Cognitive profile following COVID-19 infection: Clinical predictors leading to neuropsychological impairment

The association of post-COVID-19 fatigue in the acute phase with neuropsychiatric and neurocognitive symptoms trajectory over time and long-term health-related quality of life among Chinese adults

BACKGROUND

Post-viral fatigue is a common and debilitating neurological sequela of COVID-19, often accompanied with multidimensional neuropsychiatric symptoms (post-viral fatigue, sleep disturbance, anxiety, depression, and post-traumatic stress disorder) and neurocognitive impairment. We sought to characterize the trajectory of these neurological symptoms and investigate the relationship between acute-phase fatigue (< 1 month) and the chronicity of neuropsychiatric and neurocognitive symptoms, as well as long-term health-related quality of life (HRQoL) at 3 months post-infection.

METHODS

A prospective, multi-center, longitudinal study was conducted from January to February 2023 within a cohort of individuals with a mild SARS-COV-2 infection and contemporaneous healthy controls (HCs). Comprehensive neuropsychiatric and neurocognitive assessments were collected for COVID-19 survivors during both acute and chronic phase post-infection, with the EQ-5D-5L (a standardized instrument for assessing HRQoL) evaluated at the chronic phase. Healthy controls underwent the same protocol for recruitment to the study. Linear mixed models were used to access the impact of acute-phase fatigue on different neuropsychiatric and neurocognitive scales over time.

RESULTS

Three hundred thirty-five COVID-19 survivors and 79 HCs were included in the study. COVID-19 survivors exhibited poorer performance in various neuropsychiatric domains during the acute phase, with the exception of cognitive impairment. A significant amelioration of emotional symptoms, including anxiety and depression, was observed from the acute to chronic phase among COVID-19 survivors, reaching levels comparable to those of HCs. However, at 3 months post-infection, survivors continued to report higher levels of fatigue and poorer sleep quality compared to HCs, although the differences had diminished from the acute phase. The impact of the pandemic event persisted, and no significant changes in cognitive performance were observed. Acute-phase fatigue was associated with poorer sleep and worse emotional problems during the recovery process (from the acute to the chronic phase), and further exacerbated overall HRQoL at 3 months post-infection (EQ index score, p = 0.001, Cohen's d = -0.33; EQ-VAS, p = 0.007, Cohen's d = -0.19).

CONCLUSIONS

Our findings provide novel evidence on the distinct temporal trajectories for post-acute COVID-19 sequelae in a longitudinal study, highlighting the negative impact of acute-phase fatigue on the process of neuropsychiatric recovery and long-term HRQoL.

Long-term cognitive functioning following COVID-19: Negligible neuropsychological changes over time

Objective: Objective cognitive impairment has been shown in a minority of hospitalized COVID-19 patients, and longitudinal studies with a relatively long follow-up duration are scarce. We sought to investigate the presence and long-term change of objective cognitive functioning. Method: Forty-six initially hospitalized (18 ± 19 days) COVID-19 survivors (male/female: 30/16; age: 61 ± 11) underwent extensive neuropsychological assessment (including performance validity) approximately 1 (T1) and 2.5 years (T2) post-infection. Cognitive domains assessed were: memory, attention, executive functioning, processing speed, and language (n = 14 (sub)tests). We used normative data to derive age, sex, and education-adjusted T-scores (T ≤ 35 [≤-1.5SD], deficit cut-off). Repeated measures AN(C)OVAs were used to investigate cognitive functioning over time. Results: Mean neuropsychological performance (n = 14 tests) was within normal range at both timepoints, and number of individuals with objective cognitive deficits ranged from 0-20% (T1), and 2-22% (T2). Number of subjective cognitive complaints remained unchanged. A minority (17%) showed objective cognitive deficits on ≥2 tests at both 1 and 2.5 years post-infection, but not consistently within one cognitive domain. Longitudinal analyses on the total sample showed improvement in performance over time on phonemic fluency (p<.001), but stable cognitive performance on all other tests, independent of prior comorbidities, subjective cognitive complaints, depressive symptoms, and ICU admission. Conclusions: There were no consistent objective cognitive deficits or major cognitive disorders years after SARS-CoV-2 infection in the majority of cases. Neuropsychological functioning remained essentially unchanged over time. Future larger longitudinal studies are necessary to unravel COVID-19-related cognitive phenotypes of persisting deficits and how these can be modulated.

Impact of Fatigue on Subjective and Objective Cognitive Functions in Persons with Post-COVID-19 Condition

Post-COVID-19 condition (PCC) is a serious debilitating condition that develops after the resolution of an acute infection of severe acute respiratory syndrome-associated coronavirus 2. Some commonly reported symptoms include fatigue and cognitive deficits. Multiple lines of evidence have indicated fatigue to be associated with cognitive deficits in the general population. Herein, we perform a secondary analysis of the effects of fatigue on subjective and objective cognition in persons with PCC using a generalized linear model. In this study, fatigue was measured using the Fatigue Severity Scale (FSS) and cognition was measured using the Digit-Symbol Substitution Test (DSST) and the Trails Making Test parts A and B (TMT-A/B). FSS had a statistically significant negative correlation with DSST and TMT-A/B scores. Fatigue serves as a possible target for the development of PCC therapeutics. Fatigue and cognition correlates should be further investigated for underlying neurobiological substrates in persons with PCC.

Correlation Between COVID-19 Recovery, Executive Function Decline, and Emotional State

Objective

The aim of this study was to determine whether there is a relationship between the time since recovery from coronavirus disease 2019 (COVID-19) and alterations in executive functions. We also evaluate the emotional state of post-COVID-19 patients.

Patients and Methods

We assessed patients between 18 and 50 years old, who had a history of COVID-19 with mild, moderate, or severe illness. We used the Batería Neuropsicológica de Funciones Ejecutivas y Lóbulos Frontales-3 (BANFE-3), Mini-Mental State Examination (MMSE), and Mini-International Neuropsychiatric Interview (MINI), in addition to a semi-structured interview. Spearman's correlation coefficient was used, with a p value <0.05 indicating significance.

Results

We evaluated 67 patients with a mean age of 34.6±9.6 years, most of whom had ≥13 years of schooling (n=55, 82.1%). Among them, 52 (77.6%) reported persistent symptoms after resolution of the condition, with fatigue being the most frequent (n=20, 29.9%). Most participants had an adequate score on the MMSE (n=60, 89.6%). However, 19 (28.4%) showed alterations in the BANFE-3 total score, with mental flexibility as the most affected function (n=25, 37.3%). In participants from the first COVID-19 wave, a negative correlation was observed between the standardized orbitofrontal area scores and the time since recovery from the infection (r=-0.841, p=0.016), suggesting a pattern of deterioration over time, mainly in stimulus inhibition (r=0.880, p=0.021). Regarding emotional state, 45 subjects (67.2%) exhibited emotional alterations, with anxiety symptoms being the most frequent (n=33, 49.3%). Furthermore, individuals with depressive symptoms (n=32, 47.8%) were more likely to experience executive function impairment after COVID-19 (ExpB 0.302, 95% CI 0.098-0.933, p=0.038).

Conclusion

COVID-19 could lead to alterations in executive functions, probably resulting from progressive damage to orbitofrontal area functions, mainly in stimulus inhibition. However, the generalizability of these findings is limited, highlighting the need for further research with robust methodology. Furthermore, depression appears to be an indicator of cognitive impairment in individuals recovering from COVID-19. Therefore, cognitive rehabilitation and psychological support are essential for patients affected by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection.

COVID-19 and cognitive impairment: a review of the emerging evidence

The recent surge of COVID-19 cases has raised concerns about its potential long-term effects on cognitive function. This review explores the growing body of research investigating the link between COVID-19 infection and cognitive impairment. Studies employing observational, longitudinal, and case-control designs reveal a concerning prevalence of cognitive impairment in survivors, affecting domains like attention, memory, executive function, and processing speed. The persistence of these deficits for months after the initial infection highlights the potential for long-term consequences. While the precise mechanisms remain under investigation, potential contributing factors include neuroinflammation, hypoxia, and psychological effects. Limitations within the current research landscape necessitate further investigation into the long-term trajectory of cognitive decline, the potential for intervention and recovery, and the role of vaccination in mitigating these effects. Understanding the multifaceted nature of this issue is crucial for developing effective strategies to ensure optimal cognitive health outcomes for COVID-19 survivors.

A global survey on the associations between the lockdown group, free memory recall and emotional responses during the COVID-19 lockdown

The unprecedented outbreak of the COVID-19 pandemic has altered the course of many lives, resulting in multiple health and social challenges. Due to the speed at which this pandemic spread, various public health 'lockdown' measures were introduced to mitigate its spread. The outcome of adherence to these measures has revealed the possible influence on individuals' varying cognitive abilities. Accordingly, this study aimed to explore the predictive relationships between lockdown responses and COVID-19 restrictions, memory recall performance, and associated emotional responses while examining the sociodemographic influences of age and sex. Participants were drawn from a secondary dataset of an international online survey study of 1634 individuals aged 18-75 years across 49 countries. Participants' demographic questionnaires, free memory recall, and hospital anxiety and depression scale scores were used to collect the data for analysis. Four-way MANOVA and hierarchical multiple regression were utilised to explore the mean differences and predict relationships between the study variables. Significant differences were found in memory recall performance and anxiety and depression scores across lockdown groups (the comply, sufferer, and defiant). Regression analysis indicated that age and gender were predictive markers of lockdown responses and anxiety (R2 = 0.14, F4,1625 = 66.15, p < .001, f2 = 0.17), while age was the only predictor of lockdown responses and depression association ([Formula: see text] = -0.78, t(1625) = -4.35, p < .001). Lockdown compliance was associated with better free recall (M = 8.51, SD = 6.38, p < .001; η2 = 0.01), lockdown suffering was associated with greater anxiety (M = 9.97, SD = 4.36, p < .001; η2 = 0.06), and lockdown deviance was associated with greater depression (M = 7.90, SD = 3.12, p < .001; η2 = 0.05). The current study provides valuable information on the mechanisms of cognitive interpretations and emotional arousal in individuals' social isolation responses to recent life stress and potential severe pandemics. This may support the need for robust interventions aimed at improving people's psychological appraisals associated with anxiety in preparation for any new potential waves or future pandemics.

Functional connectivity of default mode network in non-hospitalized patients with post-COVID cognitive complaints

Introduction

Neurologic impairment is common in patients with acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. While patients with severe COVID have a higher prevalence of neurologic symptoms, as many as one in five patients with mild COVID may also be affected, exhibiting impaired memory as well as other cognitive dysfunctions.

Methods

To characterize the effect of COVID on the brain, the current study recruited a group of adults with post-COVID cognitive complaints but with mild, non-hospitalized cases. They were then evaluated through formal neuropsychological testing and underwent functional MRI of the brain. The participants in our study performed nearly as expected for cognitively intact individuals. Additionally, we characterized the functional connectivity of the default mode network (DMN), which is known for cognitive functions including memory as well as the attention functions involved in normal aging and degenerative diseases.

Results

Along with the retention of functional connectivity in the DMN, our results found the DMN to be associated with neurocognitive performance through region-of-interest and whole-brain analyses. The connectivity between key nodes of the DMN was positively correlated with cognitive scores (r = 0.51, p = 0.02), with higher performers exhibiting higher DMN connectivity.

Discussion

Our findings provide neuroimaging evidence of the functional connectivity of brain networks among individuals experiencing cognitive deficits beyond the recovery of mild COVID. These imaging outcomes indicate expected functional trends in the brain, furthering understanding and guidance of the DMN and neurocognitive deficits in patients recovering from COVID.

Long-COVID and postural orthostatic tachycardia syndrome: a preliminary comparison of neuropsychological performance

PURPOSE

The aim of the study is to analyze and compare the cognitive profile between 59 patients with long-COVID [LC; 30 of them with and 29 without a positive coronavirus disease 2019 (COVID-19) confirmatory test] and 31 patients with postural orthostatic tachycardia syndrome (POTS) and a matched group of 39 healthy control participants.

METHODS

Participants were examined on a battery of neuropsychological tests, including verbal memory, visuospatial abilities, attention, processing speed, verbal fluency, working memory, and visual memory. Anxious-depressive symptomatology was also analyzed and then controlled for possible influence on cognitive performance.

RESULTS

Patients with LC and POTS showed significantly lower performance compared with healthy peers. Differences on anxious and depressive symptoms were also found between the clinical and control groups, resulting in LC without a positive confirmatory test group exhibiting the highest rates of anxious symptoms. After controlling the effects of anxious-depressive symptomatology, the differences were eliminated for some of the cognitive variables, but additional differences were found between patients with LC and POTS after post hoc analysis.

CONCLUSIONS

Findings from the present study contribute toward the reinforcement of the evidence on cognitive alterations associated with LC and POTS. Anxious-depressive symptomatology has to be considered in both clinical groups since it could be affecting cognitive performance.

Neurologic features in hospitalized patients with COVID-19: a prospective cohort in a catalan hospital

OBJECTIVES

To study the prevalence and timing of neurological manifestations, including cognitive involvement, in patients hospitalized for Coronavirus disease 2019 (COVID-19). To analyze the pathogenic mechanisms and any association they have with disease severity.

METHODS

Longitudinal cohort study with prospective follow-up of patients who required hospitalization. Patients under 65 who had no pre-existing cognitive impairment and did not require an ICU stay were evaluated 3 and 12 months after discharge using a battery of neuropsychological tests.

RESULTS

Of 205 patients hospitalized for COVID-19, 153 (74.6%) presented with neurological manifestations. The most frequent were myalgia (32.7%), headache (31.7%), dysgeusia (29.2%), and anosmia (24.9%). Patients with more severe illness at the time of hospitalization presented fewer neurological manifestations. Of the 62 patients who underwent neuropsychological examination 3 months after discharge, 22.6% had impaired attention, 19.4% impaired working memory, 16.1% impaired learning and retrieval, 9.7% impaired executive functions, and 8.2% impaired processing speed. Patients with anosmia also presented with more headache (OR 5.45; p < 0.001) and greater risk of working memory impairment (OR 5.87; p 0.03). At follow-up 12 months after hospital discharge, 14.3% of patients still showed impaired attention, 2.4% impaired working memory, 2.5% impaired executive functions, and 2.5% impaired processing speed.

DISCUSSION

Neurological manifestations are common in patients hospitalized for COVID-19 regardless of severity. The high prevalence of anosmia and its association with headache and working memory impairment at 3 months, suggest potential direct or indirect damage to the prefrontal cortex via invasion of the olfactory bulb by COVID-19.

Immune Response and Cognitive Impairment in Post-COVID Syndrome: A Systematic Review

BACKGROUND

Altered immune response and cognitive difficulties have been demonstrated in studies of post-COVID syndrome, including differences in immune status and cognitive functioning in the months following infection. This review aimed to examine immune status and cognitive differences in post-COVID syndrome 12 or more weeks after COVID-19 infection. A further aim of this review was to explore a link between immune response and the cognitive deficits observed in this group.

METHODS

A systematic review was carried out using PubMed, PsychInfo, EMBASE, and Web of Science electronic databases of observational studies 12+ weeks after COVID-19 infection, with assessment of immune status and cognitive function in post-COVID syndrome samples. This review protocol was recorded on PROSPERO with registration number CRD42022366920.

RESULTS

Following eligibility screening, 11 studies met inclusion criteria and were selected for our review. Six of eight studies that examined between-group differences in specific domains suggested impaired cognition in the post-COVID syndrome population, with the domain of executive function particularly affected. Of 11 studies with immune data, 7 studies reported increased markers of inflammation in the post-COVID syndrome group, when compared with an age- and sex-matched "healthy control" sample, or population norms. Finally, when immune function and cognition are examined together, 6 studies presented results indicating a significant association between elevated immune response and cognitive function in post-COVID syndrome.

CONCLUSION

This review highlights the frequency of cognitive difficulties months after COVID-19 infection and explores heightened immune response as a predictor of this change. Six studies suggest that immune status is a predictor of cognitive function, examining a marker of immune function and objective cognitive performance at 12 or more weeks following infection. Future studies of cognitive function in post-COVID syndrome are needed to explore this relationship and underlying mechanisms leading to changes in cognitive performance.

Post-COVID Condition Does Not Alter Cognitive Functions in Young Adults: A Cross-Sectional Study in North India

Background Long COVID, or post-COVID condition, includes multi-system chronic sequelae that can last weeks, months, or even years in some individuals after recovery from COVID-19 infection. Prominent among these long-term sequelae are cognitive deficits that may prove to be problematic, especially for the working young adult population. The present study aimed to determine whether cognitive deficits are observed long after recovery from mild COVID-19 infection. Methods In this cross-sectional observational study, 29 young adult undergraduate medical students with a history of mild COVID-19 infection at least two years prior were included as cases, while 29 age- and sex-matched undergraduate medical students with no history of COVID-19 were recruited as controls. Sociodemographic data were collected, and the participants were then administered a series of cognitive tests using the National Institutes of Health (NIH) Toolbox V3 software (Toolbox Assessments Inc., Chicago, USA; https://nihtoolbox.org/) to evaluate the cognitive functions, including executive function, cognitive flexibility, attention, working and episodic memory, and processing speed. Results The mean age of the cases and controls was 19.37 ± 0.92 and 19.65 ± 0.99 years, respectively. However,there was no statistically significant difference in cognitive function performance across any of the tested domains between cases and controls. Conclusion The results of our study indicate that, compared to healthy controls, cognitive functions were not impaired in young adults who previously had symptomatic mild COVID-19 infection.

Neurocognitive and emotional long-term effects of COVID-19 infections in children and adolescents: results from a clinical survey in Bavaria, Germany

BACKGROUND

While children and adolescents typically experience mild symptoms during the acute phase of the COVID-19 infection, some may develop severe post-infectious symptoms. In our study Post-COVID Kids Bavaria we integrated somatic and psychiatric aspects of the post-COVID syndrome to provide a holistic description of symptoms, provide early treatment, and detect possible risk factors associated with post-infectious neurocognitive and emotional impairments.

METHODS

We conducted an observational study involving 85 pediatric patients aged 12-17 years (M = 12.48, 61.2% female) who had confirmed COVID-19 infections and were experiencing persistent symptoms for at least 4 weeks. Our neuropsychological assessment comprised infection-specific patient interviews, psychopathological examinations, emotional well-being and behavioral difficulty questionnaires, and (computerized) tests assessing concentration, attention, and memory skills. Additionally, patients underwent neurologic, pneumologic, gastrointestinal, and cardiologic assessments.

RESULTS

Overall, the majority of patients reported experiencing elevated levels of fatigue (82.4%), loss of motivation (72.9%), concentration and attention deficits (71.8%), a worsened mood (53%), and a higher level of anxiety (31.8%). The most common diagnosis was the post-COVID adjustment disorder (ICD-10 F43.2, U09.9!; 38.8%) followed by the post-COVID attention deficit disorder (ICD-10 F98.80, U09.9!; 23.5%). Neuropsychiatric evaluation primarily identified deficits in sustained attention. There was a significant association between somatic and psychiatric post-COVID diagnoses. Patients with allergies exhibited a higher risk of developing a post-COVID adjustment disorder. For the post-COVID attention deficit disorder, age, sex, obesity, pre-existing psychiatric diagnosis, and the virus variant were relevant factors.

CONCLUSIONS

Our findings indicate a diverse array of neuropsychiatric symptoms associated with the post-COVID syndrome, emphasizing the interconnectedness between somatic and neuropsychiatric diagnoses. To optimize treatment, comprehensive strategies involving both somatic and psychiatric professionals are crucial for addressing the syndrome's complexity and managing symptoms effectively.

STUDY REGISTRATION

The study Post-COVID Kids Bavaria was registered with the German Clinical Trials Register (DRKS), funded by the Bavarian State Ministry of Health, Care and Prevention and approved by the Ethics Committee of the University of Regensburg on the 29th of November, 2021 (Reference: 21-2691-101).

Unraveling Dysgeusia in SARS-CoV-2 Infection: Clinical and Laboratory Insights from Hospitalized COVID-19 Patients in Romania

Introduction: Dysgeusia has been regarded as a clinical feature associated with SARS-CoV-2 infection since the onset of the pandemic. The initial circulating variants were linked to the presence of dysgeusia; however, with the emergence of the Omicron variant, the incidence of dysgeusia has decreased. The aim of this study was to identify the incidence and characteristics of patients with dysgeusia from the onset of the pandemic to the Omicron variant. Methods: We conducted a retrospective study from March 2020 to December 2021, among adult patients hospitalized with COVID-19 in the main infectious diseases hospital in Romania. Clinical and laboratory data were collected and interpreted in relation to the presence or absence of dysgeusia. Results: The incidence of dysgeusia was 32.0%, with the majority of cases (44.2%) occurring in patients with the Beta SARS-CoV-2 variant. Dysgeusia has been predominantly observed in mild to moderate cases of the disease. The presence of obesity and hypertension has been shown to be negatively associated with the development of dysgeusia (OR = 0.45, OR = 0.39, respectively). In patients with dysgeusia, inflammatory changes such as lymphopenia were significantly less frequently identified (OR = 0.22, p < 0.001), as were increased C-reactive protein (OR = 0.12, p < 0.001) and increased interleukin-1 (OR = 0.42, p = 0.002), increased fibrinogen (OR = 0.31, p < 0.001), and increased ferritin (OR = 0.27, p < 0.001) compared to patients without dysgeusia. The incidence of acute respiratory failure was higher in the dysgeusia group (71.2% vs. 28.8%, p < 0.001). This was accompanied by a milder management of patients with dysgeusia and a median duration of hospitalization that was two days shorter. Conclusions: The presence or absence of dysgeusia in patients with COVID-19 appears to correlate with both the inflammatory response and outcome. In the context of evolving circulating viral variants, which seem to be associated with a lower incidence of dysgeusia, continuous monitoring of patients who develop this disorder remains essential to clarify the pathophysiologic mechanisms involved and to assess the potential of dysgeusia as a predictor of the course of SARS-CoV-2 infection.

Neuropsychiatric Manifestations of Long COVID-19: A Narrative Review of Clinical Aspects and Therapeutic Approaches

The COVID-19 (C-19) pandemic has highlighted the significance of understanding the long-term effects of this disease on the quality of life of those infected. Long COVID-19 (L-C19) presents as persistent symptoms that continue beyond the main illness period, usually lasting weeks to years. One of the lesser-known but significant aspects of L-C19 is its impact on neuropsychiatric manifestations, which can have a profound effect on an individual's quality of life. Research shows that L-C19 creates neuropsychiatric issues such as mental fog, emotional problems, and brain disease symptoms, along with sleep changes, extreme fatigue, severe head pain, tremors with seizures, and pain in nerves. People with cognitive problems plus fatigue and mood disorders experience great difficulty handling everyday activities, personal hygiene, and social interactions. Neuropsychiatric symptoms make people withdraw from social activity and hurt relationships, thus causing feelings of loneliness. The unpredictable state of L-C19 generates heavy psychological pressure through emotional suffering, including depression and anxiety. Neuropsychiatric changes such as cognitive impairment, fatigue, and mood swings make it hard for people to work or study effectively, which decreases their output at school or work and lowers their job contentment. The purpose of this narrative review is to summarize the clinical data present in the literature regarding the neuropsychiatric manifestations of L-C19, to identify current methods of diagnosis and treatment that lead to correct management of the condition, and to highlight the impact of these manifestations on patients' quality of life.

Cognition in COVID-19 infected patients undergoing invasive ventilation: results from a multicenter retrospective study

A growing number of scientific contributions suggest that COVID-19 infection can lead to impairment of cognition, mainly in executive functions and memory domains, even in the absence of frank neurological pathologies.The primary objective of this retrospective study is to evaluate the frequency and type of inefficiencies in a selection of cognitive tests administered to a sample of subjects who, following infection, required invasive assisted ventilation and were admitted to rehabilitation wards for the treatment of functional impairment.Fifty-seven subjects were enrolled. The recruited patients undergone an assessment of verbal and visuospatial memory and executive functions, upon entry into the rehabilitation department, after discharge from intensive care. The following tests were administered: Rey Auditory Verbal Learning Test (AVLT) (immediate and delayed recall), Rey-Osterrieth Complex Figure Test (ROCFT) (copy and delayed recall), Stroop Color-Word Test, and Trail Making Test (TMT, A and B).Deficient scores, in beyond 25% of subjects, were found in the copy of the ROCFT (32.1% of subjects), and in the delayed recall of ROCFT (27.2%). Between 10 and 20% of patients presented an abnormal result in delayed recall of AVLT (16.07%), and Stroop Test (time, 15.6%, error, 11.5%). Less than 10% of the sample had abnormal performances on TMT (A, 3.5%, and B, 9.4%), and in AVLT immediate recall (8.9%). Correlations of the performances with age, sex, and education were also found.This paper highlights the high incidence of abnormal cognitive performances in this specific subpopulation of patients with COVID-19 infection.

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.

Anosmia predicts memory impairment in post-COVID-19 syndrome: results of a neuropsychological cohort study

Recovered COVID-19 patients frequently suffer of cognitive disorders. Several etiopathogenetic mechanisms have been considered for the brain complications in COVID-19 but results are uncertain. Amongst them, an olfactory route to SARS-CoV-2 brain infection might explain cognitive and memory disturbances in post-COVID-19 patients, given the cooccurrence of anosmia and possible underlying limbic involvement. The aims of the study are to investigate cognition of patients with post-COVID-19 syndrome, and to find clinical factors predicting cognitive and memory impairments. 18 patients with post-COVID-19 syndrome underwent neuropsychological assessment and evaluation of clinical parameters. Stepwise regression analysis was used between clinical parameters as factors and cognitive global scores as dependent variables. Since only anosmia predicted memory performances, repeated measures ANOVA of memory scores was conducted between anosmic and non-anosmic patients. We found lack of association between clinical parameters and cognitive performances. Only anosmia was a good predictor for memory performances, with anosmic subjects showing a temporo-mesial amnesic profile. Our study shows novel findings of causal association between transient anosmia during COVID-19 and memory disorders with temporo-mesial dysfunction, probably sharing a common pathophysiological mechanism, and suggesting a possible SARS-CoV 2 infection of the limbic brain via the olfactory route. In contrast to previous studies, cognitive dysfunctions were not associated with respiratory distress, comorbidity, and depression.

The influence of physical fatigue on telephone-based neuropsychological test performance in COVID-19 survivors

Fatigue has been characterized as a post COVID-19 condition known to persist months after SARS-CoV-2 infection. COVID-19 has been reported to be associated with impaired cognitive function, including disorders in attention, memory, information processing, and executive functions. The objective of this study was to determine if post-COVID fatigue, manifested as tiredness while performing low-intensity physical activity, has a detrimental effect on neuropsychological performance, to achieve this, we randomly selected 20 participants with post-COVID fatigue and 20 SARS-CoV-2 negative age-matched controls from a database of 360 residents of Tijuana, Baja California in a cross-sectional study design. All 40 participants responded to a health survey, along with a neuropsychological assessment test via telephone call. Statistical analysis was performed using a multiple linear regression model including the following independent variables: study condition (post-COVID fatigue or negative control), sex, age, years of education, hypertension, asthma, administration of supplemental oxygen during COVID-19 recovery, and the hour at which the evaluation started. Significant regression analysis was obtained for all global parameters of the assessment, including BANFE-2 score (p = 0.021, R2 Adj. = 0.263), NEUROPSI score (p = 0.008, R2 Adj. = 0.319), and total errors (p = 0.021, R2 Adj. = 0.263), with significant regression coefficients for study condition on two global parameters, BANFE-2 score (p = 0.028, β = - 0.371) and NEUROPSI score (p = 0.010, β = -0.428). These findings suggest that the presence of post-COVID fatigue is a factor associated with a decrease in neuropsychological performance.

Executive functioning in subjects post COVID-19 infection in Mexico

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

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

OBJECTIVE

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

DESIGN

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

SETTING

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

PARTICIPANTS

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

RESULTS

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

CONCLUSION

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

Comprehensive neuropsychological assessment and predictors of cognitive functioning at six months after COVID-19 in patients treated in the ICU, regular hospital ward, or isolated at home

Cognitive impairment in patients with COVID-19 has been reported, but findings are inconsistent. This study assessed cognitive functioning 6 months post-infection across three COVID-19 severity groups compared to non-COVID controls. Seventy-two ICU-treated, 49 ward-treated, and 44 home-isolated patients with COVID-19, along with 48 controls, underwent neuropsychological evaluation and assessment of subjective cognitive symptoms, depressive symptoms, and fatigue. Cognitive test scores were compared using ANCOVA. Associations between cognitive functioning and variables including demographics, illness severity, comorbidities, depressive symptoms, fatigue, and ICU-related factors were examined with hierarchical linear regression models. Results showed no significant differences in cognitive test performance of impairment frequencies between COVID-19 groups and controls. However, patients with COVID-19 reported higher levels of subjective cognitive symptoms, depressive symptoms, and fatigue compared to controls. Predictors of cognitive functioning included age, education, and, to a lesser extent, comorbidities. COVID-19 severity, depression, fatigue, or ICU-related variables did not significantly impact performance. These findings suggest that while individual cognitive impairments may exist, overall cognitive functioning in patients with COVID-19 was comparable to controls.

Multicentre, multitime, multidimension, prospective follow-up cohort study on patients during the first wave of COVID-19 in China: a study protocol

INTRODUCTION

During the first wave of the COVID-19 outbreak in China, the surge of COVID-19 cases was rapid and drastic. Emerging evidence suggests that beyond the acute phase, patients with COVID-19 may experience a wide range of postacute or long COVID sequelae. However, the mechanism and burden of COVID-19, especially long COVID, have not yet been comprehensively clarified. To fill this knowledge gap, this large prospective follow-up study aims to investigate the short-term and long-term effects of COVID-19, explore the underlying biological mechanism and identify predictive neuroimaging and haematological biomarkers associated with these effects.

METHODS AND ANALYSIS

This multicentre study will recruit patients infected during the first wave of COVID-19 in China and healthy controls (HCs) with no history of COVID-19 infection from nine participating hospitals. Confirmed patients with mild or moderate COVID-19 will complete the following programmes during the acute infection phase and at 3, 12 and 24 months after infection: (a) blood test at the local laboratory, (b) multimodal brain and spine MRI scan and (c) the neuropsychological scales and questionnaires. Similarly, the uninfected HCs will complete the same programmes as the infected group mentioned above at the time of inclusion. At the first time point, 501 participants (418 patients and 83 HCs) from nine recruiting hospitals have been observed. Ultimately, all of these results will be analysed to explore the short-term and long-term effects of COVID-19.

ETHICS AND DISSEMINATION

Ethics approval was granted by Ethics Committee of the First Affiliated Hospital of Xi'an Jiaotong University (XJTU1AF2023LSK-013). Findings will be presented at national and international conferences, as well as published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

NCT05745805.

Neurocognitive Impairment in Long COVID: A Systematic Review

OBJECTIVE

Although Coronavirus disease 2019 (COVID-19) is primarily a respiratory infectious disease, it has also been associated with a wide range of other clinical manifestations. It is widely accepted in the scientific community that many patients after recovery continue to experience COVID-19-related symptoms, including cognitive impairment. The aim of this systematic review was to investigate the cognitive profile of patients with long-COVID syndrome.

METHODS

A systematic search of empirical studies was conducted through the PubMed/Medline and Scopus electronic databases. Cross-sectional and longitudinal studies published between 2020 and 2023 were included.

RESULTS

Of the 516 studies assessed for eligibility, 36 studies met the inclusion criteria. All included studies support the presence of persistent cognitive changes after COVID-19 disease. Executive function, memory, attention, and processing speed appear to be the cognitive domains that are predominantly associated with long-COVID syndrome, whereas language is an area that has not been sufficiently investigated.

CONCLUSIONS

In this review, the high frequency of cognitive impairment after COVID-19 is evident. If we consider that cognitive functioning affects our ability to live independently and is a key determinant of our quality of life, it is imperative to precisely define those factors that may induce cognitive impairment in COVID-19 survivors, with the ultimate goal of early diagnosis of cognitive changes and, consequently, the development of targeted rehabilitation interventions to address them.

Cognition, function, and mood post-COVID-19: Comparative analysis using the health and retirement study

Millions of Americans endure post-COVID conditions (PCC), yet research often lacks pre-illness measurements, relying primarily on follow-up assessments for analysis. The study aims to examine the prevalence of PCC, including cognitive impairment, functional limitation, and depressive symptoms, along with relevant risk factors, while controlling for individuals' pre-illness status measured in 2018. A cross-sectional retrospective study utilized the 2018 and 2020 Health and Retirement Study surveys. Sample included individuals with COVID-19 (n = 409; average age 64) and individuals without COVID-19 (n = 8689; average age 59). COVID-19 positive: Individuals with positive tests, physician diagnoses, emergency room visits, or hospitalizations for COVID-19 between 2019-2020. Cognition was assessed using immediate and delayed word-recall tests, serial seven subtractions, and backward counting. Functional status was measured using limitations in activities of daily living (ADLs) and instrumental ADLs. Depressive symptoms were measured using the modified Center for Epidemiology Studies Depression scale. Participants' perception of experiencing PCC was collected. Logistic regression and propensity score matching were employed for these analyses. Among 409 COVID-19-positive respondents (14% hospitalized), 24% exhibited new impairments after COVID-19 infection. Noteworthy increases in functional limitation (OR [95% CI]: 2.18 [0.95, 0.97], p < 0.001) and a marginal rise in cognitive impairment (1.79 [0.99, 3.32], p = 0.053) following COVID-19 infection were observed in comparison to their pre-COVID-19 baseline. Compared to 8689 non-COVID-19 cases, the 409 COVID-19 positives showed increased functional decline (1.78 [1.26, 2.51], p = 0.001) and depressive symptoms (1.41 [1.04, 1.91], p = 0.03). Factors associated with PCC included pre-existing impairments, lower education, female gender, prior hospitalization, higher comorbidity, lower wealth, and mild COVID-19. A notable number of respondents, especially older individuals with fewer pre-existing health conditions, experienced PCC without awareness. Compared to an individual's pre-illness baseline and uninfected individuals, being positive for COVID-19 raised the risk of functional limitation, depressive symptoms, and cognitive impairment. Additionally, addressing PCC through both subjective and objective approaches is essential to alleviate individual and societal burdens.

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

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

Neuropsychological functioning of pediatric patients with long COVID

Objective: To determine the neurocognitive profile for youth with long COVID presenting with cognitive concerns. Method: This study is a case series of 54 pediatric patients (65% female, Mage = 13.48, SDage = 3.10, 5-19) with long COVID who were referred for neuropsychological testing from a post-COVID-19 multidisciplinary clinic. The outcomes of interest were neuropsychological test scores and parent ratings of mood, attention, and executive functioning. The percentage of patients with neuropsychological test scores below the 9th percentile (below average range) and those with at-risk or clinically significant scores (T-scores > 59) on parent-informant inventories were computed. Results: A portion of children with long COVID showed weaknesses in sustained attention (29%) and divided attention (35%). This portion of patients did not significantly differ when comparing patients with and without pre-existing attention and mood concerns. A high percentage of parents reported at-risk to clinically significant concerns for cognitive regulation (53%), depression (95%), anxiety (85%), and inattention (66%) on standardized questionnaires. Conclusions: The present case series showed that approximately a third of children with long COVID demonstrate objective weaknesses on sustained and divided attention tasks but were largely intact in other domains of neuropsychological functioning. Importantly, children with long COVID had similar difficulties in attention, regardless of pre-existing attention or mood concerns. Parents reported high rates of mood, anxiety, and executive functioning difficulties which likely impact daily functioning. Attention and emotional regulation should be closely monitored and treated as necessary in pediatric patients with long COVID to aid functional recovery.

Lexical retrieval difficulties in post-COVID-19 syndrome: Insights from verbal fluency and naming tasks

BACKGROUND

Although considerable research has been conducted on post-COVID-19 syndrome (PCS), cognitive symptoms, particularly those related to language, are still not well understood.

AIMS

To provide a detailed quantitative and qualitative analysis of language performance in PCS patients using a comprehensive set of semantic and verbal production tasks.

METHODS & PROCEDURES

The study involved 195 PCS patients aged 26-64 years and 50 healthy controls aged 25-61 years. Participants were assessed using two semantic tasks, three naming tasks and four types of verbal fluency tasks, designed to evaluate different aspects of language processing.

OUTCOMES & RESULTS

PCS patients demonstrated significantly poorer performance compared with controls across all verbal fluency tasks. This was evident in both the total number of words generated and their types, with patients tending to choose more easily accessible words. In naming tasks, the pattern of errors was similar in both groups, although patients showed a higher number of non-responses and made more errors, reflecting difficulties in word retrieval. The analysis highlighted the impact of factors such as stimulus availability, educational level and cognitive reserve on performance. Notably, younger patients performed worse than older, a paradoxical trend also observed in previous research.

CONCLUSIONS & IMPLICATIONS

These findings reveal significant word retrieval difficulties in PCS patients, suggesting that cognitive impairment related to language may be more pronounced than previously understood. The results underscore the need for a thorough evaluation of language functions in PCS patients and the development of more targeted and individualized language rehabilitation strategies to address these specific challenges.

WHAT THIS PAPER ADDS

What is already known on the subject Studies on the cognitive characteristics of CPS have focused mainly on broad-spectrum neuropsychological assessments covering all cognitive functions. However, there are very few studies analysing oral production with specific lexical and semantic system tasks. Furthermore, no work has specifically included tasks assessing semantic processing or conducted qualitative analyses of the psycholinguistic variables affecting performance. Such analyses could undoubtedly help clarify the nature of the language impairments in patients with PCS. What this paper adds to the existing knowledge This study explores in depth the evaluation and analysis of the oral production of patients with PCS using several lexical and semantic tasks. In addition, psycholinguistic variables are analysed that could undoubtedly help clarify the nature of the language impairments in patients with PCS. What are the potential or actual clinical implications of this work? The study allows the identification of specific lexical-semantic deficits in the spoken language in patients with this PCS. A more detailed assessment of the oral language of these patients, keeping in mind the psycholinguistic variables that may affect the performance, will facilitate the design of more efficient and individualized rehabilitation programmes.

Cognitive outcomes and psychological symptoms in an Italian cohort with post-acute COVID-19 condition (PACC)

Background

We aim to investigate the proportion of patients (pts) with long-term cognitive outcomes (CO) of PACC and identify associated features.

Methods

We assessed participants through a neuropsychological assessment. The chi-square test was used for comparisons according with time of NPA (within or beyond 6 months since COVID19) and with previously hospitalization status (hospitalized patients, PH; not hospitalized patients, nPH).

Results

520 participants: mean age 54 years (SD 12), 53 % female, 14 years of education (SD 3.4), 35 % with >1 comorbidity, 48 % previously hospitalized. Overall, we found CO in 89 % of pts, in particular 88 % evaluated in w6M and 89 % in b6M (p = 0.801) while 90 % and 87 % in nPH and PH, respectively (p = 0.239). By fitting multivariable analysis, PH for COVID19 and female gender were associated with an increased risk of an altered PSQI [Odd Ratio, OR 2.48, 95 % CI 1.54 to 3.99, p < 0.001 and OR 2.59, 95 % CI 1.60 to 4.17, p < 0.001, respectively) and BAI [F vs M: OR 1.67, 95 % CI 1.16 to 2.40, p = 0.005).

Conclusions

We show a substantial proportion of PACC-CO; hospitalization leads to impaired memory, anxiety and sleep disorders. Women seem to be at higher risk for anxious-depressive symptoms and worse sleep quality than men.

Telehealth-delivered cognitive rehabilitation for people with cognitive impairment as part of the post-COVID syndrome: protocol for a randomised controlled trial as part of the CICERO (Cognitive Impairment in Long COVID: Phenotyping and Rehabilitation) study

BACKGROUND

Between 25 and 75% of people with persistent post-acute sequelae of SARS-CoV-2 infection (PASC) experience cognitive difficulties, compromising functional ability, quality of life, and activities of daily living, including work. Despite this significant morbidity, there is a paucity of interventions for this disorder that have undergone evaluation within a formal trial setting. Therefore, we have developed a cognitive rehabilitation programme, specifically designed to address the cognitive symptoms of PASC, notably impaired attention and processing speed, while also accounting for other PASC symptoms (fatigue, post-exertional malaise) that may aggravate the cognitive impairment. This study protocol outlines a randomised controlled trial (RCT) designed to evaluate the effectiveness of this programme compared to standard clinical care.

METHODS

This is a multi-centre, parallel-group, individually randomised controlled trial, comparing standard clinical care with and without cognitive rehabilitation. We will recruit 120 non-hospitalised adults (aged 30-60 years) from three NHS sites in England with a history of COVID-19 infection and cognitive impairment persisting more than 3 months after the acute infection. Participants will be randomised (1:1) to the intervention or control groups, with the latter represented as a provision of standard clinical care without cognitive rehabilitation. The cognitive rehabilitation programme consists of ten 1-hour sessions, delivered weekly. Outcomes will be collected at baseline, 3, and 6 months, with participant-defined goal-attainment scores, relating to functional goals, at 3 months as the primary outcome measure. Secondary outcomes will be cognitive function, measures of quality of life, social functioning, mental health, fatigue, sleep, post-exertional malaise, and social and health care service use. We will also evaluate the health-economic benefits of cognitive rehabilitation in this population.

DISCUSSION

Cognitive impairment in PASC is a major cause of functional disability with no effective treatment. Accordingly, we will undertake an RCT of cognitive rehabilitation, the protocol of which is published here. If this trial is successful in delivering improvements in trial outcomes, it will address a major unmet need relating to this emergent disorder, with a significant impact on affected individuals and the wider health economy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05731570. Registered on February 16, 2023.

Structural and functional brain markers of cognitive impairment in healthcare workers following mild SARS-CoV-2 infection during the original stream

Severe acute respiratory syndrome coronavirus 2 infection often involves the nervous system, leading to cognitive dysfunctions, fatigue and many other neurological signs that are becoming increasingly recognized. Despite mild forms of the disease accounting for most cases worldwide, research on the pathophysiology driving mild coronavirus disease 2019 (COVID-19) has received little attention. In this respect, recent evidence has pointed out that around 30-40% of non-critical, mild-to-moderate severity COVID-19 survivors may display cognitive disturbances several months post-illness. Hence, the impact of COVID-19 on the brain structure and function, through potential neuropathological mechanisms underpinning cognitive alterations in post-mild COVID-19 infections, remains largely unexplored. This retrospective multicentre observational cohort study, entirely based on a healthcare worker sample (n = 65; 55% females, aged 21-61), investigated the cognitive status and the structural and functional brain integrity among non-hospitalized individuals who developed mild COVID-19 symptoms during the occurrence of severe acute respiratory syndrome coronavirus 2 variants Alpha to Delta, compared with healthy controls tested before the pandemic onset. All evaluations were performed at an average of 9-month follow-up post-infection period. Participants completed a comprehensive neuropsychological assessment and structural and functional MRI exams. Radiological inspection sought to detect the presence of white matter hyperintensities on axial fluid-attenuated inversion recovery images. Global and regional grey matter integrity assessment, analysing changes in grey matter volumes and cortical thinning, and functional connectivity alterations of resting-state brain networks were also conducted. Regression analyses tested the relationships between the presence of specific cognitive impairments and potential structural and functional brain findings. Our results revealed that clinical, cognitive screening and neuropsychological examinations were average between both groups, except for specific impairments related to executive functions in the mild COVID-19. Compared to healthy controls, mild COVID-19 subjects exhibited increased juxtacortical white matter hyperintensities, thalamic and occipital volume loss and diminished resting-state functional connectivity involving the left precuneus and cuneus in default-mode network and affecting the right angular gyrus and left precuneus in the dorsal attentional network. Reduced thalamic volume was the only variable selected in the final model explaining the observed executive function impairment in mild COVID-19. The presence of cognitive, structural and functional brain abnormalities over time suggests that the action of widespread neurovascular and inflammatory phenomena on the nervous system might also occur in mild forms following COVID-19 infection rather than permanent brain damage linked to the direct or indirect action of the virus. Our findings emphasize the need to pay attention to the long-term brain-related consequences of mild COVID-19 infections during the original stream.

Self-reported immune status and COVID-19 associated subjective cognitive functioning in post-COVID-19 syndrome: Examination of an Irish cohort

INTRODUCTION

Cognitive changes are very frequently reported by people with post-COVID-19 syndrome (PCS), but there is limited understanding of the underpinning mechanisms leading to these difficulties. It is possible that cognitive difficulties are related to immune status and/or low mood. The aim of the present study was to examine the relationship between immune status and cognitive functioning in PCS, while considering whether depression symptoms also influence this association.

METHODS

Participants were recruited in an online study of cognitive and psychological consequences of PCS, involving individuals attending a post-COVID clinic in an acute general hospital in Ireland, and a comparison sample of age- and sex-matched community controls who had also been infected with COVID-19 but had not experienced PCS. Participants with PCS (n = 71) and community controls (n = 50) completed the immune status questionnaire, Cognitive Failures Questionnaire (CFQ), Hospital Anxiety and Depression Scale (HADS), and the Functional Assessment of Chronic Illness Therapy-Fatigue Scale (FACIT-F).

RESULTS

Significant differences were observed between groups in terms of perceived immune status, perceived cognitive function, depression scores, and fatigue, with the "PCS" group reporting lower immune status, more cognitive difficulties, and higher levels of depression and fatigue. Regression analysis in the PCS group indicated that immune status and depression significantly contributed to variance in subjective cognitive functioning, with immune status remaining a significant predictor of cognitive functioning scores even when accounting for depression, fatigue, and other covariates related to PCS, such as Body Mass Index (BMI).

CONCLUSION

Our findings suggest that subjective cognitive functioning is influenced by self-reported immune status in PCS, emphasising the importance of immune status, cognitive, and mood screening as part of routine clinical care in PCS.

Long Neurocognitive and Neuropsychiatric Sequelae in Participants with Post-COVID-19 Infection: A Longitudinal Study

OBJECTIVE

To evaluate and characterize the cognitive changes in COVID-19 participants at 6-month follow-up, and to explore a possible association with clinical symptoms, emotional disturbance and disease severity.

METHODS

This single-center longitudinal cohort study included participants aged 20 and 60 years old to exclude cognitive impairment age-associated with confirmed COVID-19 infection. The initial evaluation occurred 10 to 30 days after hospital or ambulatory discharge, with a subsequent follow-up at 6 months. Patients who had a history of cognitive impairment, neurological conditions, or serious psychiatric disorders were not included. Information on demographics and laboratory results was gathered from medical records. Cognitive outcomes were assessed with a neuropsychological battery including attention, verbal and visual memory, language and executive function tests.

RESULTS

A total of 200 participants were included in the study, and 108 completed the follow-up visit. At the 6-month follow-up, comparing the means from baseline with those of the follow-up evaluation, significant overall improvement was observed in verbal and visual memory subtests (p = 0.001), processing speed (p = 0.001), executive function (p = 0.028; p = 0.016) and naming (p = 0.001), independently of disease severity and cognitive complaints. Anxiety and depression were significantly higher in groups with Subjective Cognitive Complaints (SCC) compared to those without (p < 0.01 for both).

CONCLUSIONS

Persistent symptoms are common regardless of disease severity and are often linked to cognitive complaints. Six months after COVID-19, the most frequently reported symptoms included headache, dyspnea, fatigue, cognitive complaints, anxiety, and depression. No cognitive impairment was found to be associated with the severity of COVID-19. Overall, neuropsychological and psychopathological improvement was observed at 6 months regardless of disease severity and cognitive complaints.

Impact of elevated body mass index (BMI) on cognitive functioning and inflammation in persons with post-COVID-19 condition: a secondary analysis

BACKGROUND

Individuals who have recovered from the acute stage of SARS-CoV-2 infection may be at risk of developing post-COVID-19 condition (PCC), characterised by a spectrum of persisting, non-specific, and functionally impairing symptoms across multiple organ systems. Obesity has been implicated as a risk factor for PCC, mediated by chronic systemic inflammation. The foregoing has also been separately reported to mediate cognitive dysfunction in PCC.

METHODS

This is a post-hoc analysis of a randomised, double-blinded, placebo-controlled clinical trial evaluating vortioxetine treatment for cognitive impairments in persons with PCC who received vortioxetine or placebo for eight weeks. This analysis comprises baseline data, examining the impact of BMI on cognitive functioning measured by the Digit Symbol Substitution Test (DSST) and Trails Making Tests (TMT)-A/B, as well as inflammation, via serum c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

RESULTS

Complete data from 70 participants were statistically analysed and adjusted for age and sex. BMI was negatively correlated with performance on the DSST (β = -0.003, p = 0.047), TMT-A (β = -0.006, p = 0.025), and TMT-B (β = -0.006, p = 0.002). BMI was positively correlated with serum CRP (unstandardized β = 0.193, standardized β = 0.612, p < 0.001) and ESR (β = 0.039, p < 0.001) levels.

CONCLUSION

We observed a significant negative correlation between BMI and cognitive functioning, and a significant positive correlation between BMI and inflammation in persons with PCC, suggesting a bidirectional interplay between BMI, PCC, and cognitive function; individuals with an elevated BMI may be at a greater risk of developing PCC and/or presenting with greater cognitive deficits mediated by chronic systemic inflammation.

Neuropsychological functioning and its correlates at 1 year follow-up of severe COVID-19

BACKGROUND

Short-term cognitive impairment is associated with SARS-CoV-2 infection but the long-term impact is yet to be examined in detail. We aim to study the evolution of these symptoms in severe COVID-19 patients admitted to the intensive care unit (ICU) between April and December 2020 1 year after hospital discharge and to analyze its clinical correlates.

METHOD

A total of 58 patients agreed to participate in the 6 months follow-up and 30 at 1 year after hospital discharge. Demographic, clinical and laboratory data were collected and a comprehensive neuropsychological battery including validated tests for the main cognitive domains was administered. To test the magnitude of neurocognitive sequelae, two standard deviations below normative group were considered. To compare the neuropsychological performance at 6 and 12 months follow-up we used repeated measures tests. Finally, regression analyses were performed to test the main effects of medical and psychological factors on multiple cognition.

RESULTS

Almost half of the sample continued to have impaired performance on neuropsychological tests at 12 months follow-up. In comparison with the results obtained at 6 months, significant improvements were found in immediate recall (d = 0.49), delayed recall (d = 0.45), and inhibitory control (d = 0.53). Medical variables predicted cognitive performance at 6 months but not at 12 months follow-up, while anxiety and depression predicted cognitive deficits in the long-term.

CONCLUSIONS

A generalised improvement was observed in severe COVID-19 patients at follow-up. This improvement was particularly notable in verbal memory and executive functioning. However, a considerable proportion of the sample continued to present deficits at 1 year follow-up.

Neurocognitive and Neuropsychiatric Sequelae in Long COVID-19 Infection

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

Meta-analysis of Cognitive Function Following Non-severe SARS-CoV-2 Infection

To effectively diagnose and treat subjective cognitive symptoms in post-acute sequalae of COVID-19 (PASC), it is important to understand objective cognitive impairment across the range of acute COVID-19 severity. Despite the importance of this area of research, to our knowledge, there are no current meta-analyses of objective cognitive functioning following non-severe initial SARS-CoV-2 infection. The aim of this meta-analysis is to describe objective cognitive impairment in individuals with non-severe (mild or moderate) SARS-CoV-2 cases in the post-acute stage of infection. This meta-analysis was pre-registered with Prospero (CRD42021293124) and utilized the PRISMA checklist for reporting guidelines, with screening conducted by at least two independent reviewers for all aspects of the screening and data extraction process. Fifty-nine articles (total participants = 22,060) with three types of study designs met our full criteria. Individuals with non-severe (mild/moderate) initial SARS-CoV-2 infection demonstrated worse objective cognitive performance compared to healthy comparison participants. However, those with mild (nonhospitalized) initial SARS-CoV-2 infections had better objective cognitive performance than those with moderate (hospitalized but not requiring ICU care) or severe (hospitalized with ICU care) initial SARS-CoV-2 infections. For studies that used normative data comparisons instead of healthy comparison participants, there was a small and nearly significant effect when compared to normative data. There were high levels of heterogeneity (88.6 to 97.3%), likely reflecting small sample sizes and variations in primary study methodology. Individuals who have recovered from non-severe cases of SARS-CoV-2 infections may be at risk for cognitive decline or impairment and may benefit from cognitive health interventions.

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.

Cognitive profile, neuroimaging and fluid biomarkers in post-acute COVID-19 syndrome

We aimed to characterize the cognitive profile of post-acute COVID-19 syndrome (PACS) patients with cognitive complaints, exploring the influence of biological and psychological factors. Participants with confirmed SARS-CoV-2 infection and cognitive complaints ≥ 8 weeks post-acute phase were included. A comprehensive neuropsychological battery (NPS) and health questionnaires were administered at inclusion and at 1, 3 and 6 months. Blood samples were collected at each visit, MRI scan at baseline and at 6 months, and, optionally, cerebrospinal fluid. Cognitive features were analyzed in relation to clinical, neuroimaging, and biochemical markers at inclusion and follow-up. Forty-nine participants, with a mean time from symptom onset of 10.4 months, showed attention-executive function (69%) and verbal memory (39%) impairment. Apathy (64%), moderate-severe anxiety (57%), and severe fatigue (35%) were prevalent. Visual memory (8%) correlated with total gray matter (GM) and subcortical GM volume. Neuronal damage and inflammation markers were within normal limits. Over time, cognitive test scores, depression, apathy, anxiety scores, MRI indexes, and fluid biomarkers remained stable, although fewer participants (50% vs. 75.5%; p = 0.012) exhibited abnormal cognitive evaluations at follow-up. Altered attention/executive and verbal memory, common in PACS, persisted in most subjects without association with structural abnormalities, elevated cytokines, or neuronal damage markers.

Neurocognitive Impairment in Post-COVID-19 Condition in Adults: Narrative Review of the Current Literature

The severe acute respiratory syndrome coronavirus 2 virus has, up to the time of this article, resulted in >770 million cases of COVID-19 illness worldwide, and approximately 7 million deaths, including >1.1 million in the United States. Although defined as a respiratory virus, early in the pandemic, it became apparent that considerable numbers of people recovering from COVID-19 illness experienced persistence or new onset of multi-system health problems, including neurologic and cognitive and behavioral health concerns. Persistent multi-system health problems are defined as Post-COVID-19 Condition (PCC), Post-Acute Sequelae of COVID-19, or Long COVID. A significant number of those with PCC report cognitive problems. This paper reviews the current state of scientific knowledge on persisting cognitive symptoms in adults following COVID-19 illness. A brief history is provided of the emergence of concerns about persisting cognitive problems following COVID-19 illness and the definition of PCC. Methodologic factors that complicate clear understanding of PCC are reviewed. The review then examines research on patterns of cognitive impairment that have been found, factors that may contribute to increased risk, behavioral health variables, and interventions being used to ameliorate persisting symptoms. Finally, recommendations are made about ways neuropsychologists can improve the quality of existing research.

Cognitive Impairment in the Post-Acute Phases of COVID-19 and Mechanisms: An Introduction and Narrative Review

Cognitive impairment is a primary manifestation of neurological symptoms associated with COVID-19 and may occur after disease resolution. Although cognitive impairment has been extensively reported in the literature, its duration and rate of remission remain controversial. This study discusses the various factors that influence cognitive impairment, including demographic characteristics, genetics, as well as disease course and severity. Furthermore, imaging and laboratory data have suggested various associations with cognitive impairment, most notably changes in EEG patterns, PET imaging, and serum markers. Some findings suggest similarities and potential links between COVID-related cognitive impairment and Alzheimer's disease. Moreover, this study reviews the various mechanisms proposed to explain the development of cognitive impairment in COVID-19, including cytokine storm, damage to the blood-brain barrier, compromise of small vessel integrity, hypoxic conditions, and immune dysregulation.

SARS-CoV2 evokes structural brain changes resulting in declined executive function

BACKGROUND

Several research has underlined the multi-system character of COVID-19. Though effects on the Central Nervous System are mainly discussed as disease-specific affections due to the virus' neurotropism, no comprehensive disease model of COVID-19 exists on a neurofunctional base by now. We aimed to investigate neuroplastic grey- and white matter changes related to COVID-19 and to link these changes to neurocognitive testings leading towards a multi-dimensional disease model.

METHODS

Groups of acutely ill COVID-19 patients (n = 16), recovered COVID-19 patients (n = 21) and healthy controls (n = 13) were prospectively included into this study. MR-imaging included T1-weighted sequences for analysis of grey matter using voxel-based morphometry and diffusion-weighted sequences to investigate white matter tracts using probabilistic tractography. Comprehensive neurocognitive testing for verbal and non-verbal domains was performed.

RESULTS

Alterations strongly focused on grey matter of the frontal-basal ganglia-thalamus network and temporal areas, as well as fiber tracts connecting these areas. In acute COVID-19 patients, a decline of grey matter volume was found with an accompanying diminution of white matter tracts. A decline in executive function and especially verbal fluency was found in acute patients, partially persisting in recovered.

CONCLUSION

Changes in gray matter volume and white matter tracts included mainly areas involved in networks of executive control and language. Deeper understanding of these alterations is necessary especially with respect to long-term impairments, often referred to as 'Post-COVID'.

Insights into attention and memory difficulties in post-COVID syndrome using standardized neuropsychological tests and experimental cognitive tasks

The COVID-19 pandemic has given rise to post-acute cognitive symptoms, often described as 'brain fog'. To comprehensively grasp the extent of these issues, we conducted a study integrating traditional neuropsychological assessments with experimental cognitive tasks targeting attention control, working memory, and long-term memory, three cognitive domains most commonly associated with 'brain fog'. We enrolled 33 post-COVID patients, all self-reporting cognitive difficulties, and a matched control group (N = 27) for cognitive and psychological assessments. Our findings revealed significant attention deficits in post-COVID patients across both neuropsychological measurements and experimental cognitive tasks, evidencing reduced performance in tasks involving interference resolution and selective and sustained attention. Mild executive function and naming impairments also emerged from the neuropsychological assessment. Notably, 61% of patients reported significant prospective memory failures in daily life, aligning with our recruitment focus. Furthermore, our patient group showed significant alterations in the psycho-affective domain, indicating a complex interplay between cognitive and psychological factors, which could point to a non-cognitive determinant of subjectively experienced cognitive changes following COVID-19. In summary, our study offers valuable insights into attention challenges faced by individuals recovering from COVID-19, stressing the importance of comprehensive cognitive and psycho-affective evaluations for supporting post-COVID individuals.

Cognitive function and quantitative electroencephalogram analysis in subjects recovered from COVID-19 infection

BACKGROUND & OBJECTIVES

Objective assessment of post-COVID-19 cognitive dysfunction is highly warranted. This study aimed to evaluate the cognitive dysfunction of COVID-19 survivors with cognitive complaints, both clinically and neurophysiologically, using Quantitative Electroencephalogram (QEEG).

METHODS

This case-control study was conducted on 50 recovered subjects from COVID-19 infection with cognitive complaints and 50 age, sex, and educational-matched healthy controls. Both groups were subjected to the following neurocognitive tests: Paired associate learning Test (PALT) and Paced Auditory Serial Addition Test (PASAT). The neurophysiological assessment was also done for both groups using QEEG.

RESULTS

COVID-19 survivors had significantly lower PALT scores than controls (P < 0.001). QEEG analysis found significantly higher levels of Theta / Beta ratio in both central and parietal areas in patients than in the controls (P < 0.001 for each). The interhemispheric coherence for the frontal, central, and parietal regions was also significantly lower in patients than in the control group regarding alpha and beta bands. There were statistically significant lower scores of PALT and PASAT among cases with severe COVID-19 infection (P = 0.011, 0.005, respectively) and those who needed oxygen support (P = 0.04, 0.01, respectively). On the other hand, a statistically significantly lower mean of frontal alpha inter-hemispheric coherence among patients with severe COVID-19 infection (P = 0.01) and those needing mechanical ventilation support (P = 0.04).

CONCLUSION

Episodic memory deficit is evident in COVID-19 survivors with subjective cognitive complaints accompanied by lower inter-hemispheric coherence in frontal regions. These clinical and neurophysiological changes are associated with hypoxia and COVID-19 severity.

Cognitive impairment and neuropsychiatric symptoms among individuals with history of symptomatic SARS-CoV-2 infection: a retrospective longitudinal study

COVID-19 is a multisystem disease caused by the RNA virus (coronavirus 2 or SARS-CoV-2) that can impact cognitive measures.

Objective

To identify the main cognitive and neuropsychiatric symptoms in adults who had no cognitive complaints prior to the infection. Specifically, to observe the trajectory of cognitive and neuropsychiatric performance after 6 months.

Methods

This is a retrospective longitudinal study. Forty-nine patients (29 reassessed after 6 months), with a positive PCR test, with no prior cognitive complaints that only presented after the infection and without a history of structural, neurodegenerative or psychiatric neurological diseases. A brief cognitive assessment battery (MoCA), the Trail Making Test (TMT-A, B, ∆), and the Verbal Fluency Test were used, as well as the scales (Hospital Anxiety and Depression Scale-HADS, Fatigue Severity Scale-FSS). Correlation tests and group comparison were used for descriptive and inferential statistics. Level of significance of α=5%.

Results

Mean age of 50.4 (11.3), 12.7 (2.8) years of education, higher percentage of women (69.8%). No psycho-emotional improvement (depression and anxiety) was observed between the evaluations, and patients maintained the subjective complaint of cognitive changes. The HAD-Anxiety scale showed a significant correlation with TMT-B errors. The subgroup participating in cognitive stimulation and psychoeducation showed improvement in the global cognition measure and the executive attention test.

Conclusion

Our results corroborate other studies that found that cognitive dysfunctions in post-COVID-19 patients can persist for months after disease remission, as well as psycho-emotional symptoms, even in individuals with mild infection. Future studies, with an increase in casuistry and control samples, are necessary for greater evidence of these results.

Cognitive Symptoms of Post-COVID-19 Condition and Daily Functioning

Importance

The frequent occurrence of cognitive symptoms in post-COVID-19 condition has been described, but the nature of these symptoms and their demographic and functional factors are not well characterized in generalizable populations.

Objective

To investigate the prevalence of self-reported cognitive symptoms in post-COVID-19 condition, in comparison with individuals with prior acute SARS-CoV-2 infection who did not develop post-COVID-19 condition, and their association with other individual features, including depressive symptoms and functional status.

Design, Setting, and Participants

Two waves of a 50-state nonprobability population-based internet survey conducted between December 22, 2022, and May 5, 2023. Participants included survey respondents aged 18 years and older.

Exposure

Post-COVID-19 condition, defined as self-report of symptoms attributed to COVID-19 beyond 2 months after the initial month of illness.

Main Outcomes and Measures

Seven items from the Neuro-QoL cognition battery assessing the frequency of cognitive symptoms in the past week and patient Health Questionnaire-9.

Results

The 14 767 individuals reporting test-confirmed COVID-19 illness at least 2 months before the survey had a mean (SD) age of 44.6 (16.3) years; 568 (3.8%) were Asian, 1484 (10.0%) were Black, 1408 (9.5%) were Hispanic, and 10 811 (73.2%) were White. A total of 10 037 respondents (68.0%) were women and 4730 (32.0%) were men. Of the 1683 individuals reporting post-COVID-19 condition, 955 (56.7%) reported at least 1 cognitive symptom experienced daily, compared with 3552 of 13 084 (27.1%) of those who did not report post-COVID-19 condition. More daily cognitive symptoms were associated with a greater likelihood of reporting at least moderate interference with functioning (unadjusted odds ratio [OR], 1.31 [95% CI, 1.25-1.36]; adjusted [AOR], 1.30 [95% CI, 1.25-1.36]), lesser likelihood of full-time employment (unadjusted OR, 0.95 [95% CI, 0.91-0.99]; AOR, 0.92 [95% CI, 0.88-0.96]) and greater severity of depressive symptoms (unadjusted coefficient, 1.40 [95% CI, 1.29-1.51]; adjusted coefficient 1.27 [95% CI, 1.17-1.38). After including depressive symptoms in regression models, associations were also found between cognitive symptoms and at least moderate interference with everyday functioning (AOR, 1.27 [95% CI, 1.21-1.33]) and between cognitive symptoms and lower odds of full-time employment (AOR, 0.92 [95% CI, 0.88-0.97]).

Conclusions and Relevance

The findings of this survey study of US adults suggest that cognitive symptoms are common among individuals with post-COVID-19 condition and associated with greater self-reported functional impairment, lesser likelihood of full-time employment, and greater depressive symptom severity. Screening for and addressing cognitive symptoms is an important component of the public health response to post-COVID-19 condition.

Outcome of severe COVID-19: spotlight on fatigue, fatigability, multidomain complaints and pattern of cognitive deficits in a case series without prior brain dysfunction and without COVID-19-related stroke and/or cardiac arrest

BACKGROUND

Population-wide surveys and large-scale investigations highlighted the presence of cognitive deficits in the acute and postacute stages of severe COVID-19; a few studies documented their occurrence in cases without prior or COVID-19-related brain damage. The evolution of cognitive deficits in the latter population and their relationship to the post-COVID-19 fatigue syndrome are poorly understood.

CASE PRESENTATION

We report the outcome at 12 months after severe COVID-19 involving an intensive care unit stay and mechanical ventilation in six (five Caucasian and one Asian) patients (age range: 53-71 years, mean age 61.7 ± 6.5 years) without history of prior brain dysfunction and without stroke and/or cardiac arrest during or after COVID-19. All patients reported pervading mental and physical fatigue as well as numerous multidomain complaints, which impacted everyday life. Individual patients described mental fatigability, apathy, and/or anxiety. Standardized neuropsychological tests revealed isolated symptoms of cognitive dysfunction or performance at the lower limit of the norm in the attentional, executive, and/or working memory domains in four of the six patients. Somatic scales documented dyspnoea, muscle weakness, olfactory disorder, and/or minor sleep problems in some, but not all, patients.

CONCLUSION

Fatigue, fatigability, multidomain complaints, cognitive difficulties, or dysfunction, as well as isolated neurobehavioral and/or psychiatric and/or somatic symptoms, tend to occur in the aftermath of severe COVID-19 and persist at 12 months, even in the absence of prior and/or COVID-19-related brain damage. This clinical situation, which impacts everyday life, calls for a detailed investigation of patients' complaints, its neural underpinning, and an elaboration of specific rehabilitation programs.

SARS-CoV-2 infection and cognition in community-dwelling and nursing home residents in southern Switzerland

Background

COVID-19 patients can report 'brain fog' and may exhibit cognitive symptoms for months after recovery (Cognitive COVID). However, evidence on whether and the extent to which SARS-CoV-2 infection impacts cognition irrespective of COVID-19 course and severity is limited to clinical samples and mainly comes from prognostic studies. We aimed to explore the association between serologically confirmed SARS-CoV-2 infection and cognitive functioning in community-based and institutionalized older adults, irrespective of COVID-19 symptoms.

Methods

We conducted a case-control study nested into two cohorts in Southern Switzerland. Eligible subjects were Italian speaking older adults, without a previous diagnosis of dementia, who underwent serological testing for anti-SARS-CoV-2 antibodies between November 2020 and July 2021. We manually selected age-, sex- and education-matched cases (i.e., individuals with a serologically confirmed SARS-CoV-2 infection), with seronegative controls, and we conducted in-person neuropsychological assessments using validated, highly sensitive cognitive tests.

Results

We completed 38 neuropsychological assessments in a mostly female sample of older adults (Mean age: 83.13 ± 8.95; 86.8% women). 17 were community dwelling individuals while 21 lived in a nursing home. As expected, socio-demographic characteristics of age, gender and educational level were similarly distributed between cases (n = 14) and controls (n = 24). In linear regression models, cases had significantly lower scores in cognitive tasks of memory (β = -0.367, p = 0.023), attention (β = 0.428, p = 0.008) and executive functions (β = 0.326, p = 0.046). We found no significant difference in tests of language and spatial-temporal orientation (all p values > 0.05).

Conclusions

SARS-CoV-2 infection was associated with cognitive impairment in memory, attention, and executive functions in older adults. Our findings are consistent with mechanistic evidence of the neurotropism of the virus and provide empirical support for the "Cognitive COVID" construct also in non-clinical samples. With nearly 800 million COVID-19 cases (in April 2023), and many more infections worldwide, the clinical and public health implications of Cognitive COVID due to SARS-CoV-2 infection may be massive and warrant further epidemiological investigations.