Acute effect of transcranial direct current stimulation (tDCS) on mood in individuals with COVID-19: a randomized controlled trial

Abstract

Introduction: Covid-19 has become a challenge for the scientific community, professionals, and health authorities. The invasion of the Central Nervous System by the virus can lead to the impairment of the Left Dorsolateral Prefrontal Cortex (LDLPFC) and the consequent appearance of anxiety and depression disorders in this population. Transcranial Direct Current Stimulation (tDCS) is a safe and effective non-invasive neuromodulation technique in treating such disorders. However, studies on its effects are still needed to prove its efficacy and safety in individuals with Covid-19. Objective: To assess the safety and effects of a single tDCS session over the LDLPFC on mood in individuals with Covid-19. Methods: Double-blind RCT developed based on CONSORT clinical trial design guidelines. A convenience sample of 40 individuals with Covid-19 admitted to a semi-intensive unit was used. Participants were randomized into two groups: tDCS-Sham and tDCS-LDLPFC, to stimulate LDLPFC. The applied current was 2mA for 30 minutes. The anode and cathode electrodes were positioned under the areas corresponding to the LDLPFC and Right Dorsolateral Prefrontal Cortex (RPFDLC), respectively, in both groups. Safety was assessed through the following aspects: 1) application of Brunoni's tDCS Adverse Effects Questionnaire; 2) measurement of vital signs before and after stimulation; 3) presence of severe skin injuries at the current application site; 4) fall events; 5) occurrence of clinical worsening, including transfer to the ICU, orotracheal intubation (OTI) and death within one hour after the intervention. The mood was assessed using Beck's anxiety and depression inventories before and after the tDCS application. Results: There were no dropouts by any of the assessed individuals. There were no falls, transfers to the ICU, OTI, or deaths. A trend towards an increase in SpO2 was observed for the tDCS-LDLPFC group after the intervention. There was no significant difference between the groups regarding the occurrence and intensity of adverse effects after stimulation. There was a significant reduction in anxiety and depression levels in both groups. Conclusion: tDCS was shown to be a safe and feasible technique in our sample of Covid-19 inpatients. However, a single session was not enough to reduce anxiety and depression levels in our sample. Studies with a greater number of sessions are needed for the appreciation of more robust results in patients with Covid-19.