Improved cognitive performance, increased theta, alpha, beta and decreased delta powers after cognitive rehabilitation augmented with tDCS in a patient with post-COVID-19 cognitive impairment (brain-fog)

Abstract

Objective

COVID-19 is associated with neuropsychiatric symptoms, including delirium, confusion and neurocognitive disorders. The main aim of this report is to present results of 3-week cognitive rehabilitation augmented with transcranial direct current stimulation (tDCS) in a patients with post-COVID-19 cognitive impairments. We also presented results of quantitative EEG analysis.

Methods

We have complete a non-blinded, 3-week, single-case experimental study consisting of daily cognitive rehabilitation augmented with tDCS stimulation (current: 2.0 mA, anode: left dorsolateral prefrontal cortex (DLPFC), cathode: right DLPFC, duration: 1200 s). Major cognitive functions were evaluated a day before (V1), a day after the 3-week rehabilitation program (V2) and 8 weeks later (V3) using CANTAB cognitive research software. Routine 20-minutes eyes-closed resting EEG were recorded three times at V1, V2 and V3.

Results

Visual memory scores improved at V2 and returned to the baseline level at V3. Mixed results were observed for multitasking, emotion recognition, response speed, attention. No changes or transient decrease at V2 were seen for working memory. There was a significant delta band power decrease (at F4) and increase (at F3), and increase (at F3 and F4) of theta, alpha, and beta band powers after tDCS.

Conclusions

tDCS combined with computer-assisted cognitive rehabilitation may be an effective therapeutic options for patients with COVID-19-related brain-fog. Increased alpha power may be an underlying mechanism or marker of cognitive improvement. Reduced delta band power may be interpreted as normalization of EEG recordings due to tDCS stimulation.