Neurological symptoms in COVID-19: a cross-sectional monocentric study of hospitalized patients

Post-acute sequelae SARS-CoV-2 infection and neuropathic pain: a narrative review of the literature and future directions

PURPOSE OF REVIEW

Neuropathic pain is a recognized and debilitating symptom of SARS-CoV-2 infection across acute, post-acute, and long-COVID phases. Initially emerging as acute or subacute symptoms, these neuropathic manifestations can evolve into chronic conditions, with approximately 10% of all SARS-CoV-2 cases (estimated 65 million individuals globally) developing post-acute SARS-CoV-2 (PASC) neuropathic sequalae. Given the limited literature specifically addressing neuropathic pain related to PASC, a deeper understanding is needed to improve management and reduce patient burden.

RECENT FINDINGS

PASC symptoms are associated with disease severity, elevated body mass indexes, preexisting psychological conditions, and addiction history. Sex differences appear to influence prevalence, and the multisystem nature of PASC complicates symptom presentation, with mood disorders, fatigue, and cognitive dysfunction contributing to altered pain perception. Proposed mechanisms include immune dysregulation, persistent viral protein effects, and neuroanatomical changes. Management typically involves a multimodal approach.

SUMMARY

This review examines SARS-CoV-2 neuropathic pain across the illness trajectory, examining its pathophysiology, prevalence, and treatment. It highlights the potential for subacute neuropathic symptoms to become chronic and calls for future research to refine long-term management strategies and assess broader healthcare implications.

Significance of Neurological Manifestations and Their Association With Clinical Outcomes in Hospitalized COVID-19 Patients in Bandar Abbas, Iran: A Cross-Sectional Study

Background

Neurological manifestations are increasingly recognized in COVID-19 patients, yet their prevalence and clinical significance remain understudied. This study aimed to determine the incidence and significance of neurological symptoms and their associations with demographic, clinical, and laboratory parameters in hospitalized COVID-19 patients.

Method

A cross-sectional study was conducted at Shahid Mohammadi Hospital, Bandar Abbas, Iran, from February 2020 to February 2021. A total of 540 RT-PCR-confirmed COVID-19 patients were included. Data on demographics, comorbidities, clinical symptoms, neurological manifestations (e.g., myalgia, headache, smell/taste impairment, dizziness), and laboratory findings were collected. Statistical analyses were performed using SPSS version 20.

Results

Myalgia was the most common neurological symptom (33.9%), followed by headache (16.7%), smell/taste impairment (10.2%), and dizziness (6.9%). A significantly higher prevalence of myalgia and smell/taste impairment was observed in patients under 50 years old (p ≤ 0.05). Patients with myalgia also had a significantly higher prevalence of prior chronic heart disease and were more likely to experience concurrent smell/taste impairment (p ≤ 0.05). Notably, while some inflammatory markers were elevated in both patients with and without myalgia and smell/taste impairment, the increase was significantly less pronounced in those exhibiting these neurological symptoms (p ≤ 0.05). Additionally, patients with headache and smell/taste impairment were less frequently admitted to the ICU (p ≤ 0.05). A statistically significant co-occurrence was also observed among the presence of headache, dizziness, and smell/taste impairment in COVID-19 patients (p ≤ 0.05).

Conclusion

Neurological symptoms are prevalent in COVID-19 patients and may serve as markers of disease severity and progression. Recognizing these manifestations can aid in early diagnosis and inform tailored management strategies. Further research with larger, diverse populations and advanced diagnostic tools is needed to validate these findings and better understand the mechanisms underlying COVID-19-related neurological involvement.

Cognitive function and brain structure in COVID-19 survivors: The role of persistent symptoms

Persistent COVID-19 symptoms post-acute state have been shown to have a significant negative impact on brain structure and function. In this study, we conducted magnetic resonance imaging (MRI) of the whole brain in 43 working-age adults (mean age: 44.79±10.80; range: 24-65 years) with a history of COVID-19 (731.17±312.41 days post-diagnosis), and also assessed their cognitive function (processing speed, attention, working memory, executive function, and recognition memory), mental health, and sleep quality. MRI data were processed using FSL to derive regional volumes for bilateral nucleus accumbens, caudate, pallidum, putamen, thalamus, amygdala, and hippocampus, and total grey matter, white matter, and cerebral spinal fluid volume, and analysed in relation to persistent COVID-19 symptom load, mental health, and sleep quality. Higher persistent COVID-19 symptom load was significantly associated with smaller putamen volume, lower response accuracy on working memory, executive function, and recognition memory tasks, as well as a longer time to complete the executive function task, and poorer mental health and sleep quality. Smaller putamen fully mediated the relationship between persistent COVID-19 symptom load and lower executive function. Further research is required to confirm whether reduced putamen volume and its association with poor executive function persists in COVID-19 survivors in the long term.

Diagnostic accuracy of the Montreal Cognitive Assessment in screening for cognitive impairment in initially hospitalized COVID-19 patients: Findings from the prospective multicenter NeNeSCo study

OBJECTIVE

This study aimed to investigate the prevalence and nature of cognitive impairment among severely ill COVID-19 patients and the effectiveness of the Montreal Cognitive Assessment (MoCA) in detecting it.

METHOD

We evaluated cognition in COVID-19 patients hospitalized during the first wave (March to June 2020) from six Dutch hospitals, nine months post-discharge, using a comprehensive multi-domain neuropsychological test battery. Test performance was corrected for sex, age, and education differences and transformed into z-scores. Scores within each cognitive domain were averaged and categorized as average and above (z-score ≥ -0.84), low average (z-score -1.28 to -0.84), below average (z-score -1.65 to -1.28), and exceptionally low (z-score < -1.65). Patients were classified with cognitive impairment if at least one domain's z-score fell below -1.65. We assessed the MoCA's accuracy using both the original cutoff (<26) and an "optimal" cutoff determined by Youden's index.

RESULTS

Cognitive impairment was found in 12.1% (24/199) of patients, with verbal memory and mental speed most affected (6.5% and 7% below -1.65, respectively). The MoCA had an area under the curve of 0.84. The original cutoff showed sensitivity of 83% and specificity of 66%. Using the identified optimal cutoff of <24, maintained sensitivity while improving specificity to 81%.

CONCLUSIONS

Cognitive impairment prevalence in initially hospitalized COVID-19 patients is lower than initially expected. Verbal memory and processing speed are primarily affected. The MoCA is a valuable screening tool for these impairments and lowering the MoCA cutoff to <24 improves specificity.

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.

Decision-making ability limitations and brain neural activity changes in healthcare workers after mild COVID-19

Studies have demonstrated that the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) extensively affects brain function. Although cognitive dysfunction is considered a common manifestation in COVID-19 patients during the recovery period, the potential changes in decision-making ability, are not yet clear. Decision-making functions are essential to the work of healthcare workers. However, there is a lack of a multidimensional assessment of its functioning in COVID-19 cases. Here, we used tests combined with the resting-state functional magnetic resonance imaging (rs-fMRI) stabilization feature amplitude of low-frequency fluctuations (ALFF) to explore decision-making behavior and brain neural activity changes in healthcare workers after mild COVID-19. Participants were divided into the SARS-CoV-2 infected group (SI, n = 41) and healthy controls (HC, n = 42). All participants underwent a series of neuropsychological tests. They performed the Iowa Gambling Task (IGT) and the Game of Dice Task (GDT), followed by fMRI (n = 20) to assess their decision-making ability under ambiguous and risky conditions and changes in brain neural activity. The SI group performed worse in verbal memory than the HC group. Furthermore, the SI group performed worse in the IGT, whereas no significant difference was observed in the GDT. In addition, rs-fMRI showed enhanced spontaneous neural activity in the postcentral gyrus and inferior parietal lobe in the SI group compared to the HC group.

The molecular fingerprint of neuroinflammation in COVID-19: A comprehensive discussion on molecular mechanisms of neuroinflammation due to SARS-COV2 antigens

BACKGROUND AND OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 attacks the neural system directly and indirectly via various systems, such as the nasal cavity, olfactory system, and facial nerves. Considering the high energy requirement, lack of antioxidant defenses, and high amounts of metal ions in the brain, oxidative damage is very harmful to the brain. Various neuropathic pain conditions, neurological disorders, and neuropsychiatric complications were reported in Coronavirus disease 2019, prolonged Coronavirus disease 2019, and after Coronavirus disease 2019 immunization. This manuscript offers a distinctive outlook on the interconnectedness between neurology and neuropsychiatry through its meticulous analysis of complications.

DISCUSSION

After recovering from Coronavirus disease 2019, approximately half of the patients reported developing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Long Coronavirus disease 2019 imaging reports illustrated the hypometabolism in various parts of the brain, such as olfactory bulbs, limbic/paralimbic domains, the brainstem, and the cerebellum. Ninety imaging and neuropathological studies of Coronavirus disease 2019 have shown evidence of white matter, brainstem, frontotemporal, and oculofrontal lesions. Emotional functions, such as pleasant, long/short-term memory, movement, cognition and cognition in decision-making are controlled by these regions. The neuroinflammation and the mechanisms of defense are well presented in the discussion. The role of microglia activation, Inducible NO synthase, Cyclooxygenases ½, Reactive oxygen species, neurotoxic toxins and pro-inflammatory cytokines, such as Interleukin-1 beta, Interleukin-6 and Tumor Necrosis Factor-alpha are highlighted in neuronal dysfunction and death. Nuclear factor kappa-light-chain-enhancer of activated B cells, Mitogen-activated protein kinase, Activator Protein 1, and Interferon regulatory factors are the main pathways involved in microglia activation in Coronavirus disease 2019 neuroinflammation.

CONCLUSION

The neurological aspect of Coronavirus disease 2019 should be highlighted. Neurological, psychological, and behavioral aspects of Coronavirus disease 2019, prolonged Coronavirus disease 2019, and Coronavirus disease 2019 vaccines can be the upcoming issues. We need a global awareness where this aspect of the disease should be more considered in health research.

Topographical Distribution of Neuroanatomical Abnormalities Following COVID-19 Invasion : A Systematic Literature Review

PURPOSE

This systematic review is aimed at synthesising the literature base to date on the frequency and topographical distribution of neuroanatomical changes seen on imaging following COVID-19 invasion with a focus on both the acute and chronic phases of the disease.

METHODS

In this study, 8 databases were systematically searched to identify relevant articles published from December 2019 to March 2022 and supplemented with a manual reference search. Data were extracted from the included studies and narrative synthesis was employed to integrate the findings.

RESULTS

A total of 110 studies met the inclusion criteria and comprised 119,307 participants (including 31,073 acute and 143 long COVID-19 patients manifesting neurological alterations) and controls. Considerable variability in both the localisation and nature of neuroanatomical abnormalities are noted along the continuum with a wide range of neuropathologies relating to the cerebrovascular/neurovascular system, (sub)cortical structures (including deep grey and white matter structures), brainstem, and predominant regional and/or global alterations in the cerebellum with varying degrees of spinal involvement.

CONCLUSION

Structural regional alterations on neuroimaging are frequently demonstrated in both the acute and chronic phases of SARS-CoV‑2 infection, particularly prevalent across subcortical, prefrontal/frontal and cortico-limbic brain areas as well as the cerebrovascular/neurovascular system. These findings contribute to our understanding of the acute and chronic effects of the virus on the nervous system and has the potential to provide information on acute and long-term treatment and neurorehabilitation decisions.

Characteristic functional connectome related to Post-COVID-19 syndrome

Post-COVID-19 syndrome is a serious complication following SARS-CoV-2 infection, characterized primarily by fatigue and cognitive complaints. Although first metabolic and structural imaging alterations in Post-COVID-19 syndrome have been identified, their functional consequences remain unknown. Thus, we explored the impact of Post-COVID-19 syndrome on the functional connectome of the brain providing a deeper understanding of pathophysiological mechanisms. In a cross-sectional observational study, resting-state functional magnetic resonance imaging data of 66 patients with Post-COVID-19 syndrome after mild infection (mean age 42.3 years, 57 female) and 57 healthy controls (mean age 42.1 years, 38 female) with a mean time of seven months after acute COVID-19 were analysed using a graph theoretical approach. Network features were quantified using measures including mean distance, nodal degree, betweenness and Katz centrality, and compared between both groups. Graph measures were correlated with clinical measures quantifying fatigue, cognitive function, affective symptoms and sleep disturbances. Alterations were mainly found in the brainstem, olfactory cortex, cingulate cortex, thalamus and cerebellum on average seven months after SARS-CoV-2 infection. Additionally, strong correlations between fatigue severity, cognitive functioning and daytime sleepiness from clinical scales and graph measures were observed. Our study confirms functional relevance of brain imaging changes in Post-COVID-19 syndrome as mediating factors for persistent symptoms and improves our pathophysiological understanding.

Systematic review and evidence gap mapping of biomarkers associated with neurological manifestations in patients with COVID-19

OBJECTIVE

This study aimed to synthesize the existing evidence on biomarkers related to coronavirus disease 2019 (COVID-19) patients who presented neurological events.

METHODS

A systematic review of observational studies (any design) following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and the Cochrane Collaboration recommendations was performed (PROSPERO: CRD42021266995). Searches were conducted in PubMed and Scopus (updated April 2023). The methodological quality of nonrandomized studies was assessed using the Newcastle‒Ottawa Scale (NOS). An evidence gap map was built considering the reported biomarkers and NOS results.

RESULTS

Nine specific markers of glial activation and neuronal injury were mapped from 35 studies published between 2020 and 2023. A total of 2,237 adult patients were evaluated in the included studies, especially during the acute phase of COVID-19. Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) biomarkers were the most frequently assessed (n = 27 studies, 77%, and n = 14 studies, 40%, respectively). Although these biomarkers were found to be correlated with disease severity and worse outcomes in the acute phase in several studies (p < 0.05), they were not necessarily associated with neurological events. Overall, 12 studies (34%) were judged as having low methodological quality, 9 (26%) had moderate quality, and 9 (26%) had high quality.

CONCLUSIONS

Different neurological biomarkers in neurosymptomatic COVID-19 patients were identified in observational studies. Although the evidence is still scarce and conflicting for some biomarkers, well-designed longitudinal studies should further explore the pathophysiological role of NfL, GFAP, and tau protein and their potential use for COVID-19 diagnosis and management.

A cross-sectional case-control study on the structural connectome in recovered hospitalized COVID-19 patients

COVID-19 can induce neurological sequelae, negatively affecting the quality of life. Unravelling this illness's impact on structural brain connectivity, white-matter microstructure (WMM), and cognitive performance may help elucidate its implications. This cross-sectional study aimed to investigate differences in these factors between former hospitalised COVID-19 patients (COV) and healthy controls. Group differences in structural brain connectivity were explored using Welch-two sample t-tests and two-sample Mann-Whitney U tests. Multivariate linear models were constructed (one per region) to examine fixel-based group differences. Differences in cognitive performance between groups were investigated using Wilcoxon Rank Sum tests. Possible effects of bundle-specific FD measures on cognitive performance were explored using a two-group path model. No differences in whole-brain structural organisation were found. Bundle-specific metrics showed reduced fiber density (p = 0.012, Hedges' g = 0.884) and fiber density cross-section (p = 0.007, Hedges' g = 0.945) in the motor segment of the corpus callosum in COV compared to healthy controls. Cognitive performance on the motor praxis and digit symbol substitution tests was worse in COV than healthy controls (p < 0.001, r = 0.688; p = 0.013, r = 422, respectively). Associations between the cognitive performance and bundle-specific FD measures differed significantly between groups. WMM and cognitive performance differences were observed between COV and healthy controls.

Cranial nerve involvement among COVID-19 survivors

Introduction

COVID-19 was first reported in November 2019 in China and rapidly spread across the globe. COVID-19 causes neurologic symptoms and complications, which may persist even after recovery in patients. The objective of this research was to determine the involvement of cranial nerves in COVID-19 survivors.

Method

This was a retrospective study. The study was conducted between March and July of 2022. The analysis included 98 patients with a certain positive polymerase chain reaction. SPSS software version 19 was utilized for data analysis.

Results

The average age of the participants was 40.47 years (8.81). The olfactory nerve was found to be the most frequently involved cranial nerve (36.7%). Over 20% of participants had a taste disorder. The findings from the regression analysis indicated that lung involvement and age have a direct and significant relationship with cranial nerve involvement and can serve as its predictors (p = 0.001).

Conclusion

It seems that cranial nerve involvement was sustained in COVID-19 patients who survived. In addition, elderly patients and patients with severe illnesses were more likely to show cranial symptoms. It is necessary to monitor COVID-19 survivors for neurological symptoms.

Neurological manifestations of COVID-19 in adults and children

Different neurological manifestations of coronavirus disease 2019 (COVID-19) in adults and children and their impact have not been well characterized. We aimed to determine the prevalence of neurological manifestations and in-hospital complications among hospitalized COVID-19 patients and ascertain differences between adults and children. We conducted a prospective multicentre observational study using the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) cohort across 1507 sites worldwide from 30 January 2020 to 25 May 2021. Analyses of neurological manifestations and neurological complications considered unadjusted prevalence estimates for predefined patient subgroups, and adjusted estimates as a function of patient age and time of hospitalization using generalized linear models.

Overall, 161 239 patients (158 267 adults; 2972 children) hospitalized with COVID-19 and assessed for neurological manifestations and complications were included. In adults and children, the most frequent neurological manifestations at admission were fatigue (adults: 37.4%; children: 20.4%), altered consciousness (20.9%; 6.8%), myalgia (16.9%; 7.6%), dysgeusia (7.4%; 1.9%), anosmia (6.0%; 2.2%) and seizure (1.1%; 5.2%). In adults, the most frequent in-hospital neurological complications were stroke (1.5%), seizure (1%) and CNS infection (0.2%). Each occurred more frequently in intensive care unit (ICU) than in non-ICU patients. In children, seizure was the only neurological complication to occur more frequently in ICU versus non-ICU (7.1% versus 2.3%, P &lt; 0.001).

Stroke prevalence increased with increasing age, while CNS infection and seizure steadily decreased with age. There was a dramatic decrease in stroke over time during the pandemic. Hypertension, chronic neurological disease and the use of extracorporeal membrane oxygenation were associated with increased risk of stroke. Altered consciousness was associated with CNS infection, seizure and stroke. All in-hospital neurological complications were associated with increased odds of death. The likelihood of death rose with increasing age, especially after 25 years of age.

In conclusion, adults and children have different neurological manifestations and in-hospital complications associated with COVID-19. Stroke risk increased with increasing age, while CNS infection and seizure risk decreased with age.

Neurological manifestations of COVID-19 in adults and children

Different neurological manifestations of coronavirus disease 2019 (COVID-19) in adults and children and their impact have not been well characterized. We aimed to determine the prevalence of neurological manifestations and in-hospital complications among hospitalized COVID-19 patients and ascertain differences between adults and children. We conducted a prospective multicentre observational study using the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) cohort across 1507 sites worldwide from 30 January 2020 to 25 May 2021. Analyses of neurological manifestations and neurological complications considered unadjusted prevalence estimates for predefined patient subgroups, and adjusted estimates as a function of patient age and time of hospitalization using generalized linear models. Overall, 161 239 patients (158 267 adults; 2972 children) hospitalized with COVID-19 and assessed for neurological manifestations and complications were included. In adults and children, the most frequent neurological manifestations at admission were fatigue (adults: 37.4%; children: 20.4%), altered consciousness (20.9%; 6.8%), myalgia (16.9%; 7.6%), dysgeusia (7.4%; 1.9%), anosmia (6.0%; 2.2%) and seizure (1.1%; 5.2%). In adults, the most frequent in-hospital neurological complications were stroke (1.5%), seizure (1%) and CNS infection (0.2%). Each occurred more frequently in intensive care unit (ICU) than in non-ICU patients. In children, seizure was the only neurological complication to occur more frequently in ICU versus non-ICU (7.1% versus 2.3%, P < 0.001). Stroke prevalence increased with increasing age, while CNS infection and seizure steadily decreased with age. There was a dramatic decrease in stroke over time during the pandemic. Hypertension, chronic neurological disease and the use of extracorporeal membrane oxygenation were associated with increased risk of stroke. Altered consciousness was associated with CNS infection, seizure and stroke. All in-hospital neurological complications were associated with increased odds of death. The likelihood of death rose with increasing age, especially after 25 years of age. In conclusion, adults and children have different neurological manifestations and in-hospital complications associated with COVID-19. Stroke risk increased with increasing age, while CNS infection and seizure risk decreased with age.

Brain Disorders: Impact of Mild SARS-CoV-2 May Shrink Several Parts of the Brain

Coronavirus (COVID-19) is a highly infectious respiratory infection discovered in Wuhan, China, in December 2019. As a result of the pandemic, several individuals have experienced life-threatening diseases, the loss of loved ones, lockdowns, isolation, an increase in unemployment, and household conflict. Moreover, COVID-19 may cause direct brain injury via encephalopathy. The long-term impacts of this virus on mental health and brain function need to be analysed by researchers in the coming years. This article aims to describe the prolonged neurological clinical consequences related to brain changes in people with mild COVID-19 infection. When compared to a control group, people those who tested positive for COVID-19 had more brain shrinkage, grey matter shrinkage, and tissue damage. The damage occurs predominantly in areas of the brain that are associated with odour, ambiguity, strokes, reduced attention, headaches, sensory abnormalities, depression, and mental abilities for few months after the first infection. Therefore, in patients after a severe clinical condition of COVID-19, a deepening of persistent neurological signs is necessary.

Alteration of the blood-brain barrier by COVID-19 and its implication in the permeation of drugs into the brain

Diverse neurological symptoms have been reported in patients with SARS-CoV-2 disease (COVID-19), including stroke, ataxia, meningitis, encephalitis, and cognitive impairment. These alterations can cause serious sequelae or death and are associated with the entry of SARS-CoV-2 into the Central Nervous System (CNS). This mini-review discusses the main proposed mechanisms by which SARS-CoV-2 interacts with the blood-brain barrier (BBB) and its involvement in the passage of drugs into the CNS. We performed a search in PubMed with the terms “COVID-19” or “SARS-CoV-2” and “blood-brain barrier injury” or “brain injury” from the year 2019 to 2022. We found proposed evidence that SARS-CoV-2 infects neurovascular cells and increases BBB permeability by increasing the expression of matrix metalloproteinase-9 that degrades type IV collagen in the basement membrane and through activating RhoA, which induces restructuring of the cytoskeleton and alters the integrity of the barrier. The breakdown of the BBB triggers a severe inflammatory response, causing the cytokine storm (release of IL-1β, IL-6, TNF-α, etc.) characteristic of the severe phase of COVID-19, which includes the recruitment of macrophages and lymphocytes and the activation of astrocytes and microglia. We conclude that the increased permeability of the BBB would allow the passage of drugs that would not reach the brain in a normal physiological state, thus enhancing certain drugs’ beneficial or adverse effects. We hope this article will encourage research on the impact of drugs on patients with COVID-19 and recovered patients with sequelae, focusing mainly on possible dose adjustments and changes in pharmacokinetic parameters.

Cognitive Deficits in the Acute Phase of COVID-19: A Review and Meta-Analysis

This meta-analysis was conducted to quantify the risk of patients exhibiting cognitive deficits in the acute phase of COVID-19 at the time of the first variants (i.e., before the vaccine) and quantify the potential vulnerability of older patients and those who experienced more severe respiratory symptoms. To this end, we searched the LitCovid and EMBASE platforms for articles, including preprints, and included all studies (n = 48) that featured a measurement of cognition, which encompassed 2233 cases of COVID-19. Of these, 28 studies reported scores on global cognitive efficiency scales administered in the acute phase of COVID-19 (up to 3 months after infection). We were able to perform a meta-analysis of proportions on 24 articles (N_patients = 943), and a logistic regression on 18 articles (N_patients = 518). The meta-analysis for proportion indicated that 52.31% of patients with COVID-19 exhibited cognitive deficits in the acute phase. This high percentage, however, has to be interpreted taking in consideration the fact that the majority of patients were hospitalized, and some presented neurological complications, such as encephalopathy. A bootstrap procedure with random resampling revealed that an age of 59 was the threshold at which one would be more prone to present cognitive deficits. However, the severity of respiratory symptoms did not influence the scores on a global cognitive efficiency scale. Overall, our results indicated that neuropsychological deficits were a major consequence of the acute phase of the first forms of COVID-19.

Cognitive inhibition deficit in long COVID-19: An exploratory study

Background and objectives

An increasing number of research studies point toward the importance and prevalence of long-term neurocognitive symptoms following infection with COVID-19. Our objectives were to capture the prevalence of cognitive impairments from 1 to 16 months post-COVID-19 infection, assess the changes in neuropsychological functions over time, and identify factors that can predict long-term deficits in cognition.

Methodology

A cross-sectional research design was adopted to compare four sub-samples recruited over a 16-month timeframe (1-4, 5-8, 9-12, and 13-16 months). Phone interviews were conducted at least 6 weeks after being infected by COVID-19. Sociodemographic and clinical questionnaires were administered followed by standardized neurocognitive and psychological tests and health questionnaires screening cognitive symptoms, anxiety, depression, fatigue, and autonomy.

Results

Regarding general health questionnaires, 55.2% of the 134 participants had symptoms of psychiatric illness, while 21.6% of patients had moderate-to-severe anxiety or depression. Cognitive efficiency was diminished in 19.4% of our population. Executive dysfunction was screened in 56% of patients, and an impairment of cognitive flexibility and inhibition was revealed in 38.8%. Depression, hospital or intensive care unit (ICU) admission, and the duration of hospital or ICU stay were associated with an inhibition deficit. The duration elapsed from the initial infection, and the neurocognitive assessment was not associated with a decrease in inhibition deficit. The prevalence of cognitive impairments, other than inhibition deficit, tended to decrease during the study period.

Discussion

This study supports the extensive literature on the cognitive and neuropsychiatric sequelae of COVID-19 and highlights long-lasting inhibition deficits, while other cognitive functions seemed to improve over time. The severity of infection could interact as a catalyst in the complex interplay between depression and executive functions. The absence of a relation between inhibition deficits and sociodemographic or medical factors reinforces the need for cognitive screening in all COVID-19 patients. Future research should focus on inhibition deficits longitudinally to assess the progression of this impairment.

Making Pre-screening for Alzheimer's Disease (AD) and Postoperative Delirium Among Post-Acute COVID-19 Syndrome (PACS) a National Priority: The Deep Neuro Study

SARS-CoV-2 effects on cognition are a vibrant area of active research. Many researchers suggest that COVID-19 patients with severe symptoms leading to hospitalization sustain significant neurodegenerative injury, such as encephalopathy and poor discharge disposition. However, despite some post-acute COVID-19 syndrome (PACS) case series that have described elevated neurodegenerative biomarkers, no studies have been identified that directly compared levels to those in mild cognitive impairment, non-PACS postoperative delirium patients after major non-emergent surgery, or preclinical Alzheimer's disease (AD) patients that have clinical evidence of Alzheimer's without symptoms. According to recent estimates, there may be 416 million people globally on the AD continuum, which include approximately 315 million people with preclinical AD. In light of all the above, a more effective application of digital biomarker and explainable artificial intelligence methodologies that explored amyloid beta, neuronal, axonal, and glial markers in relation to neurological complications in-hospital or later outcomes could significantly assist progress in the field. Easy and scalable subjects' risk stratification is of utmost importance, yet current international collaboration initiatives are still challenging due to the limited explainability and accuracy to identify individuals at risk or in the earliest stages that might be candidates for future clinical trials. In this open letter, we propose the administration of selected digital biomarkers previously discovered and validated in other EU-funded studies to become a routine assessment for non-PACS preoperative cognitive impairment, PACS neurological complications in-hospital, or later PACS and non-PACS improvement in cognition after surgery. The open letter also includes an economic analysis of the implications for such national-level initiatives. Similar collaboration initiatives could have existing pre-diagnostic detection and progression prediction solutions pre-screen the stage before and around diagnosis, enabling new disease manifestation mapping and pushing the field into unchartered territory.

Cognitive Impairment after Post-Acute COVID-19 Infection: A Systematic Review of the Literature

The present study aims to provide a critical overview of the literature on the relationships between post-acute COVID-19 infection and cognitive impairment, highlighting the limitations and confounding factors. A systematic search of articles published from 1 January 2020 to 1 July 2022 was performed in PubMed/Medline. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only studies using validated instruments for the assessment of cognitive impairment were included. Out of 5515 screened records, 72 studies met the inclusion criteria. The available evidence revealed the presence of impairment in executive functions, speed of processing, attention and memory in subjects recovered from COVID-19. However, several limitations of the literature reviewed should be highlighted: most studies were performed on small samples, not stratified by severity of disease and age, used as a cross-sectional or a short-term longitudinal design and provided a limited assessment of the different cognitive domains. Few studies investigated the neurobiological correlates of cognitive deficits in individuals recovered from COVID-19. Further studies with an adequate methodological design are needed for an in-depth characterization of cognitive impairment in individuals recovered from COVID-19.

Post-COVID-19 human memory impairment: A PRISMA-based systematic review of evidence from brain imaging studies

Many people with coronavirus disease 2019 (COVID-19) report varying degrees of memory impairment. Neuroimaging techniques such as MRI and PET have been utilized to shed light on how COVID-19 affects brain function in humans, including memory dysfunction. In this PRISMA-based systematic review, we compared and summarized the current literature looking at the relationship between COVID-19-induced neuropathological changes by neuroimaging scans and memory symptoms experienced by patients who recovered from COVID-19. Overall, this review suggests a correlational trend between structural abnormalities (e.g., cortical atrophy and white matter hyperintensities) or functional abnormalities (e.g., hypometabolism) in a wide range of brain regions (particularly in the frontal, parietal and temporal regions) and memory impairments in COVID-19 survivors, although a causal relationship between them remains elusive in the absence of sufficient caution. Further longitudinal investigations, particularly controlled studies combined with correlational analyses, are needed to provide additional evidence.

Post COVID-19 neuropsychiatric complications and therapeutic role for TNF-α inhibitors: a case series study

Background

The post-COVID syndrome is the various physical and neuropsychiatric symptoms after the acute phase of COVID-19. The understanding of pathophysiology of this syndrome and its treatment need to further studies. This study aimed to present three cases of neuropsychiatric symptoms after COVID-19 and effective treatments in these patients.

Case presentation

Three patients with new or progressively neuropsychiatric symptoms such as seizures, attention difficulties, insomnia, confusion and etc., were referred to our clinic about 8 months after severe COVID-19 infection. The patients were assessed with extensive workup includes a neurological exam, brain MRI, LORETA scan, and biochemical and levels of inflammatory serum markers. All patients had elevated levels of TNF-α, poor neurological exam, and abnormal reports of MRI or LORETA scan. Diagnosis of post- COVID neuropsychiatric complications was made for the patients.TNF inhibition with Adalimumab (40 mg/weekly for a month) was initiated for the patients and led to a dramatic improvement of all symptoms.

Conclusions

To our knowledge, this report is the first case series study that suggests TNF inhibitors in the treatment of post-COVID-19 syndrome, especially neuropsychological complications. However, future studies should evaluate the best therapeutic options for this syndrome.

Brain fog as a Long-term Sequela of COVID-19

Increasing data indicate that people infected with COVID-19 are at high risk for developing long-term neurological complications, such as "brain fog" or cognitive impairment. However, little is known about the long-term outcomes of COVID-19 survivors. This also applies to the prevalence, risk factors, and pathobiological findings associated with these consequences. Although cognitive complications are anticipated in patients who require a long-lasting hospital stay or intubation, milder cases of COVID-19 with no record of hospitalization have also been shown to experience assessable cognitive challenges. Cognitive impairment can have a devastating impact on daily functioning. Understanding the long-term effect of COVID-19 on cognitive function is vital for applying specific schemes to those who wish to return to their jobs productively.

Cognitive impairments in patients with subacute coronavirus disease: Initial experiences in a post-coronavirus disease clinic

Background

A significant number of patients experience persistent cognitive impairment after coronavirus disease (COVID-19). This study aimed to investigate the cognitive function of patients in the subacute phase of COVID-19 and to identify the clinical factors associated with cognitive sequelae.

Materials and methods

Data from patients who visited the psychiatric department of our post-COVID clinic between March and May 2022 were analyzed. The results of neuropsychiatric function tests, including the digit span forward (attention/processing speed) and backward (working memory) tests, the trail making test part A (attention/processing speed) and part B (executive functioning), and the Stroop word color interference test (executive functioning), as well as clinical data from 40 patients in the subacute phase of COVID-19 were analyzed. We calculated the frequency of impairments in each cognitive measure, defined as a z-score of ≤−1.5 standard deviations below measure-specific age- and sex-adjusted norms.

Results

Of the participants, 72.5% (n = 29) had impairments in at least one cognitive domain. Impairment in executive function was the most frequent (64.9%), followed by impairments in processing speed/attention (52.5%) and working memory (42.5%). Age was inversely correlated with T scores in all cognitive function tests.

Conclusion

Regular examination of cognitive function is needed, especially in elderly individuals, regardless of the subjective symptom manifestations.

Changes in Electrical Brain Activity and Cognitive Functions Following Mild to Moderate COVID-19: A one-Year Prospective Study After Acute Infection

The coronavirus disease 2019 (COVID-19) can disrupt various brain functions. Over a one-year period, we aimed to assess brain activity and cognitive function in 53 COVID-19 patients and 30 individuals without COVID-19 (or asymptomatic). The Montreal Cognitive Assessment, Trail Making Test Parts A and B (TMT-A and B), and Digit Span Test were used to assess cognitive function. Cognitive variables and electroencephalography (EEG) data (activity, mobility, and complexity) were compared between the groups at rest and during cognitive demand (F3-F7, Fz-F3, Fz-F4, and F4-F8). There was a reduction in F3-F7 activity during the TMT-B in the COVID-19 group at 6-12 months compared to the controls (p = 0.01) at baseline (p = 0.03), a reduction in signal complexity at F3-F7 at rest in the COVID-19 group at baseline and 6-12 months compared to the controls (p < 0.001), and a reduction in Fz-F4 activity at rest from 6-12 months in the post-COVID group compared to baseline (p = 0.02) and 3-6 months (p = 0.04). At 6-12 months, there was a time increase in TMT-A in the COVID-19 group compared to that in the controls (p = 0.04). Some correlations were found between EEG data and cognitive test in both groups. In conclusion, there was a reduction in brain activity at rest in the Fz-F4 areas and during high cognitive demands in the F3-F7 areas. A reduction in signal complexity in F3-F7 at rest was found in the COVID-19 group at 6-12 months after acute infection. Furthermore, individuals with COVID-19 experience long-term changes in cognitive function.

Impact of COVID-19 pandemic on physical and mental health status and care of adults with epilepsy in Germany

Background

To mitigate the potential consequences of the coronavirus disease 2019 (COVID-19) pandemic on public life, the German Federal Government and Ministry of Health enacted a strict lockdown protocol on March 16, 2020. This study aimed to evaluate the impact of the COVID-19 pandemic on physical and mental health status and the supply of medical care and medications for people with epilepsy (PWE) in Germany.

Methods

The Epi2020 study was a large, multicenter study focused on different healthcare aspects of adults with epilepsy. In addition to clinical and demographic characteristics, patients were asked to answer a questionnaire on the impact of the first wave of the COVID-19 pandemic between March and May 2020. Furthermore, the population-based number of epilepsy-related admissions in Hessen was evaluated for the January-June periods of 2017–2020 to detect pandemic-related changes.

Results

During the first wave of the pandemic, 41.6% of PWE reported a negative impact on their mental health, while only a minority reported worsening of their seizure situation. Mental and physical health were significantly more negatively affected in women than men with epilepsy and in PWE without regular employment. Moreover, difficulties in ensuring the supply of sanitary products (25.8%) and antiseizure medications (ASMs; 19.9%) affected PWE during the first lockdown; no significant difference regarding these impacts between men and women or between people with and without employment was observed. The number of epilepsy-related admissions decreased significantly during the first wave.

Conclusions

This analysis provides an overview of the general and medical care of epilepsy patients during the COVID-19 pandemic. PWE in our cohort frequently reported psychosocial distress during the first wave of the pandemic, with significant adverse effects on mental and physical health. Women and people without permanent jobs especially reported distress due to the pandemic. The COVID‐19 pandemic has added to the mental health burden and barriers to accessing medication and medical services, as self-reported by patients and verified in population-based data on hospital admissions.

Trial registration

German Clinical Trials Register (DRKS), DRKS00022024. Registered October 2, 2020, http://www.drks.de/DRKS00022024

COVID-19 and cognitive impairment: neuroinvasive and blood‒brain barrier dysfunction

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global pandemic. Although COVID-19 was initially described as a respiratory disease, there is growing evidence that SARS-CoV-2 is able to invade the brains of COVID-19 patients and cause cognitive impairment. It has been reported that SARS-CoV-2 may have invasive effects on a variety of cranial nerves, including the olfactory, trigeminal, optic, and vagus nerves, and may spread to other brain regions via infected nerve endings, retrograde transport, and transsynaptic transmission. In addition, the blood-brain barrier (BBB), composed of neurovascular units (NVUs) lining the brain microvasculature, acts as a physical barrier between nerve cells and circulating cells of the immune system and is able to regulate the transfer of substances between the blood and brain parenchyma. Therefore, the BBB may be an important structure for the direct and indirect interaction of SARS-CoV-2 with the brain via the blood circulation. In this review, we assessed the potential involvement of neuroinvasion under the SARS-CoV-2 infection, and the potential impact of BBB disorder under SARS-CoV-2 infection on cognitive impairment.

Making pre-screening for Alzheimer's disease (AD) and Postoperative delirium among post-acute COVID-19 syndrome - (PACS) a national priority: The Deep Neuro Study

SARS-CoV-2 effects on cognition is a vibrant area of active research. Many researchers suggest that COVID-19 patients with severe symptoms leading to hospitalization, sustain significant neurodegenerative injury, such as encephalopathy and poor discharge disposition. However, despite some post-acute COVID-19 syndrome (PACS) case series that have described elevated neurodegenerative biomarkers, no studies have been identified that directly compared levels to those in mild cognitive impairment, non-PACS postoperative delirium patients after major non-emergent surgery or preclinical Alzheimer's Disease (AD) patients, that have clinical evidence of Alzheimer's without symptoms. According to recent estimates, there may be 416 million people globally on the AD continuum, which include approximately 315 million people with preclinical AD. In light of all the above, a more effective application of digital biomarker and explainable artificial intelligence methodologies that explored amyloid beta, neuronal, axonal, and glial markers in relation to neurological complications in-hospital or later outcomes could significantly assist progress in the field. Easy and scalable subjects' risk stratification is of utmost importance, yet current international collaboration initiatives are still challenging due to the limited explainability and accuracy to identify individuals at risk or in the earliest stages that might be candidates for future clinical trials. In this open letter, we propose the administration of selected digital biomarkers previously discovered and validated in other EU funded studies to become a routine assessment for non-PACS preoperative cognitive impairment, PACS neurological complications in-hospital or later PACS and non-PACS improvement in cognition after surgery. The open letter also includes an economic analysis of the implications for such national level initiatives. Similar collaboration initiatives could have existing prediagnostic detection and progression prediction solutions pre-screen the stage before and around diagnosis, enabling new disease manifestation mapping and pushing the field into unchartered territory.

COVID-19 associated cognitive impairment: A systematic review

INTRODUCTION

COVID-19 has a wide range of clinical manifestations. Neurological manifestations in COVID-19 patients were demonstrated during the pandemic, including cognitive impairment. This study aimed to determine any relationship between COVID-19 and cognitive complaints, such as dementia, mild cognitive impairment (MCI), or subjective cognitive decline (SCD).

METHODS

We performed a systematic review of MEDLINE via Ebsco, Cochrane EMBASE, SCOPUS, and LILACS electronic databases of observational studies with COVID-19 patients confirmed by serology or PCR who developed new cognitive impairment or deteriorated from previous cognitive impairment after infection. This review protocol was recorded on PROSPERO with registration number CRD 42021241590.

RESULTS

A total of 3.520 articles were retrieved and read. Twenty-two studies were selected for our review. A wide range of cognitive assessment tools (n = 25) was used. The most described affected domains in these studies were executive functions, attention, and episodic memory. Thirteen studies showed a pattern of cognitive impairment in processing speed, inattention, or executive dysfunction assessed through working memory.

CONCLUSION

This review highlights the high frequency of cognitive impairment after COVID-19 infection. However, we were unable to differentiate whether the cognitive impairment found corresponded to mild cognitive impairment or dementia through data from selected studies, and this issue serves as one objective of future studies to be addressed on this topic.

Can the choice reaction time be modified after COVID-19 diagnosis? A prospective cohort study

Assessment of cognitive processing speed through choice reaction time (CRT) can be an objective tool to assess cognitive functions after COVID-19 infection.

Objective

This study aimed to assess CRT in individuals after acute COVID-19 infection over 1 year.

Methods

We prospectively analyzed 30 individuals (male: 9, female: 21) with mild-moderate functional status after COVID-19 and 30 individuals (male: 8, female: 22) without COVID-19. Cognitive and neuropsychiatric symptoms were evaluated using the Montreal Cognitive Assessment (MoCA) and Hospital Anxiety and Depression Scale (HADS), respectively. CRT (milliseconds) was evaluated by finding the difference between the photodiode signal and the electromyographic (EMG) onset latency of anterior deltoid, brachial biceps, and triceps during the task of reaching a luminous target. CRT was evaluated three times over 1 year after COVID-19: baseline assessment (>4 weeks of COVID-19 diagnosis), between 3 and 6 months, and between 6 and 12 months.

Results

The multiple comparison analysis shows CRT reduction of the anterior deltoid in the COVID-19 group at 3-6 (p=0.001) and 6-12 months (p<0.001) compared to the control group. We also observed CRT reduction of the triceps at 6-12 months (p=0.002) and brachial biceps at 0-3 (p<0.001), 3-6 (p<0.001), and 6-12 months (p<0.001) in the COVID-19 compared to the control group. Moderate correlations were observed between MoCA and CRT of the anterior deltoid (r=-0.63; p=0.002) and brachial biceps (r=-0.67; p=0.001) at 6-12 months in the COVID-19 group.

Conclusions

There was a reduction in CRT after acute COVID-19 over 1 year. A negative correlation was also observed between MoCA and CRT only from 6 to 12 months after COVID-19 infection.

Electroencephalogram-Based Evaluation of Impaired Sedation in Patients with Moderate to Severe COVID-19 ARDS

The sedation management of patients with severe COVID-19 is challenging. Processed electroencephalography (pEEG) has already been used for sedation management before COVID-19 in critical care, but its applicability in COVID-19 has not yet been investigated. We performed this prospective observational study to evaluate whether the patient sedation index (PSI) obtained via pEEG may adequately reflect sedation in ventilated COVID-19 patients. Statistical analysis was performed by linear regression analysis with mixed effects. We included data from 49 consecutive patients. None of the patients received neuromuscular blocking agents by the time of the measurement. The mean value of the PSI was 20 (±23). The suppression rate was determined to be 14% (±24%). A deep sedation equivalent to the Richmond Agitation and Sedation Scale of −3 to −4 (correlation expected PSI 25−50) in bedside examination was noted in 79.4% of the recordings. Linear regression analysis revealed a significant correlation between the sedative dosages of propofol, midazolam, clonidine, and sufentanil (p < 0.01) and the sedation index. Our results showed a distinct discrepancy between the RASS and the determined PSI. However, it remains unclear to what extent any discrepancy is due to the electrophysiological effects of neuroinflammation in terms of pEEG alteration, to the misinterpretation of spinal or vegetative reflexes during bedside evaluation, or to other causes.

A human coronavirus OC43-derived polypeptide causes neuropathic pain

Human coronaviruses have been recently implicated in neurological sequelae by insufficiently understood mechanisms. We here identify an amino acid sequence within the HCoV-OC43 p65-like protein homologous to the evolutionarily conserved motif of myelin basic protein (MBP). Because MBP-derived peptide exposure in the sciatic nerve produces pronociceptive activity in female rodents, we examined whether a synthetic peptide derived from the homologous region of HCoV-OC43 (OC43p) acts by molecular mimicry to promote neuropathic pain. OC43p, but not scrambled peptides, induces mechanical hypersensitivity in rats following intrasciatic injections. Transcriptome analyses of the corresponding spinal cords reveal upregulation of genes and signaling pathways with known nociception-, immune-, and cellular energy-related activities. Affinity capture shows the association of OC43p with an Na+ /K+ -transporting ATPase, providing a potential direct target and mechanistic insight into virus-induced effects on energy homeostasis and the sensory neuraxis. We propose that HCoV-OC43 polypeptides released during infection dysregulate normal nervous system functions through molecular mimicry of MBP, leading to mechanical hypersensitivity. Our findings might provide a new paradigm for virus-induced neuropathic pain.

Changes in cognitive functioning after COVID-19: A systematic review and meta-analysis

Introduction

We conducted a systematic review and meta‐analysis of the cognitive effects of coronavirus disease 2019 (COVID‐19) in adults with no prior history of cognitive impairment.

Methods

Searches in Medline/Web of Science/Embase from January 1, 2020, to December 13, 2021, were performed following Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines.  A meta‐analysis of the Montreal Cognitive Assessment (MoCA) total score comparing recovered COVID‐19 and healthy controls was performed.

Results

Oof 6202 articles, 27 studies with 2049 individuals were included (mean age = 56.05 years, evaluation time ranged from the acute phase to 7 months post‐infection). Impairment in executive functions, attention, and memory were found in post‐COVID‐19 patients.  The meta‐analysis was performed with a subgroup of 290 individuals and showed a difference in MoCA score between post‐COVID‐19 patients versus controls (mean difference = −0.94, 95% confidence interval [CI] −1.59, −0.29; P = .0049).

Discussion

Patients recovered from COVID‐19 have lower general cognition compared to healthy controls up to 7 months post‐infection.

Higher Inflammatory Markers are correlated with Worse Cognitive Function in Coronavirus Disease-2019 Patients

AIM: This study aimed to determine the correlation between inflammation with cognitive function in COVID-19 patients. METHODS: We recruited COVID-19 patients using consecutive sampling methods in Adam Malik General Hospital Medan, Indonesia. The neutrophil-to-lymphocyte ratio (NLR,) C-reactive protein (CRP), D-dimer, and ferritin serum levels were measured as inflammatory markers . Cognitive function was assessed in several cognitive domains using Forward Digit Span for attention, Bacward Digit Span for working memory, and Trail Making Test parts A and B for executive function. The correlation between inflammatory markers and cognitive function was analyzed using Spearman correlation test. RESULTS: This study involved 40 COVID-19 patients consisting of 13 (32.5%) males and 27 (67.5%) females; the median age of the patients was 39.5 (19–65) years. We found that higher D-dimer and ferritin levels were significantly correlated with worse BDS scores (r = −0.369 p = 0.019 and r = −0.408 p = 0.009, respectively) and higher ferritin level was also correlated with worse FDS score (r = −0.365 p = 0.020 and). Higher D-dimer and ferritin levels were also significantly correlated with a longer time of completion of TMT-B (r = 0.363 p = 0.022 and r = 0.433 p = 0.005) and higher ferritin level was also correlated with a longer time of completion of TMT-A (r = 0.438 P=0.005). There were no significant correlations between NLR and CRP levels with cognitive function. CONCLUSION: Higher inflammatory markers are correlated with worse attention, working memory, and executive function in COVID-19 patients.

Brain Imaging Changes in Patients Recovered From COVID-19: A Narrative Review

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused several outbreaks of highly contagious respiratory diseases worldwide. The respiratory symptoms of Coronavirus Disease-19 (COVID-19) have been closely monitored and studied, while the central nervous system (CNS) and peripheral system (PNS) lesions induced by COVID-19 have not received much attention. Currently, patients with COVID-19-associated encephalopathy present with dizziness, headache, anxiety and depression, stroke, epileptic seizures, the Guillain-Barre syndrome (GBS), and demyelinating disease. The exact pathologic basis for these neurological symptoms is currently not known. Rapid mutation of the SARS-CoV-2 genome leads to the appearance of SARS-CoV-2 variants of concern (VOCs), which have higher infectivity and virulence. Therefore, this narrative review will focus on the imaging assessment of COVID-19 and its VOC. There has been an increase in technologies, such as [¹⁸F]fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) and functional magnetic resonance imaging (fMRI), that have been used to observe changes in brain microstructure over time in patients with COVID-19 recovery. Medical imaging and pathological approaches aimed at exploring the associations between COVID-19 and its VOC, with cranial nerve and abnormal nerve discharge will shed light on the rehabilitation process of brain microstructural changes related to SARS-CoV-2, and aid future research in our understanding of the treatment and prognosis of COVID-19 encephalopathy.

Clinical case of anti-NMDA receptor encephalitis associated with new coronaviral infection (COVID-19)

During the outbreak of coronavirus disease 2019 (COVID-19) clinicians are increasingly involved in the observation of possible neurological complications due to the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Some cases of encephalitis following COVID‐19 pandemic have been reported in literature that can mean possible damage to the central nervous system related to the SARS-CoV-2 infection. Early on, this was thought to be due to the direct effects of the virus itself, but the possibility of immune system mechanisms being implicated was gradually raised in scientific literature. The reports of anti‐NMDA receptor encephalitis among patients with COVID‐19 at different ages may be signs of this condition. We report the case of 16-year teenager with concomitant Anti-N-Methyl-D-Aspartate Receptor (Anti-NMDAR) encephalitis and COVID‐19. This clinical case brings arguments on the possible relationship between SARS-CoV-2 infection and autoimmune encephalitis.

Cerebrospinal fluid analysis in patients with COVID-19-associated central nervous system manifestations: a systematic review

ABSTRACT Background: Central nervous system (CNS) symptoms may occur in patients with acute COVID-19. The role of CSF examination in these patients remains to be established. Objective: A systematic review of CSF findings relating to COVID-19 was carried out. Methods: CSF parameters, including cytological and biochemical analyses, SARS-CoV-2 RT-PCR and other CSF markers, were recorded and analyzed among patients with acute COVID-19 and one of the following CNS syndromes: stroke, encephalopathy, encephalitis, inflammatory syndromes, seizure, headache and meningitis. Results: Increased white blood cells and/or increased protein concentration were found in 52.7% of the patients with encephalitis, 29.4% of the patients with encephalopathy and 46.7% of the patients with inflammatory syndromes (P < 0.05). CSF RT-PCR for SARS-CoV-2 was positive in 17.35% of the patients with encephalitis and less than 3.5% of the patients with encephalopathy or inflammatory syndromes (P < 0.05). Intrathecal production of immunoglobulins was found in only 8% of the cases. More than 85% of the patients had increased CSF cytokines and chemokines. Increased CSF neurofilament light chain (NfL) and CSF Tau were found in 71% and 36% of the cases, respectively. Conclusion: Non-specific inflammatory CSF abnormalities were frequently found in patients with COVID-19 CNS syndromes. The increase in neurodegeneration biomarkers suggests that neuronal damage occurs, with long-term consequences that are still unknown.

Alzheimer's-like signaling in brains of COVID-19 patients

Introduction

The mechanisms that lead to cognitive impairment associated with COVID‐19 are not well understood.

Methods

Brain lysates from control and COVID‐19 patients were analyzed for oxidative stress and inflammatory signaling pathway markers, and measurements of Alzheimer’s disease (AD)‐linked signaling biochemistry. Post‐translational modifications of the ryanodine receptor/calcium (Ca2⁺) release channels (RyR) on the endoplasmic reticuli (ER), known to be linked to AD, were also measured by co‐immunoprecipitation/immunoblotting of the brain lysates.

Results

We provide evidence linking SARS‐CoV‐2 infection to activation of TGF‐β signaling and oxidative overload. The neuropathological pathways causing tau hyperphosphorylation typically associated with AD were also shown to be activated in COVID‐19 patients. RyR2 in COVID‐19 brains demonstrated a “leaky” phenotype, which can promote cognitive and behavioral defects.

Discussion

COVID‐19 neuropathology includes AD‐like features and leaky RyR2 channels could be a therapeutic target for amelioration of some cognitive defects associated with SARS‐CoV‐2 infection and long COVID.

Long COVID‐19: Objectifying most self‐reported neurological symptoms

Objectives

We aimed to objectify and compare persisting self‐reported symptoms in initially hospitalized and non‐hospitalized patients after infection with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) by applying clinical standardized measures.

Methods

We conducted a cross‐sectional study of adult patients with confirmed SARS‐CoV‐2 infection including medical history, neurological examination, blood markers, neuropsychological testing, patient‐reported outcome measures (PROMs), and brain magnetic resonance imaging (MRI).

Results

Fifty patients with persisting symptoms for at least 4 weeks were included and classified by initial hospitalization status. Median time from SARS‐CoV‐2 detection to investigation was 29.3 weeks (range 3.3–57.9). Although individual cognitive performance was generally within the normative range in both groups, mostly mild deficits were found in attention, executive functions, and memory. Hospitalized patients performed worse in global cognition, logical reasoning, and processes of verbal memory. In both groups, fatigue severity was associated with reduced performance in attention and psychomotor speed tasks (r_s = −0.40, p < 0.05) and reduced quality of life (EQ5D, r_s = 0.57, p < 0.001) and with more persisting symptoms (median 3 vs. 6, p < 0.01). PROMs identified fatigue, reduced sleep quality, and increased anxiety and depression in both groups but more pronounced in non‐hospitalized patients. Brain MRI revealed microbleeds exclusively in hospitalized patients (n = 5).

Interpretation

Regardless of initial COVID‐19 severity, an individuals' mental and physical health can be severely impaired in the long‐term limitedly objectified by clinical standard diagnostic with abnormalities primarily found in hospitalized patients. This needs to be considered when planning rehabilitation therapies and should give rise to new biomarker research.

Iranian Smell Diagnostic Test in Covid-19 Disease; Report of Covid-19 Center of North of Iran

Background

SARS-CoV-2 is a pandemic coronavirus that causes the COVID-19 syndrome. In the pandemic of COVID-19 many patients were affected to new onset olfactory dysfunction. Since there is a dearth of research studies regarding the standard smell test, the present study was conducted to fill this gap.

Methods

The present retrospective cohort study was conducted on 250 clients with or without diagnosis of Covid-19 disease who referred to Covid-19 centers of North of Iran. Two groups were matched for age and sex. Data were collected by examination, demographic and clinical information questionnaire and Iranian smell diagnostic test. The binary logistic regression to estimate the odds ratio value in SPSS version 23.0 was used.

Results

One-hundred cases (42.2%) had hyposmia and 20 cases (8.4%) were found to have anosmia. Type of covid-19 sign and symptom were statistically significant with olfactory dysfunction (41 cases, 31.8%), fever (28 cases, 21.7%), weakness and dyspnea (15 cases, 11.6%), (p=0.0001). The urban residency equal OR=6.42 (3.04-13.53) to rural residency for olfactory dysfunction (p=0.0001). Covid-19 patients' OR=61.25 (27.36-137.11) chance to be affected by the olfactory dysfunction in compare to control group (p=0.0001). Also, with increasing age, chance of olfactory dysfunction changed from OR=0.61(1.16-0.13) to OR=1.89 (0.82-4.33). Furthermore, female chance OR=1.21 (0.72-2.03) and employee patients was OR=2.29 (1.30-4.04) to olfactory dysfunction.

Conclusion

Alf of the patients were affected by olfactory dysfunction. Furthermore, Covid-19 patients, urban residency, lower age, female and employee were the prognostic factors for olfactory dysfunction. The standard olfactory tests such as IR-SIT is suggested for screening and detecting the clients probably affected by covid-19 especially in younger ages.

Cognitive consequences of COVID-19: results of a cohort study from South America

BACKGROUND

Neurological and psychiatric manifestations associated with SARS-CoV-2 infection have been reported throughout the scientific literature. However, studies on post-COVID cognitive impairment in people with no previous cognitive complaint are scarce.

OBJECTIVE

We aim to investigate the impact of COVID-19 on cognitive functions in adults without cognitive complaints before infection and to study cognitive dysfunction according to disease severity and cognitive risk factors.

METHODS

Forty-five post-COVID-19 patients and forty-five controls underwent extensive neuropsychological evaluation, which assessed cognitive domains such as memory, language, attention, executive functions, and visuospatial skills, including psychiatric symptomatology scales. Data were collected on the severity of infection, premorbid medical conditions, and functionality for activities of daily living before and after COVID-19.

RESULTS

Significant differences between groups were found in cognitive composites of memory (p=0.016, Cohen's d= 0.73), attention (p<0.001, Cohen's d=1.2), executive functions (p<0.001, Cohen's d=1.4), and language (p=0.002, Cohen's d=0.87). The change from premorbid to post-infection functioning was significantly different between severity groups (WHODAS, p=0.037). Self-reported anxiety was associated with the presence of cognitive dysfunction in COVID-19 subjects (p=0.043).

CONCLUSION

Our results suggest that the presence of cognitive symptoms in post-COVID-19 patients may persist for months after disease remission and argue for the inclusion of cognitive assessment as a protocolized stage of the post-COVID examination. Screening measures may not be sufficient to detect cognitive dysfunction in post-COVID-19 patients.

Physical Function, Cognitive Function, and Daily Activities in Patients Hospitalized Due to COVID-19: A Descriptive Cross-Sectional Study in Sweden

An estimated 14–20% of people infected with COVID-19 require medical care. The aim of the present study was to evaluate physical function, cognitive function, and daily activities in patients hospitalized due to COVID-19, and to investigate differences depending on age and admission to the intensive care unit (ICU). This prospective descriptive cross-sectional study included a consecutive sample of 211 patients (mean age 65.1 years, 67.3% men) hospitalized due to COVID-19 in Sweden. Data regarding physical function and daily activities were collected in hospital from July 2020 to February 2021. The average length of hospital stay was 33.8 days, and 48.8% of the patients were admitted to the ICU. Physical function (grip- and lower body strength) was reduced in both groups, and significantly more in the older group, ≥65 years old, compared to the younger. Furthermore, the older group also had significantly less ability to perform activities in daily life, and had significantly reduced cognitive function as compared to the younger age group. In patients treated in the ICU, physical impairments as well as the activity level were significantly more pronounced compared to patients not treated in the ICU. Patients hospitalized due to COVID-19 are physically impaired, have mild cognitive impairments, and have difficulties performing daily activities. The findings in this study indicate the need for out-patient follow-up and rehabilitation for patients hospitalized due to COVID-19, especially in older patients and patients treated in the ICU.

What can the neurological manifestations of COVID-19 tell us: a meta-analysis

Background

Covid-19 became a global pandemic in 2019. Studies have shown that coronavirus can cause neurological symptoms, but clinical studies on its neurological symptoms are limited. In this meta-analysis, we aimed to summarize the various neurological manifestations that occurred in COVID-19 patients and calculate the incidence of various neurological manifestations. At the same time, we further explored the mechanism of nervous system injury and prognosis in COVID-19 patients in combination with their nervous system manifestations. This study provides a reference for early clinical identification of COVID-19 nervous system injury in the future, so as to achieve early treatment and reduce neurological sequelae.

Methods

We systematically searched all published English literature related to the neurological manifestations of COVID-19 from January 1, 2020, to April 30, 2021, in Pubmed, Embase, and Cochrane Library. The keywords used were COVID-19 and terminology related to the nervous system performance. All included studies were selected by two independent reviewers using EndNote and NoteExpress software, any disagreement was resolved by consensus or by a third reviewer, and the selected data were then collected for meta-analysis using a random-effects model.

Results

A total of 168 articles (n = 292,693) were included in the study, and the meta-analysis showed that the most common neurological manifestations of COVID-19 were myalgia(33%; 95%CI 0.30–0.37; I² = 99.17%), smell impairment(33%; 95%CI 0.28–0.38; I² = 99.40%), taste dysfunction(33%; 95%CI 0.27–0.39; I² = 99.09%), altered mental status(32%; 95%CI 0.22–0.43; I² = 99.06%), headache(29%; 95%CI 0.25–0.33; I² = 99.42%), encephalopathy(26%; 95%CI 0.16–0.38; I² = 99.31%), alteration of consciousness(13%; 95%CI 0.08–0.19; I² = 98.10%), stroke(12%; 95%CI 0.08–0.16; I² = 98.95%), dizziness(10%; 95%CI 0.08–0.13; I² = 96.45%), vision impairment(6%; 95%CI 0.03–0.09; I² = 86.82%), intracerebral haemorrhage(5%; 95%CI 0.03–0.09; I² = 95.60%), seizure(4%; 95%CI 0.02 -0.05; I² = 98.15%), encephalitis(2%; 95%CI 0.01–0.03; I² = 90.36%), Guillan-Barré Syndrome (GBS) (1%; 95%CI 0.00–0.03; I² = 89.48%).

Conclusions

Neurological symptoms are common and varied in Covid-19 infections, and a growing number of reports suggest that the prevalence of neurological symptoms may be increasing. In the future, the role of COVID-19 neurological symptoms in the progression of COVID-19 should be further studied, and its pathogenesis and assessment methods should be explored, to detect and treat early neurological complications of COVID-19 and reduce mortality.

Neurological symptoms and complications in predominantly hospitalized COVID-19 patients: Results of the European multinational Lean European Open Survey on SARS-Infected Patients (LEOSS)

Background and purpose

During acute coronavirus disease 2019 (COVID‐19) infection, neurological signs, symptoms and complications occur. We aimed to assess their clinical relevance by evaluating real‐world data from a multinational registry.

Methods

We analyzed COVID‐19 patients from 127 centers, diagnosed between January 2020 and February 2021, and registered in the European multinational LEOSS (Lean European Open Survey on SARS‐Infected Patients) registry. The effects of prior neurological diseases and the effect of neurological symptoms on outcome were studied using multivariate logistic regression.

Results

A total of 6537 COVID‐19 patients (97.7% PCR‐confirmed) were analyzed, of whom 92.1% were hospitalized and 14.7% died. Commonly, excessive tiredness (28.0%), headache (18.5%), nausea/emesis (16.6%), muscular weakness (17.0%), impaired sense of smell (9.0%) and taste (12.8%), and delirium (6.7%) were reported. In patients with a complicated or critical disease course (53%) the most frequent neurological complications were ischemic stroke (1.0%) and intracerebral bleeding (ICB; 2.2%). ICB peaked in the critical disease phase (5%) and was associated with the administration of anticoagulation and extracorporeal membrane oxygenation (ECMO). Excessive tiredness (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.20–1.68) and prior neurodegenerative diseases (OR 1.32, 95% CI 1.07–1.63) were associated with an increased risk of an unfavorable outcome. Prior cerebrovascular and neuroimmunological diseases were not associated with an unfavorable short‐term outcome of COVID‐19.

Conclusion

Our data on mostly hospitalized COVID‐19 patients show that excessive tiredness or prior neurodegenerative disease at first presentation increase the risk of an unfavorable short‐term outcome. ICB in critical COVID‐19 was associated with therapeutic interventions, such as anticoagulation and ECMO, and thus may be an indirect complication of a life‐threatening systemic viral infection.

Neurological manifestations of COVID-19 - an approach to categories of pathology

BACKGROUND

Various neurological manifestations of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported, associated with a broad spectrum of diverse neurological symptoms and syndromes. Estimating rate and relevance of these manifestations remains difficult as there is a lack of standardised case definitions.

METHODS

We defined comprehensive categories including most reported neurological manifestations associated with SARS-CoV-2 to allow for a more standardised data collection. After a literature search of MEDLINE with ten keywords, 12 selected studies and larger case series were included. We compared the rate and relevance of neurological manifestations in hospitalized patients. We propose four main categories including 1) cerebrovascular disease, 2) inflammatory syndromes of the central nervous system (CNS), peripheral nervous system (PNS) and muscle, 3) metabolic/toxic dysfunction of CNS, PNS and muscle and 4) miscellaneous disorders.

CONCLUSION

Ageusia (702) and anosmia (805) have been reported as the most common and the first occurring neurological symptoms. Cerebrovascular disease (451) and encephalopathy (663) were associated with a more severe course and worse clinical outcome. Any neurological manifestation was associated with a longer hospital stay and a higher morbidity and mortality compared to patients without neurological manifestations. We suggest reporting future neurological manifestations of coronavirus disease-19 (COVID-19) following a pathophysiology-based approach using standardized pre-defined case definitions to yield more specific and comparable data.

Is loss of smell an early predictor of COVID-19 severity: a systematic review and meta-analysis

Anecdotal evidence suggests that the severity of coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is likely to be distinguished by variations in loss of smell (LOS). Thus, we conducted a meta-analysis of 45 articles that include a total of 42,120 COVID-19 patients from 17 different countries to demonstrate that severely ill or hospitalized COVID-19 patients have a lesser chance of experiencing LOS than non-severely ill or non-hospitalized COVID-19 patients (odds ratio = 0.527 [95% CI 0.373–0.744; p < 0.001] and 0.283 [95% CI 0.173–0.462; p < 0.001], respectively). We also proposed a possible mechanism underlying the association of COVID-19 severity with anosmia, which may explain why patients without sense of smell develop severe COVID-19. Variations in LOS according to the severity of COVID-19 is a global phenomenon, with few exceptions. Since severely ill patients have a lower rate of anosmia, patients without anosmia should be monitored more closely in the early stages of COVID-19, for early diagnosis of severity of illness. An understanding of how the severity of COVID-19 infection and LOS are associated has profound implications for the clinical management and mitigation strategies for the disease.