Model-Driven Individualized Transcranial Direct Current Stimulation for the Treatment of Insomnia Disorders

The intervention uses transcranial direct current stimulation (tDCS). The targeted brain regions are identified by conducting simultaneous fMRI-EEG data collection and sleep staging, comparing fMRI data between wakefulness and sleep states. Brain regions that show differences are calculated as potential targets for electrical stimulation. If no differentiated regions are found in a participant, specific areas are chosen based on individualized modeling results from previous experiments, targeting areas such as the dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OPFC), medial prefrontal cortex (mPFC), and posterior cingulate cortex (PCC). Two regions are selected within each brain area for parameter scanning (with each stimulation lasting 10 seconds and EEG data recorded 10 seconds before and after stimulation). In our prior studies, we observed a decrease in EEG microstate complexity during sleep, with electrical stimulation influencing this complexity reduction to some

In the sham stimulation group, the placement of the tDCS electrodes is identical to that of the active stimulation group. After the stimulation begins, the current gradually increases over 15 seconds. However, upon reaching the therapeutic current level, it immediately begins to decrease, lowering to 0 mA within 15 seconds and remaining at 0 mA throughout the rest of the session. During the last 15 seconds of the stimulation, there is another gradual decrease in current to 0 mA. This approach creates a similar subjective sensation to the real stimulation, making it difficult for participants to discern which type of electrical stimulation they are receiving.