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Background SARS‐CoV‐2 causes neurological, psychiatric and neurocognitive deficits in a large proportion of patients via direct or indirect viral invasion, systemic or intracranial inflammation, micro‐ or macrovascular pathologies, and hypoxic or systemic metabolic complications. The insult to brain function during the acute phase of COVID‐19 may accelerate neurodegenerative process and potentially increase the risk of Alzheimer's Disease or Related Dementias. Ultrahigh Field (7T) MRI has an enhanced sensitivity and spatial resolution over and above clinical 3T MRI, allowing detection of small changes in brain sub‐structures and integrity. Methods The 7T COVID Consortium is an international collaboration across 5 sites which aims to study Ultrahigh Field neuroimaging correlates of clinical phenotypes, neuroimmunology, viral and host genetics, and neurodegenerative markers in a diverse, multi‐ethnic cohort of adults following SARS‐CoV2 infection. Multiple population cohorts include matched individuals following a clinically similar non‐COVID19 illness, and healthy controls including Framingham cohort and further comparative data from an independently‐funded genetically inherited Alzheimer's disease. Synergized imaging sequences across the sites with Ultrahigh Field (7T) facilities, standardized bio‐sampling protocols, and adaptation of centralised REDCAP with WHO protocols and other studies within the COVID consortia1permit harmonised data analyses. Results Pilot data from the UK site, in Nottingham, included individuals who presented with neurological disorders associated with SARS‐CoV2 Alpha variant of concern (B.1.1.7). Clinical phenotypes and biochemical measures of patients during the acute phase of COVID‐19 were documented2and a prospective follow up for neurocognitive assessments and 7T MRI were arranged. Compared with healthy controls, hospitalised patients showed neuroimaging features of cerebral white matter hyperintensities suggestive of neurovascular ischaemia or neuroinflammation. These radiological cerebral white matter hyperintensities could progress 7 months after the acute illness despite clinical silence. Long COVID appeared to have increased susceptibility, that is suggestive of iron accumulation or inflammation, within the basal ganglia structures. Conclusion Pilot data suggest persistent or emergent neuroimaging abnormalities within a year after SARS‐CoV2 infection. Serial follow up may clarify long‐term impact of COVID‐19. Funding: NIH/NIA, USA (R56AG074467), Nottingham Biomedical Research Centre (NIHR), Medical Research Council, UK (MR/T005580/1). References: 1.de Erausquin, et al. http://doi.org/10.1002/alz.12255 2.Dhillon, et al. https://doi.org/10.3389/fneur.2021.640017
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Background COVID‐19 has affected more than 380 million people. Infections may result in long term sequelae, including neuropsychiatric symptoms. In older adults COVID‐19 sequelae resemble early Alzheimer's disease, and may share risk factors and blood biomarkers with it. The Alzheimer's Association Consortium on Chronic Neuropsychiatric Sequelae of SARS‐CoV‐2 infection (CNS SC2) established harmonized definitions, ascertainment and assessment methodologies to evaluate and longitudinally follow up cohorts of older adults with exposure to COVID‐19. We present one year data in a prospective cohort from Argentina. Method Participants (n = 766) are older adults (≥60 years) recruited from the provincial health registry containing all SARS‐CoV‐2 testing data. We randomly invite older adults stratified by PCR COVID‐19 testing status regardless of symptom severity, between 3 and 6 months after recovery. Assessment includes interview with the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and Clinical Dementia Rating scale (CDR);neurocognitive assessment;emotional reactivity scale;and neurological assessment including semiquantitative olfactory function test, motor function, coordination and gait. Result We assessed 88.4% infected participants and 11.6 % controls. Education is 10.36 ± 5.6 years and age is 66.9 ± 6.14 years. Level of care during COVID‐19 is described in Figure 1. Normalized cognitive Z‐scores categorize the cohort in 3 groups with decreased performance compared to normal cognition: memory only impairment (Single‐domain,11.7%);impairment in attention+executive function without memory impairment (Two‐domain, 8.3%);and multiple domain impairment (Multiple domain,11.6%). Logistic regression showed that severity of anosmia, but not clinical status, significantly predicts cognitive impairment. No controls had olfactory dysfunction. Cognitive impairment is defined as Z‐scores below (‐ 2) (Table 1). Clinical assessment with SCAN revealed functional memory impairment in two thirds of infected patients (CDR ≥ 1), which was severe in half of them. Phone‐based follow up at 1 year revealed high adherence (4 participants declined). Five were deceased at follow up. Rates of re‐infection (between 10 and 23%) were not affected by the vaccination schedule (Table 2). Conclusion The longitudinal cohort had very high adherence. Persistent cognitive and functional impairment after SARS‐CoV‐2 infection is predicted by persistent anosmia but not by the severity of the initial COVID‐19 disease.
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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.
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Introduction: We report the COVID-19 pandemic's impact on health-care use disruption among people with mild cognitive impairment or Alzheimer's disease and related dementia (MCI/ADRD). Methods: We compared the pandemic-period health-care use between MCI/ADRD and matched non-MCI/ADRD patients. Using 4-year pre-pandemic data, we modeled three health-care use types (inpatient, outpatient, emergency encounters) to predict pandemic-period use, disaggregated for lockdown and post-lockdown periods. Observed health-care use was compared to the predicted. Proportional differences (confidence intervals) are reported. Results: Both MCI/ADRD and non-MCI/ADRD patients (n = 5479 each) experienced pandemic-related health-care use disruptions, which were significantly larger for the MCI/ADRD group for outpatient, -13.2% (-16.2%, -10.2%), and inpatient encounters, -12.8% (-18.4%, -7.3%). Large health-care disruptions during lockdown were similar for both groups. However, post-lockdown outpatient, -14.4% (-17.3%, -11.5%), and inpatient, -15.2% (-21.0%, -9.5%), disruptions were significantly greater for MCI/ADRD patients. Conclusion: MCI/ADRD patients experienced greater and sustained pandemic-related health-care use disruptions, highlighting the need for robust strategies to sustain their essential health care during pandemic-like catastrophes.
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Background COVID-19 has affected more than 150 million people. The causal coronavirus, SARS-CoV-2 has infected twice as many individuals who have remained asymptomatic. COVID-19 includes central nervous system (CNS) manifestations and may result in chronic neuropsychiatric sequelae. Risk factors for COVID-19 sequelae overlap with those for Alzheimer?s disease (AD), particularly older age and ApoE4 status. The Alzheimer?s Association Consortium on Chronic Neuropsychiatric Sequelae of SARS-CoV-2 infection (CNS SC2) established harmonized definitions, ascertainment and assessment methodologies to evaluate and longitudinally follow up cohorts of older adults with variable exposure to COVID-19. We present preliminary data from CNS SC2 in a prospective cohort of 234 older adult Amerindians from Argentina. Method Participants are ≥ 60 years recruited from the health registry of the Province of Jujuy containing all SARS-CoV-2 testing data (regardless of clinical status and of the result of the testing). We randomly invite older adults stratified by testing status regardless of symptom severity, a minimum of 3 months after clinical recovery (maximum 6 months);refusal to participate is <45%. Assessment includes interview with the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and Clinical Dementia Rating scale;neurocognitive assessment;emotional reactivity scale;and neurological assessment including semiquantitative olfactory function test, motor function, coordination and gait. We present here the results of olfactory testing and cognitive assessments. Result We assessed 233 infected participants and 64 controls. Average duration of formal learning is 9.35 ± 2.6 years and mean age is 66.7 ± 5.13 years. Normative data for the local population were available for Word list, Corsi Blocks, Oral Trails and Five Digit Tests and were used to normalize Z-scores and categorize the sample in 3 groups: normal cognition (NC,44.6%);memory only impairment (MOI,21%);and multiple domain impairment (MDI,34.4%). Individuals with MDI presented severe alterations in short-term memory;semantic memory;naming;executive function and attention compared to NC or MO groups (Table 1). Severity of cognitive impairment was significantly correlated with severity of olfactory dysfunction (?2 = 13.82;p= 0.003) but not severity of acute COVID-19. Conclusion Older adults frequently suffer persistent cognitive impairment after recovery from SARS-CoV-2 infection;cognitive impairment is correlated with persistent anosmia.
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Introduction: Persistent knowledge gaps exist as to the extent that preexisting cognitive impairment is a risk factor for susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mortality from the coronavirus disease 2019 (COVID-19). Methods: We conducted a cross-sectional analysis of adults tested for SARS-CoV-2 at a tertiary healthcare system. Cognitive impairment was identified utilizing diagnosis codes (mild cognitive impairment, Alzheimer's disease, vascular, and other dementias) or cognitive impairment-specific medication use. Propensity score (PS) matched analyses were utilized to report odds ratios (OR) and 95% confidence intervals (CI) for association of cognitive impairment with SARS-CoV-2 susceptibility and COVID-19 mortality. Results: Between March-3rd and December-11th, 2020, 179,979 adults were tested, of whom 21,607 (12.0%) tested positive. We identified 6,364 individuals with preexisting cognitive impairment (mean age: 78.5 years, 56.8% females), among whom 843 (13.2%) tested positive and 139 (19.5%) of those hospitalized died. In the pre-PS matched cohort, cognitive impairment was significantly associated with increased SARS-CoV-2 susceptibility (OR, CI: 1.12, 1.04-1.21) and COVID-19 mortality (OR, CI: 2.54, 2.07-3.12). One-to-one matches were identified for 6,192 of 6,364 (97.3%) individuals with prior cognitive impairment and 687 of 712 (96.5%) hospitalized patients with prior cognitive impairment. In the fully balanced post-matched cohort, preexisting cognitive impairment was significantly associated with higher likelihood of SARS-CoV-2 infection (OR, CI: 1.51, 1.35-1.70); however, cognitive impairment did not confer higher risk of COVID-19 mortality (OR, CI: 0.96, 0.73-1.25). Discussion: To mitigate the effects of healthcare catastrophes such as the COVID-19 pandemic, strategies for targeted prevention and risk-stratified comorbidity management are warranted among the vulnerable sub-population living with cognitive impairment.
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INTRODUCTION: The increasing evidence of SARS-CoV-2 impact on the central nervous system (CNS) raises key questions on its impact for risk of later life cognitive decline, Alzheimer's disease (AD), and other dementia. METHODS: The Alzheimer's Association and representatives from more than 30 countries-with technical guidance from the World Health Organization-have formed an international consortium to study the short-and long-term consequences of SARS-CoV-2 on the CNS-including the underlying biology that may contribute to AD and other dementias. This consortium will link teams from around the world covering more than 22 million COVID-19 cases to enroll two groups of individuals including people with disease, to be evaluated for follow-up evaluations at 6, 9, and 18 months, and people who are already enrolled in existing international research studies to add additional measures and markers of their underlying biology. CONCLUSIONS: The increasing evidence and understanding of SARS-CoV-2's impact on the CNS raises key questions on the impact for risk of later life cognitive decline, AD, and other dementia. This program of studies aims to better understand the long-term consequences that may impact the brain, cognition, and functioning-including the underlying biology that may contribute to AD and other dementias.
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Brain/virology , COVID-19/complications , Alzheimer Disease/virology , Cognitive Dysfunction/virology , Dementia/virology , Humans , SARS-CoV-2ABSTRACT
Abstract Background The pandemic of SARS-CoV-2 is focusing all energies on the impact on survival of affected individuals, treatment and prevention, but increasingly attention is focusing on its enduring consequences. We established a global consortium to study a longitudinal representative cohort of individuals, to characterize neurological and neuropsychiatric sequalae from direct viral, immune-, vascular- or accelerated neurodegenerative injury to the central nervous system (CNS). Method We propose to characterize the neurobehavioral phenomenology associated with SARS-CoV-2 in a large, multinational, longitudinal cohort of post COVID-19 infection patients following three sampling strategies: 1) Opportunity sample of patients discharged after hospital admission for COVID-19 related symptoms. 2) A stratified random sample from COVID-19 testing registries (including asymptomatic and negative participants). 3) Ascertaining COVID-19 exposure (antibody) status in ongoing longitudinal, community-based cohort studies that are already collecting biosamples, cognitive, behavioral and neuroimaging data. We will obtain core data within 6 months of discharge or testing. Core characterization will include interviews with the Schedules of Clinical Assessment in Neuropsychiatry (SCAN), neurological exams, emotional reactivity scales and a neurocognitive assessment. Wherever feasible, we will also collect neuroimaging, biosamples and genetic data. Longitudinal follow up will be conducted at 9 and 18 months of the initial evaluation. An mHealth keeping-in-touch process will be set up to minimize attrition rates. The population cohorts provide a large, unbiased, normative and validation sample, albeit with more heterogenous outcome ascertainment. They also permit examination of pre- and post-COVID trends in symptoms and biomarkers. Since some ethnic groups, as well as in individuals with blood type A, are at higher risk of COVID-19 infection and death, a role of genetics in determining susceptibility to infection and poor outcomes seems well supported. We will collect genome-wide genotypes from our cohort individuals to address the role of ancestry and genetic variation on susceptibility to neuropsychiatric sequelae. High rates of mutation in COVID-19 strongly suggest that viral infectivity, including neurotropism, may not be uniform across countries affected by the pandemic. Results Pending. Conclusion Our consortium is in a unique position to address the interaction between genetics (including ancestral DNA), and viral strain variation on CNS sequelae of SARS-CoV-2.