Neurologic and Neuroscientific Evidence in Aged COVID-19 Patients

Multiple Sclerosis and COVID-19: An Overview on Risk, Severity, and Association With Disease Modifying Therapies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus, emerged in December 2019, sparking a global health crisis. While initially recognized as a respiratory illness, it has become evident that Coronavirus disease 2019 (COVID-19) also affects the central nervous system. This comprehensive review focuses on the neurological manifestations of COVID-19 and its impact on patients with preexisting neurological disorders, particularly those with multiple sclerosis (MS) receiving disease-modifying therapies. Advancements in management, including vaccinations, antiviral therapy, and targeted prophylaxis, have led to a decline in the incidence and severity of COVID-19. Nevertheless, significant complications persist, particularly in patients with advanced MS, who are highly vulnerable to infectious agents like SARS-CoV-2. This review explores the evolving understanding of MS and its association with SARS-CoV-2, encompassing neuroinvasiveness, pathogenesis, disease severity, and outcomes. Research findings reveal substantial neurological implications for some MS patients with COVID-19, with a potential risk of disease relapse and severity. A notable proportion of MS patients experiencing COVID-19 may manifest new symptoms, experience exacerbation of existing symptoms, or encounter both simultaneously, underscoring the diverse neurological effects of the virus. While vaccination and therapeutics have mitigated the overall impact, specific subgroups, especially those on anti-CD20 therapy and with existing disability, remain at higher risk, necessitating ongoing vigilance and tailored care.

Delirium in the Era of COVID-19

BACKGROUND

Delirium has been associated with poor outcomes in hospitalized older adults. Rates of delirium have increased in the context of coronavirus disease 2019 (COVID-19).

PURPOSE

To explore the prevalence of delirium in older adult patients hospitalized with COVID-19 as well as correlations with age, gender, length of stay (LOS), occurrence of an intensive care unit admission or transfer, and in-hospital mortality in 2 hospitals in the southeast United States.

METHODS

A retrospective study of 1502 patients admitted between 2020 and 2021 was completed.

RESULTS

Older adult patients hospitalized with delirium and COVID-19 demonstrated significantly prolonged LOS (14.1 days vs 7.1 days, P < .0001) and higher rates of in-hospital mortality (33.5% vs 12.8%, P < .0001).

CONCLUSIONS

Findings of this study add to the growing literature on delirium in hospitalized patients and support the need for future initiatives to create protocols for monitoring and nursing care management of delirium to improve care delivery.

Neurologic Complications of Cardiac and Pulmonary Disease

OBJECTIVE

The heart and lungs work as a functional unit through a complex interplay. The cardiorespiratory system is responsible for the delivery of oxygen and energy substrates to the brain. Therefore, diseases of the heart and lungs can lead to various neurologic illnesses. This article reviews various cardiac and pulmonary pathologies that can lead to neurologic injury and discusses the relevant pathophysiologic mechanisms.

LATEST DEVELOPMENTS

We have lived through unprecedented times over the past 3 years with the emergence and rapid spread of the COVID-19 pandemic. Given the effects of COVID-19 on the lungs and heart, an increased incidence of hypoxic-ischemic brain injury and stroke associated with cardiorespiratory pathologies has been observed. Newer evidence has questioned the benefit of induced hypothermia in patients with out-of-hospital cardiac arrest. Further, global collaborative initiatives such as the Curing Coma Campaign are underway with the goal of improving the care of patients with coma and disorders of consciousness, including those resulting from cardiac and pulmonary pathologies.

ESSENTIAL POINTS

The neurologic complications of cardiorespiratory disorders are common and present in various forms such as stroke or hypoxic and anoxic injury related to cardiac or respiratory failure. With the emergence of the COVID-19 pandemic, neurologic complications have increased in recent years. Given the intimate and interdependent dynamics of the heart, lungs, and brain, it is crucial for neurologists to be aware of the interplay between these organs.

European Working Group on SARS-CoV-2: Current Understanding, Unknowns, and Recommendations on the Neurological Complications of COVID-19

The emergence of COVID-19 was rapidly followed by infection and the deaths of millions of people across the globe. With much of the research and scientific advancement rightly focused on reducing the burden of severe and critical acute COVID-19 infection, the long-term effects endured by those who survived the acute infection has been previously overlooked. Now, an appreciation for the post-COVID-19 condition, including its neurological manifestations, is growing, although there remain many unknowns regarding the aetiology and risk factors of the condition, as well as how to effectively diagnose and treat it. Here, drawing upon the experiences and expertise of the clinicians and academics of the European working group on COVID-19, we have reviewed the current literature to provide a comprehensive overview of the neurological sequalae of the post-COVID-19 condition. In this review, we provide a summary of the neurological symptoms associated with the post-COVID-19 condition, before discussing the possible mechanisms which may underly and manifest these symptoms. Following this, we explore the risk factors for developing neurological symptoms as a result of COVID-19 and the post-COVID-19 condition, as well as how COVID-19 infection may itself be a risk factor for the development of neurological disease in the future. Lastly, we evaluate how the post-COVID condition could be accurately diagnosed and effectively treated, including examples of the current guidelines, clinical outcomes and tools that have been developed to aid in this process, as well as addressing the protection provided by COVID-19 vaccines against post-COVID-19 condition. Overall, this review provides a comprehensive overview of the neurological sequalae of the post-COVID-19 condition.

COVID-19: Brain Effects

Severe acute respiratory syndrome coronavirus 2, the novel coronavirus responsible for the coronavirus disease (COVID-19), affects the brain. Neurologic and neuropsychiatric symptoms may manifest in the acute and post-acute phases of illness. The vulnerability of the brain with aging further increases the burden of disease in the elderly, who are at the highest risk of complications and death from COVID-19. The mechanisms underlying the effects of COVID-19 on the brain are not fully known. Emerging evidence vis-à-vis pathogenesis and etiologies of COVID-19 brain effects is promising and may pave the way for future research and development of interventions.

SARS-CoV-2 infects neurons and induces neuroinflammation in a non-human primate model of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), can induce a plethora of neurological complications in some patients. However, it is still under debate if SARS-CoV-2 directly infects the brain or if CNS sequelae result from systemic inflammatory responses triggered in the periphery. Using high-resolution microscopy, we investigated whether SARS-CoV-2 reaches the brain and how viral neurotropism can be modulated by aging in a non-human primate model of COVID-19. Seven days after infection, SARS-CoV-2 was detected in the olfactory cortex and interconnected regions, accompanied by robust neuroinflammation and neuronal damage exacerbated in aged diabetic animals. Our study provides an initial framework for identifying the molecular and cellular mechanisms underlying SARS-CoV-2 neurological complications, which will be essential to reducing both the short- and long-term burden of COVID-19.

Chronic neuropsychiatric sequelae of SARS-CoV-2: Protocol and methods from the Alzheimer's Association Global Consortium

Introduction

Coronavirus disease 2019 (COVID-19) has caused >3.5 million deaths worldwide and affected >160 million people. At least twice as many have been infected but remained asymptomatic or minimally symptomatic. COVID-19 includes central nervous system manifestations mediated by inflammation and cerebrovascular, anoxic, and/or viral neurotoxicity mechanisms. More than one third of patients with COVID-19 develop neurologic problems during the acute phase of the illness, including loss of sense of smell or taste, seizures, and stroke. Damage or functional changes to the brain may result in chronic sequelae. The risk of incident cognitive and neuropsychiatric complications appears independent from the severity of the original pulmonary illness. It behooves the scientific and medical community to attempt to understand the molecular and/or systemic factors linking COVID-19 to neurologic illness, both short and long term.

Methods

This article describes what is known so far in terms of links among COVID-19, the brain, neurological symptoms, and Alzheimer's disease (AD) and related dementias. We focus on risk factors and possible molecular, inflammatory, and viral mechanisms underlying neurological injury. We also provide a comprehensive description of the Alzheimer's Association Consortium on Chronic Neuropsychiatric Sequelae of SARS-CoV-2 infection (CNS SC2) harmonized methodology to address these questions using a worldwide network of researchers and institutions.

Results

Successful harmonization of designs and methods was achieved through a consensus process initially fragmented by specific interest groups (epidemiology, clinical assessments, cognitive evaluation, biomarkers, and neuroimaging). Conclusions from subcommittees were presented to the whole group and discussed extensively. Presently data collection is ongoing at 19 sites in 12 countries representing Asia, Africa, the Americas, and Europe.

Discussion

The Alzheimer's Association Global Consortium harmonized methodology is proposed as a model to study long-term neurocognitive sequelae of SARS-CoV-2 infection.

Key Points

The following review describes what is known so far in terms of molecular and epidemiological links among COVID-19, the brain, neurological symptoms, and AD and related dementias (ADRD)The primary objective of this large-scale collaboration is to clarify the pathogenesis of ADRD and to advance our understanding of the impact of a neurotropic virus on the long-term risk of cognitive decline and other CNS sequelae. No available evidence supports the notion that cognitive impairment after SARS-CoV-2 infection is a form of dementia (ADRD or otherwise). The longitudinal methodologies espoused by the consortium are intended to provide data to answer this question as clearly as possible controlling for possible confounders. Our specific hypothesis is that SARS-CoV-2 triggers ADRD-like pathology following the extended olfactory cortical network (EOCN) in older individuals with specific genetic susceptibility.The proposed harmonization strategies and flexible study designs offer the possibility to include large samples of under-represented racial and ethnic groups, creating a rich set of harmonized cohorts for future studies of the pathophysiology, determinants, long-term consequences, and trends in cognitive aging, ADRD, and vascular disease.We provide a framework for current and future studies to be carried out within the Consortium. and offers a "green paper" to the research community with a very broad, global base of support, on tools suitable for low- and middle-income countries aimed to compare and combine future longitudinal data on the topic.The Consortium proposes a combination of design and statistical methods as a means of approaching causal inference of the COVID-19 neuropsychiatric sequelae. We expect that deep phenotyping of neuropsychiatric sequelae may provide a series of candidate syndromes with phenomenological and biological characterization that can be further explored. By generating high-quality harmonized data across sites we aim to capture both descriptive and, where possible, causal associations.

COVID-19 and its genomic variants: Molecular pathogenesis and therapeutic interventions

Coronavirus disease-19 (COVID-19), caused by a β-coronavirus and its genomic variants, is associated with substantial morbidities and mortalities globally. The COVID-19 virus and its genomic variants enter host cells upon binding to the angiotensin converting enzyme 2 receptors that are expressed in a variety of tissues, but predominantly in the lungs, heart, and blood vessels. Patients afflicted with COVID-19 may be asymptomatic or present with critical symptoms possibly due to diverse lifestyles, immune responses, aging, and underlying medical conditions. Geriatric populations, especially men in comparison to women, with immunocompromised conditions, are most vulnerable to severe COVID-19 associated infections, complications, and mortalities. Notably, whereas immunomodulation, involving nutritional consumption, is essential to protecting an individual from COVID-19, immunosuppression is detrimental to a person with this aggressive disease. As such, immune health is inversely correlated to COVID-19 severity and resulting consequences. Advances in genomic and proteomic technologies have helped us to understand the molecular events underlying symptomatology, transmission and, pathogenesis of COVID-19 and its genomic variants. Accordingly, there has been development of a variety of therapeutic interventions, ranging from mask wearing to vaccination to medication. This review summarizes the current understanding of molecular pathogenesis of COVID-19, effects of comorbidities on COVID-19, and prospective therapeutic strategies for the prevention and treatment of this contagious disease.

Healthy Immunity on Preventive Medicine for Combating COVID-19

Immunomodulation is influenced by the consumption of nutrients, and healthy immunity is pivotal to defending an individual from a variety of pathogens. The immune system is a network of intricately regulated biological processes that is comprised of many organs, cellular structures, and signaling molecules. A balanced diet, rich in vitamins, minerals, and antioxidants, is key to a strengthened immune system and, thus, crucial to proper functioning of various physiological activities. Conversely, deficiencies of these micronutrients, involving impaired immunity, are linked to numerous health complications, along with a host of pathologies. Coronavirus disease 2019 (COVID-19) is a dangerous infectious disease caused by a β-form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its genomic variants, which enter host cells upon binding to the angiotensin converting enzyme 2 receptors, and is associated with substantial morbidities and mortalities globally. Patients afflicted with COVID-19 display asymptomatic to severe symptoms, occurrences of which are multifactorial and include diverse immune responses, sex and gender differences, aging, and underlying medical conditions. Geriatric populations, especially men in comparison to women, regardless of their states, are most vulnerable to severe COVID-19-associated infections and complications, with fatal outcomes. Advances in genomic and proteomic technologies help one understand molecular events, including host–pathogen interactions and pathogenesis of COVID-19 and, subsequently, have developed a variety of preventive measures urgently, ranging from mask wearing to vaccination to medication. Despite these approaches, no unique strategy is available today that can effectively prevent and/or treat this hostile disease. As a consequence, the maintenance of a boosted immune system could be considered a high priority of preventive medicine for combating COVID-19. Herein, we discuss the current level of understanding underlining the contribution of healthy immunity and its relevance to COVID-19 molecular pathogenesis, and potential therapeutic strategies, in the management of this devastating disease.

Clinical Outcomes of Older Persons and Persons with Dementia Admitted for Coronavirus Disease 2019: Findings from the Philippine CORONA Study

INTRODUCTION

The Philippine CORONA Study was a multicenter, retrospective, cohort study of 10,881 coronavirus disease 2019 (COVID-19) admissions between February and December 2020.

METHODS

Subgroup analysis was done on clinical outcomes of mortality, respiratory failure, duration of ventilator dependence, intensive care unit (ICU) admission, length of ICU stay, and length of hospital stay among older persons and persons with dementia.

RESULTS

The adjusted hazard ratios for mortality among the mild and severe cases were significantly higher by 3.93, 95% CI [2.81, 5.50] and by 1.81, 95% CI [1.43, 2.93], respectively, in older persons compared to younger adults. The adjusted hazard ratios for respiratory failure in older persons were increased by 2.65, 95% CI [1.92, 3.68] and by 1.27, 95% CI [1.01, 1.59] among the mild and severe cases, respectively. The adjusted hazard ratio for ICU admission in older persons was higher by 1.95, 95% CI [1.47, 2.59] among the mild cases. The adjusted hazard ratios for mortality and ICU admission in persons with dementia were higher by 7.25, 95% CI [2.67, 19.68] and by 4.37, 95% CI [1.08, 17.63], respectively, compared to those without dementia.

CONCLUSION

Older age and dementia significantly increased the risk of mortality, respiratory failure, and ICU admission among COVID-19 patients.