Cognitive and functional connectivity impairment in post-COVID-19 olfactory dysfunction

Muccioli, Lorenzo; Sighinolfi, Giovanni; Mitolo, Micaela; Ferri, Lorenzo; Rochat, Magali Jane; Pensato, Umberto; Taruffi, Lisa; Testa, Claudia; Masullo, Massimiliano; Cortelli, Pietro; Lodi, Raffaele; Liguori, Rocco; Tonon, Caterina; Bisulli, Francesca

doi:10.1016/j.nicl.2023.103410

Cited by 26 publications

(20 citation statements)

References 58 publications

(86 reference statements)

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“…The cognitive results indicate that 71% of participants had changes in cognitive screening, a finding that is consistent with other reports in which the same screening tool was used [9], [10] a tool that was used as the main mechanism of evaluation in initial studies on Long COVID and cognition. The most impaired cognitive function was visual memory, with a total of 69% of participants showing at least mild changes, followed by language with 54%, visuospatial abilities with 49% [11], [12], verbal episodic memory with 37% [13], executive functions with 34%, consistent with other findings [10], [12], [14]- [18], and 34% showing dysfunction in attention. In terms of premorbid intelligence, only 12% of participants had changes, meaning that 88% of participants had preserved cognitive abilities before Long COVID symptoms.…”

Section: Discussionsupporting

confidence: 86%

Cognitive Profile of SARS-cov-2 Recovered Patients: A Comprehensive Analysis of Persistent Dysfunctions in Long COVID

Lima¹,

Cavendish²,

Pinto³

et al. 2023

Preprint

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Long Covid is a term used for patients who have recovered from COVID-19 but exhibit persistent cognitive dysfunction, including mental confusion, difficulties in attention, impairment in executive functions and slow movements, among other common symptoms. A study was conducted with 65 patients who had a positive RT-PCR diagnosis and reported symptoms of cognitive impairment, such as memory loss and attention difficulties after recovery. The patients underwent neuropsychological evaluation and completed questionnaires on cognition, mood, and quality of life. During the cognitive screening, 71% of the patients showed alterations, with deficits in visual memory (69%), language (54%), visuospatial construction (49%), verbal episodic memory (37%), executive functions (36%), attentional abilities (34%), and premorbid intelligence (12%). It is important to highlight the need for treatments and further studies to understand the long-term side effects of this disease.

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Section: Discussionsupporting

confidence: 86%

Cognitive Profile of SARS-cov-2 Recovered Patients: A Comprehensive Analysis of Persistent Dysfunctions in Long COVID

Lima¹,

Cavendish²,

Pinto³

et al. 2023

Preprint

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“…Most studies investigating functional brain activity in patients recovered from COVID-19 have been conducted using resting-state methods. Alterations in signal properties and functional connectivity have been found in COVID-19 patients, 55,56 and have been associated with hospitalization, 57 and persistent symptoms such as headaches, 58 persistent olfactory dysfunction 48,59,60 and other behavioral markers such as working memory performance, 61,62 anxiety, 63 psychotic-like experiences in adolescents, 64 and post-traumatic stress symptoms. 65 Also, some studies found no functional alteration in recovered COVID-19 patients.…”

Section: Discussionmentioning

confidence: 99%

“…1,2 However, research has failed to find a specific marker of neuroinflammation, 67 or structural alterations were not found in other samples. 48,62 As with functional alterations, the severity of the acute episode and the presence of persistent symptoms are more closely related to structural alterations, primarily in white matter integrity. 66,68…”

Section: Discussionmentioning

confidence: 99%

Patients Recovering from COVID-19 who Presented Anosmia During their Acute Episode have Behavioral, Functional, and Structural Brain Alterations

Kausel,

Figueroa-Vargas,

Zamorano

et al. 2024

Preprint

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Patients recovering from COVID-19 commonly exhibit cognitive and brain alterations, yet the specific neuropathological mechanisms and risk factors that underlie these alterations remain elusive. Given the significant global incidence of COVID-19, identifying factors that can distinguish individuals at risk of developing medium or long-term brain alterations is crucial for prioritizing follow-up care. Here, we report findings from a sample of 100 patients who were affected by a respiratory infection during the COVID-19 pandemic. This sample comprised 73 adults with a mild to moderate SARS-CoV-2 infection (who did not require invasive ventilatory assistance) and 27 with infections attributed to other agents and no history of COVID-19. The participants underwent cognitive screening, a decision-making task to measure cognitive flexibility, and magnetic resonance imaging evaluations. We assessed two clinical factors during infection: the presence of anosmia and the requirement for hospitalization due to respiratory symptoms. Groups did not differ in age or cognitive performance, but clinical factors differentially affected task performance. Patients who presented anosmia during the acute episode exhibited more impulsive changes in alternatives after a shift in probabilities in the decision-making task, while patients who required hospitalization showed more perseverative choices. Interestingly, the presence of anosmia during SARS-CoV-2 infection correlated with several brain measures, including decreases in functional activity during the decision-making task, thinning of cortical thickness in parietal regions, and loss in white matter integrity in corticospinal tracts and parietal-thalamic fasciculi, among others. These results suggest that anosmia could be a risk factor for developing brain alterations after SARS-CoV-2 infection and may serve to identify at-risk populations for follow-up.

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“…This in ammatory milieu can lead to changes in mucus volume and composition, rendering it challenging for odorants to effectively bind to olfactory receptors, thereby impairing the sense of smell [47]. Additionally, olfactory defects in post-acute sequelae of COVID-19 have been associated with morphological changes observed in the olfactory bulbs and cortex, indicating potential neurodegenerative processes taking place [38,39]. However, the causality and the temporal relationship between these changes and peripheral inputs due to epithelial damage warrant further investigation.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, the pathophysiology underpinning olfactory dysfunctions in PASC patients remains to be fully elucidated. In some cases, damage may manifest independently or simultaneously at different levels of the olfactory pathway, from the sensory epithelium in the olfactory fossa to the olfactory bulbs and cerebral cortex [37][38][39]. A possible explanation lies in the persistent nasal in ammatory microenvironment following the primary SARS-CoV-2 infection [31,33].…”

Section: Introductionmentioning

confidence: 99%

Circulating Calprotectin as a Potential Biomarker of Persistent Olfactory Dysfunctions in Post-COVID-19 Patients

Francavilla,

Velletrani,

Fiorelli

et al. 2023

Preprint

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Objective and Design: This longitudinal prospective study aims to investigate the potential of circulating calprotectin (cCLP) as a biomarker in persistent olfactory dysfunctions following COVID-19 infection. Materials and Methods Thirty-six patients with persistent hyposmia or anosmia post COVID-19 were enrolled (HT0) and re-evaluated after three months of olfactory training (HT1). Two control groups included 18 subjects without olfactory defects post COVID-19 (CG1) and 18 healthy individuals (CG2). Nasal and blood samples were collected to assess circulating calprotectin levels. Results Higher calprotectin levels were observed in serum and nasal supernatant of hyposmic patients (HT0) compared to control groups (CG1 and CG2). Post-olfactory training (HT1), olfactory function improved significantly, paralleled by decreased calprotectin levels in serum and nasal samples. Conclusions Circulating calprotectin holds potential as a biomarker in persistent olfactory dysfunctions after COVID-19. The decrease in calprotectin levels post-olfactory training implies a role in monitoring and evaluating treatment responses. These findings contribute to the growing literature on potential biomarkers in post-COVID-19 olfactory dysfunctions and underscore the importance of investigating novel biomarkers for personalized patient management. Nevertheless, further studies are needed to validate the application of calprotectin assay in nasal diseases and its correlation with nasal cytology.

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Cognitive and functional connectivity impairment in post-COVID-19 olfactory dysfunction

Cited by 26 publications

References 58 publications

Cognitive Profile of SARS-cov-2 Recovered Patients: A Comprehensive Analysis of Persistent Dysfunctions in Long COVID

Cognitive Profile of SARS-cov-2 Recovered Patients: A Comprehensive Analysis of Persistent Dysfunctions in Long COVID

Patients Recovering from COVID-19 who Presented Anosmia During their Acute Episode have Behavioral, Functional, and Structural Brain Alterations

Circulating Calprotectin as a Potential Biomarker of Persistent Olfactory Dysfunctions in Post-COVID-19 Patients

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