Cerebral microstructural alterations in Post-COVID-condition are related to cognitive impairment, olfactory dysfunction, and fatigue

After contracting COVID-19, a substantial number of individuals develop a Post-COVID-Condition (PCC), marked by neurologic symptoms such as cognitive deficits, olfactory dysfunction, and fatigue, which can have detrimental socioeconomic consequences. Despite this, biomarkers and pathophysiological understandings of this condition remain limited. Employing magnetic resonance imaging, we conduct a comparative analysis of cerebral microstructure among patients with post-COVID condition, healthy controls, and individuals who contracted COVID-19 without long-term symptoms. This reveals widespread alterations in cerebral microstructure, attributed to a shift in volume from neuronal compartments to free fluid, associated with the severity of the initial infection. Correlating these alterations with cognition, olfaction, and fatigue unveils distinct affected networks, which are in a close anatomical-functional relationship with the respective symptoms. This plausibility of symptom-specific netw..., In this prospective monocentric study, we analyzed clinical and (micro-)structural MRI data from a cohort of 89 patients who fulfilled the WHO diagnosis criteria for PCC (49, IQR [23] years; 55 females; 85% mild course of COVID-19 infection) and underwent MRI approximately nine months (254, IQR [209] days) after a positive PCR test result for SARS-CoV-2. Due to PCC symptoms (i.e. impaired attention, multitasking, and memory, word-finding difficulties, disturbed olfaction/gustation, and fatigue), 53% of patients could not return to their previous level of independence or employment. Cognitive performance, as measured by the MoCA test, was impaired in 41% of patients (26, IQR [4] points, cut-off value: < 26/30). Olfactory performance was impaired in 74% of patients (9, IQR [4] items identified, < 11/12 is the cut-off value). The WEIMuS questionnaire indicated the presence of fatigue in 78% of patients (43, IQR [17] points, > 33/68 is the cut-off value). PCC patients were compared..., , # Cerebral microstructural alterations in Post-COVID-condition are related to cognitive impairment, olfactory dysfunction, and fatigue

## Description of the data and file structure

**1. Excel-Sheet (Demographic and Clinical Data)**

Demographic and clinical data of our cohorts. These data form the basis for Tables 1 and 2, as well as the \"Demographic and clinical characteristics\" section of the Results.

Tabular enumeration of the demographic and clinical data of PCC patients, UPC, and HNC controls. For Table 1 published in Hrynaszkiewicz et al., 2010 (PMID: 20113465), the only identifiable characteristics in our datasheet are sex and place of treatment (as we publish a monocentric cohort). We divided the patient's age into 5-year categories to complicate patient identification in this regard.

Not every group received the same assessments; for example, healthy controls showed no complaints. Therefore, in the absence of data, an empty cell was left.

* Questionnaires: Fatigue (WEIMu...