COVCOG 2: Cognitive and Memory Deficits in Long COVID: A Second Publication From the COVID and Cognition Study

Acute serum protein biomarker profile and prevalence of persistent (>6 months) neuropsychiatric symptoms in a cohort of SARS-CoV-2 PCR positive patients in Cape Town, South Africa

Background

SARS-CoV-2 is a neurotrophic and pro-inflammatory virus, with several acute and more persistent neuropsychiatric sequelae reported. There are limited data from African cohorts and few acute illness biomarkers of persistent neuropsychiatric symptoms.

Objectives

To examine the association of neuropsychiatric outcomes with clinical illness severity, systemic inflammation, cardiovascular and renin-angiotensin-system (RAS) biomarkers. Second, to determine the prevalence of neuropsychiatric symptoms in a cohort of South African SARS-CoV-2 PCR positive patients at least six months following infection/hospitalization.

Methodology

SARS-CoV-2 PCR positive patients were recruited prospectively from Cape Town, South Africa, including hospitalized patients from ancestral, beta and delta-dominant COVID-19 waves (pre-vaccine rollout); and asymptomatic/mild SARS-CoV-2 positive patients. The 96-protein O-link inflammation and cardiovascular panels, RAS fingerprinting, and antibody responses were measured in serum samples collected at peak severity and recovery (>3 months post-infection). Telephonic interviews were conducted at least six months post infection/hospitalization. Validated measures employed were: WHO Self-Report Questionnaire (SRQ-20), Generalized Anxiety Disorder Scale (GAD-7), Chalder Fatigue Scale (CFS-11) and Telephonic Montreal Cognitive Assessment (T-MoCA).

Results

Ninety-seven participants completed telephonic interviews. The median (IQR) age was 48 (37-59) years, and 54 % were female. There were no significant associations between neuropsychiatric outcomes and illness severity, systemic inflammation, cardiovascular and/or renin-angiotensin-system (RAS) biomarkers from either peak illness or recovery samples. More than half of this SA COVID-19 cohort had one or more persistent neuropsychiatric symptoms >6 months post vaccine-naïve infection. On the T-MoCA, 44 % of participants showed evidence of cognitive and/or memory impairments.

Conclusion

The high prevalence of persistent neuropsychiatric symptoms in this African cohort supports ongoing attention to long COVID. Acute and early serum protein biomarkers were not associated with persistent neuropsychiatric outcomes post-COVD-19.

Cognitive Slowing, Dysfunction in Verbal Working Memory, Divided Attention and Response Inhibition in Post COVID-19 Condition in Young Adults

After COVID-19 infection, about 30% of people have clinically persisting symptoms, characterized as Post COVID-19 Condition (PCC). One of the most reported symptoms in PCC is cognitive dysfunction, yet there are only a few studies investigating long-term effects on different domains of cognitive function. A total of 107 young adults, university students aged 18-34 years, participated. In total, 68.2% had contracted SARS-CoV-2; 21.9% showed PCC. Three groups were compared: no-C19 (COVID-19-negative controls), C19 (COVID-19-recovered without PCC) and PCC. Attention and executive function were measured with the Vienna Test System (Schuhfried®, Mödling, Austria). In verbal working memory, the PCC group had a significantly lower performance with a moderate effect. The rate of below-average performance was higher in PCC (56.2%) compared to no-C19 (20.6%) and C19 (15.8%). In divided attention and response inhibition, PCC also showed lower performance, 62.5% and 37.5%, respectively, than no-C19 and C19. The co-occurrence of decreased cognitive functions was pronounced in PCC. The present study revealed significant long-lasting cognitive dysfunction in PCC in young adults, two years after COVID-19 infection. Verbal working memory was significantly impaired, and a lower performance was found in divided attention and response inhibition. In addition, there was an increased reaction time in most cognitive tasks, demonstrating cognitive slowing in young people with PCC.

Long-term consequences of COVID-19 on sleep, mental health, fatigue, and cognition: a preliminary study

INTRODUCTION

Post-COVID-19 Syndrome (PCS) is defined as symptoms persisting beyond 12 weeks from the onset of symptoms. Notably, COVID-19 has been associated with long-term effects on the brain and mental health. This cross-sectional study aims to investigate depression, fatigue, sleep quality, and cognitive dysfunction, particularly working memory, in individuals with PCS compared to a healthy control group.

MATERIAL AND METHODS

Between April and December 2021, 45 COVID-19 individuals and 60 healthy individuals met the eligibility criteria. Demographic information and the Montreal Cognitive Assessment were collected. Two visual working memory tasks, Delayed Match-to-Sample (DMS) and n-back, were performed, along with self-report questionnaires: Beck Depression Inventory, Modified Fatigue Impact Scale, and Pittsburgh Sleep Quality Index.

RESULTS

A total of 105 participants were enrolled. Findings reveal that the PCS group exhibited notably higher levels of cognitive impairment (13.3% vs. 1.6%, p = 0.04), depression (53.9% vs. 25.9%, p = 0.03), and sleep disturbances (53.9% vs. 18.6%, p = 0.01) compared to the healthy control group. Sleep latency and sleep duration were particularly affected. No significant differences in working memory function were observed between the two groups (p = 0.90 for DMS and p = 0.98 for n-back).

CONCLUSION

The study highlights the higher prevalence of sleep disturbance, depression, and cognitive impairment in the PCS phase, with inflammation likely playing a significant role. Moreover, the study suggests that untreated depression and sleep disturbances may pose long-term risks for dementia. Understanding the underlying mechanisms is crucial for developing effective interventions and support for individuals recovering from the infection. Prospective longitudinal studies with larger and more diverse samples are warranted to confirm and expand upon these findings.

Changes in cerebrovascular reactivity within functional networks in older adults with long-COVID

Introduction

Cognitive symptoms are reported in the vast majority of individuals with long-COVID and there is growing support to suggest neurovascular mechanisms may play a role. Older adults are at increased risk for developing complications associated with COVID-19, including heightened risk for cognitive decline. Cerebrovascular Reactivity (CVR), a marker of neurovascular health, has been linked to age related cognitive decline and may play a role in long-COVID, however, this has not yet been explored.

Methods

The present study examined group differences in CVR in 31 older adults with long-COVID compared to 31 cognitively unimpaired older adults without long-COVID symptoms. Follow up analyses were conducted to examine how CVR was associated with both subjective cognitive symptoms and neuropsychological (NP) test performance. A subject-specific approach, Distribution-Corrected Z-scores (DisCo-Z), was used.

Results

Analyses revealed the long-COVID group demonstrated significantly greater incidence of extreme CVR clusters within the brain (>100 voxels) and within functional networks thought to drive attention and executive function. Extreme positive CVR clusters were positively associated with greater number of subjective cognitive symptoms and negatively correlated with NP performance.

Discussion

These findings are among the first to provide a link between cognitive functioning in long-COVID and neurovascular changes relevant for aging and mechanistic studies of long-COVID.

Increased galanin-galanin receptor 1 signaling, inflammation, and insulin resistance are associated with affective symptoms and chronic fatigue syndrome due to long COVID

BACKGROUND

Patients with Long COVID (LC) often experience neuropsychiatric symptoms such as depression, anxiety, and chronic fatigue syndrome (CFS), collectively referred to as the physio-affective phenome of LC. Activated immune-inflammatory pathways and insulin resistance significantly contribute to the physio-affective phenome associated with LC.

METHODS

In a cohort of 90 individuals, categorized into those with and without LC, we evaluated, 3-6 months following acute SARS-CoV-2 infection, the correlations between the Hamilton Depression (HAMD), Hamilton Anxiety (HAMA), and Fibro-Fatigue (FF) Rating Scale scores, and serum C-reactive protein (CRP), prostaglandin E2 (PGE2), galanin-galanin receptor 1 (GAL-GALR1) signaling, insulin resistance, insulin-like growth factor (IGF-1), plasminogen activator inhibitor-1 (PAI1), S100B and neuron-specific enolase (NSE).

RESULTS

HAMD, HAMA, FF scores, CRP, PGE2, GAL-GALR1 signaling, insulin resistance, PAI1, NSE, and S100B are all higher in people with LC compared to those without LC. The HAMD/HAMA/FF scores were significantly correlated with PGE, CRP, GAL, GALR1, insulin resistance, and PAI1 levels, and a composite score based on peak body temperature (PBT) - oxygen saturation (SpO2) (PBT/SpO2 index) during the acute infectious phase. A combination of biomarkers explained a large part of the variance in CFS and affective scores (33.6%-42.0%), with GAL-GALR1 signaling, PGE2, and CRP being the top 3 most important biomarkers. The inclusion of the PBT/SpO2 index increased the prediction (55.3%-67.1%). The PBT/SpO2 index predicted the increases in GAL-GALR1 signaling.

CONCLUSION

These results indicate that the CFS and affective symptoms that are linked to LC are the consequence of metabolic aberrations, activated immune-inflammatory pathways, and the severity of inflammation during the acute phase of SARS-CoV-2 infection.

Clinic evaluation of cognitive impairment in post-COVID syndrome: Performance on legacy pen-and-paper and new digital cognitive tests

Background

Cognitive impairment, colloquially termed "brain fog", is one of the most prevalent manifestations of post-Covid syndrome and a major contributor to impaired daily function and reduced quality of life. However, despite the high numbers of affected individuals presenting to clinical services with cognitive impairment, little work has been undertaken to date on the suitability of current memory clinic tests for identifying the cognitive deficits in this new acquired cognitive disorder.The aim of this study was therefore to determine the performance of people with post-Covid syndrome presenting with cognitive impairment on the Addenbrooke's Cognitive Examination-III (ACE-III), a cognitive test used widely in memory clinics. A subset of individuals also underwent testing on a novel battery of short digital tests assessing attention, speed of information processing and executive function, representing the domains primarily implicated in post-Covid cognitive dysfunction.

Methods

102 individuals with post-Covid syndrome presenting with subjective cognitive complaints were recruited from a specialist cognitive long Covid clinic at University Hospitals Sussex NHS Trust. All participants completed self-report questionnaires on depression, anxiety, sleep and fatigue. Cognitive performance was assessed using the ACE-III, with 20 participants also being tested on the digital Long COVID Assessment Battery (LCCAB) (N = 20).

Results

The overall sample had a mean ACE-III score of 91/100 (SD 6) with 15.7% (16/102) scoring at or below the cut-off score considered to represent objective cognitive impairment. Of the 20 individuals who also completed the LCCAB, 89.47% were impaired on at least one task, primarily in the domains of attention, executive function and processing speed. Cognitive performance was not associated with depression, anxiety, sleep quality or fatigue.

Conclusion

The vast majority of individuals with post-Covid syndrome presenting with subjective cognitive complaints do not exhibit impaired performance on the ACE-III. This likely reflects the historical use of ACE-III and other pen and paper cognitive tests to detect cognitive impairment in diseases causing dementia, but they are ill-equipped to identify impairment in those cognitive domains affected in post-Covid syndrome. The LCCAB detected cognitive impairments in nearly 90% of participants, primarily affecting attention, executive function, and processing speed. These observations highlight the need for alternative cognitive tests for use in routine clinical practice to detect the impairments in new acquired cognitive disorders that are not adequately captured by legacy tests.

Cerebromicrovascular mechanisms contributing to long COVID: implications for neurocognitive health

Long COVID (also known as post-acute sequelae of SARS-CoV-2 infection [PASC] or post-COVID syndrome) is characterized by persistent symptoms that extend beyond the acute phase of SARS-CoV-2 infection, affecting approximately 10% to over 30% of those infected. It presents a significant clinical challenge, notably due to pronounced neurocognitive symptoms such as brain fog. The mechanisms underlying these effects are multifactorial, with mounting evidence pointing to a central role of cerebromicrovascular dysfunction. This review investigates key pathophysiological mechanisms contributing to cerebrovascular dysfunction in long COVID and their impacts on brain health. We discuss how endothelial tropism of SARS-CoV-2 and direct vascular infection trigger endothelial dysfunction, impaired neurovascular coupling, and blood-brain barrier disruption, resulting in compromised cerebral perfusion. Furthermore, the infection appears to induce mitochondrial dysfunction, enhancing oxidative stress and inflammation within cerebral endothelial cells. Autoantibody formation following infection also potentially exacerbates neurovascular injury, contributing to chronic vascular inflammation and ongoing blood-brain barrier compromise. These factors collectively contribute to the emergence of white matter hyperintensities, promote amyloid pathology, and may accelerate neurodegenerative processes, including Alzheimer's disease. This review also emphasizes the critical role of advanced imaging techniques in assessing cerebromicrovascular health and the need for targeted interventions to address these cerebrovascular complications. A deeper understanding of the cerebrovascular mechanisms of long COVID is essential to advance targeted treatments and mitigate its long-term neurocognitive consequences.

Cognitive functions in COVID-19 survivors, approaches strategies, and impact on health systems: a qualitative systematic review

Post-COVID syndrome has been defined as signs and symptoms that develop after an infection consistent with COVID-19 and continue for more than 12 weeks, including neurocognitive signs and symptoms that have an impact on the functioning and quality of life of middle-aged adult and older survivors. This systematic review describes the current knowledge of long-term cognitive impairments in COVID-19 survivors, approaches strategies, and their impact on public and private health services worldwide. The systematic review was conducted under the criteria and flowchart established in the PRISMA statement, considering studies from the PubMed, Scopus, and Web of Science databases between 2020 and 2023. The included studies considered participants over 40 years of age, COVID-19 survivors. A total of 68 articles were included, most of which had high to excellent quality. The analysis showed the presence of heterogeneous cognitive symptoms in COVID survivors, persistent for at least 12 weeks from the onset of infection, mostly unsystematized and nonspecific approaches strategies, and a lack of methods for monitoring their effectiveness, with a significant economic and logistical impact on health systems. Specific protocols are required for the rehabilitation of persistent cognitive dysfunction in COVID-19 survivors, as well as longitudinal studies to evaluate the effectiveness of these interventions.

Review of organ damage from COVID and Long COVID: a disease with a spectrum of pathology

Long COVID, as currently defined by the World Health Organization (WHO) and other authorities, is a symptomatic condition that has been shown to affect an estimated 10 %-30 % of non-hospitalized patients after one infection. However, COVID-19 can also cause organ damage in individuals without symptoms, who would not fall under the current definition of Long COVID. This organ damage, whether symptomatic or not, can lead to various health impacts such as heart attacks and strokes. Given these observations, it is necessary to either expand the definition of Long COVID to include organ damage or recognize COVID-19-induced organ damage as a distinct condition affecting many symptomatic and asymptomatic individuals after COVID-19 infections. It is important to consider that many known adverse health outcomes, including heart conditions and cancers, can be asymptomatic until harm thresholds are reached. Many more medical conditions can be identified by testing than those that are recognized through reported symptoms. It is therefore important to similarly recognize that while Long COVID symptoms are associated with organ damage, there are many individuals that have organ damage without displaying recognized symptoms and to include this harm in the characterization of COVID-19 and in the monitoring of individuals after COVID-19 infections.

Executive functioning in subjects post COVID-19 infection in Mexico

Over the past three years, conflicting evidence has emerged regarding the impact of COVID-19 on executive functions and the frontal lobe. In this study, we evaluated executive functions in individuals from the state of Jalisco who had contracted COVID-19. Sixty individuals with a history of mild COVID-19 were included and compared to historical controls from the Mexican population, who had been assessed prior to the pandemic during the validation of the Trail Making Test Form B, the Stroop Color and Word Test, and the Modified Wisconsin Card Sorting Test (M-WCST). The post-infection group exhibited lower scores only on the M-WCST. Therefore, we concluded that individuals who have recovered from mild COVID-19 do not display widespread impairments in executive functions, with the exception of deficits observed on the M-WCST. This suggests possible neurophysiological alterations in the prefrontal cortex during SARS-CoV-2 infection, given that cognitive flexibility is primarily mediated in this region. These findings contribute to the growing body of evidence indicating that even non-hospitalized COVID-19 patients can experience executive function deficits, providing a foundation for further neurophysiological research into the mechanisms underlying this phenomenon.

Exploring the experiences of cognitive symptoms in Long COVID: a mixed-methods study in the UK

OBJECTIVE

To explore the lived experiences and extent of cognitive symptoms in Long COVID (LC) in a UK-based sample.

DESIGN

This study implemented a mixed-methods design. Eight focus groups were conducted to collect qualitative data, and the Framework Analysis was used to reveal the experiences and impact of cognitive symptoms. A self-report questionnaire was used to collect the quantitative data to assess the perceived change and extent of symptomology post COVID-19.

SETTING

Focus groups were conducted in April 2023 online via Zoom and in-person at the University of Leeds, UK.

PARTICIPANTS

25 people with LC living in the UK participated in the study. Participants were aged 19-76 years (M=43.6 years, SD=14.7) and included 17 women and 8 men.

RESULTS

Reduced cognitive ability was among the most prevalent symptoms reported by the study participants. Three key themes were identified from the qualitative data: (1) rich accounts of cognitive symptoms; (2) the impact on physical function and psychological well-being and (3) symptom management. Descriptions of cognitive symptoms included impairments in memory, attention, language, executive function and processing speed. Cognitive symptoms had a profound impact on physical functioning and psychological well-being, including reduced ability to work and complete activities of daily living. Strategies used for symptom management varied in effectiveness.

CONCLUSION

Cognitive dysfunction in LC appears to be exacerbated by vicious cycle of withdrawal from daily life including loss of employment, physical inactivity and social isolation driving low mood, anxiety and poor cognitive functioning. Previous evidence has revealed the anatomical and physiological biomarkers in the brain affecting cognition in LC. To synthesise these contributing factors, we propose the Long-COVID Interacting Network of factors affecting Cognitive Symptoms. This framework is designed to inform clinicians and researchers to take a comprehensive approach towards LC rehabilitation, targeting the neural, individual and lifestyle factors.

Association of cognitive deficits with sociodemographic characteristics among adults with post-COVID conditions: Findings from the United States household pulse survey

People infected with coronavirus disease-19 (COVID-19) may continue to experience symptoms for several weeks or even months after acute infection, a condition known as long COVID. Cognitive problems such as memory loss are among the most commonly reported symptoms of long COVID. However, a comprehensive evaluation of the risks of cognitive decline following COVID-19 infection among different sociodemographic groups has not been undertaken at the national level in the USA. We conducted a secondary analysis on the datasets from the U.S. Census Bureau Household Pulse Survey, encompassing data collected from 1 June 2022 to 19 December 2022. Based on a cohort of 385 370 individuals aged 18 years or older, we employed logistic regression analysis to examine the association between self-reported cognitive deficits and different sociodemographic factors among individuals with long COVID conditions. We have demonstrated that individuals with long COVID had a significantly higher risk of cognitive deficits compared to those with no history of COVID infection. Cognitive deficits vary across sociodemographic groups. In individuals without long COVID, men, older adults, and those with higher education reported fewer cognitive deficits, while Hispanics and residents of the South reported more. Long COVID had similar impacts across genders and regions but appeared to have the smallest impact on Hispanics compared to other racial groups. Conversely, the effects of long COVID were most significant in older adults and individuals with higher education. The state-level analysis further suggests potential variation in long COVID's effects across different states. The risks of cognitive deficits among adults with post-COVID conditions are substantial. Various sociodemographic groups can have different risks of developing cognitive deficits after experiencing long COVID. The findings of this large-scale study can help identify sociodemographic groups at higher risk of cognitive deficits, facilitate medical interventions, and guide resource allocation to target populations at risk and prioritize areas with a high rate of cognitive decline.

Animal Models of Non-Respiratory, Post-Acute Sequelae of COVID-19

Post-acute sequelae of COVID-19 (PASC) are a diverse set of symptoms and syndromes driven by dysfunction of multiple organ systems that can persist for years and negatively impact the quality of life for millions of individuals. We currently lack specific therapeutics for patients with PASC, due in part to an incomplete understanding of its pathogenesis, especially for non-pulmonary sequelae. Here, we discuss three animal models that have been utilized to investigate PASC: non-human primates (NHPs), hamsters, and mice. We focus on neurological, gastrointestinal, and cardiovascular PASC and highlight advances in mechanistic insight that have been made using these animal models, as well as discussing the sequelae that warrant continued and intensive research.

Hippocampal subfield volume alterations and associations with severity measures in long COVID and ME/CFS: A 7T MRI study

Long COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) patients share similar symptoms including post-exertional malaise, neurocognitive impairment, and memory loss. The neurocognitive impairment in both conditions might be linked to alterations in the hippocampal subfields. Therefore, this study compared alterations in hippocampal subfields of 17 long COVID, 29 ME/CFS patients, and 15 healthy controls (HC). Structural MRI data was acquired with sub-millimeter isotropic resolution on a 7 Telsa MRI scanner and hippocampal subfield volumes were then estimated for each participant using FreeSurfer software. Our study found significantly larger volumes in the left hippocampal subfields of both long COVID and ME/CFS patients compared to HC. These included the left subiculum head (long COVID; p = 0.01, ME/CFS; p = 0.002,), presubiculum head (long COVID; p = 0.004, ME/CFS; p = 0.005), molecular layer hippocampus head (long COVID; p = 0.014, ME/CFS; p = 0.011), and whole hippocampal head (long COVID; p = 0.01, ME/CFS; p = 0.01). Notably, hippocampal subfield volumes were similar between long COVID and ME/CFS patients. Additionally, we found significant associations between hippocampal subfield volumes and severity measures of 'Pain', 'Duration of illness', 'Severity of fatigue', 'Impaired concentration', 'Unrefreshing sleep', and 'Physical function' in both conditions. These findings suggest that hippocampal alterations may contribute to the neurocognitive impairment experienced by long COVID and ME/CFS patients. Furthermore, our study highlights similarities between these two conditions.

An Exploratory Analysis of Contributors to Cognitive Functioning Among Sexual and Gender Minority Individuals Who Had COVID-19

Sexual and gender minority (SGM) individuals face mental health disparities. However, research analyzing SGM people's mental health after a COVID-19 diagnosis is scarce. In this secondary analysis of a remote study, we 1) examined associations between cognitive and psychosocial health and 2) explored differences between these health outcomes among SGM (n = 14) and heterosexual cisgender (n = 64) U.S. adults who had COVID-19. We used the Patient Reported Outcome Measures Information System (PROMIS) v2.0 to assess subjective cognition and the BrainCheck cognitive test to analyze objective cognition. We administered the Perceived Stress Scale and PROMIS 57 Profile V.2.0 to measure psychosocial health. SGM COVID-19 survivors had worse scores in depression, anxiety, sleep disturbance, pain, stress, and objective cognition than heterosexual cisgender participants (p-values < .05). Objective cognition was associated with age, SGM classification, racial or ethnic minority classification, income, comorbidities, COVID-19 severity, number of symptoms, and pain (|0.137| < r < |0.373|, p-values < .05). Subjective cognition was associated with comorbidities, number of symptoms, depression, anxiety, sleep disturbance, pain, and stress (|0.158| < r < |0.537|, p-values < .05). Additional studies are needed to expand what is known about post-COVID-19 health disparities and to guide policies and interventions that promote cognitive functioning.

The impact of COVID-19 on accelerating of immunosenescence and brain aging

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, has profoundly impacted global health, affecting not only the immediate morbidity and mortality rates but also long-term health outcomes across various populations. Although the acute effects of COVID-19 on the respiratory system have initially been the primary focus, it is increasingly evident that the virus can have significant impacts on multiple physiological systems, including the nervous and immune systems. The pandemic has highlighted the complex interplay between viral infection, immune aging, and brain health, that can potentially accelerate neuroimmune aging and contribute to the persistence of long COVID conditions. By inducing chronic inflammation, immunosenescence, and neuroinflammation, COVID-19 may exacerbate the processes of neuroimmune aging, leading to increased risks of cognitive decline, neurodegenerative diseases, and impaired immune function. Key factors include chronic immune dysregulation, oxidative stress, neuroinflammation, and the disruption of cellular processes. These overlapping mechanisms between aging and COVID-19 illustrate how the virus can induce and accelerate aging-related processes, leading to an increased risk of neurodegenerative diseases and other age-related conditions. This mini-review examines key features and possible mechanisms of COVID-19-induced neuroimmune aging that may contribute to the persistence and severity of long COVID. Understanding these interactions is crucial for developing effective interventions. Anti-inflammatory therapies, neuroprotective agents, immunomodulatory treatments, and lifestyle interventions all hold potential for mitigating the long-term effects of the virus. By addressing these challenges, we can improve health outcomes and quality of life for millions affected by the pandemic.

Subjective and objective measures of cognitive function are correlated in persons with Post-COVID-19 Condition: a secondary analysis of a Randomized Controlled Trial

BACKGROUND

It remains unclear whether subjective and objective measures of cognitive function in Post COVID-19 Condition (PCC) are correlated. The extent of correlation has mechanistic and clinical implications.

METHODS

This post-hoc analysis of a randomized, double-blind, placebo-controlled clinical trial contains baseline data of subjective and objective measures of cognition in a rigorously characterized cohort living with PCC. Herein, we evaluated the association between subjective and objective condition function, as measured by the Perceived Deficits Questionnaire, 20-item (PDQ-20) and the Digit Symbol Substitution Test (DSST) and Trails Making Test (TMT)-A/B, respectively.

RESULTS

A total of 152 participants comprised the baseline sample. Due to missing data, our statistical analyses included 150 for self-reported PDQ-20, 147 individuals for combined DSST-measured cognitive function (composite z-score of the Pen/Paper plus Online CogState Version, NcombinedDSST), 71 for in-person DSST-measured cognitive function (Pen/Paper Version), 70 for TMT-A-measured cognitive function, and 70 for TMT-B-measured cognitive function. After adjusting for age, sex, and education, PDQ-20 was significantly correlated with pen-and-paper DSST (β = -0.003, p = 0.002) and TMT-B (β = 0.003, p = 0.008) scores, but not with TMT-A scores (β = -0.001, p = 0.751).

CONCLUSIONS

Overall, a statistically significant correlation was observed between subjective and objective cognitive functions. Clinicians providing care for individuals with PCC who have subjective cognitive function complaints may consider taking a measurement-based approach to cognition at the point of care that focuses exclusively on patient-reported measures.

A Step Forward in Long COVID Research: Validating the Post-COVID Cognitive Impairment Scale

Long COVID, or post-acute sequelae of SARS-CoV-2 infection, includes a variety of enduring symptoms that endure beyond the acute phase of the illness, impacting multiple facets of patients' psychological and physical health. The persistent symptoms encompass fatigue, breathing difficulties, musculoskeletal pain, and cognitive impairments, which can significantly affect daily functioning and overall quality of life. The objective of this study was to create and validate the accuracy of the Post-COVID Cognitive Impairment Scale, which is used to evaluate cognitive impairments resulting from a COVID-19 infection. This study was conducted in Iran between January and September 2023. It consisted of three phases: developing the scale, evaluating its content validity with experts, and validating its structure with 454 participants using exploratory and confirmatory factor analysis. The exploratory factor analysis revealed two variables, namely memory and attention, which accounted for 40.38% of the variation. Confirmatory factor analysis verified the model's fit, with indices indicating satisfactory alignment: CMIN/DF = 2.80, RMSEA = 0.06, SRMR = 0.05, CFI = 0.93, and TLI = 0.92. The factor loadings were statistically significant (p < 0.001), and Cronbach's Alpha values indicated strong internal consistency (working memory = 0.81, attention = 0.80). These results affirm the Post-COVID Cognitive Impairment Scale is a valid and reliable instrument for evaluating cognitive deficiencies in individuals with long COVID. Its application in clinical and research environments aids in the prompt detection and tracking of the treatment of such impairments.

Fatigue and cognitive dysfunction in previously hospitalized patients with COVID-19: A 1-year follow-up

PURPOSE

The aim was to longitudinally explore changes in fatigue- and cognition-related symptoms during the first year after hospital treatment for COVID-19.

METHOD

Patients hospitalized for COVID-19 in Gothenburg, Sweden, were consecutively included from 01-07-2020 to 28-02-2021. Patients were assessed at the hospital (acute) and at 3 and 12 months after hospital discharge. Cognition was assessed with the Montreal Cognitive Assessment (MoCA), the Trail Making Test B (TMTB), and the Cognitive Failure Questionnaire (CFQ). Fatigue was assessed using the Multidimensional Fatigue Inventory-20 (MFI-20) and the Mental Fatigue Scale (MFS). Data was analyzed with demographics and changes over time calculated with univariable mixed-effects models.

RESULT

In total, 122 participants were included. Analyzes of Z-scores for MoCA indicated improvement over the year, however the results were 1 SD below norm at all assessments. Alertness (TMTB scores) improved significantly from the acute assessment to the 12- month follow-up (p = <0.001, 95% CI 34.67-69.67). CFQ scores indicated cognitive impairment, and the sum scores for MFI reflected a relatively high degree of fatigue at follow-up.

CONCLUSION

In the first year after hospitalization for COVID-19, most patients experienced fatigue and cognitive impairment. Alertness improved, but improvements in other domains were limited.

Measuring subjective cognitive complaints with covid-19 brain fog using the subjective scale to investigate cognition (SSTICS)

The term "brain fog" has emerged from the observations of neuropsychiatric conditions present in post-COVID-19 infections. This is characterized by concentration and memory problems, selective attention disorders and difficulties in executive functions, yet it is unclear how long these deficits may persist and which cognitive functions are most vulnerable. Therefore, there is a need to properly evaluate these cognitive complaints using an assessment tool that specifies their intensity and nature. Our primary objective was to explore subjective perceptions of cognitive functioning in COVID-19-associated with brain fog using a tool that was previously validated for assessing subjective cognitive complaints. A total of 68 participants were recruited and the Subjective Scale to Investigate Cognition (SSTICS) was used to assess cognitive complaints. This was the first time that the SSTICS was used for this purpose in subjects with COVID-19. In addition, participants were administered a questionnaire assessing for the presence of various symptoms, as well as COVID-19 clinical parameters. The neuropsychological basis for the construct of the SSTICS was related to the cognitive complaints expressed by participants. A reliability analysis of our sample indicated a high degree of internal consistency (Cronbach's alpha= 0.951). Associations between various SSTICS scores and COVID-related symptomatology and the differences between group of participants who reported cognitive complaints ("complainers") and those who did not were assessed. We performed an exploratory factorial analysis based on Principal Component Analysis (PCA). Based on their distribution, participants were grouped into: "good functioning" - scores 0-9 (35.3%); "medium functioning" - scores 14-23 (25%); and "poor functioning" - scores 26-71 (39.7%). The mean SSTICS score was 20.59 (SD 16.61) and correlated with the quarantine duration and loss of smell. Complainers differed significantly from non-complainers in the total number of symptoms, the quarantine duration and the presence/absence of specific symptoms, such as loss of smell, tiredness and aches/pains. Our study showed that >10% of patients reported subjective cognitive complaints following COVID-19, with most reporting mild or serious cognitive complaints, mostly within the domains of memory, attention, language, executive functioning or praxis.

Cognitive recovery of post critical care patients with and without COVID-19: differences and similarities, an observational study

BACKGROUND

Coronavirus disease (COVID-19) patients treated in an intensive care unit (ICU) are at high risk of developing cognitive impairments of a "post-intensive care syndrome" (PICS). We explored whether critically ill COVID-19 and non-COVID-19 survivors differ in their post-ICU recovery course in terms of severity and affected cognitive domains.

METHODS

An observational prospective study was conducted in a German post-acute neurological early rehabilitation clinic. Critically ill patients with or without SARS-CoV-2 infection (at least mechanically ventilated for one week) underwent repeated standardized assessments during their subsequent inpatient rehabilitation stay. Cognitive functions (information processing speed, learning, recognition, short-term and working-memory, word fluency, flexibility) assigned to different domains (attention, memory, executive functions) were assessed as primary outcome. Secondary outcomes included mental (depression, anxiety) and physical (Barthel index, modified ranking scale) state.

RESULTS

Out of 92 eligible patients (screened between June 2021 and August 2023), 34 were examined, and 30 were available for analysis (15 per group). Both groups were ventilated for a similar period (COVID-19 vs. Non-COVID-19: median: 48 vs. 53 days). Patients of COVID-19 group spend on average 10 days longer at ICU and developed slightly more complications, but subsequent inpatient rehabilitation was of comparable duration (median: 36.5 vs. 37 days). On the group-level both groups showed similar cognitive dysfunctions with striking impairments (normative T-scores < 41) in information processing speed, word fluency, flexibility, and recognition memory on admission. Significant gains until discharge were only revealed for information processing speed in both groups (main effect visit, mean difference [95%CI] - 7.5 [- 13.1, - 2.0]). Physical and mental state were also similarly affected in both groups on admission, but improved over time, indicating that overall recovery for higher-order cognitive functions is slowest. Interestingly, majority of patients stated correctly being still physically disabled, while a discrepancy was found between subjective and objective evaluation of cognitive health.

CONCLUSIONS

Results suggest a substantial overlap of cognitive, mental and physical dysfunction in post-acute recovery of ICU survivors independent of SARS-CoV-2 infection which warrants further monitoring to reduce the risk of long-term burden and enable a return to previous functionality.

TRIAL REGISTRATION

Retrospectively registered at https://drks.de/search/de/trial/DRKS00025523 , 21.06.2021.

MRI evidence of gray matter loss in COVID-19 patients with cognitive and olfactory disorders

OBJECTIVE

The aim of this study was to assess COVID-19-related gray matter (GM) structural alterations in two distinct groups of patients presenting with the prevailing and distinctive COVID-19-related neurological symptoms - isolated olfactory disorders as sole neurological manifestation (COVID-OD) and cognitive disorders (COVID-CD) - as compared to a control group of unaffected individuals.

METHODS

The study included 61 COVID-CD patients (57 [60-63] years, 62% females), 84 COVID-OD patients (49 [35-57] years, 60% females), and 17 controls (51 [41-52] years, 41% females). Region-based morphometry (RBM) and voxel-based morphometry (VBM) were performed on T1-weighted MRI scans to assess GM regional volume and voxel-wise density differences between COVID-19 patients and controls. Surface-based morphometry (SBM) was applied to investigate cortical thickness alterations. The statistical models built to assess GM structural differences among groups included total intracranial volume and age as nuisance variables.

RESULTS

The multi-morphometric analysis revealed statistically significant (p < 0.05 corrected for multiple comparisons) reduction in GM regional volumes, in voxel-wise GM density and in cortical thickness in both COVID-CD and COVID-OD patient groups as compared to controls. Across all three analyses, COVID-CD patients showed more distributed and severe GM loss than COVID-OD patients. The most prominently affected GM regions in the COVID-CD group included the hippocampus, putamen, cingulate gyrus, precuneus, precentral and postcentral gyri, amygdala, lingual gyrus, and caudate nucleus.

INTERPRETATION

Our MRI findings show that COVID-19-related olfactory and cognitive disorders both induce GM atrophy, although at different degrees of severity, likely indicative of neurodegeneration and neuroinflammation.

Multifactorial Memory Questionnaire: a comparison of young and older adults

The Multifactorial Memory Questionnaire (MMQ; Troyer & Rich, [2002]. Psychometric properties of a new metamemory questionnaire for older adults. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 57(1), P19-P27) is a widely used measure of subjective memory consisting of three scales: Satisfaction, Ability, and Strategies. Although subjective memory complaints are prevalent across different age groups, the factor structure and psychometric properties of the MMQ have yet to be examined in young adults. Here, we independently replicated the original MMQ factor structure in N = 408 young adults (YA) recruited from undergraduate courses and N = 327 older adults (OA) and, for the first time, assessed the age-invariance of the scale using measurement invariance testing. YAs made significantly higher ratings than OAs on MMQ-Satisfaction and MMQ-Strategies, indicating greater satisfaction with their memory and greater use of strategies, but the groups were similar on MMQ-Ability. The original MMQ factor structure was replicated in OAs but not in YAs, and age invariance was not supported. Future studies seeking to compare young and older adults could therefore consider either requesting modification of the MMQ for use with young adults or using a different scale.

Patient-Reported Experiences of Persistent Post-COVID-19 Conditions After Hospital Discharge During the Second and Third Waves of the Pandemic in Switzerland: Cross-Sectional Questionnaire Study

BACKGROUND

Hospitalized patients infected with SARS-CoV-2 should recover within a few weeks. However, even those with mild versions can experience symptoms lasting 4 weeks or longer. These post-COVID-19 condition (PCC) comprise various new, returning, or ongoing symptoms that can last for months or years and cause disability. Few studies have investigated PCC using self-reports from discharged patients infected with SARS-CoV-2 to complement clinical and biomarker studies.

OBJECTIVE

This study aimed to investigate self-reported, persistent PCC among patients infected with SARS-CoV-2 who were discharged during the second and third waves of the COVID-19 pandemic.

METHODS

We designed, pretested, and posted an ad hoc paper questionnaire to all eligible inpatients discharged between October 2020 and April 2021. At 4 months post discharge, we collected data on PCC and scores for the Multidimensional Fatigue Inventory (MFI), the Patient Health Questionnaire-4 (PHQ-4), a Brief Memory Screening Scale (Q3PC), and a posttraumatic stress disorder scale (PCL-5). Descriptive, inferential, and multivariate linear regression statistics assessed PCC symptomatology, associations, and differences regarding sociodemographic characteristics and hospital length of stay (LOS). We examined whether our variables of interest significantly predicted MFI scores.

RESULTS

Of the 1993 valid questionnaires returned, 245 were from discharged patients with SARS-CoV-2 (median age 71, IQR 62.7-77 years). Only 28.2% (69/245) of respondents were symptom-free after 4 months. Women had significantly more persistent PCC symptoms than men (P≤.001). Patients with a hospital LOS ≥11 days had more PCC symptoms as well (P<.001)-women had more symptoms and longer LOS. No significant differences were found between age groups (18-64, 65-74, and ≥75 years old; P=.50) or between intensive care units and other hospitalization units (P=.09). Patients self-reported significantly higher PHQ-4 scores during their hospitalization than at 4 months later (P<.001). Three-fourth (187/245, 76.4%) of the respondents reported memory loss and concentration disorders (Q3PC). No significant differences in the median MFI score (56, IQR 1-3, range 50-60]) were associated with sociodemographic variables. Patients with a hospital LOS of ≥11 days had a significantly higher median PCL-5 score (P<.001). Multivariate linear regression allowed us to calculate that the combination of PHQ-4, Q3PC, and PCL-5 scores, adjusted for age, sex, and LOS (of either ≥11 days [median 2 symptoms, IQR 1-5] or <11 days), did not significantly predict MFI scores (R2=0.09; F4,7 =1.5; P=.22; adjusted R2=0.06).

CONCLUSIONS

The majority of inpatients infected with SARS-CoV-2 presented with PCC 4 months after discharge, with complex clinical pictures. Only one-third of them were symptom-free during that time. Based on our findings, MFI scores were not directly related to self-reported depression, anxiety, or posttraumatic scores adjusted for age, sex, or LOS. Further research is needed to explore PCC and fatigue based on self-reported health experiences of discharged inpatients infected with SARS-CoV-2.

Dissociable effects of mild COVID-19 on short- and long-term memories

Recent studies have highlighted the presence of cognitive deficits following COVID-19 that persist beyond acute infection, regardless of the initial disease severity. Impairments in short- and long-term memory are among the core deficits reported by patients and observed in objective tests of memory performance. We aimed to extend previous studies by examining performance in a task that allows us to directly compare and contrast memories at different timescales. More specifically, we assessed both short- and long-term memories for contextual-spatial associations encoded during a common session and probed at different durations using an equivalent task in non-hospitalized individuals recovering from mild COVID-19 compared to healthy controls. The approach equated all aspects of memory materials and response demands, isolating performance changes resulting only from memory timescales and thus allowing us to quantify the impact of COVID-19 on cognition. In addition to providing measures of accuracy and response times, the task also provided a sensitive continuous readout of the precision of memory representations, specifically by examining the resolution with which spatial locations were retained in memory. The results demonstrated selective impairment of long-term memory performance in individuals recovering from mild COVID-19 infection. Short-term memory performance remained comparable to healthy controls. Specifically, poor precision of long-term memory representations was demonstrated, which improved with days since diagnosis. No such relationship was observed for short-term memory performance. Our findings reveal a specific impairment to the precision of spatial-contextual long-term memory representations in individuals recovering from mild COVID-19 and demonstrate evidence of recovery in long-term memory over time. Further, the experimental design provides a carefully controlled and sensitive framework to assess memory across different durations with the potential to provide more detailed phenotyping of memory deficits associated with COVID-19 in general.

Coronavirus disease 2019 and its impact on the cognition of older adults: Unraveling the role of inflammation

BACKGROUND

The Coronavirus Disease 2019 (COVID-19) pandemic significantly impacted the older adult population globally. This study aimed to investigate cognitive function and its relationship with inflammation in older COVID-19 survivors over a three-month follow-up to address concerns about cognitive impairment and its risk factors.

METHODS

In this descriptive-analytical study, 177 hospitalized COVID-19 patients aged >60 were assessed from July 2021 to February 2022. Psychiatric, global cognitive assessments and activities of daily living were conducted at discharge, 1 month, and 3 months post-discharge. Statistical analyses were conducted using SPSS Version 24. The evolution of cognitive status over time was evaluated using the Repeated Measures Test. The study probed into the association between inflammatory markers and cognitive function through the Pearson correlation test and the Mann-Whitney U test. Additionally, the link between anxiety/depression and cognitive performance was examined using the Pearson correlation.

RESULTS

Results indicated that higher levels of C-reactive protein (CRP), D-dimer, and Lactate Dehydrogenase (LDH) were correlated to reduced cognitive performance. Conversely, Erythrocyte Sedimentation Rate (ESR) and Creatine Phosphokinase (CPK) did not exhibit a significant relationship with cognitive scores. A positive correlation was observed between improved cognitive function (reflected by higher GPCOG scores) and lower levels of anxiety and depression (indicated by lower scores on the Hospital Anxiety and Depression Scale). Over the study period, cognitive function and anxiety scores showed an upward trend, whereas symptoms of depression and challenges in daily activities remained consistent.

CONCLUSIONS

The study highlights the enduring effects and detrimental role of inflammation on overall cognitive abilities among older survivors of COVID-19. It underscores the urgent need for specialized interventions and rehabilitative strategies to facilitate sustained cognitive recuperation among these individuals.

Vaccination reduces central nervous system IL-1β and memory deficits after COVID-19 in mice

Up to 25% of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibit postacute cognitive sequelae. Although millions of cases of coronavirus disease 2019 (COVID-19)-mediated memory dysfunction are accumulating worldwide, the underlying mechanisms and how vaccination lowers risk are unknown. Interleukin-1 (IL-1), a key component of innate immune defense against SARS-CoV-2 infection, is elevated in the hippocampi of individuals with COVID-19. Here we show that intranasal infection of C57BL/6J mice with SARS-CoV-2 Beta variant leads to central nervous system infiltration of Ly6Chi monocytes and microglial activation. Accordingly, SARS-CoV-2, but not H1N1 influenza virus, increases levels of brain IL-1β and induces persistent IL-1R1-mediated loss of hippocampal neurogenesis, which promotes postacute cognitive deficits. Vaccination with a low dose of adenoviral-vectored spike protein prevents hippocampal production of IL-1β during breakthrough SARS-CoV-2 infection, loss of neurogenesis and subsequent memory deficits. Our study identifies IL-1β as one potential mechanism driving SARS-CoV-2-induced cognitive impairment in a new mouse model that is prevented by vaccination.

Exploring the impact of cognitive dysfunction, fatigue, and shortness of breath on activities of daily life after COVID-19 infection, until 1-year follow-up

OBJECTIVE

Despite expanding knowledge on COVID-19,  the long-term effects on daily-life activities remain unclear. The prevalence and changes in fatigue, cognitive dysfunction, and activity limitations in the first year after COVID-19 infection in hospitalized and non-hospitalized patients were explored.

SUBJECTS

A total of 122 patients were recruited from hospital care and 90 from primary care.

METHOD

Baseline data comprised the Montreal Cognitive Assessment and Trail Making Test. Participants were followed up at 3 and 12 months using these tests and a semi-structured interview to identify symptoms and how they affected participation in daily-life activities. Both within- and between-group analyses were performed to explore changes over time and compare groups.

RESULT

High levels of fatigue and cognitive dysfunction were found in both groups, which persisted for 12 months. A significant impact on daily-life activities was also observed, with marginal change at the 12-month follow-up. The hospital care group performed worse than the primary care group in the cognitive tests, although the primary care group perceived a higher level of fatigue and cognitive dysfunction. Activity limitations were higher in the primary care group than in the hospital care group.

CONCLUSION

These findings highlight the need for long-term follow-up and further investigation of the impact of persistent deficits on rehabilitation.

Neurocognitive and Neuropsychiatric Sequelae in Long COVID-19 Infection

Objective: To characterize the cognitive profile of long COVID-19 subjects and its possible association with clinical symptoms, emotional disturbance, biomarkers, and disease severity. Methods: We performed a single-center cross-sectional cohort study. Subjects between 20 and 60 years old with confirmed COVID-19 infection were included. The assessment was performed 6 months following hospital or ambulatory discharge. Excluded were those with prior neurocognitive impairment and severe neurological/neuropsychiatric disorders. Demographic and laboratory data were extracted from medical records. Results: Altogether, 108 participants were included, 64 were male (59.25%), and the mean age was 49.10 years. The patients were classified into four groups: non-hospitalized (NH, n = 10), hospitalized without Intensive Care Unit (ICU) or oxygen therapy (HOSPI, n = 21), hospitalized without ICU but with oxygen therapy (OXY, n = 56), and ICU (ICU, n = 21) patients. In total, 38 (35.18%) reported Subjective Cognitive Complaints (SCC). No differences were found considering illness severity between groups. Females had more persistent clinical symptoms and SCC than males. Persistent dyspnea and headache were associated with higher scores in anxiety and depression. Persistent fatigue, anxiety, and depression were associated with worse overall cognition. Conclusions: No cognitive impairment was found regarding the severity of post-COVID-19 infection. SCC was not associated with a worse cognitive performance, but with higher anxiety and depression. Persistent clinical symptoms were frequent independent of illness severity. Fatigue, anxiety, and depression were linked to poorer cognitive function. Tests for attention, processing speed, and executive function were the most sensitive in detecting cognitive changes in these patients.

Brain microstructure and connectivity in COVID-19 patients with olfactory or cognitive impairment

INTRODUCTION

The COVID-19 pandemic has affected millions worldwide, causing mortality and multi-organ morbidity. Neurological complications have been recognized. This study aimed to assess brain structural, microstructural, and connectivity alterations in patients with COVID-19-related olfactory or cognitive impairment using post-acute (time from onset: 264[208-313] days) multi-directional diffusion-weighted MRI (DW-MRI).

METHODS

The study included 16 COVID-19 patients with cognitive impairment (COVID-CM), 35 COVID-19 patients with olfactory disorder (COVID-OD), and 14 controls. A state-of-the-art processing pipeline was developed for DW-MRI pre-processing, mean diffusivity and fractional anisotropy computation, fiber density and cross-section analysis, and tractography of white-matter bundles. Brain parcellation required for probing network connectivity, region-specific microstructure and volume, and cortical thickness was based on T1-weighted scans and anatomical atlases.

RESULTS

Compared to controls, COVID-CM patients showed overall gray matter atrophy (age and sex corrected p = 0.004), and both COVID-19 patient groups showed regional atrophy and cortical thinning. Both groups presented an increase in gray matter mean diffusivity (corrected p = 0.001), decrease in white matter fiber density and cross-section (corrected p < 0.05), , and COVID-CM patients also displayed an overall increased diffusivity (p = 0.022) and decreased anisotropy (corrected p = 0.038) in white matter. Graph-based analysis revealed reduced network modularity, with an extensive pattern of connectivity increase, in conjunction with a localized reduction in a few connections, mainly located in the left hemisphere. The left cingulate, anterior cingulate, and insula were primarily involved.

CONCLUSION

Expanding upon previous findings, this study further investigated significant alterations in brain morphology, microstructure, and connectivity in COVID-19 patients with olfactory or cognitive disfunction. These findings suggest underlying neurodegeneration, neuroinflammation, and concomitant compensatory mechanisms. Future longitudinal studies are required to monitor the alterations over time and assess their transient or permanent nature.

Long COVID in Brain Health Research: A Call to Action

The COVID-19 pandemic has brought attention to the long-term consequences of the virus, particularly the persistent symptoms that characterize long COVID. This syndrome, which can last for months after the initial infection, includes a range of neurological and neuropsychiatric manifestations that have significant implications for brain health and dementia research. This review explores the current understanding of long COVID's cognitive, neurological, and psychiatric symptoms and their potential impact on brain stimulation and neuroimaging studies. It argues that researchers must adapt their study designs and screening processes to account for the confounding effects of long COVID and ensure the accuracy and reliability of their findings. To advance the understanding of this condition and its long-term effects on brain health, the review proposes a series of strategies, including the development of standardized screening tools, the investigation of underlying mechanisms, and the identification of risk factors and protective factors. It also emphasizes the importance of collaborative research efforts and international data sharing platforms in accelerating the pace of discovery and developing targeted interventions for individuals with long COVID. As the prevalence of this condition continues to grow, it is imperative that the neuroscience community comes together to address this challenge and support those affected by long COVID.

Subjective brain fog: a four-dimensional characterization in 25,796 participants

Importance

Brain fog is associated with significant morbidity and reduced productivity and gained increasing attention after COVID-19. However, this subjective state has not been systematically characterised.

Objective

To characterise self-reported brain fog.

Design

We systematically studied the cross-sectional associations between 29 a priori variables with the presence of "brain fog." The variables were grouped into four categories: demographics, symptoms and functional impairments, comorbidities and potential risk factors (including lifestyle factors), and cognitive score. Univariate methods determined the correlates of brain fog, with long-COVID and non-long-COVID subgroups. XGBoost machine learning model retrospectively characterised subjective brain fog. Bonferroni-corrected statistical significance was set at 5%.

Setting

Digital application for remote data collection.

Participants

25,796 individuals over the age of 18 who downloaded and completed the application.

Results

7,280 of 25,796 individuals (28.2%) reported experiencing brain fog, who were generally older (mean brain fog 35.7 ± 11.9 years vs. 32.8 ± 11.6 years, p < 0.0001) and more likely to be female (OR = 1.2, p < 0.001). Associated symptoms and functional impairments included difficulty focusing or concentrating (OR = 3.3), feeling irritable (OR = 1.6), difficulty relaxing (OR = 1.2, all p < 0.0001), difficulty following conversations (OR = 2.2), remembering appointments (OR = 1.9), completing paperwork and performing mental arithmetic (ORs = 1.8, all p < 0.0001). Comorbidities included long-COVID-19 (OR = 3.8, p < 0.0001), concussions (OR = 2.4, p < 0.0001), and higher migraine disability assessment scores (MIDAS) (+34.1%, all p < 0.0001). Cognitive scores were marginally lower with brain fog (-0.1 std., p < 0.001). XGBoost achieved a training accuracy of 85% with cross-validated accuracy of 74%, and the features most predictive of brain fog in the model were difficulty focusing and following conversations, long-COVID, and severity of migraines.

Conclusions and relevance

This is the largest study characterising subjective brain fog as an impairment of concentration associated with functional impairments in activities of daily living. Brain fog was particularly associated with a history of long-COVID-19, migraines, concussion, and with 0.1 standard deviations lower cognitive scores, especially on modified Stroop testing, suggesting impairments in the ability to inhibit cognitive interference. Further prospective studies in unselected brain fog sufferers should explore the full spectrum of brain fog symptoms to differentiate it from its associated conditions.

Combining Double-Dose and High-Dose Pulsed Dapsone Combination Therapy for Chronic Lyme Disease/Post-Treatment Lyme Disease Syndrome and Co-Infections, Including Bartonella: A Report of 3 Cases and a Literature Review

Three patients with relapsing and remitting borreliosis, babesiosis, and bartonellosis, despite extended anti-infective therapy, were prescribed double-dose dapsone combination therapy (DDDCT) for 8 weeks, followed by one or several two-week courses of pulsed high-dose dapsone combination therapy (HDDCT). We discuss these patients' cases to illustrate three important variables required for long-term remission. First, diagnosing and treating active co-infections, including Babesia and Bartonella were important. Babesia required rotations of multiple anti-malarial drug combinations and herbal therapies, and Bartonella required one or several 6-day HDDCT pulses to achieve clinical remission. Second, all prior oral, intramuscular (IM), and/or intravenous (IV) antibiotics used for chronic Lyme disease (CLD)/post-treatment Lyme disease syndrome (PTLDS), irrespective of the length of administration, were inferior in efficacy to short-term pulsed biofilm/persister drug combination therapy i.e., dapsone, rifampin, methylene blue, and pyrazinamide, which improved resistant fatigue, pain, headaches, insomnia, and neuropsychiatric symptoms. Lastly, addressing multiple factors on the 16-point multiple systemic infectious disease syndrome (MSIDS) model was important in achieving remission. In conclusion, DDDCT with one or several 6-7-day pulses of HDDCT, while addressing abnormalities on the 16-point MSIDS map, could represent a novel effective clinical and anti-infective strategy in CLD/PTLDS and associated co-infections including Bartonella.

Cognitive performance of post-covid patients in mild, moderate, and severe clinical situations

BACKGROUND

Studying individuals with varying symptoms, from mild to severe, can provide valuable insights into the spectrum of cognitive outcomes after COVID-19. We investigated the cognitive performance of adults who recovered from the novel coronavirus disease (COVID-19) without prior cognitive complaints, considering mild (not hospitalized), moderate (ward), and severe (intensive care unit) symptoms.

METHODS

This cross-sectional study included 302 patients who recovered from COVID-19 (mild, n = 102; moderate, n = 102; severe, n = 98). We assessed intellectual quotient (IQ), attention, memory, processing speed, visual-constructive ability, as well as symptoms of depression, anxiety, and stress, at least eighteen months after infection. The mean length of hospitalization was Mdays=8.2 (SD = 3.9) and Mdays=14.4 (SD = 8.2) in the moderate and severe groups, respectively.

RESULTS

Cognitive difficulties were present in all three groups: mild (n = 12, 11.7%), moderate (n = 40, 39.2%), and severe (n = 48, 48.9%). Using Multinomial Logistic Regression and considering the odds ratio, our results indicated that a one-point increase in sustained attention, visual memory, and working memory might decrease the odds of being categorized in the severe group by 20%, 24%, and 77%, respectively, compared to the mild group.

CONCLUSIONS

Our findings provide empirical evidence regarding the long-term cognitive effects of COVID-19, particularly in individuals experiencing severe manifestations of the disease. We also highlighted the need for a comprehensive, multidimensional approach in rehabilitation programs to address the enduring cognitive impacts of COVID-19.

Pathophysiological Mechanisms in Long COVID: A Mixed Method Systematic Review

INTRODUCTION

Long COVID (LC) is a global public health crisis affecting more than 70 million people. There is emerging evidence of different pathophysiological mechanisms driving the wide array of symptoms in LC. Understanding the relationships between mechanisms and symptoms helps in guiding clinical management and identifying potential treatment targets.

METHODS

This was a mixed-methods systematic review with two stages: Stage one (Review 1) included only existing systematic reviews (meta-review) and Stage two (Review 2) was a review of all primary studies. The search strategy involved Medline, Embase, Emcare, and CINAHL databases to identify studies that described symptoms and pathophysiological mechanisms with statistical analysis and/or discussion of plausible causal relationships between mechanisms and symptoms. Only studies that included a control arm for comparison were included. Studies were assessed for quality using the National Heart, Lung, and Blood Institute quality assessment tools.

RESULTS

19 systematic reviews were included in Review 1 and 46 primary studies in Review 2. Overall, the quality of reporting across the studies included in this second review was moderate to poor. The pathophysiological mechanisms with strong evidence were immune system dysregulation, cerebral hypoperfusion, and impaired gas transfer in the lungs. Other mechanisms with moderate to weak evidence were endothelial damage and hypercoagulation, mast cell activation, and auto-immunity to vascular receptors.

CONCLUSIONS

LC is a complex condition affecting multiple organs with diverse clinical presentations (or traits) underpinned by multiple pathophysiological mechanisms. A 'treatable trait' approach may help identify certain groups and target specific interventions. Future research must include understanding the response to intervention based on these mechanism-based traits.

Subjective and Objective Measures of Cognitive Function are Correlated in Persons with Post-COVID-19 Condition: A Secondary Analysis of a Randomized Controlled Trial

Background

It remains unclear whether subjective and objective measures of cognitive function in Post COVID-19 Condition (PCC) are correlated. The extent of correlation has mechanistic and clinical implications.

Methods

This post-hoc analysis of a randomized, double-blind, placebo-controlled clinical trial contains baseline data of subjective and objective measures of cognition in a rigorously characterized cohort living with PCC. Herein, we evaluated the association between subjective and objective condition function, as measured by the Perceived Deficits Questionnaire, 20-item (PDQ-20) and the Digit Symbol Substitution Test (DSST) and Trails Making Test (TMT)-A/B, respectively.

Results

A total of 152 participants comprised the baseline sample. Due to missing data, our statistical analyses included 150 for self-reported PDQ-20, 147 individuals for combined DSST-measured cognitive function (composite z-score of the Pen/Paper plus Online CogState Version, N combinedDSST ), 71 for in-person DSST-measured cognitive function (Pen/Paper Version), 70 for TMT-A-measured cognitive function, and 70 for TMT-B-measured cognitive function. After adjusting for age, sex, and education, PDQ-20 was significantly correlated with pen-and-paper DSST (β = -0.003, p = 0.002) and TMT-B (β = 0.003, p = 0.008) scores, but not with TMT-A scores (β = -0.001, p = 0.751).

Conclusions

Overall, a statistically significant correlation was observed between subjective and objective cognitive functions. Clinicians providing care for individuals with PCC who have subjective cognitive function complaints may consider taking a measurement-based approach to cognition at the point of care that focuses exclusively on patient-reported measures.

Neurovascular coupling impairment as a mechanism for cognitive deficits in COVID-19

Components that comprise our brain parenchymal and cerebrovascular structures provide a homeostatic environment for proper neuronal function to ensure normal cognition. Cerebral insults (e.g. ischaemia, microbleeds and infection) alter cellular structures and physiologic processes within the neurovascular unit and contribute to cognitive dysfunction. COVID-19 has posed significant complications during acute and convalescent stages in multiple organ systems, including the brain. Cognitive impairment is a prevalent complication in COVID-19 patients, irrespective of severity of acute SARS-CoV-2 infection. Moreover, overwhelming evidence from in vitro, preclinical and clinical studies has reported SARS-CoV-2-induced pathologies in components of the neurovascular unit that are associated with cognitive impairment. Neurovascular unit disruption alters the neurovascular coupling response, a critical mechanism that regulates cerebromicrovascular blood flow to meet the energetic demands of locally active neurons. Normal cognitive processing is achieved through the neurovascular coupling response and involves the coordinated action of brain parenchymal cells (i.e. neurons and glia) and cerebrovascular cell types (i.e. endothelia, smooth muscle cells and pericytes). However, current work on COVID-19-induced cognitive impairment has yet to investigate disruption of neurovascular coupling as a causal factor. Hence, in this review, we aim to describe SARS-CoV-2's effects on the neurovascular unit and how they can impact neurovascular coupling and contribute to cognitive decline in acute and convalescent stages of the disease. Additionally, we explore potential therapeutic interventions to mitigate COVID-19-induced cognitive impairment. Given the great impact of cognitive impairment associated with COVID-19 on both individuals and public health, the necessity for a coordinated effort from fundamental scientific research to clinical application becomes imperative. This integrated endeavour is crucial for mitigating the cognitive deficits induced by COVID-19 and its subsequent burden in this especially vulnerable population.

The knowns and unknowns of long COVID-19: from mechanisms to therapeutical approaches

The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has been defined as the greatest global health and socioeconomic crisis of modern times. While most people recover after being infected with the virus, a significant proportion of them continue to experience health issues weeks, months and even years after acute infection with SARS-CoV-2. This persistence of clinical symptoms in infected individuals for at least three months after the onset of the disease or the emergence of new symptoms lasting more than two months, without any other explanation and alternative diagnosis have been named long COVID, long-haul COVID, post-COVID-19 conditions, chronic COVID, or post-acute sequelae of SARS-CoV-2 (PASC). Long COVID has been characterized as a constellation of symptoms and disorders that vary widely in their manifestations. Further, the mechanisms underlying long COVID are not fully understood, which hamper efficient treatment options. This review describes predictors and the most common symptoms related to long COVID's effects on the central and peripheral nervous system and other organs and tissues. Furthermore, the transcriptional markers, molecular signaling pathways and risk factors for long COVID, such as sex, age, pre-existing condition, hospitalization during acute phase of COVID-19, vaccination, and lifestyle are presented. Finally, recommendations for patient rehabilitation and disease management, as well as alternative therapeutical approaches to long COVID sequelae are discussed. Understanding the complexity of this disease, its symptoms across multiple organ systems and overlapping pathologies and its possible mechanisms are paramount in developing diagnostic tools and treatments.

Cognition and Memory after Covid-19 in a Large Community Sample

BACKGROUND

Cognitive symptoms after coronavirus disease 2019 (Covid-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are well-recognized. Whether objectively measurable cognitive deficits exist and how long they persist are unclear.

METHODS

We invited 800,000 adults in a study in England to complete an online assessment of cognitive function. We estimated a global cognitive score across eight tasks. We hypothesized that participants with persistent symptoms (lasting ≥12 weeks) after infection onset would have objectively measurable global cognitive deficits and that impairments in executive functioning and memory would be observed in such participants, especially in those who reported recent poor memory or difficulty thinking or concentrating ("brain fog").

RESULTS

Of the 141,583 participants who started the online cognitive assessment, 112,964 completed it. In a multiple regression analysis, participants who had recovered from Covid-19 in whom symptoms had resolved in less than 4 weeks or at least 12 weeks had similar small deficits in global cognition as compared with those in the no-Covid-19 group, who had not been infected with SARS-CoV-2 or had unconfirmed infection (-0.23 SD [95% confidence interval {CI}, -0.33 to -0.13] and -0.24 SD [95% CI, -0.36 to -0.12], respectively); larger deficits as compared with the no-Covid-19 group were seen in participants with unresolved persistent symptoms (-0.42 SD; 95% CI, -0.53 to -0.31). Larger deficits were seen in participants who had SARS-CoV-2 infection during periods in which the original virus or the B.1.1.7 variant was predominant than in those infected with later variants (e.g., -0.17 SD for the B.1.1.7 variant vs. the B.1.1.529 variant; 95% CI, -0.20 to -0.13) and in participants who had been hospitalized than in those who had not been hospitalized (e.g., intensive care unit admission, -0.35 SD; 95% CI, -0.49 to -0.20). Results of the analyses were similar to those of propensity-score-matching analyses. In a comparison of the group that had unresolved persistent symptoms with the no-Covid-19 group, memory, reasoning, and executive function tasks were associated with the largest deficits (-0.33 to -0.20 SD); these tasks correlated weakly with recent symptoms, including poor memory and brain fog. No adverse events were reported.

CONCLUSIONS

Participants with resolved persistent symptoms after Covid-19 had objectively measured cognitive function similar to that in participants with shorter-duration symptoms, although short-duration Covid-19 was still associated with small cognitive deficits after recovery. Longer-term persistence of cognitive deficits and any clinical implications remain uncertain. (Funded by the National Institute for Health and Care Research and others.).

Microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19

Although some studies have shown neuroimaging and neuropsychological alterations in post-COVID-19 patients, fewer combined neuroimaging and neuropsychology evaluations of individuals who presented a mild acute infection. Here we investigated cognitive dysfunction and brain changes in a group of mildly infected individuals. We conducted a cross-sectional study of 97 consecutive subjects (median age of 41 years) without current or history of psychiatric symptoms (including anxiety and depression) after a mild infection, with a median of 79 days (and mean of 97 days) after diagnosis of COVID-19. We performed semi-structured interviews, neurological examinations, 3T-MRI scans, and neuropsychological assessments. For MRI analyses, we included a group of non-infected 77 controls. The MRI study included white matter (WM) investigation with diffusion tensor images (DTI) and functional connectivity with resting-state functional MRI (RS-fMRI). The patients reported memory loss (36%), fatigue (31%) and headache (29%). The quantitative analyses confirmed symptoms of fatigue (83% of participants), excessive somnolence (35%), impaired phonemic verbal fluency (21%), impaired verbal categorical fluency (13%) and impaired logical memory immediate recall (16%). The WM analyses with DTI revealed higher axial diffusivity values in post-infected patients compared to controls. Compared to controls, there were no significant differences in the functional connectivity of the posterior cingulum cortex. There were no significant correlations between neuropsychological scores and neuroimaging features (including DTI and RS-fMRI). Our results suggest persistent cognitive impairment and subtle white matter abnormalities in individuals mildly infected without anxiety or depression symptoms. The longitudinal analyses will clarify whether these alterations are temporary or permanent.

"Brain Fog" After COVID-19 Infection: How the Field of Neuropsychology Can Help Clear the Air

The chapter explores the role of neuropsychology in understanding brain fog as a subjective complaint in the context of COVID-19. It discusses the historical and medical significance of the term "brain fog" and its psychological and neurological aspects. The chapter identifies the cognitive domains commonly affected by brain fog, such as attention, executive function, memory, and language. Additionally, it emphasizes the impact of societal changes during the COVID-19 pandemic on the general population as a crucial backdrop for understanding the issue. The chapter also highlights the important role of clinical and research neuropsychologists in gaining clarity on grouped data and individual patients' cognitive and emotional difficulties after COVID-19 infection. It discusses indications for neuropsychological rehabilitation and therapy and describes typical therapy phases and methods, including new approaches like telemedicine, virtual reality, and mobile app-based rehabilitation and self-tracking. The chapter underscores that experiences of brain fog can vary among COVID-19 patients and may change over time. It provides clinicians and interested parties with an in-depth understanding of brain fog and its manifestations, concomitant subtypes, and concrete strategies for addressing it. The chapter emphasizes the critical role of neuropsychology in scientifically examining brain fog and advocating for personalized approaches to cognitive rehabilitation.

[Cognitive alterations in patients recovered from COVID-19 treated in Cardiopulmonary Rehabilitation]

Background

COVID-19 is associated with multiple complications, in addition to those produced at the pulmonary level. Post-COVID-19 cognitive deficits have been detected in the cognitive domain of attention and executive functions, even 4 months after COVID-19.

Objective

to determine the frequency of cognitive alterations in patients recovered from COVID-19.

Material and methods

A cross-sectional, descriptive and analytical study was carried out. Records of patients in care after infection by SARS-CoV-2 were integrated, the Neuropsi test was applied. Descriptive statistics and association tests were used through the Chi square test, taking p < 0.05 as significant.

Results

Data from 44 files were integrated. The median age, I place them in the sixth decade of life. There was a predominance of men (63.6%). The most frequent comorbidities were systemic arterial hypertension (50%) and diabetes mellitus (40.9%). Most of the patients were managed only at home (61.4%) with a moderate-severe COVID-19 picture (68.2%). The most affected dimensions of the Neuropsi test were attention and concentration (47.7%, mild alteration) and short-term memory (77.3%, mild alteration).

Conclusions

Cognitive impairment in patients recovered from COVID-19 assessed through the Neuropsi test presented mild alterations in attention and concentration, as well as in short-term memory. These could affect functionality, quality of life and ability to perform work.

The Effect of Beta-Carotene on Cognitive Function: A Systematic Review

β-carotene is a powerful antioxidant and dietary precursor of vitamin A whose role in maintaining mental health and cognitive performance, either alone or in combination with other dietary compounds, has been a topic of recent research. However, its effectiveness is still unclear. This systematic review, conducted according to the PRISMA guideline and assisted by the MySLR platform, addressed this issue. A total of 16 eligible original research articles were identified. Dietary intake or β-carotene serum levels were associated with improved measures of cognitive function in 7 out of 10 epidemiological studies included. In intervention studies, β-carotene consumption alone did not promote better cognitive function in the short term, but only in a long-term intervention with a mean duration of 18 years. However, all but one intervention study suggested the beneficial effects of β-carotene supplementation at doses ranging from 6 mg to 50 mg per day in combination with a multicomplex such as vitamin E, vitamin C, zinc, or selenium for a period of 16 weeks to 20 years. Despite the current limitations, the available evidence suggests a potential association between β-carotene dietary/supplementary intake and the maintenance of cognitive function. The β-carotene most probably does not act alone but in synergy with other micronutrients.

Association of adiposity and its changes over time with COVID-19 risk in older adults with overweight/obesity and metabolic syndrome: a longitudinal evaluation in the PREDIMED-Plus cohort

BACKGROUND

Cross-sectionally, older age and obesity are associated with increased coronavirus disease-2019 (COVID-19) risk. We assessed the longitudinal associations of baseline and changes in adiposity parameters with COVID-19 incidence in older adults at high cardiovascular risk.

METHODS

This analysis included 6874 men and women (aged 55-75 years) with overweight/obesity and metabolic syndrome in the PREDIMED-Plus lifestyle intervention trial for cardiovascular risk reduction. Body weight, body-mass-index (BMI), waist circumference, waist-to-height ratio (WHtR), and a body shape index (ABSI) were measured at baseline and annual follow-up visits. COVID-19 was ascertained by an independent Event Committee until 31 December 2021. Cox regression models were fitted to evaluate the risk of COVID-19 incidence based on baseline adiposity parameters measured 5-6 years before the pandemic and their changes at the visit prior to censoring.

RESULTS

At the time of censoring, 653 incident COVID-19 cases occurred. Higher baseline body weight, BMI, waist circumference, and WHtR were associated with increased COVID-19 risk. During the follow-up, every unit increase in body weight (HRadj (95%CI): 1.01 (1.00, 1.03)) and BMI (HRadj: 1.04 (1.003, 1.08)) was associated with increased COVID-19 risk.

CONCLUSIONS

In older adults with overweight/obesity, clinically significant weight loss may protect against COVID-19.

TRIAL REGISTRATION

This study is registered at the International Standard Randomized Controlled Trial (ISRCT; http://www.isrctn.com/ISRCTN89898870 ).

Hyperbaric Oxygen Therapy Counters Oxidative Stress/Inflammation-Driven Symptoms in Long COVID-19 Patients: Preliminary Outcomes

Long COVID-19 patients show systemic inflammation and persistent symptoms such as fatigue and malaise, profoundly affecting their quality of life. Since improving oxygenation can oppose inflammation at multiple tissue levels, we hypothesized that hyperbaric oxygen therapy (HBOT) could arrest inflammation progression and thus relieve symptoms of COVID-19. We evaluated oxy-inflammation biomarkers in long COVID-19 subjects treated with HBOT and monitored with non-invasive methods. Five subjects (two athletes and three patients with other comorbidities) were assigned to receive HBOT: 100% inspired O2 at 2.4 ATA in a multiplace hyperbaric chamber for 90 min (three athletes: 15 HBOT × 5 days/wk for 3 weeks; two patients affected by Idiopathic Sudden Sensorineural Hearing Loss: 30 HBOT × 5 days/wk for 6 weeks; and one patient with osteomyelitis: 30 HBOT × 5 days/wk for week for 6 weeks and, after a 30-day break, followed by a second cycle of 20 HBOT). Using saliva and/or urine samples, reactive oxygen species (ROS), antioxidant capacity, cytokines, lipids peroxidation, DNA damage, and renal status were assessed at T1_pre (basal level) and at T2_pre (basal level after treatment), and the results showed attenuated ROS production, lipid peroxidation, DNA damage, NO metabolites, and inflammation biomarker levels, especially in the athletes post-treatment. Thus, HBOT may represent an alternative non-invasive method for treating long COVID-19-induced long-lasting manifestations of oxy-inflammation.

Vaccination prevents IL-1β-mediated cognitive deficits after COVID-19

Up to 25% of SARS-CoV-2 patients exhibit post-acute cognitive sequelae. Although millions of cases of COVID-19-mediated memory dysfunction are accumulating worldwide, the underlying mechanisms and how vaccination lowers risk are unknown. Interleukin-1, a key component of innate immune defense against SARS-CoV-2 infection, is elevated in the hippocampi of COVID-19 patients. Here we show that intranasal infection of C57BL/6J mice with SARS-CoV-2 beta variant, leads to CNS infiltration of Ly6Chi monocytes and microglial activation. Accordingly, SARS-CoV-2, but not H1N1 influenza virus, increases levels of brain IL-1β and induces persistent IL-1R1-mediated loss of hippocampal neurogenesis, which promotes post-acute cognitive deficits. Breakthrough infection after vaccination with a low dose of adenoviral vectored Spike protein prevents hippocampal production of IL-1β during breakthrough SARS-CoV-2 infection, loss of neurogenesis, and subsequent memory deficits. Our study identifies IL-1β as one potential mechanism driving SARS-CoV-2-induced cognitive impairment in a new murine model that is prevented by vaccination.

What Is the Role of Palmitoylethanolamide Co-Ultramicronized with Luteolin on the Symptomatology Reported by Patients Suffering from Long COVID? A Retrospective Analysis Performed by a Group of General Practitioners in a Real-Life Setting

Long COVID is a recognized post-viral syndrome characterized by neurological, somatic and neuropsychiatric symptoms that might last for long time after SARS-CoV-2 infection. An ever-growing number of patients come to the observation of General Practitioners complaining of mild or moderate symptoms after the resolution of the acute infection. Nine General Practitioners from the Rome area (Italy) performed a retrospective analysis in order to evaluate the role of the supplementation with Palmitoylethanolamide co-ultramicronized with Luteolin (PEALUT) on neurologic and clinical symptoms reported by their patients after COVID-19 resolution. Supplementation with PEALUT helped to improve all patient-reported symptoms, especially pain, anxiety and depression, fatigue, brain fog, anosmia and dysgeusia, leading to an overall improvement in patients' health status. To our knowledge these are the first data presented on Long COVID patients collected in a territorial setting. Despite their preliminary nature, these results highlight the pathogenetic role of "non-resolving" neuroinflammation in Long COVID development and consequently the importance of its control in the resolution of the pathology and put the focus on the General Practitioner as the primary figure for early detection and management of Long COVID syndrome in a real-life setting. Future randomized, controlled, perspective clinical trials are needed to confirm this preliminary observation.

Hematological alterations associated with long COVID-19

Long COVID-19 is a condition characterized by persistent symptoms lasting beyond the acute phase of COVID-19. Long COVID-19 produces diverse symptomatology and can impact organs and systems, including the hematological system. Several studies have reported, in COVID-19 patients, hematological abnormalities. Most of these alterations are associated with a higher risk of severe disease and poor outcomes. This literature review identified studies reporting hematological parameters in individuals with Long COVID-19. Findings suggest that Long COVID-19 is associated with a range of sustained hematological alterations, including alterations in red blood cells, anemia, lymphopenia, and elevated levels of inflammatory markers such as ferritin, D-dimer, and IL-6. These alterations may contribute to a better understanding of the pathophysiology of Long COVID-19 and its associated symptoms. However, further research is needed to elucidate the underlying mechanisms and potential treatments for these hematological changes in individuals with Long COVID-19.

Immunoglobulin A as a Key Immunological Molecular Signature of Post-COVID-19 Conditions

COVID-19 has infected humans worldwide, causing millions of deaths or prolonged symptoms in survivors. The transient or persistent symptoms after SARS-CoV-2 infection have been defined as post-COVID-19 conditions (PCC). We conducted a study of 151 Brazilian PCC patients to analyze symptoms and immunoglobulin profiles, taking into account sex, vaccination, hospitalization, and age. Fatigue and myalgia were the most common symptoms, and lack of vaccination, hospitalization, and neuropsychiatric and metabolic comorbidities were relevant to the development of PCC. Analysis of serological immunoglobulins showed that IgA was higher in PCC patients, especially in the adult and elderly groups. Also, non-hospitalized and hospitalized PCC patients produced high and similar levels of IgA. Our results indicated that the detection of IgA antibodies against SARS-CoV-2 during the course of the disease could be associated with the development of PCC and may be an immunological signature to predict prolonged symptoms in COVID-19 patients.

Long COVID prevalence and impact on quality of life 2 years after acute COVID-19

There has been an increasing interest in the long-term impact of long COVID. However, only a few studies have investigated the clinical manifestations of long COVID after 24 months of acute infection. In this study, prospective online surveys were conducted in adults previously diagnosed with coronavirus disease 2019 (COVID-19) in South Korea between February 13 and March 13, 2020, at 6, 12, and 24 months after COVID-19. We investigated self-reported symptoms and the EuroQol-5-dimension index. Among 900 individuals enrolled initially, 150 completed all 3 surveys. After excluding the cases of COVID-19 reinfection, 132 individuals were included in the final analysis. Among the 132 participants, 94 (71.2%) experienced symptoms of long COVID. The most frequently reported symptoms were fatigue (34.8%), amnesia (30.3%), concentration difficulties (24.2%), insomnia (20.5%), and depression (19.7%). Notably, no significant differences were noted in the incidence of long COVID at 24 months in terms of the number of vaccinations received. Although the neuropsychiatric quality of life improved over time, it continued to affect 32.7% of participants. Symptoms of long COVID, particularly neuropsychiatric symptoms, tend to persist over time, and COVID-19 vaccination or the number of vaccinations received may not significantly affect the incidence of long COVID.