Cognitive dysfunction in post-COVID-19 condition: Mechanisms, management, and rehabilitation

Abstract:

The long-term effects of COVID-19 on cognitive function have become an area of increasing concern. This paper provides an overview of characteristics, risk factors, possible mechanisms, and management strategies for cognitive dysfunction in post-COVID-19 condition (PCC).

Prolonged cognitive dysfunction is one of the most common impairments in PCC, affecting between 17% and 28% of the individuals more than 12 weeks after the infection and persisting in some cases for several years. Cognitive dysfunctions can be manifested as a wide range of symptoms including memory impairment, attention deficit, executive dysfunction, and reduced processing speed. Risk factors for developing PCC, with or without cognitive impairments, include advanced age, preexisting medical conditions, and the severity of acute illness. The underlying mechanisms remain unclear, but proposed contributors include neuroinflammation, hypoxia, vascular damage, and latent virus reactivation not excluding the possibility of direct viral invasion of the central nervous system, illustrating complex viral pathology.

As the individual variation of the cognitive impairments is large, a neuropsychological examination and a person-centered multidimensional approach are required. According to the World Health Organization, limited evidence on COVID-19-related cognitive impairments necessitates implementing rehabilitation interventions from established practices of similar conditions. Psychoeducation and compensatory skills training are recommended. Assistive products and environmental modifications adapted to individual needs might be helpful. In specific attention- and working memory dysfunctions, cognitive training—carefully monitored for intensity—might be effective for people who do not suffer from post-exertional malaise. Further research is crucial for evidence-based interventions specific to COVID-19-related cognitive impairments.

Source: Möller M, Borg K, Janson C, Lerm M, Normark J, Niward K. Cognitive dysfunction in post-COVID-19 condition: Mechanisms, management, and rehabilitation. J Intern Med. 2023 Sep 27. doi: 10.1111/joim.13720. Epub ahead of print. PMID: 37766515. https://onlinelibrary.wiley.com/doi/10.1111/joim.13720 (Full text)

Investigating the Effect of COVID-19 Infection on Professional Athletes’ Post-infection With a Focus on Fatigue and Chronic Fatigue Syndrome

Abstract:

Introduction and objectives: COVID-19 has been reported to cause long-term sequela including persistent fatigue and Chronic Fatigue Syndrome (CFS) in the general population. However, it remains to be seen if similar effects are observed in an athlete population. The aetiology and pathophysiology are poorly understood but is thought to be multi-factorial. Patient reported outcome measures are commonly used to improve patient-centred outcomes (PROMs). They are essential to assess patient quality of life post-COVID infection. This paper aims to assess the effect of COVID-19 on athletes’ long-term fatigue and CFS and identify the PROMs used to characterise this.

Methodology: Articles were selected for extraction based on the eligibility criteria and PRISMA guidelines. The inclusion criteria required papers to assess competitive athletes over eighteen years of age who were clinically diagnosed with COVID-19. Articles were extracted to assess different variables including type of sport, type of athlete and ethnicity. Key terms were obtained using MeSH trees and utilised with Web of Science and NCBI Pubmed. Papers were graded by quality using the Hawker quality assessment tool.

Results and discussion: Forty articles (N=40) were identified for full-text screening (N=8). Eight were selected for extraction based on the eligibility criteria. Data was obtained on athlete characteristics, sport characteristics, properties of PROM measurement techniques and fatigue presentation. Male athletes were found to be 10-50% more likely than female athletes to suffer from persistent fatigue symptoms (N=2). Persistent fatigue was present in 9-10% Athletes from mixed backgrounds and genders (N=2). Initial fatigue was documented to be between 47-56% (N=2). A heterogenous range of PROMs were utilised to assess symptoms including fatigue and excluded emotional or mental fatigue.

Conclusion: COVID-19 is associated with signs of persisting fatigue and potentially CFS in athlete populations. More work needs to be done to develop standardised and validated PROMs specific to CFS.

Source: Sarwary, Reza and Tareen, Manahil and Hocaoglu, Mevhibe, Investigating the Effect of COVID-19 Infection on Professional Athletes’ Post-infection With a Focus on Fatigue and Chronic Fatigue Syndrome (January 16, 2023). Available at SSRN: https://ssrn.com/abstract=4573649 or http://dx.doi.org/10.2139/ssrn.4573649 (Full text available as PDF file)

Prevalence of musculoskeletal pain as a long-covid symptom after hospitalisation in covid-19 survivors

Abstract:

Background and aims: Up to 60% of COVID-19 survivors develop long-COVID symptomatology with 90 different manifestations. The aim of this large cohort study was to study the prevalence of persistent musculoskeletal pain as a long-COVID symptom in COVID-19 survivors.
Methods: This cross-sectional exploratory study was based on responses to pain-related questionnaires from a national survey including data from 1) 4.833 previously hospitalised patients with a confirmed SARS-CoV-2 infection and from 2) a population of 132.427 non-hospitalised SARS-CoV-2 infected persons. Time from confirmed infection to response was 8-30 months. The questionnaire was designed to focus specifically on the type of post-COVID persistent pain, pain intensities, and quality of life.
Results: Data from 1.000 randomly selected previously hospitalised (51.2% males; 60.4±15.2 years; 85.6±18.5 kg) and 1.000 randomly selected non-hospitalised COVID-19 survivors (43.5% males; 50.4±15.9 years; 79.2±16.6 kg) were included. Long-COVID pain symptoms were more prevalent within the hospital group (38.8% vs. 12.7%, p<0.001). When analysing specifically for de novo musculoskeletal pain, the prevalence was likewise highest in the hospital group (20% vs. 4.2%, p<0.001). A higher proportion (p<0.001) of previously hospitalised survivors (20%) reported presence of widespread pain when compared with non-hospitalised patients (4.2%). Long-COVID pain intensities were not different between groups (p<0.329).
Conclusions: This study showed that long-COVID musculoskeletal pain was more prevalent in the hospital group compared to a non-hospitalised group. The high prevalence of long-COVID musculoskeletal and widespread pain symptoms following SARS-CoV-2 infection highlights the need of attention to this new group of pain patients.
Source: Ebbesen, B. D., Giordano, R., Varol, U., Fernández-de-Las-Peñas, C., Rasmussen, B. S., Nielsen, H., Schiøttz-Christensen, B., Lykke Petersen, P., Castaldo, M., & Arendt-Nielsen, L. (2023). Prevalence of musculoskeletal pain as a long-covid symptom after hospitalisation in covid-19 survivors. Abstract from 13th Congress of the European Pain Federation EFIC, Budapest, Hungary. https://vbn.aau.dk/en/publications/prevalence-of-musculoskeletal-pain-as-a-long-covid-symptom-after-

Characterization of long COVID temporal sub-phenotypes by distributed representation learning from electronic health record data: a cohort study

Abstract:

Background: Characterizing Post-Acute Sequelae of COVID (SARS-CoV-2 Infection), or PASC has been challenging due to the multitude of sub-phenotypes, temporal attributes, and definitions. Scalable characterization of PASC sub-phenotypes can enhance screening capacities, disease management, and treatment planning.

Methods: We conducted a retrospective multi-centre observational cohort study, leveraging longitudinal electronic health record (EHR) data of 30,422 patients from three healthcare systems in the Consortium for the Clinical Characterization of COVID-19 by EHR (4CE). From the total cohort, we applied a deductive approach on 12,424 individuals with follow-up data and developed a distributed representation learning process for providing augmented definitions for PASC sub-phenotypes.

Findings: Our framework characterized seven PASC sub-phenotypes. We estimated that on average 15.7% of the hospitalized COVID-19 patients were likely to suffer from at least one PASC symptom and almost 5.98%, on average, had multiple symptoms. Joint pain and dyspnea had the highest prevalence, with an average prevalence of 5.45% and 4.53%, respectively.

Interpretation: We provided a scalable framework to every participating healthcare system for estimating PASC sub-phenotypes prevalence and temporal attributes, thus developing a unified model that characterizes augmented sub-phenotypes across the different systems.

Source: Dagliati A, Strasser ZH, Hossein Abad ZS, Klann JG, Wagholikar KB, Mesa R, Visweswaran S, Morris M, Luo Y, Henderson DW, Samayamuthu MJ, Tan BWQ, Verdy G, Omenn GS, Xia Z, Bellazzi R; Consortium for Clinical Characterization of COVID-19 by EHR (4CE),; Murphy SN, Holmes JH, Estiri H; Consortium for Clinical Characterization of COVID-19 by EHR (4CE). Characterization of long COVID temporal sub-phenotypes by distributed representation learning from electronic health record data: a cohort study. EClinicalMedicine. 2023 Sep 14;64:102210. doi: 10.1016/j.eclinm.2023.102210. PMID: 37745021; PMCID: PMC10511779. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10511779/ (Full text)

Analyzing the Interplay between COVID-19 Viral Load, Inflammatory Markers, and Lymphocyte Subpopulations on the Development of Long COVID

Abstract:

The global impact of the SARS-CoV-2 infection has been substantial, affecting millions of people. Long COVID, characterized by persistent or recurrent symptoms after acute infection, has been reported in over 40% of patients. Risk factors include age and female gender, and various mechanisms, including chronic inflammation and viral persistence, have been implicated in long COVID’s pathogenesis. However, there are scarce studies in which multiple inflammatory markers and viral load are analyzed simultaneously in acute infection to determine how they predict for long COVID at long-term follow-up. This study explores the association between long COVID and inflammatory markers, viral load, and lymphocyte subpopulation during acute infection in hospitalized patients to better understand the risk factors of this disease.
This longitudinal retrospective study was conducted in patients hospitalized with COVID-19 in northern Mexico. Inflammatory parameters, viral load, and lymphocyte subpopulation during the acute infection phase were analyzed, and long COVID symptoms were followed up depending on severity and persistence (weekly or monthly) and assessed 1.5 years after the acute infection.
This study analyzed 79 patients, among them, 41.8% presented long COVID symptoms, with fatigue being the most common (45.5%). Patients with long COVID had higher lymphocyte levels during hospitalization, and NK cell subpopulation levels were also associated with long COVID. ICU admission during acute COVID-19 was also linked to the development of long COVID symptoms.
Source: Rivera-Cavazos A, Luviano-García JA, Garza-Silva A, Morales-Rodríguez DP, Kuri-Ayache M, Sanz-Sánchez MÁ, Santos-Macías JE, Romero-Ibarguengoitia ME, González-Cantú A. Analyzing the Interplay between COVID-19 Viral Load, Inflammatory Markers, and Lymphocyte Subpopulations on the Development of Long COVID. Microorganisms. 2023; 11(9):2241. https://doi.org/10.3390/microorganisms11092241 https://www.mdpi.com/2076-2607/11/9/2241 (Full text)

Post-COVID symptoms are associated with endotypes reflecting poor inflammatory and hemostatic modulation

Abstract:

Introduction: Persistent symptoms after COVID-19 infection (“long COVID”) negatively affects almost half of COVID-19 survivors. Despite its prevalence, its pathophysiology is poorly understood, with multiple host systems likely affected. Here, we followed patients from hospital to discharge and used a systems-biology approach to identify mechanisms of long COVID.

Methods: RNA-seq was performed on whole blood collected early in hospital and 4-12 weeks after discharge from 24 adult COVID-19 patients (10 reported post-COVID symptoms after discharge). Differential gene expression analysis, pathway enrichment, and machine learning methods were used to identify underlying mechanisms for post-COVID symptom development.

Results: Compared to patients with post-COVID symptoms, patients without post-COVID symptoms had larger temporal gene expression changes associated with downregulation of inflammatory and coagulation genes over time. Patients could also be separated into three patient endotypes with differing mechanistic trajectories, which was validated in another published patient cohort. The “Resolved” endotype (lowest rate of post-COVID symptoms) had robust inflammatory and hemostatic responses in hospital that resolved after discharge. Conversely, the inflammatory/hemostatic responses of “Suppressive” and “Unresolved” endotypes (higher rates of patients with post-COVID symptoms) were persistently dampened and activated, respectively. These endotypes were accurately defined by specific blood gene expression signatures (6-7 genes) for potential clinical stratification.

Discussion: This study allowed analysis of long COVID whole blood transcriptomics trajectories while accounting for the issue of patient heterogeneity. Two of the three identified and externally validated endotypes (“Unresolved” and “Suppressive”) were associated with higher rates of post-COVID symptoms and either persistently activated or suppressed inflammation and coagulation processes. Gene biomarkers in blood could potentially be used clinically to stratify patients into different endotypes, paving the way for personalized long COVID treatment.

Source: An AY, Baghela A, Zhang PGY, Blimkie TM, Gauthier J, Kaufmann DE, Acton E, Lee AHY, Levesque RC, Hancock REW. Post-COVID symptoms are associated with endotypes reflecting poor inflammatory and hemostatic modulation. Front Immunol. 2023 Aug 23;14:1243689. doi: 10.3389/fimmu.2023.1243689. PMID: 37680625; PMCID: PMC10482103. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10482103/ (Full text)

SARS-CoV-2-Specific Immune Responses in Patients With Postviral Syndrome After Suspected COVID-19

Abstract:

Background and objectives: Millions of Americans were exposed to SARS-CoV-2 early in the pandemic but could not get diagnosed with COVID-19 due to testing limitations. Many have developed a postviral syndrome (PVS) including neurologic manifestations similar to those with postacute sequelae of SARS-CoV-2 infection (Neuro-PASC). Owing to those circumstances, proof of SARS-CoV-2 infection was not required for evaluation at Northwestern Medicine’s Neuro COVID-19 clinic. We sought to investigate clinical and immunologic findings suggestive of SARS-CoV-2 exposure in patients with PVS.

Methods: We measured SARS-CoV-2-specific humoral and cell-mediated immune responses against Nucleocapsid and Spike proteins in 29 patients with PVS after suspected COVID-19, 32 confirmed age-matched/sex-matched Neuro-PASC (NP) patients, and 18 unexposed healthy controls. Neurologic symptoms and signs, comorbidities, quality of life, and cognitive testing data collected during clinic visits were studied retrospectively.

Results: Of 29 patients with PVS, 12 (41%) had detectable humoral or cellular immune responses consistent with prior exposure to SARS-CoV-2. Of 12 PVS responders (PVS+), 75% harbored anti-Nucleocapsid and 50% harbored anti-Spike responses. Patients with PVS+ had similar neurologic symptoms as patients with NP, but clinic evaluation occurred 5.3 months later from the time of symptom onset (10.7 vs 5.4 months; p = 0.0006). Patients with PVS+ and NP had similar subjective impairments in quality of life measures including cognitive function and fatigue. Patients with PVS+ had similar results in objective cognitive measures of processing speed, attention, and executive function and better results in working memory than patients with NP.

Discussion: Antibody and T-cell assays showed evidence of prior SARS-CoV-2 exposure in approximately 40% of the PVS group. Three-quarters of patients with PVS+ had detectable anti-Nucleocapsid and one-half anti-Spike responses, highlighting the importance of multitargeted COVID-19 immunologic evaluation and the limitations of commercially available diagnostic tests. Despite their persistent symptoms, lack of COVID-19 diagnosis likely delayed clinical care in patients with PVS. Our data suggest that millions of Americans presenting with PVS resembling Neuro-PASC were indeed exposed to SARS-CoV-2 at the beginning of the pandemic, and they deserve the same access to care and inclusion in research studies as patients with NP with confirmed COVID-19 diagnosis.

Source:Orban ZS, Visvabharathy L, Perez Giraldo GS, Jimenez M, Koralnik IJ. SARS-CoV-2-Specific Immune Responses in Patients With Postviral Syndrome After Suspected COVID-19. Neurol Neuroimmunol Neuroinflamm. 2023 Aug 23;10(6):e200159. doi: 10.1212/NXI.0000000000200159. PMID: 37612134; PMCID: PMC10448973. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10448973/ (Full text)

Prevalence of Symptoms ≤12 Months After Acute Illness, by COVID-19 Testing Status Among Adults — United States, December 2020–March 2023

Summary:

What is already known about this topic? Post-COVID conditions, or long COVID, can persist for months or years after an acute COVID-19 illness and can include emergence of new symptoms or the occurrence of symptoms that come and go.

What is added by this report? In a multicenter study of adults with a COVID-like illness, symptom prevalence decreased over time after the acute illness. Approximately 16% of adults with COVID-like symptoms reported persistent symptoms 12 months after a positive or negative SARS-CoV-2 test result. At 3, 6, 9, and 12 months after testing, some symptomatic persons had ongoing symptoms, and others had emerging symptoms not reported during the previous period.

What are the implications for public health practice? Health care providers should be aware that symptoms can persist, emerge, reemerge, or resolve after COVID-like illness and are not unique to COVID-19 or to post-COVID conditions.

Abstract:

To further the understanding of post-COVID conditions, and provide a more nuanced description of symptom progression, resolution, emergence, and reemergence after SARS-CoV-2 infection or COVID-like illness, analysts examined data from the Innovative Support for Patients with SARS-CoV-2 Infections Registry (INSPIRE), a prospective multicenter cohort study. This report includes analysis of data on self-reported symptoms collected from 1,296 adults with COVID-like illness who were tested for SARS-CoV-2 using a Food and Drug Administration–approved polymerase chain reaction or antigen test at the time of enrollment and reported symptoms at 3-month intervals for 12 months.

Prevalence of any symptom decreased substantially between baseline and the 3-month follow-up, from 98.4% to 48.2% for persons who received a positive SARS-CoV-2 test results (COVID test–positive participants) and from 88.2% to 36.6% for persons who received negative SARS-CoV-2 test results (COVID test–negative participants).

Persistent symptoms decreased through 12 months; no difference between the groups was observed at 12 months (prevalence among COVID test–positive and COVID test–negative participants = 18.3% and 16.1%, respectively; p>0.05).

Both groups reported symptoms that emerged or reemerged at 6, 9, and 12 months. Thus, these symptoms are not unique to COVID-19 or to post-COVID conditions. Awareness that symptoms might persist for up to 12 months, and that many symptoms might emerge or reemerge in the year after COVID-like illness, can assist health care providers in understanding the clinical signs and symptoms associated with post-COVID–like conditions.

Source: Montoy JC, Ford J, Yu H, et al. Prevalence of Symptoms ≤12 Months After Acute Illness, by COVID-19 Testing Status Among Adults — United States, December 2020–March 2023. MMWR Morb Mortal Wkly Rep 2023;72:859–865. DOI: http://dx.doi.org/10.15585/mmwr.mm7232a2 (Full text)

The effects of COVID-19 on cognitive performance in a community-based cohort: a COVID symptom study biobank prospective cohort study

Abstract:

Background: Cognitive impairment has been reported after many types of infection, including SARS-CoV-2. Whether deficits following SARS-CoV-2 improve over time is unclear. Studies to date have focused on hospitalised individuals with up to a year follow-up. The presence, magnitude, persistence and correlations of effects in community-based cases remain relatively unexplored.

Methods: Cognitive performance (working memory, attention, reasoning, motor control) was assessed in a prospective cohort study of participants from the United Kingdom COVID Symptom Study Biobank between July 12, 2021 and August 27, 2021 (Round 1), and between April 28, 2022 and June 21, 2022 (Round 2). Participants, recruited from the COVID Symptom Study smartphone app, comprised individuals with and without SARS-CoV-2 infection and varying symptom duration. Effects of COVID-19 exposures on cognitive accuracy and reaction time scores were estimated using multivariable ordinary least squares linear regression models weighted for inverse probability of participation, adjusting for potential confounders and mediators. The role of ongoing symptoms after COVID-19 infection was examined stratifying for self-perceived recovery. Longitudinal analysis assessed change in cognitive performance between rounds.

Findings: 3335 individuals completed Round 1, of whom 1768 also completed Round 2. At Round 1, individuals with previous positive SARS-CoV-2 tests had lower cognitive accuracy (N = 1737, β = -0.14 standard deviations, SDs, 95% confidence intervals, CI: -0.21, -0.07) than negative controls. Deficits were largest for positive individuals with ≥12 weeks of symptoms (N = 495, β = -0.22 SDs, 95% CI: -0.35, -0.09). Effects were comparable to hospital presentation during illness (N = 281, β = -0.31 SDs, 95% CI: -0.44, -0.18), and 10 years age difference (60-70 years vs. 50-60 years, β = -0.21 SDs, 95% CI: -0.30, -0.13) in the whole study population. Stratification by self-reported recovery revealed that deficits were only detectable in SARS-CoV-2 positive individuals who did not feel recovered from COVID-19, whereas individuals who reported full recovery showed no deficits. Longitudinal analysis showed no evidence of cognitive change over time, suggesting that cognitive deficits for affected individuals persisted at almost 2 years since initial infection.

Interpretation: Cognitive deficits following SARS-CoV-2 infection were detectable nearly two years post infection, and largest for individuals with longer symptom durations, ongoing symptoms, and/or more severe infection. However, no such deficits were detected in individuals who reported full recovery from COVID-19. Further work is needed to monitor and develop understanding of recovery mechanisms for those with ongoing symptoms.

Source: Cheetham NJ, Penfold R, Giunchiglia V, Bowyer V, Sudre CH, Canas LS, Deng J, Murray B, Kerfoot E, Antonelli M, Rjoob K, Molteni E, Österdahl MF, Harvey NR, Trender WR, Malim MH, Doores KJ, Hellyer PJ, Modat M, Hammers A, Ourselin S, Duncan EL, Hampshire A, Steves CJ. The effects of COVID-19 on cognitive performance in a community-based cohort: a COVID symptom study biobank prospective cohort study. EClinicalMedicine. 2023 Jul 21;62:102086. doi: 10.1016/j.eclinm.2023.102086. PMID: 37654669; PMCID: PMC10466229. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10466229/ (Full text)

Acute blood biomarker profiles predict cognitive deficits 6 and 12 months after COVID-19 hospitalization

Abstract:

Post-COVID cognitive deficits, including ‘brain fog’, are clinically complex, with both objective and subjective components. They are common and debilitating, and can affect the ability to work, yet their biological underpinnings remain unknown.

In this prospective cohort study of 1,837 adults hospitalized with COVID-19, we identified two distinct biomarker profiles measured during the acute admission, which predict cognitive outcomes 6 and 12 months after COVID-19.

A first profile links elevated fibrinogen relative to C-reactive protein with both objective and subjective cognitive deficits. A second profile links elevated D-dimer relative to C-reactive protein with subjective cognitive deficits and occupational impact. This second profile was mediated by fatigue and shortness of breath. Neither profile was significantly mediated by depression or anxiety.

Results were robust across secondary analyses. They were replicated, and their specificity to COVID-19 tested, in a large-scale electronic health records dataset. These findings provide insights into the heterogeneous biology of post-COVID cognitive deficits.

Source: Taquet, M., Skorniewska, Z., Hampshire, A. et al. Acute blood biomarker profiles predict cognitive deficits 6 and 12 months after COVID-19 hospitalization. Nat Med (2023). https://doi.org/10.1038/s41591-023-02525-y https://www.nature.com/articles/s41591-023-02525-y (Full text)