Otto-von-Guericke-Universität Magdeburg

The influence of transcranial direct current stimulation on post-COVID fatigue: a comprehensive analysis of the electrophysiological and immunological influences

Magdalena Mischke (1), Stefanie Linnhoff (1), Tino Zähle (1)

(1) Otto-von-Guericke-Universität Magdeburg

Permanent symptoms of cardiovascular, pneumatic, and cognitive nature occur in up to 43% of people after an acute SARS-CoV-2 infection. With a prevalence of 23%, fatigue is described as one of the most common and most distressing symptoms of the post-COVID. The cognitive form of fatigue is manifested by concentration and memory problems, word-finding difficulties and decreased attention performance. Etiologic explanations of the symptomatology include maladaptive changes in fatigue-associated fronto-striato-thalamo-cortical networks, particularly frontoparietal hypoactivity, as well as inflammation-related changes and impaired cortical blood flow regulation. Transcranial direct current stimulation [tDCS] enhances cortical blood flow and modulates excitability of cortical areas. Repetitive application of anodal tDCS on the dorsolateral prefrontal cortex [dlPFC] has been shown to improve fatigue in post-COVID patients. In the preset study, we investigated the effect of anodal tDCS over the left dlPFC on post COVID-related fatigue and fatigability 40 post-COVID-patients. The patients were randomly assigned to receive four sessions of either verum or sham stimulation in a double-blind manner. EEG was recorded before and after to evaluate fatigability related changes in alpha and theta oscillations as well as the auditory p50 component as a sensory gating parameter. Subjective fatigue ratings were evaluated using the MFIS and general subjective health was assessed using the EQ-5D-5L. Additionally, we collected blood samples before and after stimulation and assessed immune parameters. The results show that demographic, electrophysiological, and immunological parameters are effective in predicting both subjective and objective fatigue and have also the potential to optimise the prediction of stimulation effects.