Long COVID syndrome-associated brain fog

Psychological symptoms and risk factors associated with long COVID: a study on the Indian cohort

The long-term neurological effects of COVID-19, such as lack of concentration, loss of memory, and anxiety, present major concerns for COVID-19 Recovered Individuals (CRIs). Our study aims at understanding these long-term COVID-19 symptoms (LCS) and associated risk factors among the Indian cohort. In this two-part study, we analyze self-reported symptom information such as fatigue in different life spheres, symptoms experienced in past months, hospitalization status, and sex of Healthy Controls (HCs) and CRIs. In Study 1, we compare the symptoms of 62 CRIs (16 Females; 30.60   ±   10.34 years) with 36 hCs (11 Females; 27.53   ±   7.3 years). Chi-square analysis revealed that both the groups differ significantly from each other in terms of self-reported major symptoms experienced (MSEs) (p < 0.001) and major life spheres being affected by fatigue (MLSA) (p = 0.008). Further, in Study 2, we explore predictive models for these symptoms as reported by 57 of the CRIs (15 Females; 31.28   ±   10.50 years) using logistic regression and receiver operator characteristic (ROCs) information, with unrefreshing sleep, hospitalization status, and sex as the predictors for LCS. Statistical analysis reveals unrefreshing sleep as an important predictor of attention issues (odds ratio (OR) = 6.25, p = 0.003), anxiety issues (OR = 7.75, p = 0.018), and fatigue (OR = 5.83, p = 0.018) but was found non-significant for memory issues (OR = 1.86, p = 0.513) among CRIs. Hospitalization status and sex were not found to significantly affect these reported symptoms.

Persistent cognitive symptoms in mild COVID-19 infection: a retrospective cohort study

BACKGROUND

The COVID-19 pandemic represented a healthcare challenge of unparalleled magnitude worldwide. As patients recovered from the acute infection, a new challenge emerged, i.e., the development of post-acute symptoms. The main goal of this study was to evaluate the trajectory of cognitive symptoms since the acute phase of COVID-19 among patients followed through a telehealth program in Brazil.

METHODS

A retrospective cohort study was conducted with confirmed COVID-19 patients followed by a Brazilian telehealth program who presented cognitive symptoms in the acute phase of infection. The objective of the current analysis was to assess the persistence or remission of cognitive symptoms at 24 weeks after the onset of acute COVID-19 symptoms, as well as the factors associated with such manifestations. The study used chi-square tests and multivariate logistic regression models to assess the association between patients' parameters and the presence of cognitive symptoms. A backward stepwise method was applied to define significant characteristics, which were then evaluated using odds ratios and 95% confidence intervals.

RESULTS

Among 319 patients who had cognitive symptoms during acute COVID-19, 89 (27.9%) reported persistence of cognitive symptoms for more than 24 weeks from the acute onset of the infection. Female sex (OR 2.33 [95% CI 1.23-4.43]) and having been infected during the second wave of COVID-19 (OR 2.30 [95% CI 1.34-3.96]) were associated with the persistence of symptoms beyond 24 weeks.

CONCLUSIONS

Approximately one-third of patients with COVID-19, mainly women and people infected during the second wave of infection, experienced persistent cognitive symptoms.

Follow-up of long COVID based on the definition of WHO: a multi-centre cross-sectional questionnaire-based study

BACKGROUND

Since long COVID has hindered people from normal life, it is essential to understand its full spectrum of manifestation. However, it was heterogeneous in the existing studies and few large-scale studies have been conducted on Asian populations. Here, we conducted a multi-centre questionnaire-based study among Chinese people to explore the long COVID based on the definition of WHO.

METHODS

During March 20, 2023 and June 18, 2023, individuals with a history of confirmed or self-reported SARS-CoV-2 infection were recruited from three hospitals to fill out the questionnaire for long COVID. Each symptom was assigned with 0 to 3 points based on their severity. And the long COVID score was a sum of these points of each symptom. The reporting rate, time trend and risk factors of long COVID stratified by different systems were explored.

RESULTS

3,693 individuals were recruited for the study. The reporting rate of at least one persistent long COVID symptoms and symptoms impacting daily life was 30.2% (1,117) and 10.7% (394). Systemic symptoms (20.7%, 765) were most easily reported. The most common symptoms were fatigue (16.3%, 602), cough (6.3%, 234) and expectoration (5.5%, 203). The reporting rate of long COVID and long COVID score decreased over time during a 180-day follow-up period (P < 0.05). For long COVID, older age (OR: 1.63, 1.38-1.93), female (OR: 1.19, 1.03-1.38) and SARS-CoV-2 reinfection (OR: 3.56, 2.63-4.80) were risk factors; while number of COVID-19 vaccine doses (OR: 0.87, 0.81-0.94) was a protective factor. The use of traditional Chinese medicine (OR: 0.51, 0.37-0.71) was a protective factor for symptoms impacting daily life.

CONCLUSIONS

Early interventions should be taken to minimize the impact of long COVID, especially for the elderly, females and those with SARS-CoV-2 reinfection. COVID-19 booster vaccination might play a potential role in minimizing the impact of long COVID.

Cutting through the fog: recognising brain fog as a significant public health concern

Brain fog is a highly common condition that can have significant impacts on quality of life and functioning. Most people will experience a condition, illness, or infection that might result in the development of brain fog. We provide a call to action to minimise the impacts of brain fog.

Sex-related differences in the association between migraine, COVID-19, and long COVID: a population-based cohort

Background

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, placed unprecedented pressure on public health systems due to its mortality and global panic-and later due to long COVID challenges. One of these long COVID symptoms, headache, often resembles migraine-like features. Migraine shares similarities with COVID-19 and long COVID, yet the influence of sex is understudied. Our primary objective was to study the interrelationship between COVID-19 and migraine prevalence, while considering sex differences. The secondary objective was to examine how long COVID symptoms (headache, anosmia, memory, and concentration problems) affect males and females with and without COVID-19 and migraine.

Methods

All analyses were conducted using Lifelines, a prospective cohort study in the northern Netherlands. Baseline characteristics (2006-2014), self-reported migraine diagnoses (until 2021), and questionnaires on COVID-19 and long COVID symptoms (2020-2022) were collected. Logistic regression analyses were conducted to study the association between lifetime migraine and current SARS-CoV-2 infections while adjusting for age, sex, diet, educational attainment, activity, and smoking. Descriptive and sex-stratified analyses were conducted on long COVID symptoms.

Results

A total of 150,507 individuals were included, of which 29,680 (19.7%) reported migraine and 120,827 (80.3%) not. A total of 1,867 individuals with migraine [6.3% of individuals with migraine, 44.0 years (IQR 36.1-50.3)] and 6,797 individuals without migraine [5.6% of individuals without migraine, 44.4 years (IQR 35.3-52.2)] reported to be SARS-CoV-2 infected. The majority of individuals with migraine consisted of females (77.0% of those with migraine vs. 54.0% of those without migraine). The adjusted odds of having SARS-CoV-2 infections was 6.3% higher among those with (a history of) migraine compared with individuals without migraine in the logistic regression model (OR = 1.06, 95% CI 1.01-1.12). A slightly higher OR was observed in females (OR = 1.08, 95% CI 1.02-1.15), and the association was not apparent in males (OR = 1.00, 95% CI 0.88-1.12). Secondary analyses revealed that individuals with both migraine and COVID-19, and females in particular, were the most frequently bothered by long COVID symptoms headache, anosmia, concentration, and memory problems. Individuals with none of these diseases were the least bothered.

Conclusions

Individuals with migraine, especially females, are slightly more likely to report and/or contract COVID-19. Those with both conditions report long COVID symptoms more frequently, suggesting a shared vulnerability or pathophysiology. This may indicate the need for clinical surveillance of migraine patients recovering from COVID-19.

Brain fog

'Brain fog' is a term that patients use increasingly frequently in the neurology clinic. We may think that we know what patients are talking about but at least some of the time we are likely to be getting it wrong. Patients use the term 'brain fog' to describe a wide range of subjective phenomena and symptoms. This paper suggests useful lines of questioning, and discusses the clinical correlates of a range of common 'brain fog' experiences.

Brain Fog and Cognitive Dysfunction in Posttraumatic Stress Disorder: An Evidence-Based Review

The term "brain fog" has long been used both colloquially and in research literature in reference to various neurocognitive phenomenon that detract from cognitive efficiency. We define "brain fog" as the subjective experience of cognitive difficulties, in keeping with the most common colloquial and research use of the term. While a recent increase in use of this term has largely been in the context of the post-coronavirus-19 condition known as long COVID, "brain fog" has also been discussed in relation to several other conditions including mental health conditions such as post-traumatic stress disorder (PTSD). PTSD is associated with both subjective cognitive complaints and relative deficits on cognitive testing, but the phenomenology and mechanisms contributing to "brain fog" in this population are poorly understood. PTSD psychopathology across cognitive, affective and physiological symptom domains have been tied to "brain fog". Furthermore, dissociative symptoms common in PTSD also contribute to the experience of "brain fog". Comorbid physical and mental health conditions may also increase the risk of experiencing "brain fog" among individuals with PTSD. Considerations for the assessment of "brain fog" in PTSD as part of psychodiagnostic assessment are discussed. While standard psychological intervention for PTSD is associated with a reduction in subjective cognitive deficits, other cognitive interventions may be valuable when "brain fog" persists following PTSD remission or when "brain fog" interferes with treatment. Limitations of current research on "brain fog" in PTSD include a lack of consistent definition and operationalization of "brain fog" in the literature, as well as limited tools for measurement. Future research should address these limitations, as well as further evaluate the use of cognitive remediation as an intervention for "brain fog".

COVID-19 related complications

The COVID-19 pandemic has significantly impacted global healthcare systems, revealed vulnerabilities and prompted a re-evaluation of medical practices. Acute complications from the virus, including cardiovascular and neurological issues, have underscored the necessity for timely medical interventions. Advances in diagnostic methods and personalized therapies have been pivotal in mitigating severe outcomes. Additionally, Long COVID has emerged as a complex challenge, affecting various body systems and leading to respiratory, cardiovascular, neurological, psychological, and musculoskeletal problems. This broad spectrum of complications highlights the importance of multidisciplinary management approaches that prioritize therapy, rehabilitation, and patient-centered care. Vulnerable populations such as paediatric patients, pregnant women, and immunocompromised individuals face unique risks and complications, necessitating continuous monitoring and tailored management strategies to reduce morbidity and mortality associated with COVID-19.

Global prevalence of post-COVID-19 condition: a systematic review and meta-analysis of prospective evidence

INTRODUCTION

We investigated the prevalence of new or persistent manifestations experienced by COVID-19 survivors at 3 or more months after their initial infection, collectively known as post-COVID-19 condition (PCC).

METHODS

We searched four electronic databases and major grey literature resources for prospective studies, systematic reviews, authoritative reports and population surveys. A random-effects meta-analysis pooled the prevalence data of 22 symptoms and outcomes. The GRADE approach was used to assess the certainty of evidence. PROSPERO CRD42021231476.

RESULTS

Of 20 731 identified references, 194 met our inclusion criteria. These studies followed 483 531 individuals with confirmed COVID-19 diagnosis over periods of up to 2 years. Most focused on adults, nearly two-thirds were conducted in Europe and 63% were of high or moderate quality. The supplementary search identified 17 systematic reviews, five authoritative reports and four population surveys that reported on PCC prevalence. Our analysis revealed that more than half of COVID-19 survivors experienced one or more symptoms more than a year after their initial infection. The most common symptoms were fatiguedyspneamemory, sleep or concentration disturbances; depressionand pain. Limitation in returning to work was the most common outcome. Prevalence tended to be higher among females, individuals hospitalized during their initial infection and those who experienced severe COVID-19 illness.

CONCLUSION

PCC presents a significant health burden, affecting some groups more than others. This information will help inform health care system policies and services for people living with PCC and those caring for them.

Exploring Cognitive Dysfunction in Long COVID Patients: Eye Movement Abnormalities and Frontal-Subcortical Circuits Implications via Eye-Tracking and Machine Learning

BACKGROUND

Cognitive dysfunction is regarded as one of the most severe aftereffects following coronavirus disease 2019 (COVID-19). Eye movements, controlled by several brain areas, such as the dorsolateral prefrontal cortex and frontal-thalamic circuits, provide a potential metric for assessing cortical networks and cognitive status. We aimed to examine the utility of eye movement measurements in identifying cognitive impairments in long COVID patients.

METHODS

We recruited 40 long COVID patients experiencing subjective cognitive complaints and 40 healthy controls and used a certified eye-tracking medical device to record saccades and antisaccades. Machine learning was applied to enhance the analysis of eye movement data.

RESULTS

Patients did not differ from the healthy controls regarding age, sex, and years of education. However, the patients' Montreal Cognitive Assessment total score was significantly lower than healthy controls. Most eye movement parameters were significantly worse in patients. These included the latencies, gain (computed as the ratio between stimulus amplitude and gaze amplitude), velocities, and accuracy (evaluated by the presence of hypermetric or hypometria dysmetria) of both visually and memory-guided saccades; the number of correct memory saccades; the latencies and duration of reflexive saccades; and the number of errors in the antisaccade test. Machine learning permitted distinguishing between long COVID patients experiencing subjective cognitive complaints and healthy controls.

CONCLUSION

Our findings suggest impairments in frontal subcortical circuits among long COVID patients who report subjective cognitive complaints. Eye-tracking, combined with machine learning, offers a novel, efficient way to assess and monitor long COVID patients' cognitive dysfunctions, suggesting its utility in clinical settings for early detection and personalized treatment strategies. Further research is needed to determine the long-term implications of these findings and the reversibility of cognitive dysfunctions.

Neurological long COVID in the outpatient clinic: Is it so long?

BACKGROUND AND PURPOSE

Neurological involvement in long COVID (coronavirus disease 2019) is well known. In a previous study we identified two subtypes of neurological long COVID, one characterized by memory disturbances, psychological impairment, headache, anosmia and ageusia, and the other characterized by peripheral nervous system involvement, each of which present a different risk factor profile. In this study, we aimed to clarify the persistence of neurological long COVID symptoms with a significantly longer term follow-up.

METHODS

We prospectively collected data from patients with prior COVID-19 infection who showed symptoms of neurological long COVID. We conducted a descriptive analysis to investigate the progression of neurological symptoms over time at 3-, 6-, 12-, and 18-month follow-ups. We performed a k-means clustering analysis on the temporal evolution of the symptoms at 6, 12, and 18 months. Finally, we assessed the difference between the recovery course of vaccinated and non-vaccinated patients by computing the cumulative recovery rate of symptoms in the two groups.

RESULTS

The study confirmed the presence of two subtypes of neurological long COVID. Further, 50% of patients presented a complete resolution of symptoms at 18 months of follow-up, regardless of which subtype of neurological long COVID they had. Vaccination against SARS-Cov-2 appeared to imply a higher overall recovery rate for all neurological symptoms, although the statistical reliability of this finding is hampered by the limited sample size of the unvaccinated patients included in this study.

CONCLUSIONS

Neurological long COVID can undergo complete resolution after 18 months of follow-up in 50% of patients and vaccination can accelerate the recovery.

Defining brain fog across medical conditions

'Brain fog' is commonly reported in more than a dozen chronic diseases, but what is it? We review research across conditions which has characterised brain fog and evaluate its definitions and objective correlates. Brain fog has been used to refer to a variable set of overlapping symptoms implicating cognition, fatigue, and affect. It has been defined as a distinct symptom, a syndrome, or a nonspecific term. We consider the evidence that brain fog is a transdiagnostic entity with a common phenomenology and profile of objective cognitive deficits. We discuss where these commonalities arise and argue that linguistic ambiguity, shared cognitive impairments, and noncognitive factors are more likely than shared neurobiology. We suggest how future research might apply existing tools to disambiguate the phenomena that brain fog conflates.

How Are Brain Fog Symptoms Related to Diet, Sleep, Mood and Gastrointestinal Health? A Cross-Sectional Study

Background and Objectives: Brain fog, characterized by cognitive difficulties such as memory impairment, lack of focus, and mental fatigue, is a common symptom reported during recovery from COVID-19, particularly in long COVID cases. This study explores potential triggers such as sleep quality, mood, and gastrointestinal health and examines the link between adherence to the MIND diet and brain fog severity. Materials and Methods: A cross-sectional study was conducted between 1 July and 15 December 2022. The questionnaire assessed brain fog symptoms, dietary habits, sleep quality, mood, and gastrointestinal symptoms. Linear regression analysis examined the relationships between brain fog symptoms, demographic factors, sleep quality, MIND diet adherence, and gastrointestinal symptoms. Results: Brain Fog Scale (BFS) scores were significantly higher in individuals who had COVID-19 (p < 0.05) and even higher in those with reinfection. Women had higher BFS and Brain Fog Severity Score (BFSS), MIND Diet, The Gastrointestinal Symptom Rating Scale (GSRS), Brief Mood Introspection Scale (BMIS) Pleasant-Unpleasant scores (p < 0.05). BFS and BFSS were positively correlated with GSRS (p < 0.05), while no correlation was found with MIND diet adherence. A negative correlation was observed between BFS and Sleep Quality Scale (SQS) (p < 0.05), but this was not significant in regression (p = 0.367). GSRS, Pleasant-Unpleasant Dimension, and Arousal-Calm Dimension were significant predictors of BFS (R = 0.599, R2 = 0.358, p < 0.01). Conclusions: This study identifies being female as a risk factor for brain fog symptoms, with women reporting higher BFS and BFSS scores. While sleep quality showed a negative correlation with brain fog symptoms, this relationship was not significant in the regression model, suggesting that other factors, such as mood and gastrointestinal symptoms, may play a more dominant role. However, adherence to the MIND diet showed no significant relationship with brain fog symptoms. These findings suggest that addressing mood and gastrointestinal health may be key to managing brain fog in long COVID.

Neurological sequelae of long COVID: a comprehensive review of diagnostic imaging, underlying mechanisms, and potential therapeutics

One lingering effect of the COVID-19 pandemic created by SARS-CoV-2 is the emergence of Long COVID (LC), characterized by enduring neurological sequelae affecting a significant portion of survivors. This review provides a thorough analysis of these neurological disruptions with respect to cognitive dysfunction, which broadly manifest as chronic insomnia, fatigue, mood dysregulation, and cognitive impairments with respect to cognitive dysfunction. Furthermore, we characterize how diagnostic tools such as PET, MRI, EEG, and ultrasonography provide critical insight into subtle neurological anomalies that may mechanistically explain the Long COVID disease phenotype. In this review, we explore the mechanistic hypotheses of these neurological changes, which describe CNS invasion, neuroinflammation, blood-brain barrier disruption, and gut-brain axis dysregulation, along with the novel vascular disruption hypothesis that highlights endothelial dysfunction and hypoperfusion as a core underlying mechanism. We lastly evaluate the clinical treatment landscape, scrutinizing the efficacy of various therapeutic strategies ranging from antivirals to anti-inflammatory agents in mitigating the multifaceted symptoms of LC.

A Systems Neuroscience Approach to Diagnosis and Rehabilitation of Post COVID Neurological Syndrome Based on the Systems Neuroscience Test Battery (SNTB) Study Protocol

The proposed study reports the design and development of a rapid screening tool, the Systems Neuroscience Test Battery (SNTB), for diagnosing and evaluating the neurological manifestations of Post-COVID-19 Neurological Syndrome (PCNS) within the broader context of Post-Acute Sequelae to COVID-19 (PASC). The SNTB is designed to incorporate a behaviorally relevant Telehealth component that enhances consumer confidence in symptom discrimination, management of PCNS, and guides rehabilitation programs while allowing for continuous evaluation of intervention effectiveness.The study employs a longitudinal design, with telehealth and routine blood assessments conducted at three-month intervals, including at least two follow-ups post-recruitment. These assessments will involve Consumer-Reported Symptoms, Clinical History, Neuropsychological Data, and Timed Psychophysics, aimed at rapid screening of PCNS-related symptoms including 'brain fog" and its affect on visually driven attention, cognition and visually driven motor behaviors. These assessments are intended to validate the characteristics of 'brain fog' and identify predictive behavioral biomarkers for the development of PCNS.The target population includes adults aged 18-65 who have experienced persistent neurological symptoms for at least three months following a confirmed COVID-19 infection. Exclusion criteria include individuals unable to undergo radiological examinations, such as pregnant women or those with contraindications to MRI, ensuring the robustness of the sample and reducing potential selection bias.The SNTB tool will facilitate the online identification of predictive biomarkers for PCNS and aid in the discovery of effective molecular biomarker combinations for medical intervention and rehabilitation. Complementary to the Telehealth Assessment, hospital facilities will be utilized for radiological and blood-based molecular assessments, ensuring concurrent profiling of structural and functional changes during 'brain fog' and recovery from PCNS symptoms.

Genomic Patterns are Associated with Different Sequelae of Patients with Long-Term COVID-19

In the post-large era, various COVID-19 sequelae are getting more and more attention to health problems. Although the mortality rate of the COVID-19 infection is now declining, it is often accompanied by new clinical sequelae with different symptoms such as fatigue after infection, loss of smell. The degree of age, gender, virus infection seems to be weakly correlated with clinical symptoms. Human genetic variation plays a significant role in the sequelae of the COVID-19 infection. This study aims to analyze the genomic differences between individuals with different COVID-19 sequelae. In this study, the exomes of 97 patients with Omicron with 8 unique clinical manifestations are sequenced, and conducted a systematic analysis. Based on non-negative matrix factorization algorithms, the trinucleotide mutation spectrum of four long-term COVID-19 genomes is summarized and found that individuals with different clinical symptoms have unique DNA mutation patterns and indel patterns. By constructing a Genomic Fingerprinting Framework, the driver genes of variation in each symptomatic population are deciphered and analyzed. This study showed that population-specific mutational fingerprint differences are the main cause of heterogeneity in long-term COVID-19 sequelae. This study provides new ideas and insights into the causes of the long-term COVID-19 sequelae.

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.

Childhood hand, foot and mouth disease sequelae cohort study in Henan, China: cohort profile

PURPOSE

The childhood hand, foot and mouth disease (HFMD) sequelae cohort study (HNHFMDCS) is an ambispective cohort study of patients with HFMD based in Henan Province, China, consisting of patients treated in a key hospital for the diagnosis and treatment of HFMD in Henan Province. The study aims to investigate the long-term sequelae of HFMD survivors and to provide a comprehensive understanding of the potential harm caused by this infectious disease.

PARTICIPANTS

In the retrospective phase of the cohort study, children diagnosed with HFMD from January 2014 to January 2023 were included, and clinical and demographic information about the patients was collected through a self-developed questionnaire. Patients hospitalised with HFMD since January 2023 were enrolled in the prospective cohort phase of the study, and long-term follow-up will be performed after completion of the baseline investigation (interview and comprehensive physical examination), clinical laboratory examination and biospecimen collection.

FINDINGS TO DATE

For the retrospective analysis of the cohort, a total of 18 705 HFMD cases (11 834 males and 6871 females) were observed between 2014 and 2022, of which 17 202 were mild cases (10 839 males and 6363 females) and 1503 were severe cases (995 males and 508 females). Statistical analysis was performed on the collected clinical examination data, and descriptive statistical methods, including mean value, SD and t-test, were used to compare the intergroup data. All tests were bilateral, and p<0.05 was considered statistically significant. There were significant differences in the hospitalisation duration and clinical examination indicators, such as platelets (PLT), C reactive protein (CRP), aspartate amino transferase (AST), alanine amino transferase (ALT), T lymphocyte subsets (CD3+ and CD3+CD4+) and B lymphocytes (CD19+) between mild and severe patients. The differences in these clinical examination indicators also help to detect changes in the disease in time so as to deeply understand the potential harm and social burden of the disease, and provide strong support for the rehabilitation of patients.

FUTURE PLANS

Prospective cohort studies are currently underway, primarily enrolling hospitalised patients with HFMD to participate in our study. After the baseline investigation is completed, we will conduct long-term follow-up of the enrolled cases. In the coming year, we expect to obtain preliminary data on the incidence of sequelae in patients with HFMD 1-10 years after discharge, as well as information on the occurrence of sequelae. This dataset will be updated and expanded on an annual basis to support the continuous monitoring of patient health and disease progression. From HNHFMDCS, the study will provide a comprehensive overview of the potential harm caused by this common infectious disease, assess the social burden caused by this disease and make recommendations for the rehabilitation of survivors and prevention of further disability.

The neuropsychological impacts of coronavirus disease 2019 in nonhospitalized patients with long coronavirus disease and brain fog

BACKGROUND

Coronavirus disease 2019 (COVID-19) causes persistent symptoms, including brain fog. Based on limited research on the long-term consequences of mild COVID-19, which has yielded inconsistent results, we investigated which cognitive functions were most affected by COVID-19 in nonhospitalized Asian patients with long-term COVID and subjective cognitive complaints.

METHODS

Fifty-five nonhospitalized patients with subjective cognitive complaints after COVID infection (24 males and 31 females, mean age: 45.6 ± 14.6 years, mean duration of education: 14.4 ± 3.0 years) finished the study. Neuropsychological assessments included screening tests for overall cognition, and comprehensive tests for memory, executive function, processing speed, and subjective emotional and disease symptoms. Cognitive test scores were converted into Z -scores. Moreover, principal component analysis (PCA) was used to define cognitive domains across subtest scores.

RESULTS

Comprehensive assessments revealed cognitive impairment in 69.1% of patients (<1.5 SD in at least one test). The processing speed (27.3%), memory recall (21.8%), memory learning (20.0%), and inhibitory control (18.2%) were the most affected areas. Self-reported anxiety and depression were observed in 35% and 33% of patients, respectively. Furthermore, the degree of anxiety was predictive of learning performance.

CONCLUSION

Nearly 70% of patients with subjective cognitive complaints and long COVID had objective cognitive impairments. A comprehensive evaluation is essential for these patients, even when they present with mild symptoms.

Acute and long-term effects of COVID-19 on brain and mental health: A narrative review

BACKGROUND

COVID infection has been associated with long term sequalae (Long COVID) which include neurological and behavioral effects in thousands of patients, but the etiology and scope of symptoms is not well understood. This paper reviews long term sequelae of COVID on brain and mental health in patients with the Long COVID syndrome.

METHODS

This was a literature review which queried databases for Pubmed, Psychinfo, and Medline for the following topics for January 1, 2020-July 15, 2023: Long COVID, PASC, brain, brain imaging, neurological, neurobiology, mental health, anxiety, depression.

RESULTS

Tens of thousands of patients have developed Long COVID, with the most common neurobehavioral symptoms anosmia (loss of smell) and fatigue. Anxiety and mood disorders are elevated and seen in about 25% of Long COVID patients. Neuropsychological testing studies show a correlation between symptom severity and cognitive dysfunction, while brain imaging studies show global decreases in gray matter and alterations in olfactory and other brain areas.

CONCLUSIONS

Studies to date show an increase in neurobehavioral disturbances in patients with Long COVID. Future research is needed to determine mechanisms.

Persistent post COVID-19: Implications for women's health research and policy from members of the Women's Health Expert Panel of the American Academy of Nursing

BACKGROUND

Despite that globally the percent of women and men who tested positive for COVID-19 appears equal and that men with COVID-19 were 60% more likely than women to be severely ill and to die from complications (Rozenberg et al., 2020), studies of sex differences show that women compared with men are more likely to manifest persistent post-COVID-19 syndrome (PPCS).

PURPOSE

In this paper, we address some of the extant evidence for impact of the PPCS on women's health and well-being to underpin our suggestions for research and policy considerations.

METHODS

We assessed key papers in the extant literature to formulate views on needed health-related research and policies.

DISCUSSION

We discuss how key PPCS manifestations vary by sex, resemble sequelae uncovered for other chronically fatiguing or serious postinfectious trauma conditions, influence women's reproductive health (e.g., menstrual cycle, fertility, pregnancy, and menopause transition), impair women's social function and economic productivity, and challenge what is required for influential treatment and prevention.

CONCLUSION

To inform effective diagnosis, management and prevention of the significantly prevalent and debilitating PPCS, high on research and policy agendas should be uncovering multidimensional evidence of the impact on women, especially on their overall and reproductive health, well-being, social function and economic productivity.

Association between combination COVID-19-influenza vaccination and long COVID in middle-aged and older Europeans: A cross-sectional study

The potential impact of combined COVID-19 and influenza vaccination on long COVID remains uncertain. In the present cross-sectional study, we aimed to investigate the plausible association between them in middle-aged and older Europeans based on the Survey of Health, Ageing, and Retirement in Europe (SHARE). A total of 1910 participants were recruited in the analyses. The study outcome was long COVID. Participants were divided into 4 groups through the self-reported status of COVID-19 and influenza vaccination. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. 1397 participants experienced long COVID. After multivariable adjustment, those vaccinated with neither COVID-19 nor influenza vaccine had higher risk of long COVID (OR, 1.72; 95% CI, 1.26-2.35) compared to those vaccinated with both vaccines. Furthermore, adding the 4 statuses of COVID-19 vaccination/influenza vaccination to conventional risk model improved risk reclassification for long COVID (continuous net reclassification improvement was 16.26% [p = .003], and integrated discrimination improvement was 0.51% [p = .005]). No heterogeneity was found in the subgroup analyses (all p-interaction ≥0.05). Our study might provide a strategy for people aged 50 and over to reduce the occurrence of long COVID, that is, to combine the use of the COVID-19 vaccine and influenza vaccines.

Proteomic and metabolomic profiling of plasma uncovers immune responses in patients with Long COVID-19

Long COVID is an often-debilitating condition with severe, multisystem symptoms that can persist for weeks or months and increase the risk of various diseases. Currently, there is a lack of diagnostic tools for Long COVID in clinical practice. Therefore, this study utilizes plasma proteomics and metabolomics technologies to understand the molecular profile and pathophysiological mechanisms of Long COVID, providing clinical evidence for the development of potential biomarkers. This study included three age- and gender-matched cohorts: healthy controls (n = 18), COVID-19 recovered patients (n = 17), and Long COVID patients (n = 15). The proteomics results revealed significant differences in proteins between Long COVID-19 patients and COVID-19 recovered patients, with dysregulation mainly focused on pathways such as coagulation, platelets, complement cascade reactions, GPCR cell signal transduction, and substance transport, which can participate in regulating immune responses, inflammation, and tissue vascular repair. Metabolomics results showed that Long COVID patients and COVID-19 recovered patients have similar metabolic disorders, mainly involving dysregulation in lipid metabolites and fatty acid metabolism, such as glycerophospholipids, sphingolipid metabolism, and arachidonic acid metabolism processes. In summary, our study results indicate significant protein dysregulation and metabolic abnormalities in the plasma of Long COVID patients, leading to coagulation dysfunction, impaired energy metabolism, and chronic immune dysregulation, which are more pronounced than in COVID-19 recovered patients.

Association between COVID-19 infection and new-onset dementia in older adults: a systematic review and meta-analysis

BACKGROUND

The relationship between COVID-19 infection and a possible increased likelihood of older adults developing new-onset dementia (NOD) remains elusive.

METHODS

A thorough search was performed across several databases including MEDLINE/PubMed, PsycINFO, Scopus, medRxiv, and PQDT Global for studies published in English from January 2020 to December 2023. Only original investigations exploring the link between COVID-19 infection and NOD were selected for inclusion. We assessed the risk of developing NOD, using Risk Ratio (RR) for measurement. Control groups were categorized as: (i) a non-COVID cohort with other respiratory infections [control group (C1)]; and (ii) a non-COVID cohort with otherwise unspecified health status [control group (C2)]. Follow-up periods were divided into intervals of 3, 6, 12, and 24 months post-COVID.

RESULTS

11 studies (involving 939,824 post-COVID-19 survivors and 6,765,117 controls) were included in the review. Across a median observation period of 12 months post-COVID, the overall incidence of NOD was about 1.82% in the COVID-infected group, compared to 0.35% in the non-COVID-infected group. The overall pooled meta-analysis showed a significantly increased NOD risk among COVID-19 older adult survivors compared to non-COVID-19 controls (RR = 1.58, 95% CI 1.21-2.08). Similar increased NOD risks were observed in subgroup analyses restricted to an observational period of 12 months (RR = 1.56, 95% CI 1.21-2.01), as well as in five studies that employed propensity score matching to sufficiently and effectively control for multiple confounding covariates (RR = 1.46, 95% CI 1.10-1.94). COVID-19 group and C1 group shared a comparably increased risk of developing NOD (overall RR = 1.13, 95% CI 0.92-1.38).

DISCUSSION

Under normal circumstances, we believe that COVID-19 infection is likely to be a risk factor for developing NOD in older adults over time. While the increased NOD risk due to COVID-19 infection appears to be similar to that associated with other respiratory infections, it warrants and necessitates investigation with longer observations.

Detrimental Effects of Anti-Nucleocapsid Antibodies in SARS-CoV-2 Infection, Reinfection, and the Post-Acute Sequelae of COVID-19

Antibody-dependent enhancement (ADE) is a phenomenon in which antibodies enhance subsequent viral infections rather than preventing them. Sub-optimal levels of neutralizing antibodies in individuals infected with dengue virus are known to be associated with severe disease upon reinfection with a different dengue virus serotype. For Severe Acute Respiratory Syndrome Coronavirus type-2 infection, three types of ADE have been proposed: (1) Fc receptor-dependent ADE of infection in cells expressing Fc receptors, such as macrophages by anti-spike antibodies, (2) Fc receptor-independent ADE of infection in epithelial cells by anti-spike antibodies, and (3) Fc receptor-dependent ADE of cytokine production in cells expressing Fc receptors, such as macrophages by anti-nucleocapsid antibodies. This review focuses on the Fc receptor-dependent ADE of cytokine production induced by anti-nucleocapsid antibodies, examining its potential role in severe COVID-19 during reinfection and its contribution to the post-acute sequelae of COVID-19, i.e., prolonged symptoms lasting at least three months after the acute phase of the disease. We also discuss the protective effects of recently identified anti-spike antibodies that neutralize Omicron variants.

Persistence of spike protein at the skull-meninges-brain axis may contribute to the neurological sequelae of COVID-19

SARS-CoV-2 infection is associated with long-lasting neurological symptoms, although the underlying mechanisms remain unclear. Using optical clearing and imaging, we observed the accumulation of SARS-CoV-2 spike protein in the skull-meninges-brain axis of human COVID-19 patients, persisting long after viral clearance. Further, biomarkers of neurodegeneration were elevated in the cerebrospinal fluid from long COVID patients, and proteomic analysis of human skull, meninges, and brain samples revealed dysregulated inflammatory pathways and neurodegeneration-associated changes. Similar distribution patterns of the spike protein were observed in SARS-CoV-2-infected mice. Injection of spike protein alone was sufficient to induce neuroinflammation, proteome changes in the skull-meninges-brain axis, anxiety-like behavior, and exacerbated outcomes in mouse models of stroke and traumatic brain injury. Vaccination reduced but did not eliminate spike protein accumulation after infection in mice. Our findings suggest persistent spike protein at the brain borders may contribute to lasting neurological sequelae of COVID-19.

Neurological complications caused by SARS-CoV-2

SUMMARYSARS-CoV-2 can not only cause respiratory symptoms but also lead to neurological complications. Research has shown that more than 30% of SARS-CoV-2 patients present neurologic symptoms during COVID-19 (A. Pezzini and A. Padovani, Nat Rev Neurol 16:636-644, 2020, https://doi.org/10.1038/s41582-020-0398-3). Increasing evidence suggests that SARS-CoV-2 can invade both the central nervous system (CNS) (M.S. Xydakis, M.W. Albers, E.H. Holbrook, et al. Lancet Neurol 20: 753-761, 2021 https://doi.org/10.1016/S1474-4422(21)00182-4 ) and the peripheral nervous system (PNS) (M.N. Soares, M. Eggelbusch, E. Naddaf, et al. J Cachexia Sarcopenia Muscle 13:11-22, 2022, https://doi.org/10.1002/jcsm.12896), resulting in a variety of neurological disorders. This review summarized the CNS complications caused by SARS-CoV-2 infection, including encephalopathy, neurodegenerative diseases, and delirium. Additionally, some PNS disorders such as skeletal muscle damage and inflammation, anosmia, smell or taste impairment, myasthenia gravis, Guillain-Barré syndrome, ICU-acquired weakness, and post-acute sequelae of COVID-19 were described. Furthermore, the mechanisms underlying SARS-CoV-2-induced neurological disorders were also discussed, including entering the brain through retrograde neuronal or hematogenous routes, disrupting the normal function of the CNS through cytokine storms, inducing cerebral ischemia or hypoxia, thus leading to neurological complications. Moreover, an overview of long-COVID-19 symptoms is provided, along with some recommendations for care and therapeutic approaches of COVID-19 patients experiencing neurological complications.

Phase-dependent trends in the prevalence of myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) related to long COVID: A criteria-based retrospective study in Japan

BACKGROUND

The characteristics of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) related to COVID-19 have remained uncertain. To elucidate the clinical trend of ME/CFS induced by long COVID, we examined data for patients who visited our outpatient clinic established in a university hospital during the period from Feb 2021 to July 2023.

METHODS

Long COVID patients were classified into two groups, an ME/CFS group and a non-ME/CFS group, based on three diagnostic criteria.

RESULTS

The prevalence of ME/CFS in the long COVID patients was 8.4% (62 of 739 cases; female: 51.6%) and factors related to ME/CFS were severe illness, smoking and alcohol drinking habits, and fewer vaccinations. The frequency of ME/CFS decreased from 23.9% in the Preceding period to 13.7% in the Delta-dominant period and to 3.3% in the Omicron-dominant period. Fatigue and headache were commonly frequent complaints in the ME/CFS group, and the frequency of poor concentration in the ME/CFS group was higher in the Omicron period. Serum ferritin levels were significantly higher in female patients in the ME/CFS group infected in the Preceding period. In the ME/CFS group, the proportion of patients complaining of brain fog significantly increased from 22.2% in the Preceding period to 47.9% in the Delta period and to 81.3% in the Omicron period. The percentage of patients who had received vaccination was lower in the ME/CFS group than the non-ME/CFS group over the study period, whereas there were no differences in the vaccination rate between the groups in each period.

CONCLUSION

The proportion of long COVID patients who developed ME/CFS strictly diagnosed by three criteria was lower among patients infected in the Omicron phase than among patients infected in the other phases, while the proportion of patients with brain fog inversely increased. Attention should be paid to the variant-dependent trends of ME/CFS triggered by long COVID (300 words).

Clinical Features of Long COVID Patients Coinfected With Mycoplasma pneumoniae

Background: Since the SARS-CoV-2 pandemic, many patients have suffered prolonged complications, called "long COVID." Mycoplasma pneumoniae is a common respiratory pathogen. Reports of simultaneous long COVID and M. pneumoniae infections are rare in the literature. Methods: We analyzed the clinical data of patients with long COVID-19 who visited the Respiratory Clinic of The Affiliated Hospital of Hangzhou Normal University between January 1 and January 31, 2023, together with their laboratory and radiographic findings, with Pearson's χ 2 test. Results: Fifty-two patients diagnosed with both long COVID and M. pneumoniae infection and 77 with long COVID only were compared. The ages, clinical symptoms, and comorbidities of the two groups did not differ significantly (p > 0.05). However, sex and imaging findings differed between the groups. Conclusions: Our study showed that long COVID-M. pneumoniae coinfection was more commonly seen in females and patients with typical chest computed tomography (CT) images.

Brain Fog: a Narrative Review of the Most Common Mysterious Cognitive Disorder in COVID-19

It has been more than three years since COVID-19 impacted the lives of millions of people, many of whom suffer from long-term effects known as long-haulers. Notwithstanding multiorgan complaints in long-haulers, signs and symptoms associated with cognitive characteristics commonly known as "brain fog" occur in COVID patients over 50, women, obesity, and asthma at excessive. Brain fog is a set of symptoms that include cognitive impairment, inability to concentrate and multitask, and short-term and long-term memory loss. Of course, brain fog contributes to high levels of anxiety and stress, necessitating an empathetic response to this group of COVID patients. Although the etiology of brain fog in COVID-19 is currently unknown, regarding the mechanisms of pathogenesis, the following hypotheses exist: activation of astrocytes and microglia to release pro-inflammatory cytokines, aggregation of tau protein, and COVID-19 entry in the brain can trigger an autoimmune reaction. There are currently no specific tests to detect brain fog or any specific cognitive rehabilitation methods. However, a healthy lifestyle can help reduce symptoms to some extent, and symptom-based clinical management is also well suited to minimize brain fog side effects in COVID-19 patients. Therefore, this review discusses mechanisms of SARS-CoV-2 pathogenesis that may contribute to brain fog, as well as some approaches to providing therapies that may help COVID-19 patients avoid annoying brain fog symptoms.

Mapping the Potential Genes and Associated Pathways Involved in Long COVID-Associated Brain Fog Using Integrative Bioinformatics and Systems Biology Strategy

One of the recent emerging global health issues is long COVID. Among long COVID patients, long COVID-associated brain fog is an important area. We noted an immense gap in understanding the genes and associated pathways involved in long COVID-associated brain fog. Therefore, the study has been selected to understand the genes and pathways involved in patients with long COVID-associated brain fog. A GEO dataset, which was developed through the RNA-seq, was used for the analysis. The dataset encompasses 22 human samples of PBMC. The dataset (human samples of PBMC) was grouped into four cohorts for this study: healthy cohort, COVID convalescent, long COVID, and long COVID brain fog. Therefore, the selection criteria for the 22 PBMC samples were based on the individual infection type (COVID convalescent, long COVID, and long COVID brain fog) and the healthy cohort. Using DEG profile evaluation, we revealed 250 top-ranked DEGs with P values, Padj, baseMean, etc. From the top-ranked DEGs, we listed 24 significant DEGs and some significant DEGs are SMAD3 (P value = 6.34e-07), PF4 (P value = 1.88e-05), TNFAIP3 (P value = 3.70e-06), CXCL5 (P value = 1.22e-08), etc. Among the top-ranked DEGs, we found some genes linked with different biological functions, such as inflammatory cytokine secretion, inflammation, microclot formation, and BBB disruption. From our investigation, we found some genes that are associated with this condition, namely PF4, SMAD3, CXCL5, TNFAIP3, etc. From the literature survey and functional pathway enrichment analysis, we noted the function of the genes such as PF4, SMAD3, and CXCL5. We found that PF4 assists in clot formation, and SMAD3 is associated with neuroinflammation. Similarly, CXCL5 is an inflammatory marker associated with neuroinflammation and BBB damage. At the same time, the study with functional pathway enrichment analysis reflects that DEGs of long COVID-related brain fog might be associated with several biological pathways and processes, cell signatures, and gene-disease associations. It reflects that the disease is a highly complex one. Our study will provide an understanding of the genes and associated pathways in long COVID-related brain fog, which will assist in the next-generation biomarker discovery and therapeutics for these patients.

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.

Long COVID: A Comprehensive Overview of the Signs and Symptoms across Multiple Organ Systems

Long coronavirus disease (COVID), also known as the post-acute sequelae of coronavirus disease 2019 (COVID-19) (PASC), is a significant concern since the end of the COVID-19 pandemic, as it still manifests in individuals with persistent symptoms and complications beyond the acute phase of infection. Defining this disease is challenging, as it manifests as a spectrum of symptoms varying in severity among individuals who have previously tested positive for COVID-19. Long COVID is more prevalent in hospitalized COVID-19 patients and presents in various ways, ranging from pulmonary to extrapulmonary symptoms. This literature review examines the current body of research on long COVID with a focus on its effects on the cardiovascular, hematological, respiratory, renal, and neurological systems with systematically analyzed, peer-reviewed articles retrieved from the PubMed database. There have been several proposed pathophysiological mechanisms by which severe acute respiratory syndrome coronavirus 2 affects the aforementioned organ systems; however, research on the definite mechanisms is lacking, especially when considering the management of long COVID in the perioperative setting. The impact of post-COVID sequelae necessitates individualized management strategies tailored to each symptomatic profile, particularly in patients with comorbidities. The COVID-19 pandemic affected millions of people and had a profound impact on those who developed PASC, lowering their quality of life and increasing potential surgical risks. However, there is still uncertainty regarding the specific risk factors for long COVID and who is most susceptible to it. Further research is required to fill these gaps and explore potential avenues for preventing PASC.

Neurological long-COVID: Associations among fatigue, dysautonomia, depression, and subjective memory complaints

INTRODUCTION

Long-COVID is a multisystem disease characterized by a varied presentation of symptoms. According to most recent research, the most common symptom of long-COVID is fatigue, which up to this date lacks a universally accepted definition. This study aimed to investigate neurocognitive and physical manifestations of neurological long-COVID, particularly fatigue and its relation with autonomic disfunction, cognitive impairment (known as, brain fog), and depressive symptoms. Furthermore, the study provided insights into predictors of fatigue in long-COVID.

METHODS

The included patients (n=141) were referred to the neuro-long-COVID ambulatory service of Trieste from 30 September 2021-02 March 2022. Patients were given self-reporting questionnaires to screen for fatigue, autonomic dysfunction, cognitive impairment and depressive symptoms. The questionnaires adopted for these conditions to be assessed were Fatigue Severity Scale (FSS), COMPASS-31, Prospective-Retrospective Memory Questionnaire (PRMQ), and Beck Depression Inventory (BDI). Participants were divided into two groups, fatigued and non-fatigued patients, based on FSS scoring (scores > 4.67 indicate fatigued patients). The questionnaire scores of the two groups were then compared.

RESULTS

Fatigued patients had significantly higher scores in COMPASS (p<0.001, Cohen's d=1.077), BDI (p<0.001, Cohen's d=0.862), and PRMQ ( p<0.001, Cohen's d=1.159). Furthermore, the multivariate regression analysis showed that predictors of fatigue in long-COVID were symptomatological burden in acute infection (OR=1.38, 95 % CI 1.020-1.887, p=0.037) and in long-COVID (OR=1.78, 95 % CI 1.133-2.2824, p=0.013), COMPASS-31>16 (OR=3.44, 95 % CI 1240-9.560, p=0.018) and BDI>15 (OR=5.1, 95 % CI 1.715-15.164, p=0.003).

CONCLUSION

This study showed associations between fatigue, dysautonomia and depression, as well as with symptom burden in acute and long-COVID.

Brain Fog in Gastrointestinal Disorders: Small Intestinal Bacterial Overgrowth, Gastroparesis, Irritable Bowel Syndrome

INTRODUCTION

Brain fog (BF) is a term used to describe difficulties with concentration, memory, and overall mental clarity. Links of BF to chronic fatigue syndrome and COVID-19 have been described, as well as recently to small intestinal bacterial overgrowth (SIBO) and probiotics.

AIM

To investigate the association between BF, SIBO, intestinal methanogen overgrowth (IMO), gastrointestinal (GI) medications, and specific GI disorders [irritable bowel syndrome (IBS) and gastroparesis] by utilizing a questionnaire to help diagnose BF.

METHODS

Patients undergoing lactulose breath testing (LBT) for clinical assessment of SIBO filled out a demographic questionnaire, including an inquiry about the presence of BF, a symptom questionnaire (PAGI-SYM), and a BF Questionnaire (BFQ; 20 BF symptoms rated never=0 to always=4, total score 0 to 80).

RESULTS

A total of 102 patients underwent LBT, with the most common indication being bloating (67%), of whom 55 (54%) reported BF. The BFQ score was significantly higher in patients reporting BF than those not [38.2±15.6 vs. 10.9±9.4 (SEM) (P=0.001)]. Patients with BF were more likely to be on probiotics and proton pump inhibitors compared with those without BF (P=0.04). There was no major difference in the use of narcotics, prokinetics, or prebiotics. Gastroparesis and IBS were more common in patients who reported BF (P=0.01 and 0.05, respectively), but not SIBO or IMO by breath testing.

CONCLUSIONS

BF was observed in over one-half of patients with common GI disorders. The prevalence of BF was higher in patients on probiotics and those with gastroparesis and IBS. The BFQ may be useful to diagnose and quantify BF severity.

Memory complaints after COVID-19: a potential indicator of primary cognitive impairment or a correlate of psychiatric symptoms?

Cognitive impairment and symptoms of psychiatric disorders have been reported frequently as features of post-acute sequelae of SARS-CoV-2 infection. This study aims to investigate subjective memory complaints in COVID-19 survivors and determine if these are more strongly associated with objective cognitive impairment related to sequelae of SARS-CoV-2 infection or with symptoms of psychiatric conditions. A total of 608 COVID-19 survivors were evaluated in-person 6-11 months after hospitalization, with 377 patients assigned to a "no subjective memory complaint (SMC)" group and 231 patients assigned to an SMC group based on their Memory Complaint Scale scores. Follow-up evaluations included an objective cognitive battery and scale-based assessments of anxiety, depression, and post-traumatic stress symptoms. We found the perception of memory impairment in COVID-19 survivors to be more strongly associated to core symptoms of psychiatric conditions rather than to primary objective cognitive impairment. Univariate analysis indicated significant differences between the "no SMC" and SMC groups, both for the psychiatric symptom evaluations and for the cognitive evaluations (p < 0.05); however, the psychiatric symptoms all had large partial eta-squared values (ranging from 0.181 to 0.213), whereas the cognitive variables had small/medium partial eta-squared values (ranging from 0.002 to 0.024). Additionally, multiple regression analysis indicated that only female sex and depressive and post-traumatic stress symptoms were predictors of subjective memory complaints. These findings may help guide clinical evaluations for COVID-19 survivors presenting with memory complaints while also serving to expand our growing understanding of the relationship between COVID-19, subjective memory complaints, and the risk of cognitive decline.

Much more than a biological phenomenon: A qualitative study of women's experiences of brain fog across their reproductive journey

Whilst 'brain fog' is mostly considered a biological problem little is understood about an individual's experience. This qualitative study explored women's experiences of brain fog focusing on those at the start (aged 18-25; n = 10) and end (aged 45-60; n = 10) of their reproductive journey. Descriptive thematic analysis described three themes: (i) 'daily disruptions' describing cognitive dysfunctions and the main triggers; (ii) 'the cycle of impact' with a focus on women's emotional experiences and how these can exacerbate brain fog; (iii) 'taking control' highlighting the use of self-care, physical prompts and Hormonal Replacement Therapy (HRT) to manage brain fog. Transcending these themes was the notion of 'crisis of identity' illustrating the negative impact of brain fog on the women's sense of self with some older women describing acceptance and finding it less challenging. Brain fog is much more than a biological phenomenon and has broader implications for a woman's sense of self.

Long-term neurological dysfunction associated with COVID-19: Lessons from influenza and inflammatory diseases?

As the COVID-19 pandemic persists, SARS-CoV-2 infection is increasingly associated with long-term neurological side effects including cognitive impairment, fatigue, depression, and anxiety, colloquially known as "long-COVID." While the full extent of long-COVID neuropathology across years or even decades is not yet known, we can perhaps take direction from long-standing research into other respiratory diseases, such as influenza, that can present with similar long-term neurological consequences. In this review, we highlight commonalities in the neurological impacts of influenza and COVID-19. We first focus on the common potential mechanisms underlying neurological sequelae of long-COVID and influenza, namely (1) viral neurotropism and (2) dysregulated peripheral inflammation. The latter, namely heightened peripheral inflammation leading to central nervous system dysfunction, is emerging as a shared mechanism in various peripheral inflammatory or inflammation-associated diseases and conditions. We then discuss historical and modern examples of influenza- and COVID-19-associated cognitive impairment, depression, anxiety, and fatigue, revealing key similarities in their neurological sequelae. Although we are learning that the effects of influenza and COVID differ somewhat in terms of their influence on the brain, as the impacts of long-COVID grow, such comparisons will likely prove valuable in guiding ongoing research into long-COVID, and perhaps foreshadow what could be in store for individuals with COVID-19 and their brain health.

Neuroimaging Correlates of Post-COVID-19 Symptoms: A Functional MRI Approach

BACKGROUNDS AND PURPOSE

Post-COVID syndrome is characterized by persistent symptoms, including fatigue and cognitive impairment. These symptoms may be experienced by up to 80% of patients. We aimed to identify possible patterns of brain activation underlying post-COVID fatigue.

METHODS

The study used functional MRI (Siemens MAGNETOM Prisma 3T scanner with a specially created protocol) of the brain in 30 patients with post-COVID fatigue syndrome and 20 healthy volunteers. Task functional MRI (fMRI) was performed using a cognitive paradigm (modified Stroop test). Eligible patients included adults aged 18-50 years with a >12 weeks before enrolment (less than 12 months) prior history of documented COVID-19 with symptoms of fatigue not attributable to any other cause, and with MFI-20 score > 30 and MoCA at first visit. Healthy control participants had no prior history of COVID-19 and negative tests for severe acute coronavirus respiratory syndrome with MFI-20 score < 30 and MoCA at first visit. Task fMRI data were processed using the SPM12 software package based on MATLAB R2022a.

RESULTS

Cognitive task fMRI analysis showed significantly higher activation in the post-COVID group versus healthy volunteers' group. Between-group analysis showed significant activation differences. Using a threshold of T > 3 we identified eight clusters of statistically significant activation: supramarginal gyri, posterior cingulate cortex, opercular parts of precentral gyri and cerebellum posterior lobe bilaterally.

CONCLUSIONS

Post-COVID fatigue syndrome associated with subjective cognitive impairment could show changes in brain functional activity in the areas connected with information processing speed and quality.

Retinal Microvasculature Changes Linked to Executive Function Impairment after COVID-19

Background/Objectives: Studies using optical coherence tomography angiography (OCTA) have revealed that individuals recovering from COVID-19 have a reduced retinal vascular density (VD) and larger foveal avascular zones (FAZs) than healthy individuals, with more severe cases showing greater reductions. We aimed to examine aspects of the retinal microvascularization in patients with post-COVID-19 condition (PCC) classified by COVID-19 severity and how these aspects relate to cognitive performance. Methods: This observational cross-sectional study included 104 PCC participants from the NAUTILUS Project, divided into severe (n = 59) and mild (n = 45) COVID-19 groups. Participants underwent cognitive assessments and OCTA to measure VD and perfusion density (PD) in the superficial capillary plexus (SVP) and FAZ. Analysis of covariance and partial Pearson and Spearman correlations were used to study intergroup differences and the relationships between cognitive and OCTA variables. Results: Severe PCC participants had significantly lower central (p = 0.03) and total (p = 0.03) VD, lower central (p = 0.02) PD measurements, and larger FAZ areas (p = 0.02) and perimeters (p = 0.02) than mild cases. Severe cases showed more cognitive impairment, particularly in speed processing (p = 0.003) and executive functions (p = 0.03). Lower central VD, lower central PD, and larger FAZ areas and perimeters were associated with worse executive function performance in the entire PCC sample and in the mild COVID-19 group. Conclusions: Retinal microvascular alterations, characterized by reduced VD and PD in the SVP and larger FAZ areas, were associated with cognitive impairments in PCC individuals. These findings suggest that severe COVID-19 leads to long-lasting microvascular damage, impacting retinal and cognitive health.

Deep into Cognition: The Neuropsychological Identikit of Younger and Older Individuals after COVID-19 Infection

The literature on COVID-19 continues to increase daily. Cognitive sequelae associated with COVID-19 infection still draw the attention of the scientific community given the lack of consensus about their existence, etiology, characterization and reversibility. The aim of this study is to provide a neuropsychological identikit for younger (<65 years) and older (≥65 years) individuals diagnosed with COVID-19 infection, at baseline and after 3 and 6 months. In total, 226 individuals took part in a retrospective observational study and their cognitive performance was compared across groups (younger adults vs. older adults) and time (T0, T1, T2). The results highlighted differences between younger and older adults in the Montreal Cognitive Assessment (MoCA) global score, as expected in consideration of the different physiological conditions of the two populations. However, memory performance highlighted the two groups as characterized by a difference in patterns of recall that may move beyond a physiological explanation and provide information about COVID-19 cognitive sequelae. This study suggests that cognitive deficits observed in COVID-19 survivors may reflect a difficulty in attention and concentration that interferes mainly with retrieval processes. This result fits well with the concept of "brain fog" typical of post-COVID-19 syndrome and may also reflect the stress experienced while facing the pandemic.

Neurocognitive changes in a patient receiving esketamine for treatment-resistant depression

ABSTRACT

Esketamine, the s(+) enantiomer of ketamine, was approved in 2019 as the first rapid-acting intranasal spray medication for treatment-resistant depression; the drug is given in combination with an antidepressant. The treatment is self-administered in a clinical setting under the supervision of a healthcare provider and usually is well tolerated. Many of its adverse reactions are mild, temporary, and dose-dependent, and they improve with subsequent treatments. Although the prescribing information lists difficulty remembering or thinking as possible adverse reactions, a neurocognitive evaluation is not part of the initial patient evaluation. This case report focuses on a patient whose neurocognitive symptoms worsened with esketamine treatment, necessitating treatment discontinuation.

The influence of COVID-19 on attention-deficit/hyperactivity disorder diagnosis and treatment rates across age, gender, and socioeconomic status: A 20-year national cohort study

Infection and lockdowns resulting from COVID-19 have been suggested to increase the prevalence and treatment rates of Attention Deficit/Hyperactivity Disorder (ADHD). To accurately estimate the pandemic's effects, pre-pandemic data can be used to estimate diagnosis and treatment rates during the COVID-19 years as if the COVID-19 pandemic did not occur. However, accurate predictions require a broad dataset, both in terms of the number of cases and the pre-pandemic timeframe. In the current study, we modeled monthly ADHD diagnosis and treatment rates over the 18 years preceding the COVID-19 pandemic. The dataset included ∼3 million cases for individuals aged 6 to 18 from the Clalit Health Services' electronic database. Using a trained model, we projected monthly rates for post-lockdown and post-infection periods, enabling us to estimate the expected diagnosis and treatment rates without the COVID-19 pandemic. We then compared these predictions to observed data, stratified by age groups, gender, and socioeconomic status. Our findings suggest no influence of the COVID-19 pandemic on ADHD diagnosis or treatment rates. We show that a narrower timeframe for pre-COVID-19 data points can lead to incorrect conclusions that COVID-19 affected ADHD diagnosis rates. Findings are discussed, given the assumed impact of the COVID-19 pandemic on ADHD.

Covid-19 psychological distress: Analysis of antipsychotic drugs' use in an Italian population sample

BACKGROUND

The current pandemic, in addition to putting a strain on healthcare systems and global economies, has exacerbated psychiatric problems and undermined the mental health of many individuals. In an Italian cohort, this phenomenon has been assessed through a retrospective study aimed at evaluating the consumption and costs of antipsychotic drugs between 2020 and 2022.

METHODS

All dispensations made in local pharmacies accessible to the public have been extracted from a database called 'Sistema Tessera Sanitaria', which covers a population of approximately one million people residents in the ASL Napoli 3 Sud. Consumption data expressed in defined daily dose (DDD) and expenditure data expressed in Euro have been extrapolated.

RESULTS

The results in the years 2020-2021 were relatively consistent, with consumption and expenditure decreasing slightly from 2020 to 2021. In 2022, the results showed a decrease in consumption and expenditure (2,706,951.07 DDD and €1,700,897.47) representing the reduced accessibility of patients to the healthcare facilities due to the pandemic. However, it should be noted that the antipsychotic drug aripiprazole showed an upward trend, registering an increase in consumption.

CONCLUSION

Despite expectations of increased consumption of antipsychotic medications, real-world evidence indicated a different phenomenon, with the pandemic seemingly not affecting the consumption of these drugs. The difficulty in accessing care and medical appointments has probably influenced this data, masking the therapeutic needs of citizens. It will be necessary to assess in the coming years, as normal clinical activity resumes, whether there will be a growing consumption of these medications, which represent one of the main expenditure categories for the National Healthcare System.

Characteristics and Impact of Long COVID at a Neurology Clinic

INTRODUCTION

Long COVID can also lead to neurological sequelae that affect existing diseases. This study explored how COVID-19 infection affects neurological patients and the relationship between long COVID and exacerbating factors.

METHODS

This retrospective study was conducted on 85 patients with neurological diseases after COVID-19 at the Neurology Department, Inje University Busan Paik Hospital, Korea. The data were collected between August and October 2022. The patients had a medical history, including COVID-19 infection, and completed symptom questionnaires. A long COVID questionnaire consisting of 35 inquiries in 10 categories was completed. Anxiety, depression, fatigue, functional difficulties, QOL, and health status changes were assessed.

RESULTS

The analysis comprised 85 participants (age: 56.4 ± 15.2 years; 63.5% women). Of the categories, neurological symptoms (68.2%) were the most prevalent, followed by systemic symptoms (64.7%) and cardiopulmonary symptoms (56.5%). Anxiety, depression, and fatigue symptoms were reported by 36.5%, 34.1%, and 42.4% of the participants. Subjective neurological deterioration after COVID-19 was reported in 28 participants (28/81, 34.6%). Anxiety, depression, and fatigue were influenced by long COVID symptoms and the subjective deterioration of neurological conditions.

CONCLUSION

This study analyzed the long COVID symptoms in patients with preexisting neurological conditions and their impact on mental health and quality of life. One-third of the participants reported a subjective worsening of their preexisting neurological conditions. This study highlights the need for comprehensive follow-ups and a multidisciplinary approach for patients with neurological conditions and prolonged COVID-19 symptoms.

Social impact of brain fog and analysis of risk factors: Long COVID in Japanese population

OBJECTIVE

To reveal the clinical features and assess risk factors linked to brain fog and its societal implications, including labor productivity, providing valuable insights for the future care of individuals who have experienced coronavirus disease 2019 (COVID-19).

METHODS

We analyzed a comprehensive cohort dataset comprising 1,009 patients with COVID-19 admitted to Japanese hospitals. To assess brain fog, we analyzed patients who responded to a questionnaire indicating symptoms such as memory impairment and poor concentration.

RESULTS

The prevalence of brain fog symptoms decreased 3 months posthospitalization but remained stable up to 12 months. Neurological symptoms such as taste and smell disorders and numbness at hospitalization correlated with a higher frequency of identifying brain fog as a long COVID manifestation. Our findings indicated that advanced age, female sex, a high body mass index, oxygen required during hospitalization, chronic obstructive pulmonary disease, asthma, and elevated C-reactive protein and elevated D-dimer levels were risk factors in patients exhibiting brain fog. Additionally, we demonstrated the negative impact of brain fog on labor productivity by presenteeism scores.

INTERPRETATIONS

This study clarified the clinical characteristics of patients experiencing brain fog as a long COVID manifestation, specifically emphasizing neurological symptoms during hospitalization and their correlation with brain fog. Additionally, the study identified associated risk factors for its onset and revealed that the emergence of brain fog was linked to a decline in labor productivity.

Psychosocial Factors Associated With Long-Term Cognitive Impairment Among COVID-19 Survivors: A Cross-Sectional Study

ABSTRACT

COVID-19 survivors complained of the experience of cognitive impairments, which also called "brain fog" even recovered. The study aimed to describe long-term cognitive change and determine psychosocial factors in COVID-19 survivors. A cross-sectional study was recruited 285 participants from February 2020 to April 2020 in 17 hospitals in Sichuan Province. Cognitive function, variables indicative of the virus infection itself, and psychosocial variables were collected by telephone interview. Univariate logistic regression and Lasso logistic regression models were used for variable selection which plugged into a multiple logistics model. Overall prevalence of moderate or severe cognitive impairment was 6.3%. Logistic regression showed that sex, religion, smoking status, occupation, self-perceived severity of illness, sleep quality, perceived mental distress after COVID-19, perceived discrimination from relatives and friends, and suffered abuse were associated with cognitive impairment. The long-term consequences of cognitive function are related to multiple domains, in which psychosocial factors should be taken into consideration.

Adaptation and Validation of the Turkish Version of the Brain Fog Scale

Brain fog is a condition that is characterized by poor concentration, memory loss, decreased cognitive function, and mental fatigue. Although it is generally known as a long-term COVID-19 symptom, brain fog has also been reported to be caused by many other diseases. Thus, it is necessary to assess this condition in certain populations. This study aimed to evaluate the reliability and validity of the Brain Fog Scale in a Turkish population. We conducted the study in two phases. In a pilot study including 125 participants, we confirmed the suitability of the scale for validity analyses and then conducted exploratory (n = 230) and confirmatory factor analyses (n = 343). The Cronbach's alpha value of the 23-item Brain Fog Scale was 0.966. In addition, the 23-item and three-factor structure was confirmed as a result of the analyses. These three factors are mental fatigue, impaired cognitive acuity, and confusion. We also found that participants previously diagnosed with COVID-19 had higher brain fog scores. This finding indicates that brain fog is an important condition that can accompany COVID-19. Furthermore, this validated construct has an acceptable fit and is a valid and useful tool for the Turkish population.

Profiles of objective and subjective cognitive function in Post-COVID Syndrome, COVID-19 recovered, and COVID-19 naïve individuals

Post-COVID Syndrome has emerged as a significant public health concern worldwide with increasing evidence to suggest that individuals who have had an acute COVID-19 infection report lingering memory and attention difficulties, even in individuals who have fully recovered and no longer experiencing symptoms of COVID-19. The present study sought to investigate the profile of objective and subjective cognitive difficulties in people who have Post-COVID Syndrome, people who have fully recovered from an acute COVID infection and people who have never had COVID-19. We further sought to explore the extent to which self-reported fatigue and stress are related to subjective and objective cognitive difficulties. 162 participants including 50 people living with Post-COVID Syndrome, 59 people who have had COVID-19 but have fully recovered and 53 people who have never experienced symptoms of COVID-19 and had never tested positive for COVID-19 were recruited from Academic Prolific to complete a series of online questionnaires and neurocognitive tasks. Subjective cognitive function was measured using the Cognitive Failures Questionnaire and objective cognitive function was measured using the Cognitron cognitive test battery. We found that objective and subjective measures of cognitive function were not significantly related, suggesting that self-reports of "brain fog" are not reflecting objectively measured cognitive dysfunction. A MANOVA revealed that subjective cognitive deficits were driven by heightened perceived stress and fatigue and not significantly related to COVID-19 status. Objective cognitive function, however, was significantly related to perceived stress and COVID status whereby we observed significant objective cognitive deficits in people who have been exposed to an acute COVID-19 infection regardless of whether they had Post-COVID Syndrome or had fully recovered, as compared to people who had never had COVID-19. This suggests that an acute infection can have long term effects on cognitive function, even without persistent COVID-19 symptoms. Encouragingly, objective cognitive function was significantly associated with time since initial infection showing that cognitive deficits improved over time for people who had recovered from COVID-19. However, we did not observe the same improvement in individuals with Post-COVID Syndrome and observed that cognitive dysfunction was significantly related to the number of neurological symptoms presently experienced. These results add to the accumulating literature that COVID-19 is associated with significant cognitive difficulties following a COVID-19 infection, which appear to improve over time for those who have recovered from COVID-19 yet persist in people living with Post-COVID Syndrome.