Long COVID: Plasma levels of neurofilament light chain in mild COVID-19 patients with neurocognitive symptoms (preprint)

It is well known the potential of severe acute respiratory coronavirus type 2 (SARS-CoV-2) infection to induce post-acute sequelae, a condition called Long COVID. This syndrome includes several symptoms, but the central nervous system (CNS) main one is neurocognitive dysfunction. Recently it has been demonstrated the relevance of plasma levels of neurofilament light chain (pNfL), as a biomarker of early involvement of the CNS in COVID-19. The aim of this study was to investigate the relationship between pNfL in patients with post-acute neurocognitive symptoms and the potential of NfL as a prognostic biomarker in these cases. A group of 63 long COVID patients ranging from 18 to 59 years-old were evaluated, submitted to a neurocognitive battery assessment, and subdivided in different groups, according to results. Plasma samples were collected during the long COVID assessment and used for measurement of pNfL with the Single molecule array (SIMOA) assays. Levels of pNfL were significantly higher in long COVID patients with neurocognitive symptoms when compared to HC (p = 0.0031). Long COVID patients with cognitive impairment and fatigue symptoms presented higher pNfL levels when compared to long COVID patients without these symptoms, individually and combined (p = 0.0263, p = 0.0480, and 0.0142, respectively). Correlation analysis showed that levels of cognitive lost and exacerbation of fatigue in the neurocognitive evaluation had a significative correlation with higher pNfL levels (p = 0.0219 and 0.0255, respectively). Previous reports suggested that pNfL levels are related with higher risk of severity and predict lethality of COVID-19. Our findings demonstrate that SARS-CoV-2 infection seems to have a long-term impact on the brain, even in patients who presented mild acute disease. NfL measurements might be useful to identify CNS involvement in long COVID associated with neurocognitive symptoms and to identify who will need continuous monitoring and treatment support.

Cognitive Complaints Assessment and Neuropsychiatric Disorders After Mild COVID-19 Infection.

OBJECTIVES: This study aimed to analyze cognitive impairment associated with long-term coronavirus disease 2019 (COVID-19) syndrome and its correlation with anxiety, depression, and fatigue in patients infected with severe acute respiratory syndrome coronavirus. METHODS: This was a cross-sectional study of 127 patients with COVID-19. Tests to screen for neuropsychiatric symptoms included the Fatigue Severity Scale, Mini-Mental State Exam 2 (MMSE-2), Symbol Digit Modalities Test (SDMT), and Hospital Anxiety and Depression Scale. RESULTS: In cognitive tests, SDMT was abnormal in 22%, being more sensitive than MMSE-2 to detect cognitive changes. Furthermore, although manifestations such as fatigue, depression, and anxiety were frequent in the post-COVID-19 phase, these 3 conditions, known to contribute to cognitive impairment, were slightly correlated with worse performance on the rapid screening tests. CONCLUSIONS: In patients with mild COVID-19 and cognitive complaints, SDMT helped to confirm disturbances in the attention domain and processing speed.

Post-COVID-19 olfactory dysfunction: carbamazepine as a treatment option in a series of cases.

Olfactory dysfunction is reported frequently in patients with coronavirus disease 2019. However, an effective treatment for this dysfunction is unknown. The present study evaluated carbamazepine as a treatment option for olfactory dysfunction based on its use in cases of neuralgia, especially of the V cranial nerve. The study included 10 patients with coronavirus disease with olfactory complaints who were part of a cohort of 172 coronavirus disease patients monitored for late neurological manifestations. Carbamazepine was administered for 11 weeks. The adverse effects reported were drowsiness (9/10) and dizziness (2/10); 9 of the 10 patients reported improved olfactory function after carbamazepine treatment. While the role of carbamazepine in the control of post-coronavirus disease olfactory dysfunction could not be confirmed in this study, the satisfactory response observed in most patients in this series suggests that further studies are warranted.