Tag: memory

Brain temperature and free water increases after mild COVID-19 infection

Abstract:

The pathophysiology underlying the post-acute sequelae of COVID-19 remains understudied and poorly understood, particularly in healthy adults with a history of mild infection. Chronic neuroinflammation may underlie these enduring symptoms, but studying neuroinflammatory phenomena in vivo is challenging, especially without a comparable pre-COVID-19 dataset.

In this study, we present a unique dataset of 10 otherwise healthy individuals scanned before and after experiencing mild COVID-19. Two emerging MR-based methods were used to map pre- to post-COVID-19 brain temperature and free water changes. Post-COVID-19 brain temperature and free water increases, which are indirect biomarkers of neuroinflammation, were found in structures functionally associated with olfactory, cognitive, and memory processing.

The largest pre- to post-COVID brain temperature increase was observed in the left olfactory tubercle (p = 0.007, 95% CI [0.48, 3.01]), with a mean increase of 1.75 °C. Notably, the olfactory tubercle is also the region of the primary olfactory cortex where participants with chronic olfactory dysfunction showed the most pronounced increases as compared to those without lingering olfactory dysfunction (adjusted pFDR = 0.0189, 95% CI [1.42, 5.27]). These preliminary insights suggest a potential link between neuroinflammation and chronic cognitive and olfactory dysfunction following mild COVID-19, although further investigations are needed to improve our understanding of what underlies these phenomena.

Source: Sharma AA, Nenert R, Goodman AM, Szaflarski JP. Brain temperature and free water increases after mild COVID-19 infection. Sci Rep. 2024 Mar 28;14(1):7450. doi: 10.1038/s41598-024-57561-6. PMID: 38548815; PMCID: PMC10978935. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10978935/ (Full text)

Cognition and Memory after Covid-19 in a Large Community Sample

Abstract:

Background: Cognitive symptoms after coronavirus disease 2019 (Covid-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are well-recognized. Whether objectively measurable cognitive deficits exist and how long they persist are unclear.

Methods: We invited 800,000 adults in a study in England to complete an online assessment of cognitive function. We estimated a global cognitive score across eight tasks. We hypothesized that participants with persistent symptoms (lasting ≥12 weeks) after infection onset would have objectively measurable global cognitive deficits and that impairments in executive functioning and memory would be observed in such participants, especially in those who reported recent poor memory or difficulty thinking or concentrating (“brain fog”).

Results: Of the 141,583 participants who started the online cognitive assessment, 112,964 completed it. In a multiple regression analysis, participants who had recovered from Covid-19 in whom symptoms had resolved in less than 4 weeks or at least 12 weeks had similar small deficits in global cognition as compared with those in the no-Covid-19 group, who had not been infected with SARS-CoV-2 or had unconfirmed infection (-0.23 SD [95% confidence interval {CI}, -0.33 to -0.13] and -0.24 SD [95% CI, -0.36 to -0.12], respectively); larger deficits as compared with the no-Covid-19 group were seen in participants with unresolved persistent symptoms (-0.42 SD; 95% CI, -0.53 to -0.31). Larger deficits were seen in participants who had SARS-CoV-2 infection during periods in which the original virus or the B.1.1.7 variant was predominant than in those infected with later variants (e.g., -0.17 SD for the B.1.1.7 variant vs. the B.1.1.529 variant; 95% CI, -0.20 to -0.13) and in participants who had been hospitalized than in those who had not been hospitalized (e.g., intensive care unit admission, -0.35 SD; 95% CI, -0.49 to -0.20). Results of the analyses were similar to those of propensity-score-matching analyses. In a comparison of the group that had unresolved persistent symptoms with the no-Covid-19 group, memory, reasoning, and executive function tasks were associated with the largest deficits (-0.33 to -0.20 SD); these tasks correlated weakly with recent symptoms, including poor memory and brain fog. No adverse events were reported.

Conclusions: Participants with resolved persistent symptoms after Covid-19 had objectively measured cognitive function similar to that in participants with shorter-duration symptoms, although short-duration Covid-19 was still associated with small cognitive deficits after recovery. Longer-term persistence of cognitive deficits and any clinical implications remain uncertain. (Funded by the National Institute for Health and Care Research and others.).

Source: Hampshire A, Azor A, Atchison C, Trender W, Hellyer PJ, Giunchiglia V, Husain M, Cooke GS, Cooper E, Lound A, Donnelly CA, Chadeau-Hyam M, Ward H, Elliott P. Cognition and Memory after Covid-19 in a Large Community Sample. N Engl J Med. 2024 Feb 29;390(9):806-818. doi: 10.1056/NEJMoa2311330. PMID: 38416429. https://www.nejm.org/doi/10.1056/NEJMoa2311330 (Full text)

Effect of transcutaneous electrical acupoint stimulation on learning and memory ability of chronic fatigue syndrome rats and its mechanisms

Abstract:

in English, Chinese

Objective: To observe the effect of transcutaneous electrical acupoint stimulation (TEAS) on the histomorphological manifestations of hippocampal CA1 region and the expression of extracellular regulatory protein kinase (ERK), cyclic adenosine response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in chronic fatigue syndrome (CFS) rats, so as to explore the mechanisms of TEAS in improving the learning and memory abilities of CFS rats.

Methods: Forty male Wistar rats were randomly divided into normal group (10 rats) and modeling group (30 rats); then after modeling, they were selected and randomly divided into model group (10 rats) and TEAS group (10 rats). CFS rats model was prepared by sleep deprivation combined with weight-bearing swimming. Rats in the TEAS group were stimulated with Han’s acupoint nerve stimulator at bilateral “Zusanli” (ST36) and “Shenshu” (BL23) (2 Hz/15 Hz, 1-2 mA), 20 min each time, once a day for 4 weeks with 1 d rest every 6 d. The score of general conditions of rats was evaluated. The learning and memory ability was tested with Morris water maze. The morphology and ultrastructure of hippocampal CA1 region were observed by HE staining and transmission electron microscopy. The expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were detected by real time quantitative PCR and Western blot, respectively.

Results: Compared with the normal group, the score of general condition was increased (P<0.01); the escape latency was prolonged (P<0.05, P<0.01) and the times of crossing the original platform was decreased (P<0.05); the expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were decreased (P<0.05, P<0.01) in the model group. Compared with the model group, the scores of general condition on the 42nd and 49th day were decreased (P<0.05, P<0.01); the escape latency was shortened (P<0.01, P<0.05)and the times of crossing the original platform were increased (P<0.05); the expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were increased (P<0.01, P<0.05) in the TEAS group. The morphology of neurons in hippocampal CA1 region was normal in the normal group. In the model group, the number of neurons in hippocampal CA1 region decreased, the arrangement of nerve cells was scattered, the number of apoptotic cells increased, some nuclear structures disappeared, nuclear heterochromatin increased, the cell membrane wrinkled, the chromatin appeared empty bright area, and the crista was incomplete. Compared with the model group, the nerve cells morphology in hippocampal CA1 region was more regular, the number of apoptotic cells decreased, the chromatin and the cytoplasm were uniformly distributed, and the crista was relatively intact in the TEAS group.

Conclusion: TEAS can improve the learning and memory ability of CFS rats, the mechanisms may be related to improving the neural structure of hippocampal CA1 region and up-regulating the expression levels of ERK/CREB/BDNF.

Source: Zhong XL, Tong BY, Yang YH, Zeng HL, Lin C, Jing Y, He LL, You SJ. [Effect of transcutaneous electrical acupoint stimulation on learning and memory ability of chronic fatigue syndrome rats and its mechanisms]. Zhen Ci Yan Jiu. 2023 Apr 25;48(4):317-24. Chinese. doi: 10.13702/j.1000-0607.20221032. PMID: 37186194. https://pubmed.ncbi.nlm.nih.gov/37186194/

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

Abstract:

The present study aims to provide a critical overview of the literature on the relationships between post-acute COVID-19 infection and cognitive impairment, highlighting the limitations and confounding factors. A systematic search of articles published from 1 January 2020 to 1 July 2022 was performed in PubMed/Medline. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only studies using validated instruments for the assessment of cognitive impairment were included. Out of 5515 screened records, 72 studies met the inclusion criteria.

The available evidence revealed the presence of impairment in executive functions, speed of processing, attention and memory in subjects recovered from COVID-19. However, several limitations of the literature reviewed should be highlighted: most studies were performed on small samples, not stratified by severity of disease and age, used as a cross-sectional or a short-term longitudinal design and provided a limited assessment of the different cognitive domains. Few studies investigated the neurobiological correlates of cognitive deficits in individuals recovered from COVID-19. Further studies with an adequate methodological design are needed for an in-depth characterization of cognitive impairment in individuals recovered from COVID-19.

Source: Perrottelli A, Sansone N, Giordano GM, Caporusso E, Giuliani L, Melillo A, Pezzella P, Bucci P, Mucci A, Galderisi S. Cognitive Impairment after Post-Acute COVID-19 Infection: A Systematic Review of the Literature. J Pers Med. 2022 Dec 15;12(12):2070. doi: 10.3390/jpm12122070. PMID: 36556290; PMCID: PMC9781311. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9781311/ (Full text)

COVID-19 induces CNS cytokine expression and loss of hippocampal neurogenesis

Abstract:

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with acute and postacute cognitive and neuropsychiatric symptoms including impaired memory, concentration, attention, sleep and affect. Mechanisms underlying these brain symptoms remain understudied.

Here we report that SARS-CoV-2-infected hamsters exhibit a lack of viral neuroinvasion despite aberrant blood-brain barrier permeability. Hamsters and patients deceased from coronavirus disease 2019 (COVID-19) also exhibit microglial activation and expression of interleukin (IL)-1β and IL-6, especially within the hippocampus and the medulla oblongata, when compared with non-COVID control hamsters and humans who died from other infections, cardiovascular disease, uraemia or trauma. In the hippocampal dentate gyrus of both COVID-19 hamsters and humans, we observed fewer neuroblasts and immature neurons.

Protracted inflammation, blood-brain barrier disruption and microglia activation may result in altered neurotransmission, neurogenesis and neuronal damage, explaining neuropsychiatric presentations of COVID-19. The involvement of the hippocampus may explain learning, memory and executive dysfunctions in COVID-19 patients.

Source: Soung AL, Vanderheiden A, Nordvig AS, Sissoko CA, Canoll P, Mariani MB, Jiang X, Bricker T, Rosoklija GB, Arango V, Underwood M, Mann JJ, Dwork AJ, Goldman JE, Boon ACM, Boldrini M, Klein RS. COVID-19 induces CNS cytokine expression and loss of hippocampal neurogenesis. Brain. 2022 Aug 25:awac270. doi: 10.1093/brain/awac270. Epub ahead of print. PMID: 36004663. https://academic.oup.com/brain/advance-article/doi/10.1093/brain/awac270/6672950?login=false  (Full text)

Task Related Cerebral Blood Flow Changes of Patients with Chronic Fatigue Syndrome: An Arterial Spin Labeling Study.

Abstract:

PURPOSE: One hallmark of chronic fatigue syndrome (ME/CFS) is task related worsening of fatigue. Global brain hypoperfusion, abnormal regional activation, and altered functional connectivity of brain areas associated with cognition and memory have been reported but remain controversial.

METHODS: We enrolled 17 female participants fulfilling the CDC Criteria for ME/CFS and 16 matched healthy controls (HC). Using a 3T-Phillips Achieva MRI-scanner, pseudo-continuous arterial spin-labeling (pCASL), was used to study the dynamics of regional cerebral blood flow (rCBF) and their relationship to mental fatigue in ME/CFS patients and HC during a demanding cognitive task, i.e. modified Paced-Auditory-Serial-Addition-Testing (PASAT).

RESULTS: ME/CFS subjects reported more fatigue than HC at baseline (p < .01). Global brain perfusion of ME/CFS and HC subjects was similar at rest. The PASAT resulted in significantly increased fatigue in ME/CFS participants and HC. Although not different between groups, overall CBF significantly increased over the first 3 min of the PASAT and then decreased thereafter. Regional CBF (rCBF) changes were significantly different between groups during the post-task recovery period. Whereas improvement of fatigue of ME/CFS subjects was associated with decreased rCBF in both superior temporal gyri (STG), precuneus, and fusiform gyrus, it was associated with increased rCBF in the same areas in HC.

CONCLUSIONS: Our results suggest that ME/CFS is associated with normal global CBF at rest and during a strenuous task (PASAT); however rCBF of several brain regions associated with memory, goal-oriented attention, and visual function was differentially associated with recovery from fatigue in ME/CFS patients and HC.

Source: Staud R, Boissoneault J, Craggs JG, Lai S, Robinson ME. Task Related Cerebral Blood Flow Changes of Patients with Chronic Fatigue Syndrome: An Arterial Spin Labeling Study. Fatigue. 2018;6(2):63-79. doi: 10.1080/21641846.2018.1453919. Epub 2018 Mar 20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5914525/  (Full study)

Psychosocial factors involved in memory and cognitive failures in people with myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by persistent emotional, mental, and physical fatigue accompanied by a range of neurological, autonomic, neuroendocrine, immune, and sleep problems. Research has shown that psychosocial factors such as anxiety and depression as well as the symptoms of the illness, have a significant impact on the quality of life of people with ME/CFS. In addition, individuals may suffer from deficits in memory and concentration. This study set out to explore the relationships between variables which have been found to contribute to cognitive performance, as measured by prospective and retrospective memory, and cognitive failures.

METHODS: Eighty-seven people with ME/CFS answered questionnaires measuring fatigue, depression, anxiety, social support, and general self-efficacy. These were used in a correlational design (multiple regression) to predict cognitive function (self-ratings on prospective and retrospective memory), and cognitive failures.

RESULTS: Our study found that fatigue, depression, and general self-efficacy were directly associated with cognitive failures and retrospective (but not prospective) memory.

CONCLUSION: Although it was not possible in this study to determine the cause of the deficits, the literature in this area leads us to suggest that although the pathophysiological mechanisms of ME/CFS are unclear, abnormalities in the immune system, including proinflammatory cytokines, can lead to significant impairments in cognition. We suggest that fatigue and depression may be a result of the neurobiological effects of ME/CFS and in addition, that the neurobiological effects of the illness may give rise to both fatigue and cognitive deficits independently.

 

Source: Attree EA, Arroll MA, Dancey CP, Griffith C, Bansal AS. Psychosocial factors involved in memory and cognitive failures in people with myalgic encephalomyelitis/chronic fatigue syndrome. Psychol Res Behav Manag. 2014 Feb 25;7:67-76. doi: 10.2147/PRBM.S50645. ECollection 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3940708/ (Full article)

 

Cognitive functioning in people with chronic fatigue syndrome: a comparison between subjective and objective measures

Abstract:

OBJECTIVE: The purpose of this study was to examine the relationship between subjective and objective assessments of memory and attention in people with chronic fatigue syndrome (CFS), using tests that have previously detected deficits in CFS samples and measures of potential confounds.

METHOD: Fifty people with CFS and 50 healthy controls were compared on subjective (memory and attention symptom severity, Cognitive Failures Questionnaire, Everyday Attention Questionnaires) and objective (California Verbal Learning Test, Rey-Osterreith Complex Figure Test, Paced Auditory Serial Addition Test, Stroop task) measures of memory and attention. Fatigue, sleep, depression, and anxiety were also assessed.

RESULTS: The CFS group reported experiencing more cognitive problems than the controls, but the two groups did not differ on the cognitive tests. Scores on the subjective and objective measures were not correlated in either group. Depression was positively correlated with increased severity of cognitive problems in both the CFS and control groups.

CONCLUSIONS: There is little evidence for a relationship between subjective and objective measures of cognitive functioning for both people with CFS and healthy controls, which suggests that they may be capturing different constructs. Problems with memory and attention in everyday life are a significant part of CFS. Depression appears to be related to subjective problems but does not fully explain them.

 

Source: Cockshell SJ, Mathias JL. Cognitive functioning in people with chronic fatigue syndrome: a comparison between subjective and objective measures. Neuropsychology. 2014 May;28(3):394-405. doi: 10.1037/neu0000025. Epub 2013 Dec 23. https://www.ncbi.nlm.nih.gov/pubmed/24364389

 

Regional grey and white matter volumetric changes in myalgic encephalomyelitis (chronic fatigue syndrome): a voxel-based morphometry 3 T MRI study

Abstract:

OBJECTIVE: It is not established whether myalgic encephalomyelitis/chronic fatigue syndrome (CFS) is associated with structural brain changes. The aim of this study was to investigate this by conducting the largest voxel-based morphometry study to date in CFS.

METHODS: High-resolution structural 3 T cerebral MRI scanning was carried out in 26 patients with CFS and 26 age- and gender-matched healthy volunteers. Voxel-wise generalised linear modelling was applied to the processed MR data using permutation-based non-parametric testing, forming clusters at t>2.3 and testing clusters for significance at p<0.05, corrected for multiple comparisons across space.

RESULTS: Significant voxels (p<0.05, corrected for multiple comparisons) depicting reduced grey matter volume in the CFS group were noted in the occipital lobes (right and left occipital poles; left lateral occipital cortex, superior division; and left supracalcrine cortex), the right angular gyrus and the posterior division of the left parahippocampal gyrus. Significant voxels (p<0.05, corrected for multiple comparisons) depicting reduced white matter volume in the CFS group were also noted in the left occipital lobe.

CONCLUSION: These data support the hypothesis that significant neuroanatomical changes occur in CFS, and are consistent with the complaint of impaired memory that is common in this illness; they also suggest that subtle abnormalities in visual processing, and discrepancies between intended actions and consequent movements, may occur in CFS.

 

Source: Puri BK, Jakeman PM, Agour M, Gunatilake KD, Fernando KA, Gurusinghe AI, Treasaden IH, Waldman AD, Gishen P. Regional grey and white matter volumetric changes in myalgic encephalomyelitis (chronic fatigue syndrome): a voxel-based morphometry 3 T MRI study. Br J Radiol. 2012 Jul;85(1015):e270-3. doi: 10.1259/bjr/93889091. Epub 2011 Nov 29. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3474083/ (Full article)

 

Cognitive deficits in patients with chronic fatigue syndrome compared to those with major depressive disorder and healthy controls

Abstract:

OBJECT: Chronic fatigue syndrome (CFS) patients report usually cognitive complaints. They also have frequently comorbid depression that can be considered a possible explanation for their cognitive dysfunction. We evaluated the cognitive performance of patients with CFS in comparison with a control group of healthy volunteers and a group of patients with MDD.

PATIENTS AND METHODS: Twenty-five patients with CFS, 25 patients with major depressive disorder (MDD), and 25 healthy control subjects were given standardized tests of attention, working memory, and verbal and visual episodic memory, and were also tested for effects related to lack of effort/simulation, suggestibility, and fatigue.

RESULTS: Patients with CFS had slower phasic alertness, and also had impaired working, visual and verbal episodic memory compared to controls. They were, however, no more sensitive than the other groups to suggestibility or to fatigue induced during the cognitive session. Cognitive impairments in MDD patients were strongly associated with depression and subjective fatigue; in patients with CFS, there was a weaker correlation between cognition and depression (and no correlation with fatigue).

CONCLUSIONS: This study confirms the presence of an objective impairment in attention and memory in patients with CFS but with good mobilization of effort and without exaggerated suggestibility.

Copyright © 2011 Elsevier B.V. All rights reserved.

 

Source: Constant EL, Adam S, Gillain B, Lambert M, Masquelier E, Seron X. Cognitive deficits in patients with chronic fatigue syndrome compared to those with major depressive disorder and healthy controls. Clin Neurol Neurosurg. 2011 May;113(4):295-302. doi: 10.1016/j.clineuro.2010.12.002. Epub 2011 Jan 20. https://www.ncbi.nlm.nih.gov/pubmed/21255911