Neurological Complications of COVID-19 and Possible Neuroinvasion Pathways: A Systematic Review

Sources of negative emotions and tactics of self-emotion regulation among college students during COVID-19 school closure in China

Background

This study investigated the level of anxiety and depression in Chinese college students since the COVID-19 pandemic and explored the sources of their negative emotions and students' self-emotion regulation strategies.

Methods

A stratified cluster sampling questionnaire was used to survey college students during the pandemic via the Anxiety Depression, Self-made Negative Emotion Source, and Negative Emotion Regulation Strategy Scales.

Results

The prevalence of anxiety and depression was 23.3 and 20.1%, respectively. These levels were higher in women than in men. Furthermore, senior students reported higher levels than freshmen. Anxiety and depression mainly came from the pressure to grow and the narrowed scope of social activities. Proper relaxation via entertainment and communication with family and friends were popular ways of regulating their negative emotions.

Conclusion

College students should confront their negative emotions and understand their source, use psychological methods to regulate their anxiety and depression or seek professional help, improve their psychological resilience, and adopt positive coping measures.

COVID-19 related neurological manifestations in Parkinson's disease: has ferroptosis been a suspect?

A rising number of patient cases point to a probable link between SARS-CoV-2 infection and Parkinson's disease (PD), yet the mechanisms by which SARS-CoV-2 affects the brain and generates neuropsychiatric symptoms in COVID-19 patients remain unknown. Ferroptosis, a distinct iron-dependent non-apoptotic type of cell death characterized by lipid peroxidation and glutathione depletion, a key factor in neurological disorders. Ferroptosis may have a pathogenic role in COVID-19, according to recent findings, however its potential contributions to COVID-19-related PD have not yet been investigated. This review covers potential paths for SARS-CoV-2 infection of the brain. Among these putative processes, ferroptosis may contribute to the etiology of COVID-19-associated PD, potentially providing therapeutic methods.

A Systematic Review Unraveling the Intricate Neurological Spectrum of COVID-19: Manifestations, Complications, and Transformative Insights for Patient Care

The coronavirus disease 2019 (COVID-19) pandemic has strained global healthcare and financial infrastructures. Neurological manifestations of COVID-19 have gained recognition, emphasizing the need for comprehensive research in this area. This systematic review aims to comprehensively examine the neurological manifestations and complications associated with COVID-19 and assess their prevalence, impact on patient outcomes, and potential relationships with comorbidities, while emphasizing the significance of ongoing research in this field. We conducted a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) 2020 guidelines. A comprehensive search of PubMed, Google Scholar, Science Direct, and ResearchGate databases was conducted to identify eligible studies focusing on COVID-19 patients, reporting neurological symptoms or complications, and published between 2020 and 2022 in English. The data extracted is performed in a Microsoft Excel spreadsheet. Two independent reviewers assessed study quality and bias using the AMSTAR 2 scale before inclusion. This systematic includes 12 systematic reviews and meta-analysis with 191,412 participants and average age of 60 years. Neurological symptoms included headaches, dizziness, anosmia, and ageusia. Complications ranged from cerebrovascular events to Guillain-Barré syndrome. Comorbidities, such as hypertension and diabetes, exacerbated severity. Mortality rates associated with neurological manifestations varied from 29.1% to 84.8%. The study underscores the complex neurological impact of COVID-19, affecting patients across age groups. Ongoing research is vital to understand mechanisms and develop targeted interventions, improving patient care and addressing pandemic consequences. This review provides a holistic view of COVID-19's neurological effects, emphasizing the need for sustained research efforts and collaborative endeavors to combat the neurological issues.

A Machine Learning Approach Unveils the Relationships between Sickness Behavior and Interoception after Vaccination: Suggestions for Psychometric Indices of Higher Vulnerability

OBJECTIVE

Prior research has suggested a possible connection between vaccination and manifestations of Sickness Behavior; however, a need remains to first delve deeper into this association and second examine how Interoceptive Awareness and emotional factors may modulate individuals' perceptions of their health status post vaccination.

METHOD

An online retrospective cross-sectional survey of 647 individuals who received a COVID-19 vaccination was conducted. Together with vaccination side effects, socio-demographic characteristics, health status, level of concern about vaccination, and Interoceptive Awareness were collected at the baseline level. Mood, sleep, and Sickness Behavior were assessed at baseline and after vaccination. Data were analyzed using inferential statistics and machine learning techniques.

RESULTS

After vaccination, there was a significant increase in Sickness Behavior levels (mean (±SD) SicknessQ T0 = 1.57 (±2.72), mean (±SD) SicknessQ T1 = 5.54 (±5.51); p-value = 0.001; ES = 0.77). A Machine Learning analysis revealed specific patterns of individual dispositions (sex and age), baseline emotional characteristics (levels of depression, anxiety, stress, and concern about adverse reactions), as well as some components of Interoceptive Awareness (Noticing, Body Listening, and Attention Regulation), as predictors of high levels of Sickness Behavior, both in terms of overall scores (JRIP: 72.65% accuracy, AUC = 0.692, d = 0.709; F1 = 0.726) and individual items (JRIP: 75.77% accuracy, AUC = 0.694; d = 0.717; F1 = 0.754).

CONCLUSIONS

Our results provide new insight into post-immune reactions by highlighting the contribution of Interoceptive Awareness in modulating the severity of Sickness Behavior. This sheds light on the role of awareness of bodily sensations in modulating perceptions of health status, helping to identify the characteristics that make individuals more prone to feeling sick.

Acute Necrotizing Encephalopathy in Adult Patients With COVID-19: A Systematic Review of Case Reports and Case Series

BACKGROUND AND PURPOSE

Acute necrotizing encephalopathy (ANE) is a rare neurological disorder that is often associated with viral infections. Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a few COVID-19-associated ANE cases have been reported. Since very little is known about ANE, the present study aimed to determine the clinical, biochemical, and radiological characteristics of affected patients.

METHODS

A search was conducted on PubMed, Scopus, Embase, and Web of Science databases for articles published up to August 30, 2022 using relevant keywords. Case reports and series in the English language that reported ANE in adult patients with COVID-19 confirmed by reverse transcription polymerase chain reaction were included in this study. Data on the demographic, clinical, laboratory, and radiological characteristics of patients were extracted and analyzed using the SPSS software (version 26).

RESULTS

The study included 30 patients (18 males) with COVID-19 and ANE who were aged 49.87±18.68 years (mean±standard deviation). Fever was the most-prevalent symptom at presentation (66.7%). Elevated C-reactive protein was observed in the laboratory assessments of 13 patients. Computed tomography and magnetic resonance imaging were the most-common radiological modalities used for brain assessments. The most commonly prescribed medications were methylprednisolone (30%) and remdesivir (26.7%). Sixteen patients died prior to discharge.

CONCLUSIONS

The diagnosis of COVID-19-associated ANE requires a thorough knowledge of the disease. Since the clinical presentations of ANE are neither sensitive nor specific, further laboratory and brain radiological evaluations will be needed to confirm the diagnosis. The suspicion of ANE should be raised among patients with COVID-19 who present with progressive neurological symptoms.

COVID-19 Pandemic and Internet Addiction in Young Adults: A Pilot Study on Positive and Negative Psychosocial Correlates

Objective

During and after the lockdowns of the COVID-19 pandemic period, a strain was put on young adults who have taken refuge in the problematic use of internet, social media, gaming, and gambling. This paper aims to investigate possible correlates of Internet Addiction Disorder (IAD), hypothesizing anxiety, depression and perceived stress would promote addiction, while mindfulness skills, resilience and socialization would, conversely, hamper IAD, and promote, consequently, a more functional internet use.

Method

A pilot study was carried out with a sample of 31 young adults, recruited through a snowball sampling using social networks. Participants filled out an online questionnaire including the following measures: Internet Use, Abuse and Addiction (UADI), Beck Depression Inventory (BDI-II); State-Trait Anxiety Inventory (STAI-Y); Perceived Stress Scale (PSS); Five Facet Mindfulness Questionnaire (FFMQ); Mindfulness Attention and Awareness Scale (MAAS); Resilience Scale (RS-14). It was also administered an ad hoc questionnaire for the assessment of socialization behaviour (6 items) and gambling (2 items).

Results

All the measures, but socialization, showed adequate reliability. Our sample showed high levels of anxiety, stress, IA and gambling, while presenting low levels of resilience, the mindful skill of no-reactivity and socialization. The first hypothesis was confirmed, finding positive and significant correlations between Internet Addiction on one side and PSS, STAI-Y1, STAY-2, and BDI II on the other side. We also partially confirmed the second hypothesis about UADI negatively correlated with both RS-14 and Mindful Acting. Finally, no correlations were found between Gambling and IA.

Conclusions

In conclusion, the more one perceives an emotional overload with less stress-control, high anxiety, and depression, and the less one can leverage on the skills of mindful acting and resilience, the more one uses the internet as a strategy to escape from a threatening reality.

Cerebral Vasomotor Reactivity in COVID-19: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily affects the respiratory system but can also lead to neurological complications. Among COVID-19 patients, the endothelium is considered the Achilles heel. A variety of endothelial dysfunctions may result from SARS-CoV-2 infection and subsequent endotheliitis, such as altered vascular tone, oxidative stress, and cytokine storms. The cerebral hemodynamic impairment that is caused is associated with a higher probability of severe disease and poor outcomes in patients with COVID-19. This review summarizes the most relevant literature on the role of vasomotor reactivity (VMR) in COVID-19 patients. An overview of the research articles is presented. Most of the studies have supported the hypothesis that endothelial dysfunction and cerebral VMR impairment occur in COVID-19 patients. Researchers believe these alterations may be due to direct viral invasion of the brain or indirect effects, such as inflammation and cytokines. Recently, researchers have concluded that viruses such as the Human Herpes Virus 8 and the Hantavirus predominantly affect endothelial cells and, therefore, affect cerebral hemodynamics. Especially in COVID-19 patients, impaired VMR is associated with a higher risk of severe disease and poor outcomes. Using VMR, one can gain valuable insight into a patient's disease progression and make more informed decisions regarding appropriate treatment options. A new pandemic may develop with the COVID-19 virus or other viruses, making it essential that healthcare providers and researchers remain focused on developing new strategies for improving survival in such patients, particularly those with cerebrovascular risk factors.

MOLECULAR MIMICRY OF SARS-COV-2 SPIKE PROTEIN IN THE NERVOUS SYSTEM: A BIOINFORMATICS APPROACH

Introduction

The development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in record time to cope with the ongoing coronavirus disease 2019 (COVID-19) pandemic has led to uncertainty about their use and the appearance of adverse neurological reactions. The SARS-CoV-2 spike protein (SP) is used to produce neutralizing antibodies and stimulate innate immunity. However, considering the alterations in the nervous system (NS) caused by COVID- 19, cross-reactions are plausible.

Objective

To identify peptides in Homo sapiens SP-like proteins involved in myelin and axon homeostasis that may be affected due to molecular mimicry by antibodies and T cells induced by interaction with SP.

Materials and methods

A bioinformatics approach was used. To select the H. sapiens proteins to be studied, related biological processes categorized based on gene ontology were extracted through the construction of a protein–protein interaction network. Peripheral myelin protein 22, a major component of myelin in the peripheral nervous system, was used as the query protein. The extracellular domains and regions susceptible to recognition by antibodies were extracted from UniProt. In the study of T cells, linear sequence similarity between H. sapiens proteins and SP was assessed using BLASTp. This study considered the similarity in terms of biochemical groups per residue and affinity to the human major histocompatibility complex (human leukocyte antigen I), which were evaluated using Needle and NetMHCpan 4.1, respectively.

Results

A large number of shared pentapeptides between SP and H. sapiens proteins were identified. However, only a small group of 39 proteins was linked to axon and myelin homeostasis. In particular, some proteins, such as phosphacan, attractin, and teneurin-4, were susceptible targets of B and T cells. Other proteins closely related to myelin components in the NS, such as myelin-associated glycoprotein, were found to share at least one pentamer with SP in extracellular domains.

Conclusion

Proteins involved in the maintenance of nerve conduction in the central and peripheral NS were identified in H. sapiens. Based on these findings, re-evaluation of the vaccine composition is recommended to prevent possible neurological side effects.

Mindfulness and Defense Mechanisms as Explicit and Implicit Emotion Regulation Strategies against Psychological Distress during Massive Catastrophic Events

Emotion regulation is an important aspect of psychological functioning that influences subjective experience and moderates emotional responses throughout the lifetime. Adaptive responses to stressful life events depend on the positive interaction between explicit and implicit emotion regulation strategies, such as mindfulness and defense mechanisms. This study demonstrates how these emotion regulation strategies predict psychological health during the early phase of the COVID-19 pandemic. A convenience sample of 6385 subjects, recruited via snowball sampling on various social media platforms, responded to an online survey assessing psychological reaction to social restrictions imposed to limit the spread of COVID-19 in Italy. Psychological distress, post-traumatic stress symptoms, mindfulness, and defense mechanisms were assessed using SCL-90, IES-R, MAAS, and DMRS-30-SR, respectively. Higher mindfulness was significantly associated with higher overall defensive maturity and a greater use of high-adaptive defenses (p < 0.0001). Both mindfulness and defense mechanisms acted as good predictors of psychological health (R² = 0.541) and posttraumatic symptoms (R² = 0.332), confirming the role of emotion regulation in protecting against maladaptive responses to stressful situations.

Predictors of fatal neurological complications among admitted COVID-19 patients with their implication in outcome: A Case Control study

Background

COVID-19 is known to be associated to potentially fatal neurological complications; therefore, it is essential to understand the risk factors for its development and the impact they have on the outcome of COVID-19 patients.

Aims

To determine the risk factors for developing fatal neurological complications and their outcome in hospitalized COVID-19 patients.

Material and methods

Case control study based on hospitalized patients was conducted from July 15th 2021 to December 15th 2021. Cases and controls were COVID-19 confirmed patients with and without severe neurological manifestations. Age, comorbid conditions, vaccination status, Blood Sugar Random (BSR), D-dimers levels, anticoagulation type and dosage were taken as predictors (exposure variables) for developing neurological complications. In the case-only (subgroup) analysis, 28-day mortality were analyzed using the same predictors including admission hypoxemia. Chi square test and regression model were built to calculate OR with 95%CI.

Results

Among 383 patients (median age, 56 years [IQR, 24–110]; 49.9% men); 95 had neurological complications (cases) and 288 did not (controls). Development of neurological complications among COVID-19 related hospitalizations was significantly associated with old age >71 yrs. (cases, 23.2%; controls, 13.5%; OR, 3.31; 95% CI, 1.28–8.55), presence of diabetes mellitus (37.9% vs. 24%; OR, 1.9; 95% CI, 1.2–3.1), admission hyperglycemia (BSR 351–600 mg/dl), (29.5% vs. 7.6%; OR, 3.11; 95%CI, 1.54–6.33), raised D-dimer levels 5000–10,000 ng/ml (41% vs. 11.8%; OR, 5.2; 95% CI, 3.02–8.9), prophylactic dose anticoagulation (43.2% vs. 28.1%; OR, 1.9; 95%CI, 1.2–3.1), and unvaccinated status of COVID-19 patients (90.5% vs. 75.6%; OR, 3.01; 95% CI, 1.44–6.25). Neurological complications with COVID-19 were associated with increased likelihood of death or invasive mechanical ventilation by day 28 (86.3% vs. 45.1%; OR, 7.66; 95% CI, 4.08–14.4). In case-only analysis (median age, 56 years [IQR, 27,110]; 50.5% women), 67 (70.5%) had CVE, 21 (22.1%) had Encephalitis, and 7 (7.4%) had GBS as neurological manifestations. 28-day mortality among these patients was strongly associated with a lower likelihood of vaccination. (6.1% cases vs. 30.8% controls; OR, .146; 95%CI, .033- .64), being younger 17–45 yrs. (12.2% vs. 46.2%; OR, .162; 95%CI, .045-.58), having no comorbid condition (19.5% vs. 61.5%; OR, .151; 95%CI, .044- .525), having cerebrovascular events and GBS as type of neurological manifestation (76.8% vs.30.8%; OR, 7.46; 95%CI, 2.06–26.96), (2.4% vs. 38.4%; OR, .04; 95%CI, .007- 0.24) respectively, and presence of hypoxemia at admission (91.5% vs. 15.4%; OR, 58.92; 95%CI, 10.83–320.67).

Conclusion

Old age, presence of Diabetes Mellitus, unvaccinated status of patients, high BSR at admission, high D-dimers, and prophylactic dose anticoagulation were identifies as increased risk factors for developing serious neurological complications among COVID-19 patients. Neurological problems in COVID-19 patients raised death risk 7.6-fold. The most common neurological complication was cerebrovascular events, followed by encephalitis and GBS. Unvaccinated status, cerebrovascular events, and admission hypoxemia are associated with an increased likelihood of 28-day mortality among these patients.

Epidemiology of COVID-19 and Its Cardiac and Neurologic Complications Among Chinese and South Asians in Ontario: Waves 1, 2, and 3

Background

Although we had previously reported the cardiac and neurologic outcomes of Chinese and South Asian Ontarians in wave 1 of COVID-19, data on subsequent waves of COVID-19 remain unexamined. This is an extension study of this cohort in waves 2 and 3.

Methods

We identified adult Ontarians with a positive COVID-19 polymerase chain reaction test from January 1, 2020 to June 30, 2021, and they were classified as being Chinese or South Asian using a validated surname algorithm; we compared their outcomes of mortality, and cardiac and neurologic complications with those of the general population using multivariable logistic regression models.

Results

Compared to the general population (n = 439,977), the Chinese population (n = 15,208) was older (mean age 44.2 vs 40.6 years, P < 0.001) and the South Asian population (n = 46,333) was younger (39.2 years, P < 0.001). The Chinese population had a higher 30-day mortality (odds ratio [OR] 1.44; 95% confidence interval [CI] 1.28-1.61) and more hospitalization or emergency department visits (OR, 1.14; 95% CI, 1.09-1.28), with a trend toward a higher incidence of cardiac complications (OR, 1.03; 95% CI, 0.87-1.12) and neurologic complications (OR, 1.23; 95% CI, 0.96-1.58). South Asians had a lower 30-day mortality (OR, 0.88; 95% CI, 0.78-0.98) but a higher incidence of hospitalization or emergency department visits (OR, 1.17; 95% CI, 1.14-1.20) with a trend toward a lower incidence of cardiac complications (OR, 0.76; 95% CI, 0.67-0.87) and neurologic complications (OR, 0.89; 95% CI, 0.73-1.09). There was also a significant difference in these outcomes between wave 1, 2 and 3, with a greater mortality in all groups in waves 2 and 3.

Conclusions

Ethnicity continues to be an important determinant of mortality, cardiac and neurologic outcomes, and healthcare use among patients with COVID-19, requiring further studies to understand factors driving these differences.

Central nervous system outcomes of COVID-19

The worldwide pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected an estimated 200 million people with over 4 million deaths. Although COVID-19, the disease caused by the SARS-CoV-2 virus, is primarily a respiratory disease, an increasing number of neurologic symptoms have been reported. Some of these symptoms, such as loss of smell or taste, are mild and non-life threatening, while others, such as stroke or seizure, are more critical. Many of these symptoms remain long after the acute illness has passed, a phenomenon known as "long COVID" or postacute sequelae of SARS-CoV-2 infection (PASC). Neurological symptoms can be difficult to study due to the complexity of the central and peripheral nervous system. These neurologic symptoms can be difficult to identify and quantitate. This narrative review will describe approaches for assessing neurologic manifestations of COVID-19, with examples of the data they provide, as well as some directions for future research to aid in understanding the pathophysiology of COVID-19-related neurological implications.

Potential for Stem Cell-Based Therapy in the Road of Treatment for Neurological Disorders Secondary to COVID-19

Abstract

The severe acute respiratory syndrome coronavirus 2 has led to the worldwide pandemic named coronavirus disease 2019 (COVID-19). It has caused a significant increase in the number of cases and mortalities since its first diagnosis in December 2019. Although COVID-19 primarily affects the respiratory system, neurological involvement of the central and peripheral nervous system has been also reported. Herein, the higher risk of neurodegenerative diseases in COVID-19 patients in future is also imaginable. Neurological complications of COVID-19 infection are more commonly seen in severely ill individuals; but, earlier diagnosis and treatment can lead to better long-lasting results. In this respect, stem cell biotechnologies with considerable self-renewal and differentiation capacities have experienced great progress in the field of neurological disorders whether in finding out their underlying processes or proving them promising therapeutic approaches. Herein, many neurological disorders have been found to benefit from stem cell medicine strategies. Accordingly, in the present review, the authors are trying to discuss stem cell-based biotechnologies as promising therapeutic options for neurological disorders secondary to COVID-19 infection through reviewing neurological manifestations of COVID-19 and current stem cell-based biotechnologies for neurological disorders.

Lay Summary

Due to the substantial burden of neurological disorders in the health, economic, and social system of society, the emergence of neurological manifestations following COVID-19 (as a life-threatening pandemic) creates the need to use efficient and modern methods of treatment. Since stem cell-based methods have been efficient for a large number of neurological diseases, it seems that the use of mentioned methods is also effective in the process of improving neurological disorders caused by COVID-19. Hereupon, the current review aims to address stem cell-based approaches as treatments showing promise to neurological disorders related to COVID-19.

A review of ischemic stroke in COVID-19: currently known pathophysiological mechanisms

Coronavirus disease 2019 (COVID-19), the third type of coronavirus pneumonia after severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), is spreading widely worldwide now. This pneumonia causes not only respiratory symptoms but also multiple organ dysfunction, including thrombotic diseases such as ischemic stroke. The purpose of this review is to explore whether COVID-19 is a risk factor for ischemic stroke and its related pathophysiological mechanisms. Based on the high thrombosis rate and frequent strokes of COVID-19 patients, combined with related laboratory indicators and pathological results, the discussion is mainly from two aspects: nerve invasion and endothelial dysfunction. SARS-CoV-2 can directly invade the CNS through blood-borne and neuronal retrograde pathways, causing cerebrovascular diseases. In addition, the endothelial dysfunction in COVID-19 is almost certain. Cytokine storm causes thromboinflammation, and downregulation of ACE2 leads to RAS imbalance, which eventually lead to ischemic stroke.

COVID-19 pandemic and reasons to prioritize the needs of the health care system to ensure its sustainability: A scoping review from January to October 2020 (Review)

The worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led the World Health Organization to characterize the pandemic as a public health emergency of international concern. National health care systems in countries during the initial surge of the pandemic were unable to handle the sanitarian crisis that had emerged. Thus, the prevention and control of future global health emergencies must be a priority. The present scoping review aimed to retrieve articles that summarize the current experience on issues related to historical knowledge, and epidemiology, clinical features and overall burden of SARS-CoV-2 on health care services. In summary, a comprehensive overview of the information that has been learnt during this period is presented in the current review. Furthermore, taking into account the global experience, the need for planning cohesive and functional health services before similar pandemic events occur in the future is highlighted. The next public health issue should be prevented rather than treated. In spite of the vaccination benefits, a number of sporadic cases of SARS-CoV-2infections will persist. Information collected remains relevant for appraising how similar threats can be faced in the future. Overall, collaborative health care plans need to be rethought to increase preparedness.

Neurological manifestations of COVID-19 infection: an umbrella review

BACKGROUND

Neurological involvements of COVID-19 are one of the most reported manifestations of this infection. This study aims to systematically review the previous systematic reviews which addressed the neurological manifestations of the COVID-19 infection.

METHODS

Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, a comprehensive search was conducted in PubMed, Embase, Scopus, Web of Science databases and Google Scholar from December 2019 to December 2020. Articles were critically screened by two independent reviewers and if met the inclusion criteria, entered the study. Assessment of methodological quality was conducted by Assessment of Multiple Systematic Reviews-2 (AMSTAR-2) tool. Statistical analysis was not applicable. From a total of 1302 studies, 308 studies were removed due to their irrelevant title and abstract. After screening the full texts, a total of 66 found to be eligible. Twenty-one studies reported general manifestations of the COVID-19, 13 studies reported cerebrovascular events, 19 olfactory and oral dysfunctions, 5 systematic reviews on Guillen-Barré syndrome (GBS) and 8 articles on the sporadic manifestations like ocular signs and symptoms. The majority of the studies were classified as critically low or low in terms of quality.

CONCLUSION

Despite great heterogeneity in the current literature, neurological involvements are an important extra-pulmonary aspect of the COVID-19; most commonly in the form of general manifestations like headache and olfactory disturbances. Long-term effects of this virus on the nervous system must be a research priority for future references.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s41983-021-00366-5.

Olfactory and gustatory dysfunctions in SARS-CoV-2 infection: A systematic review

BACKGROUND

Among Coronavirus Disease 2019 (COVID-19) manifestations, Olfactory (OD) and Gustatory (GD) Dysfunctions (OGD) have drawn considerable attention, becoming a sort of hallmark of the disease. Many have speculated on the pathogenesis and clinical characteristics of these disturbances; however, no definite answers have been produced on the topic. With this systematic review, we aimed to collect all the available evidence regarding the prevalence of OGD, the timing of their onset and their resolution, their rate of recovery and their role as diagnostic and prognostic tools for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection.

METHODS

A systematic review comprising all the observational studies that reported the prevalence and/or the longitudinal trajectories of OGD in COVID-19 patients, as self-reported by patients or measured through objective psychophysical tests.

RESULTS

After the selection process, 155 studies were included, with a total of 70,920 patients and 105,291 not-infected individuals. Prevalence reports were extremely variable across studies, with wide ranges for OD (0%-98%) and GD (0-89%) prevalence. OGD occurred early during the disease course and only rarely preceded other symptoms; out of 30 studies with a follow-up time of at least 20 days, only in 5 studies OGD fully resolved in more than 90% of patients. OGD had low sensitivity and high specificity for SARS-CoV-2 infection; accuracy of OD and GD for infection identification was higher than 80% in 10 out of 33 studies and in 8 out of 22 studies considered, respectively. 28 out of 30 studies that studied the association between OGD and disease severity found how OGD were associated with lower rates of severe pneumonia, hospitalization and mortality.

CONCLUSIONS

OGD seem to be highly prevalent in SARS-CoV-2 infection. They occur early, concomitantly with other symptoms and often persist after recovery, in some cases for months; whether a full recovery eventually occurs in all cases is not clear yet. OGD are good predictors of SARS-CoV-2 infection and are associated with a milder disease course.

Emerging COVID-19 Neurological Manifestations: Present Outlook and Potential Neurological Challenges in COVID-19 Pandemic

The unremitting coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) marked a year-long phase of public health adversaries and has severely compromised healthcare globally. Early evidence of COVID-19 noted its impact on the pulmonary and cardiovascular functions, while multiple studies in recent time shed light on its substantial neurological complications, though a comprehensive understanding of the cause(s), the mechanism(s), and their neuropathological outcomes is scarce. In the present review, we conferred evidence of neurological complications in COVID-19 patients and shed light on the SARS-CoV-2 infection routes including the hematogenous, direct/neuronal, lymphatic tissue or cerebrospinal fluid, or infiltration through infected immune cells, while the underlying mechanism of SARS-CoV-2 invasion to the central nervous system (CNS) was also discussed. In an up-to-date manner, we further reviewed the impact of COVID-19 in developing diverse neurologic manifestations associated with CNS, peripheral nervous system (PNS), skeletal muscle, and also pre-existing neurological diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, and myasthenia gravis. Furthermore, we discussed the involvement of key factors including age, sex, comorbidity, and disease severity in exacerbating the neurologic manifestations in COVID-19 patients. An outlook of present therapeutic strategies and state of existing challenges in COVID-19 management was also accessed. Conclusively, the present report provides a comprehensive review of COVID-19-related neurological complications and emphasizes the need for their early clinical management in the ongoing COVID-19 pandemic.

A Psychometric Examination of the Coronavirus Anxiety Scale and the Fear of Coronavirus Disease 2019 Scale in the Italian Population

The coronavirus disease 2019 (COVID-19) outbreak has caused not only significant physical health problems but also mental health disorders. Anxiety and fear appear to be the main psychological symptoms associated with COVID-19. The aim of this study was to investigate whether anxiety and fear related to COVID-19 are influenced by sociodemographics and whether specific conditions, such as positivity for COVID-19 or death among relatives and friends, can further enhance these symptoms. In this cross-sectional study, 697 Italians responded to an online survey assessing sociodemographic information, the presence/absence of positive cases, or deaths due to COVID-19 among relatives or acquaintances. The Coronavirus Anxiety Scale (CAS) and Fear of COVID-19 Scale (FCS-19S) were administered in order to assess the levels of anxiety and fear associated with COVID-19. The data were collected in November 2020. Anxiety and fear scores were positively correlated. Both male and female subjects with higher CAS scores also displayed higher FCS-19S scores. The CAS and FCS-19S scores tended to increase with age, with older subjects exhibiting higher scores than younger subjects. Additionally, respondents with lower educational levels demonstrated higher scores on both the CAS and FCS-19S. Similarly, respondents living with older people and/or experiencing the death of one or more relatives due to COVID-19 exhibited corresponding outcomes. This study demonstrates how the levels of anxiety and fear, measured by CAS and FCS-19S associated with COVID-19, are influenced by gender, age, cohabitation status, educational levels, and the presence of positive cases or deaths due to COVID-19.

Long-COVID Syndrome? A Study on the Persistence of Neurological, Psychological and Physiological Symptoms

BACKGROUND

Emerging aspects of the Covid-19 clinical presentation are its long-term effects, which are characteristic of the so-called "long COVID". The aim of the present study was to investigate the prevalence of physical, psychological, and sleep disturbances and the quality of life in the general population during the ongoing pandemic.

METHODS

This study, based on an online survey, collected demographic data, information related to COVID-19, sleep disturbances, and quality of life data from 507 individuals. The level of sleep disturbances and quality of life was assessed through the Insomnia Severity Index (ISI) and the EuroQol-5D (EQ-5D), respectively.

RESULTS

In total, 507 individuals (M = 91 and F = 416 women) completed the online survey. The main symptoms associated with "long COVID" were headache, fatigue, muscle aches/myalgia, articular pains, cognitive impairment, loss of concentration, and loss of smell. Additionally, the subjects showed significant levels of insomnia (p < 0.05) and an overall reduced quality of life (p < 0.05).

CONCLUSIONS

The results of the study appear in line with recent publications, but uncertainty regarding the definition and specific features of "long COVID" remains. Further studies are needed in order to better define the clinical presentation of the "long COVID" condition and related targeted treatments.

Factors associated with COVID-19 in people with Parkinson's disease: a systematic review and meta-analysis

Background

There is debate as to whether there is an increased risk of COVID‐19 infection in people with Parkinson's disease (PD), possibly due to associated factors. This study aimed to systematically review the factors associated with COVID‐19 in people with PD.

Methods

A search was carried out in PubMed, Scopus, and Web of Science up to November 2020 (updated until 1 April 2021). Observational studies that analyzed factors associated with COVID‐19 in people with PD were selected and revised.

Results

The authors included six studies (four case‐controlled studies and two cross‐sectional studies) in the qualitative and quantitative syntheses. The authors found that the following factors were associated with COVID‐19 in people with PD: obesity (OR: 1.79, 95% CI: 1.07–2.99, I²: 0%), any pulmonary disease (OR: 1.92, 95% CI: 1.17–3.15, I²: 0%), COVID‐19 contact (OR: 41.77, 95% CI: 4.77 – 365.56, I²: 0%), vitamin D supplementation (OR: 0.50, 95% CI: 0.30–0.83, I²: 0%), hospitalization (OR: 11.78, 95% CI: 6.27–22.12, I²: 0%), and death (OR: 11.23, 95% CI: 3.92–32.18, I²: 0%). The authors did not find any significant association between COVID‐19 and hypertension, diabetes, cardiopathy, cancer, any cognitive problem, dementia, chronic obstructive pulmonary disease, renal or hepatic disease, smoking, and tremor.

Conclusions

Meta‐analyses were limited by the number of events and some methodological limitations. Despite this, the authors assessed the available evidence, and the results may be useful for future health policies.

Zebrafish as a Translational Model: An Experimental Alternative to Study the Mechanisms Involved in Anosmia and Possible Neurodegenerative Aspects of COVID-19?

The Coronavirus disease-2019 (COVID-19) presents a variability of clinical symptoms, ranging from asymptomatic to severe respiratory and systemic conditions. In a cohort of patients, the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2), beyond the classical respiratory manifestations, induces anosmia. Evidence has suggested SARS-CoV-2-induced anosmia can be the result of neurodegeneration of the olfactory pathway. Neurologic symptoms associated with COVID-19 have been reported; however, the precise mechanism and possible long-lasting effects remain poorly investigated. Preclinical models are valuable tools for describing and testing new possible treatments for neurologic disorders. In this way, the zebrafish (Danio rerio) organism model represents an attractive tool in the field of neuroscience, showing economic and logistic advantages besides genetic and physiologic similarities with mammalian, including the brain structure and functions. Besides, its external embryonic development, high availability of eggs, and fast development allows easy genetic manipulation and fast replications. In the present review, we suggest that the zebrafish model can be advantageous to investigate the neurologic features of COVID-19.

The neurological symptoms of COVID-19: a systematic overview of systematic reviews, comparison with other neurological conditions and implications for healthcare services

AIMS

In response to the rapid spread of COVID-19, this paper provides health professionals with better accessibility to available evidence, summarising findings from a systematic overview of systematic reviews of the neurological symptoms seen in patients with COVID-19. Implications of so-called 'Long Covid' on neurological services and primary care and similarities with other neurological disorders are discussed.

METHODS

Firstly, a systematic overview of current reviews of neurological symptoms of COVID-19 was conducted. Secondly, the implications of these findings are discussed in relation to the potential effect on neurological services and the similarities in the experience of patients with COVID-19 and those with other neurological disorders. A total of 45 systematic reviews were identified within seven databases, published between 11 April 2020 and 15 October 2020, following a search in June 2020, updated on 20 October 2020.

RESULTS

The results indicated that COVID-19 exhibits two types of neurological symptoms; life-threatening symptoms such as Guillain-Barre Syndrome (GBS) and encephalitis, and less devastating symptoms such as fatigue and myalgia. Many of these so-called lesser symptoms appear to be emerging as longer-term for some sufferers and have been recently labelled Long Covid. When compared, these less devastating symptoms are very similar to other neurological conditions such as chronic fatigue syndrome (CFS) and functional neurological disorder (FND).

CONCLUSION

Implications for neurological healthcare services in the United Kingdom (UK) may include longer waiting times and a need for more resources (including more qualified health professionals). There is also a possible change-effect on health professionals' perceptions of other neurological conditions such as CFS and FND. Future research is recommended to explore changes in health professionals' perceptions of neurological symptoms because of COVID-19.

Body Localization of ACE-2: On the Trail of the Keyhole of SARS-CoV-2

The explosion of the new coronavirus (SARS-CoV-2) pandemic has brought the role of the angiotensin converting enzyme 2 (ACE2) back into the scientific limelight. Since SARS-CoV-2 must bind the ACE2 for entering the host cells in humans, its expression and body localization are critical to track the potential target organ of this infection and to outline disease progression and clinical outcomes. Here, we mapped the physiological body distribution, expression, and activities of ACE2 and discussed its potential correlations and mutal interactions with the disparate symptoms present in SARS-CoV-2 patients at the level of different organs. We highlighted that despite during SARS-CoV-2 infection ACE2-expressing organs may become direct targets, leading to severe pathological manifestations, and subsequent multiple organ failures, the exact mechanism and the potential interactions through which ACE2 acts in these organs is still heavily debated. Further scientific efforts, also considering a personalized approach aimed to consider specific patient differences in the mutual interactions ACE2-SARS-CoV-2 and the long-term health effects associated with COVID-19 are currently mandatory.

Psychological Impact of Coronavirus Disease 2019 Among Italians During the First Week of Lockdown

Pandemics and government-mandated quarantining measures have a substantial impact on mental health. This study investigated the psychological impact of the coronavirus disease 2019 (COVID-19) crisis on Italian residents during the first week of government-imposed lockdown and the role of defense mechanisms as protective factors against distress. In this cross-sectional study, 5,683 Italians responded to an online survey assessing socio-demographics, overall psychological distress, post-traumatic symptoms, and defense mechanisms using validated measures as the Symptom Checklist-90 (SCL-90), the Impact of Event Scale-Revised (IES-R), and the Defense Mechanisms Rating Scale-Self-Report-30 (DMRS-SR-30). Data were collected from March 13 to March 18, within the first week of lockdown in Italy. Results showed that younger age and female gender were associated with increased psychological distress. Having positive cases nearby, more days on lockdown, and having to relocate were also associated with greater distress. Higher overall defensive functioning (ODF) was associated with lower levels of depression (r = -.44, 95% CI -0.48, -0.40), anxiety (r = -.38, 95% CI -0.42, -0.35), and post-traumatic stress symptoms (PTSS) (r = -.34, 95% CI -0.38, -0.30). Conversely, less adaptive defensive functioning was related to greater affective distress across all domains. Each increased unit of ODF decreased the chances of developing post-traumatic stress symptoms (PTSS) by 71% (odds ratio = 0.29, p < 0.001, 95% CI.026,.032). The psychological impact of COVID-19 among Italians during the early weeks of government lockdown has been significant. The pandemic continues to have extraordinary mental health impact as it moves across the globe. Given the salience of defensive functioning in psychological distress, consideration of interventions that foster the use of more adaptive defenses may be an important component of building resilience amidst a pandemic.