Disorders of consciousness (DoC), including unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), remain difficult to diagnose at the bedside. Electroencephalography (EEG) microstate analysis provides a high-temporal-resolution approach for characterizing large-scale resting-state brain dynamics, and its application in neuromodulation studies remains under investigation.
This study is designed to investigate the effects of a single 20-minute session of 40 Hz transcranial alternating current stimulation (tACS) applied over the bilateral dorsolateral prefrontal cortex (DLPFC) on resting-state EEG microstate parameters in patients with DoC. Participants undergo resting-state EEG recordings immediately before and after a 2 mA, 40 Hz bilateral DLPFC tACS session. EEG microstate maps (A-G) are identified by back-fitting to individual recordings, and microstate parameters including mean duration, occurrence, coverage, and global explained variance (GEV) are calculated. Behavioral assessments are performed using the Coma Recovery Scale-Revised (CRS-R) and the Simplified Evaluation of CONsciousness Disorders (SECONDs). The study aims to characterize changes in EEG microstate dynamics following tACS and to examine their associations with behavioral measures of consciousness.