Reduced TMS-evoked EEG oscillatory activity in cortical motor regions in patients with post-COVID fatigue

Casula, Elias P.;Esposito, Romina;Dezi, Sabrina;Ortelli, Paola;Sebastianelli, Luca;Ferrazzoli, Davide;Saltuari, Leopold;Pezzopane, Valentina;Borghi, Ilaria;Rocchi, Lorenzo

Writing - Review & Editing

;Ajello, Valentina;Trinka, Eugen;Oliviero, Antonio;Koch, Giacomo;Versace, Viviana

2024-01-01

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Abstract

Objective: Persistent fatigue is a major symptom of the so-called 'long-COVID syndrome', but the pathophysiological processes that cause it remain unclear. We hypothesized that fatigue after COVID-19 would be associated with altered cortical activity in premotor and motor regions. Methods: We used transcranial magnetic stimulation combined with EEG (TMS-EEG) to explore the neural oscillatory activity of the left primary motor area (l-M1) and supplementary motor area (SMA) in a group of sixteen post-COVID patients complaining of lingering fatigue as compared to a sample of age-matched healthy controls. Perceived fatigue was assessed with the Fatigue Severity Scale (FSS) and Fatigue Rating Scale (FRS). Results: Post-COVID patients showed a remarkable reduction of beta frequency in both areas. Correlation analysis exploring linear relation between neurophysiological and clinical measures revealed a significant inverse correlation between the individual level of beta oscillations evoked by TMS of SMA with the individual scores in the FRS (r(15) = -0.596; p = 0.012). Conclusions: Post-COVID fatigue is associated with a reduction of TMS-evoked beta oscillatory activity in SMA. Significance: TMS-EEG could be used to identify early alterations of cortical oscillatory activity that could be related to the COVID impact in central fatigue.