteria of influenza-like illness during the influenza seasons 2010-2011 through 2021-2022 were included. The seasonal cumulative incidence of influenza per 1000 patients at risk and the prevalence of headache as an influenza symptom were calculated, including the 95% confidence intervals (CIs). Subgroup analyses were done based on patients' sex, age group, microbiological confirmation, vaccination status, and influenza type/subtype/lineage.

RESULTS

During the study period, 8171 patients were eligible. The incidence of headache in the context of influenza varied between 0.24 cases per 1000 patients (season 2020-2021) and 21.69 cases per 1000 patients (season 2017-2018). The prevalence of headache was 66.1% (95% CI = 65.1%-67.1%), varying between 49.6% (season 2021-2022) and 80.1% (season 2010-2011). The prevalence of headache was higher in women (67.9% vs. 65.7%, p = 0.03) and higher in patients between 15 and 65 years old. Headache was more prevalent in patients infected with B subtypes than A subtypes (68.7% vs. 56.9%, p < 0.001). There were no notable differences regarding vaccination status or microbiological confirmation of the infection.

CONCLUSIONS

Headache is a common symptom in patients with influenza, with a prevalence higher than that observed in other viral infections.

Pitfalls and biases in neuroepidemiological studies of COVID-19 and the nervous system: a critical appraisal of the current evidence and future directions

BACKGROUND

Neurological manifestations frequently occur in individuals with COVID-19, manifesting during the acute phase, persisting beyond the resolution of acute symptoms, and appearing days or weeks after the initial onset of COVID-19 symptoms. However, predicting the incidence, course, and outcome of these neurological manifestations at the individual patient level remains challenging. Biases in study design and limitations in data collection may contribute to the inconsistency and limited validity of the reported findings. Herein, we focused on critically appraising pitfalls and biases of prior reports and provide guidance for improving the quality and standardization of future research. Patients with COVID-19 exhibit diverse demographic features, sociocultural backgrounds, lifestyle habits, and comorbidities, all of which can influence the severity and progression of the infection and its impact on other organ systems. Overlooked or undocumented comorbidities and related treatments may contribute to neurological sequelae, which may not solely be attributable to COVID-19. It is crucial to consider the potential side effects of vaccines in relation to neurological manifestations.

CONCLUSION

To investigate neurological manifestations of COVID-19, it is essential to employ valid and reliable diagnostic criteria and standard definitions of the factors of interest. Although population-based studies are lacking, well-defined inception cohorts, including hospitalized individuals, outpatients, and community residents, can serve as valuable compromises. These cohorts should be evaluated for the presence of common comorbidities, alongside documenting the primary non-neurological manifestations of the infectious disease. Lastly, patients with COVID-19 should be followed beyond the acute phase to assess the persistence, duration, and severity of neurological symptoms, signs, or diseases.

Neurological diagnoses in hospitalized COVID-19 patients during the B.1.1.529 surge

OBJECTIVE

Emerging variants and sublineages of SARS-CoV-2 have differing disease severity, transmissibility, and immune evasion. The neurological conditions associated with the original strain of SARS-CoV-2 are well established. Our study assessed the neurological presentations specific to hospitalized patients during the B.1.1.529 (Omicron) variant surge in New York City.

METHODS

A total of 178 cases with positive RT-PCR result within 6 weeks before admission, and subsequent development of select neurological conditions during the SARS-CoV-2 B.1.1.529 (Omicron) surge between December 1, 2021 and February 28, 2022, were included from 12,800 SARS-CoV-2-positive hospital admissions. Clinical data from acute hospitalizations were compared to findings of inpatient neurological cases with COVID-19 infections from the initial surge in NYC in the same hospital system.

RESULTS

Compared to SARS-CoV-2 infections of the original strain, COVID-19 cases hospitalized during the Omicron surge (B.1.1.529) were associated with incidental and/or asymptomatic COVID-19 cases (96, 53.9%) and an increased incidence of pre-existing neurological and immunocompromising conditions. Encephalopathy, seizures, and stroke remained the most prevalent neurological conditions identified in hospitalized COVID-19 cases during the study period, reflecting a similar distribution of neurological presentations associated with the original strain.

INTERPRETATION

In our cohort of 178 admitted SARS-CoV-2-positive patients with select neurological conditions during the Omicron B.1.1.529 surge, 54% of COVID-19 cases were considered incidental and/or asymptomatic, and the identified neurological conditions resembled those associated with the original SARS-CoV-2 strain. Further studies characterizing neurological presentation in Omicron sublineages and other variants are warranted in an ongoing COVID-19 pandemic.

Observational Study of Patients Hospitalized With Neurologic Events After SARS-CoV-2 Vaccination, December 2020-June 2021

Background and Objectives

The global spread of the COVID-19 pandemic accelerated the vaccine development time line, regulatory approval, and widespread implementation in the population underscoring the importance of postauthorization/postlicensure vaccine safety surveillance. To monitor for vaccine-related adverse events, we prospectively identified patients hospitalized for prespecified neurologic conditions who received mRNA or adenovirus COVID-19 vaccines and assessed cases for potential risk factors and alternative etiologies of the adverse event.

Methods

We identified prespecified neurologic conditions in hospitalized individuals within 6 weeks of receipt of a dose of any COVID-19 vaccination between December 11, 2020, and June 22, 2021 (Columbia University Irving Medical Center/New York Presbyterian Hospital, New York City, New York). Clinical data from electronic medical records in these vaccinated patients were reviewed for assessment of contributing risk factors and etiologies for these neurologic conditions by use of a published algorithm.

Results

Among 3,830 individuals screened for COVID-19 vaccination status and neurologic conditions, 138 (3.6%) cases were included in this study (126 after mRNA and 6 after Janssen vaccines). The 4 most prevalent neurologic syndromes included ischemic stroke (52, 37.7%), encephalopathy (45, 32.6%), seizure (22, 15.9%), and intracranial hemorrhage (ICH) (13, 9.4%). All 138 cases (100%) had 1 or more risk factors and/or evidence for established causes. Metabolic derangement was the most common etiology for seizures (24, 53.3%) and encephalopathy (5, 22.7%) while hypertension was the most significant risk factor in ischemic stroke (45, 86.5%) and ICH cases (4, 30.8%).

Discussion

All cases in this study were determined to have at least 1 risk factor and/or known etiology accounting for their neurologic syndromes. Our comprehensive clinical review of these cases supports the safety of mRNA COVID-19 vaccines.

Global uncertainty in the diagnosis of neurological complications of SARS-CoV-2 infection by both neurologists and non-neurologists: An international inter-observer variability study

INTRODUCTION

Uniform case definitions are required to ensure harmonised reporting of neurological syndromes associated with SARS-CoV-2. Moreover, it is unclear how clinicians perceive the relative importance of SARS-CoV-2 in neurological syndromes, which risks under- or over-reporting.

METHODS

We invited clinicians through global networks, including the World Federation of Neurology, to assess ten anonymised vignettes of SARS-CoV-2 neurological syndromes. Using standardised case definitions, clinicians assigned a diagnosis and ranked association with SARS-CoV-2. We compared diagnostic accuracy and assigned association ranks between different settings and specialties and calculated inter-rater agreement for case definitions as "poor" (κ ≤ 0.4), "moderate" or "good" (κ > 0.6).

RESULTS

1265 diagnoses were assigned by 146 participants from 45 countries on six continents. The highest correct proportion were cerebral venous sinus thrombosis (CVST, 95.8%), Guillain-Barré syndrome (GBS, 92.4%) and headache (91.6%) and the lowest encephalitis (72.8%), psychosis (53.8%) and encephalopathy (43.2%). Diagnostic accuracy was similar between neurologists and non-neurologists (median score 8 vs. 7/10, p = 0.1). Good inter-rater agreement was observed for five diagnoses: cranial neuropathy, headache, myelitis, CVST, and GBS and poor agreement for encephalopathy. In 13% of vignettes, clinicians incorrectly assigned lowest association ranks, regardless of setting and specialty.

CONCLUSION

The case definitions can help with reporting of neurological complications of SARS-CoV-2, also in settings with few neurologists. However, encephalopathy, encephalitis, and psychosis were often misdiagnosed, and clinicians underestimated the association with SARS-CoV-2. Future work should refine the case definitions and provide training if global reporting of neurological syndromes associated with SARS-CoV-2 is to be robust.

Comparative features and outcomes of major neurological complications of COVID-19

BACKGROUND AND PURPOSE

The aim of this study was to assess the neurological complications of SARS-CoV-2 infection and compare phenotypes and outcomes in infected patients with and without selected neurological manifestations.

METHODS

The data source was a registry established by the European Academy of Neurology during the first wave of the COVID-19 pandemic. Neurologists collected data on patients with COVID-19 seen as in- and outpatients and in emergency rooms in 23 European and seven non-European countries. Prospective and retrospective data included patient demographics, lifestyle habits, comorbidities, main COVID-19 complications, hospital and intensive care unit admissions, diagnostic tests, and outcome. Acute/subacute selected neurological manifestations in patients with COVID-19 were analysed, comparing individuals with and without each condition for several risk factors.

RESULTS

By July 31, 2021, 1523 patients (758 men, 756 women, and nine intersex/unknown, aged 16-101 years) were registered. Neurological manifestations were diagnosed in 1213 infected patients (79.6%). At study entry, 978 patients (64.2%) had one or more chronic general or neurological comorbidities. Predominant acute/subacute neurological manifestations were cognitive dysfunction (N = 449, 29.5%), stroke (N = 392, 25.7%), sleep-wake disturbances (N = 250, 16.4%), dysautonomia (N = 224, 14.7%), peripheral neuropathy (N = 145, 9.5%), movement disorders (N = 142, 9.3%), ataxia (N = 134, 8.8%), and seizures (N = 126, 8.3%). These manifestations tended to differ with regard to age, general and neurological comorbidities, infection severity and non-neurological manifestations, extent of association with other acute/subacute neurological manifestations, and outcome.

CONCLUSIONS

Patients with COVID-19 and neurological manifestations present with distinct phenotypes. Differences in age, general and neurological comorbidities, and infection severity characterize the various neurological manifestations of COVID-19.

Post-COVID-19 human memory impairment: A PRISMA-based systematic review of evidence from brain imaging studies

Many people with coronavirus disease 2019 (COVID-19) report varying degrees of memory impairment. Neuroimaging techniques such as MRI and PET have been utilized to shed light on how COVID-19 affects brain function in humans, including memory dysfunction. In this PRISMA-based systematic review, we compared and summarized the current literature looking at the relationship between COVID-19-induced neuropathological changes by neuroimaging scans and memory symptoms experienced by patients who recovered from COVID-19. Overall, this review suggests a correlational trend between structural abnormalities (e.g., cortical atrophy and white matter hyperintensities) or functional abnormalities (e.g., hypometabolism) in a wide range of brain regions (particularly in the frontal, parietal and temporal regions) and memory impairments in COVID-19 survivors, although a causal relationship between them remains elusive in the absence of sufficient caution. Further longitudinal investigations, particularly controlled studies combined with correlational analyses, are needed to provide additional evidence.

MRI-negative myelitis associated with cerebral venous thrombosis after COVID-19 infection

Transverse myelitis and cerebral venous thrombosis represent some of the described neurological complications of coronavirus disease. A woman in her early 30s presented with headache, left-sided sensory symptoms and voiding difficulty. The patient also reported dry cough, fever, nasal congestion, anosmia and ageusia 2 weeks before presentation. The clinical examination showed sensory disturbances on the left side of the body, starting from the lower abdomen and extending to the left leg, which was consistent with transverse myelitis. The laboratory assessment confirmed a previous infection with coronavirus disease and excluded autoimmune entities. Radiological investigations revealed left transverse sinus thrombosis with no spinal cord abnormalities. The treatment was started with therapeutic anticoagulation and intravenous high-dose steroids. The patient showed significant improvement, and the neurological deficits resolved after 3 months. This is the first documented case of imaging-negative myelitis associated with cerebral venous thrombosis after coronavirus disease.

Neurological effects of COVID-19 in infants and children

Neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children are becoming increasingly apparent as the coronavirus disease (COVID-19) pandemic continues. While children manifest relatively milder features of the disease, accumulating evidence warrants concern that COVID-19 exacts both acute- and long-term effects on the developing central and peripheral nervous systems. This review focuses on the relatively underinvestigated topic of the effects of SARS-CoV-2 on the brain in infancy and childhood, concluding that clinicians should be attentive to both the acute effects and long-term consequences of COVID-19 from a neurological perspective.

Non-Productive Infection of Glial Cells with SARS-CoV-2 in Hamster Organotypic Cerebellar Slice Cultures

The numerous neurological syndromes associated with COVID-19 implicate an effect of viral pathogenesis on neuronal function, yet reports of direct SARS-CoV-2 infection in the brain are conflicting. We used a well-established organotypic brain slice culture to determine the permissivity of hamster brain tissues to SARS-CoV-2 infection. We found levels of live virus waned after inoculation and observed no evidence of cell-to-cell spread, indicating that SARS-CoV-2 infection was non-productive. Nonetheless, we identified a small number of infected cells with glial phenotypes; however, no evidence of viral infection or replication was observed in neurons. Our data corroborate several clinical studies that have assessed patients with COVID-19 and their association with neurological involvement.

Short- and long-term outcome and predictors in an international cohort of patients with neuro COVID-19

Background and purpose

Despite the increasing number of reports on the spectrum of neurological manifestations of COVID‐19 (neuro‐COVID), few studies have assessed short‐ and long‐term outcome of the disease.

Methods

This is a cohort study enrolling adult patients with neuro‐COVID seen in neurological consultation. Data were collected prospectively or retrospectively in the European Academy of Neurology NEuro‐covid ReGistrY ((ENERGY). The outcome at discharge was measured using the modified Rankin Scale and defined as ‘stable/improved’ if the modified Rankin Scale score was equal to or lower than the pre‐morbid score, ‘worse’ if the score was higher than the pre‐morbid score. Status at 6 months was also recorded. Demographic and clinical variables were assessed as predictors of outcome at discharge and 6 months.

Results

From July 2020 to March 2021, 971 patients from 19 countries were included. 810 (83.4%) were hospitalized. 432 (53.3%) were discharged with worse functional status. Older age, stupor/coma, stroke and intensive care unit (ICU) admission were predictors of worse outcome at discharge. 132 (16.3%) died in hospital. Older age, cancer, cardiovascular complications, refractory shock, stupor/coma and ICU admission were associated with death. 262 were followed for 6 months. Acute stroke or ataxia, ICU admission and degree of functional impairment at discharge were predictors of worse outcome. 65/221 hospitalized patients (29.4%) and 10/32 non‐hospitalized patients (24.4%) experienced persisting neurological symptoms/signs. 10/262 patients (3.8%) developed new neurological complaints during the 6 months of follow‐up.

Conclusions

Neuro‐COVID is a severe disease associated with worse functional status at discharge, particularly in older subjects and those with comorbidities and acute complications of infection.

ADAR Editing in Viruses: An Evolutionary Force to Reckon with

Adenosine Deaminases that Act on RNA (ADARs) are RNA editing enzymes that play a dynamic and nuanced role in regulating transcriptome and proteome diversity. This editing can be highly selective, affecting a specific site within a transcript, or nonselective, resulting in hyperediting. ADAR editing is important for regulating neural functions and autoimmunity, and has a key role in the innate immune response to viral infections, where editing can have a range of pro- or antiviral effects and can contribute to viral evolution. Here we examine the role of ADAR editing across a broad range of viral groups. We propose that the effect of ADAR editing on viral replication, whether pro- or antiviral, is better viewed as an axis rather than a binary, and that the specific position of a given virus on this axis is highly dependent on virus- and host-specific factors, and can change over the course of infection. However, more research needs to be devoted to understanding these dynamic factors and how they affect virus-ADAR interactions and viral evolution. Another area that warrants significant attention is the effect of virus-ADAR interactions on host-ADAR interactions, particularly in light of the crucial role of ADAR in regulating neural functions. Answering these questions will be essential to developing our understanding of the relationship between ADAR editing and viral infection. In turn, this will further our understanding of the effects of viruses such as SARS-CoV-2, as well as many others, and thereby influence our approach to treating these deadly diseases.

COVID-19 and mental health in children and adolescents: a diagnostic panel to map psycho-social consequences in the pandemic context

Since the beginning of the COVID-19 pandemic, much research has been done on the psycho-social consequences, especially for children, adolescents and families. In the long run, there is a large set of quantitative data available. However, these still seem to be not well understood. Theoretical classifications of the evidence also diagnostic tools still seem to be open. This paper elaborates a possible systematisation based on theoretical models of systemic self-organisation theories. This leads to a model for a comprehensive psycho-social child-in-environment diagnostic to map potential problem areas. Such a theoretical framing should enable both: a deeper understanding of the impact of pandemics on young people and hypotheses for intervention strategies in the context of pandemic management as well as in the context of diagnostic-systemic interventions in psycho-social working settings. In the coming months and years, it will be essential to be able to understand and describe psychosocial disabilities that have developed in the context of the pandemic in a differentiated way in order to establish targeted interventions.

Acute and post-acute neurological manifestations of COVID-19: present findings, critical appraisal, and future directions

Acute and post-acute neurological symptoms, signs and diagnoses have been documented in an increasing number of patients infected by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which causes Coronavirus Disease 2019 (COVID-19). In this review, we aimed to summarize the current literature addressing neurological events following SARS-CoV-2 infection, discuss limitations in the existing literature and suggest future directions that would strengthen our understanding of the neurological sequelae of COVID-19. The presence of neurological manifestations (symptoms, signs or diagnoses) both at the onset or during SARS-CoV-2 infection is associated with a more severe disease, as demonstrated by a longer hospital stay, higher in-hospital death rate or the continued presence of sequelae at discharge. Although biological mechanisms have been postulated for these findings, evidence-based data are still lacking to clearly define the incidence, range of characteristics and outcomes of these manifestations, particularly in non-hospitalized patients. In addition, data from low- and middle-income countries are scarce, leading to uncertainties in the measure of neurological findings of COVID-19, with reference to geography, ethnicity, socio-cultural settings, and health care arrangements. As a consequence, at present a specific phenotype that would specify a post-COVID (or long-COVID) neurological syndrome has not yet been identified.