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
networks not only provides insights into the disease's
pathophysiological foundations, which align well with an accelerated aging
process but also underscores the significance of microstructure as an
imaging biomarker.