Cognitive Complications of COVID-19 Infection

Abstract:

SARS-CoV-2 is associated with a post-infectious neurocognitive syndrome characterized by fatigue and deficits in attention, memory, and executive function. As screening cognitive testing generally remains normal, the pathophysiologic basis of these symptoms remains controversial and there is no standardized treatment paradigm.

We present a clinical case demonstrative of typical neurocognitive sequelae of SARS-CoV-2 infection, highlighting medical and social factors that may have contributed to the severity of symptoms. We discuss the pathophysiologic evidence for cognitive “brain fog” following COVID-19 infection as well as lifestyle changes and rehabilitation strategies that may improve recovery. As the benefits of pharmacologic therapy remain unproven, we close with a brief discussion of medication options that might be appropriate targets for future clinical trials in the context of rehabilitative treatment.

Source: Warren S, Drake J, Wu CK. Cognitive Complications of COVID-19 Infection. R I Med J (2013). 2022 Sep 1;105(7):27-30. PMID: 35930487. https://pubmed.ncbi.nlm.nih.gov/35930487/ http://rimed.org/rimedicaljournal/2022/09/2022-09-27-covid-warren.pdf  (Full text available as PDF file)

Cognitive task performance and subjective cognitive symptoms in individuals with Chronic Fatigue Syndrome or Fibromyalgia: A cross-sectional analysis of the Lifelines cohort study

Abstract:

Objective: This study examined cognitive task performance and self-reported cognitive functioning in individuals with chronic fatigue syndrome (CFS) and fibromyalgia (FM) in a population-based sample and investigated the role of mood and anxiety disorders as well as severity of the physical symptoms.

Methods: This study was performed in 79,966 participants (Mean age: 52.9, SD = ±12.6 years, 59.2% women) from the Lifelines general-population. Symptoms consistent with the diagnostic criteria for CFS and FM were assessed using questionnaires. Two comparison groups were used: participants with self-reported medical disorders with well-defined pathophysiology (i.e., multiple sclerosis and rheumatic arthritis) and controls without these diseases. Objective task-performance was based on the computerized CogState cognitive battery and subjective cognitive symptoms using the concentration subscale of the Checklist Individual Strength.

Results: Cognitive task performance was poorer in individuals with CFS vs. controls without disease and controls with a medical disorder, although the severity of cognitive dysfunction was mild. Participants meeting criteria for CFS (n = 2,461) or FM (n = 4,295) reported more subjective cognitive symptoms compared to controls without a medical disorder (d = 1.53, 95%CI = 1.49-1.57 for CFS; d = 1.25, 95%CI = 1.22-1.29 for FM) and participants with a medical disease (d = 0.62, 95%CI = 0.46-0.79 for CFS; d = 0.75, 95%CI = 0.70-0.80 for FM). These differences remained essentially the same when excluding participants with comorbid mood or anxiety disorders or adjusting for physical symptom severity.

Conclusions: Subjective cognitive symptoms and to a lesser extent suboptimal cognitive task performance are more prevalent in individuals with CFS or FM compared to controls without these conditions.

Source: Joustra ML, Hartman CA, Bakker SJL, Rosmalen JGM. Cognitive task performance and subjective cognitive symptoms in individuals with Chronic Fatigue Syndrome or Fibromyalgia: A cross-sectional analysis of the Lifelines cohort study. Psychosom Med. 2022 Aug 2. doi: 10.1097/PSY.0000000000001117. Epub ahead of print. PMID: 35980775.  https://pubmed.ncbi.nlm.nih.gov/35980775/

High-density EEG sleep correlates of cognitive and affective impairment at 12-month follow-up after COVID-19

Abstract:

Objective: To disentangle the pathophysiology of cognitive/affective impairment in Coronavirus Disease-2019 (COVID-19), we studied long-term cognitive and affective sequelae and sleep high-density electroencephalography (EEG) at 12-month follow-up in people with a previous hospital admission for acute COVID-19.

Methods: People discharged from an intensive care unit (ICU) and a sub-intensive ward (nonICU) between March and May 2020 were contacted between March and June 2021. Participants underwent cognitive, psychological, and sleep assessment. High-density EEG recording was acquired during a nap. Slow and fast spindles density/amplitude/frequency and source reconstruction in brain gray matter were extracted. The relationship between psychological and cognitive findings was explored with Pearson correlation.

Results: We enrolled 33 participants ( 17 nonICU) and 12 controls. We observed a lower Physical Quality of Life index, higher post-traumatic stress disorder (PTSD) score, and a worse executive function performance in nonICU participants. Higher PTSD and Beck Depression Inventory scores correlated with lower executive performance. The same group showed a reorganization of spindle cortical generators.

Conclusions: Our results show executive and psycho-affective deficits and spindle alterations in COVID-19 survivors – especially in nonICU participants – after 12 months from discharge.

Significance: These findings may be suggestive of a crucial contribution of stress experienced during hospital admission on long-term cognitive functioning.

Source: Rubega M, Ciringione L, Bertuccelli M, Paramento M, Sparacino G, Vianello A, Masiero S, Vallesi A, Formaggio E, Del Felice A. High-density EEG sleep correlates of cognitive and affective impairment at 12-month follow-up after COVID-19. Clin Neurophysiol. 2022 Jun 15;140:126-135. doi: 10.1016/j.clinph.2022.05.017. Epub ahead of print. PMID: 35763985; PMCID: PMC9292469. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9292469/ (Full text)

Study on the active components and mechanism of Suanzaoren decoction in improving cognitive impairment caused by sleep deprivation

Abstract:

Ethnopharmacological relevance: Suanzaoren Decoction (SZRD) is a traditional and classic prescription for the treatment of insomnia, with a history of more than 1,000 years. It replenishes blood components, calms the nerves, reduces fever and irritability. It is commonly used in the clinical treatment of chronic fatigue syndrome, cardiac neurosis, and menopausal syndromes. Modern pharmacological studies have shown that it improves cognitive impairment; however, its mechanism of action remains unclear.

Aim of the study: This study preliminarily investigated the potential bioactive components and mechanism of SZRD in improving cognitive impairment by exploring network pharmacology, molecular docking, and conducting in vivo experiments.

Materials and methods: The components of various Chinese herbs in SZRD and their disease-related targets were identified through network pharmacology and literature. Gene ontology (GO) function enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of intersection targets were performed using the relevant database. Next, the “Components-Targets-Pathways” (C-T-P) and “Protein-Protein interaction” networks were constructed using the enrichment analysis results to further identify potential pathways, bioactive components, and hub genes. At the same time, molecular docking was used to further distinguish the key bioactive components and genes of SZRD responsible for improving cognitive impairment. Finally, the potential mechanism of action was further analysed and verified using in vivo experiments.

Results: A total of 117 potential active components and 138 intersection targets were identified by network pharmacology screening. The key bioactive components, including calycosin, 5-Prenylbutein, licochalcone G, glypallichalcone, and ZINC189892, were identified by analysing the networks and molecular docking results. Hub genes included ACHE, CYP19A1, EGFR, ESR1, and ESR2. The oestrogen signalling pathway was the most important in the enrichment analysis. In vivo experiments further proved that SZRD could improve cognitive impairment by affecting the oestrogen signalling pathway and the expression of ACHE and CYP19A1.

Conclusions: Network pharmacology and in vivo experiments demonstrate that SZRD improves cognitive impairment caused by sleep disturbance through estrogen receptor pathway, which provides a basis for its clinical application.

Source: Cheng L, Wang F, Li ZH, Wen C, Ding L, Zhang SB, You QY. Study on the active components and mechanism of Suanzaoren decoction in improving cognitive impairment caused by sleep deprivation. J Ethnopharmacol. 2022 Jun 28:115502. doi: 10.1016/j.jep.2022.115502. Epub ahead of print. PMID: 35777606. https://www.sciencedirect.com/science/article/abs/pii/S0378874122005414 (Full text)

Comprehensive clinical assessment identifies specific neurocognitive deficits in working-age patients with long-COVID

Abstract:

Introduction: There have been more than 425 million COVID-19 infections worldwide. Post-COVID illness has become a common, disabling complication of this infection. Therefore, it presents a significant challenge to global public health and economic activity.

Methods: Comprehensive clinical assessment (symptoms, WHO performance status, cognitive testing, CPET, lung function, high-resolution CT chest, CT pulmonary angiogram and cardiac MRI) of previously well, working-age adults in full-time employment was conducted to identify physical and neurocognitive deficits in those with severe or prolonged COVID-19 illness.

Results: 205 consecutive patients, age 39 (IQR30.0-46.7) years, 84% male, were assessed 24 (IQR17.1-34.0) weeks after acute illness. 69% reported ≥3 ongoing symptoms. Shortness of breath (61%), fatigue (54%) and cognitive problems (47%) were the most frequent symptoms, 17% met criteria for anxiety and 24% depression. 67% remained below pre-COVID performance status at 24 weeks. One third of lung function tests were abnormal, (reduced lung volume and transfer factor, and obstructive spirometry). HRCT lung was clinically indicated in <50% of patients, with COVID-associated pathology found in 25% of these. In all but three HRCTs, changes were graded ‘mild’. There was an extremely low incidence of pulmonary thromboembolic disease or significant cardiac pathology. A specific, focal cognitive deficit was identified in those with ongoing symptoms of fatigue, poor concentration, poor memory, low mood, and anxiety. This was notably more common in patients managed in the community during their acute illness.

Conclusion: Despite low rates of residual cardiopulmonary pathology, in this cohort, with low rates of premorbid illness, there is a high burden of symptoms and failure to regain pre-COVID performance 6-months after acute illness. Cognitive assessment identified a specific deficit of the same magnitude as intoxication at the UK drink driving limit or the deterioration expected with 10 years ageing, which appears to contribute significantly to the symptomatology of long-COVID.

Source: Holdsworth DA, Chamley R, Barker-Davies R, O’Sullivan O, Ladlow P, Mitchell JL, Dewson D, Mills D, May SLJ, Cranley M, Xie C, Sellon E, Mulae J, Naylor J, Raman B, Talbot NP, Rider OJ, Bennett AN, Nicol ED. Comprehensive clinical assessment identifies specific neurocognitive deficits in working-age patients with long-COVID. PLoS One. 2022 Jun 10;17(6):e0267392. doi: 10.1371/journal.pone.0267392. PMID: 35687603; PMCID: PMC9187094. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9187094/ (Full text)

Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study

Abstract:

Background: Fatigue is the most prevalent and debilitating long COVID symptom, however risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long COVID fatigue and explored its possible pathophysiology.

Methods: Nested case-control study in a COVID recovery clinic. Individuals with (cases) and without (controls) significant fatigue were included. We performed a multidimensional assessment evaluating various parameters, including pulmonary function tests and cardiopulmonary exercise testing, and implemented multivariable logistic regression to assess risk factors for significant long COVID fatigue.

Results: Total of 141 individuals were included. Mean age was 47 (SD 13) years; 115 (82%) were recovering from mild COVID-19. Mean time for evaluation was 8 months following COVID-19. Sixty-six (47%) individuals were classified with significant long COVID fatigue. They had significantly higher number of children, lower proportion of hypothyroidism, higher proportion of sore throat during acute illness and long COVID symptoms, and of physical limitation in daily activities. Individuals with fatigue had poorer sleep quality and higher degree of depression. They had significantly lower heart rate [153.52 (22.64) vs 163.52 (18.53), p=0.038] and oxygen consumption per Kg [27.69 (7.52) vs 30.71 (7.52), p=0.036] at peak exercise. The two independent risk factors for fatigue identified in multivariable analysis were peak exercise heart rate (odds ratio [OR] 0.79 per 10 beats/minute, 95% confidence interval [CI] 0.65-0.96, p=0.019); and long COVID memory impairment (OR 3.76, 95% CI 1.57-9.01, p=0.003).

Conclusions: Long COVID fatigue may be related to autonomic dysfunction, impaired cognition and decreased mood. This may suggest a limbic-vagal pathophysiology. Clinical Trial registration: NCT04851561.

Source: Margalit I, Yelin D, Sagi M, Rahat MM, Sheena L, Mizrahi N, Gordin Y, Agmon H, Epstein NK, Atamna A, Tishler O, Daitch V, Babich T, Abecasis D, Yarom Y, Kazum S, Shitenberg D, Baltaxe E, Elkana O, Shapira-Lichter I, Leibovici L, Yahav D. Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study. Clin Infect Dis. 2022 Apr 11:ciac283. doi: 10.1093/cid/ciac283. Epub ahead of print. PMID: 35403679.  https://pubmed.ncbi.nlm.nih.gov/35403679/

Cognitive impairments in chronic fatigue syndrome patients: choice reaction time, encoding of new information, response organisation and selective attention

ABSTRACT:

Background: One of the features of Chronic Fatigue Syndrome (CFS) is the reporting of cognitive impairment. Prior research has confirmed this using cognitive performance test batteries. Psychomotor slowing and episodic memory impairments appear to be robust, but little is known about selective attention or the stages of processing leading to slower reaction times. The present study addressed these gaps in the literature.

Methods: CFS patients were recruited from a health service clinic. Sixty-seven patients agreed to carry out cognitive tasks measuring aspects of focused attention and categoric search and the components (encoding and response organisation) of choice reaction time. They were compared with 126 healthy controls. As well as carrying out the performance tasks, the participants also completed symptom checklists and questionnaires measuring fatigue, mental health and cognitive failures.

Results: The questionnaires revealed the typical profile of symptoms of CFS patients. With regards to the objective performance tasks, the CFS patients had significantly slower choice reaction times on both tasks. This is likely to be due to slower motor responses as neither of the measures of stimulus encoding or response organisation showed differences between the groups. There was also little evidence for the groups differing in aspects of selective attention.

Conclusions: CFS patients report greater fatigue, more somatic symptoms, greater mental health issues and more cognitive difficulties. Objective testing revealed slower choice reaction times which probably reflect motor slowing. These measures can now be used to assess the efficacy of the management of CFS.

Source: Smith AP. Cognitive impairments in chronic fatigue syndrome patients: choice reaction time, encoding of new information, response organisation and selective attention. World Journal of Pharmaceutical and Medical Research 8(4): 27-36 https://www.wjpmr.com/home/article_abstract/4110 (Full text available as PDF file)

Systematic review and meta-analysis of cognitive impairment in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is commonly associated with cognitive complaints. To bring out the neuropsychological symptomatology inherent to ME/CFS, we conducted a systematic review according to PRISMA and MOOSE guidelines of the literature through the analysis of 764 studies published between 1988 and 2019 by using PubMed Central website and Clarivate analytics platform. We performed a meta-analysis to delineate an idea of the neuropsychological profile inherent in ME/CFS.

The clinical picture typically affects visuo-spatial immediate memory (g = – 0.55, p = 0.007), reading speed (g = – 0.82, p = 0.0001) and graphics gesture (g = – 0.59, p = 0.0001). Analysis also revealed difficulties in several processes inherent in episodic verbal memory (storage, retrieval, recognition) and visual memory (recovery) and a low efficiency in attentional abilities. Executive functions seemed to be little or not affected and instrumental functions appeared constantly preserved.

With regard to the complexity and heterogeneity of the cognitive phenotype, it turns out that determining a sound clinical picture of ME/CFS cognitive profile must go through a neuropsychological examination allowing a complete evaluation integrating the notion of agreement between the choice and the number of tests and the complexity intrinsic to the pathology.

Source: Aoun Sebaiti M, Hainselin M, Gounden Y, Sirbu CA, Sekulic S, Lorusso L, Nacul L, Authier FJ. Systematic review and meta-analysis of cognitive impairment in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Sci Rep. 2022 Feb 9;12(1):2157. doi: 10.1038/s41598-021-04764-w. PMID: 35140252. https://pubmed.ncbi.nlm.nih.gov/35140252/

Premorbid vulnerability and disease severity impact on Long-COVID cognitive impairment

Abstract:

Background: Cognitive deficits have been increasingly reported as possible long-term manifestations after SARS-CoV-2 infection.

Aims: In this study we aimed at evaluating the factors associated with cognitive deficits 6 months after hospitalization for Coronavirus Disease 2019 (COVID-19).

Methods: One hundred and six patients, discharged from a pneumology COVID-19 unit between March 1 and May 30 2020, accepted to be evaluated at 6 months according to an extensive neurological protocol, including the Montreal Cognitive Assessment (MoCA).

Results: Abnormal MoCA scores at 6 months follow-up were associated with higher pre-hospitalization National Health System (NHS) score (Duca et al. in Emerg Med Pract 22:1-2, 2020) (OR 1.27; 95% CI 1.05-1.6; p = 0.029) and more severe pulmonary disease expressed by the Brescia-COVID Respiratory Severity Scale (Duca et al. in Emerg Med Pract 22:1-2, 2020) (BCRSS > 1OR 4.73; 95% CI 1.53-14.63; p = 0.003) during the acute phase of the disease.

Discussion: This longitudinal study showed that the severity of COVID-19, indicated by BCRSS, and a complex score given by age and premorbid medical conditions, expressed by NHS, play a major role in modulating the long-term cognitive consequences of COVID-19 disease.

Conclusions: These findings indicate that the association of age and premorbid factors might identify people at risk for long-term neurological consequences of COVID-19 disease, thus deserving longer and proper follow-up.

Source: Cristillo V, Pilotto A, Cotti Piccinelli S, Bonzi G, Canale A, Gipponi S, Bezzi M, Leonardi M, Padovani A; Neuro Covid Next Study group. Premorbid vulnerability and disease severity impact on Long-COVID cognitive impairment. Aging Clin Exp Res. 2022 Jan 11:1–4. doi: 10.1007/s40520-021-02042-3. Epub ahead of print. PMID: 35014002; PMCID: PMC8747881. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8747881/ (Full text)

Fatigue and Cognitive Impairment in Post-COVID-19 Syndrome: A Systematic Review and Meta-Analysis

Abstract:

Importance: COVID-19 is associated with clinically significant symptoms despite resolution of the acute infection (i.e., post-COVID-19 syndrome). Fatigue and cognitive impairment are amongst the most common and debilitating symptoms of post-COVID-19 syndrome.

Objective: To quantify the proportion of individuals experiencing fatigue and cognitive impairment 12 or more weeks following COVID-19 diagnosis, and to characterize the inflammatory correlates and functional consequences of post-COVID-19 syndrome.

Data sources: Systematic searches were conducted without language restrictions from database inception to June 8, 2021 on PubMed/MEDLINE, The Cochrane Library, PsycInfo, Embase, Web of Science, Google/Google Scholar, and select reference lists.

Study selection: Primary research articles which evaluated individuals at least 12 weeks after confirmed COVID-19 diagnosis and specifically reported on fatigue, cognitive impairment, inflammatory parameters, and/or functional outcomes were selected.

Data extraction & synthesis: Two reviewers independently extracted published summary data and assessed methodological quality and risk of bias. A meta-analysis of proportions was conducted to pool Freeman-Turkey double arcsine transformed proportions using the random-effects restricted maximum-likelihood model.

Main outcomes & measures: The co-primary outcomes were the proportions of individuals reporting fatigue and cognitive impairment, respectively, 12 or more weeks after COVID-19 infection. The secondary outcomes were inflammatory correlates and functional consequences of post-COVID-19 syndrome.

Results: The literature search yielded 10,979 studies, and 81 studies were selected for inclusion. The fatigue meta-analysis comprised 68 studies, the cognitive impairment meta-analysis comprised 43 studies, and 48 studies were included in the narrative synthesis. Meta-analysis revealed that the proportion of individuals experiencing fatigue 12 or more weeks following COVID-19 diagnosis was 0.32 (95% CI, 0.27, 0.37; p < 0.001; n = 25,268; I2=99.1%). The proportion of individuals exhibiting cognitive impairment was 0.22 (95% CI, 0.17, 0.28; p < 0.001; n = 13,232; I2=98.0). Moreover, narrative synthesis revealed elevations in proinflammatory markers and considerable functional impairment in a subset of individuals.

Conclusions & relevance: A significant proportion of individuals experience persistent fatigue and/or cognitive impairment following resolution of acute COVID-19. The frequency and debilitating nature of the foregoing symptoms provides the impetus to characterize the underlying neurobiological substrates and how to best treat these phenomena.

Study Registration PROSPERO (CRD42021256965).

Source: Ceban F, Ling S, Lui LMW, Lee Y, Gill H, Teopiz KM, Rodrigues NB, Subramaniapillai M, Di Vincenzo JD, Cao B, Lin K, Mansur RB, Ho RC, Rosenblat JD, Miskowiak KW, Vinberg M, Maletic V, McIntyre RS. Fatigue and Cognitive Impairment in Post-COVID-19 Syndrome: A Systematic Review and Meta-Analysis. Brain Behav Immun. 2021 Dec 29;101:93–135. doi: 10.1016/j.bbi.2021.12.020. Epub ahead of print. PMID: 34973396; PMCID: PMC8715665. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8715665/ (Full text)