Transcranial Direct Current Stimulation-Based Neuromodulation Improves the Performance of Brain–Computer Interfaces Based on Steady-State Visual Evoked Potential

Abstract

The study of brain state estimation and intervention methods is of great significance for the utility of brain-computer interfaces (BCIs). In this paper, a neuromodulation technology using transcranial direct current stimulation (tDCS) is explored to improve the performance of steady-state visual evoked potential (SSVEP)-based BCIs. The effects of pre-stimulation, sham-tDCS and anodal-tDCS are analyzed through a comparison of the EEG oscillations and fractal component characteristics. In addition, in this study, a novel brain state estimation method is introduced to assess neuromodulation-induced changes in brain arousal for SSVEP-BCIs. The results suggest that tDCS, and anodal-tDCS in particular, can be used to increase SSVEP amplitude and further improve the performance of SSVEP-BCIs. Furthermore, evidence from fractal features further validates that tDCS-based neuromodulation induces an increased level of brain state arousal. The findings of this study provide insights into the improvement of BCI performance based on personal state interventions and provide an objective method for quantitative brain state monitoring that may be used for EEG modeling of SSVEP-BCIs.

Improving SSVEP-BCI Performance Through Repetitive Anodal tDCS-Based Neuromodulation: Insights From Fractal EEG and Brain Functional Connectivity

“…Post-anodal-tDCS, both offsets and exponents show a reduction compared to their pre-anodal-tDCS values. This observed positive linear relationship between exponent and offset corroborates earlier research [26,31]. eyes open) are more sensitive to tDCS treatment, as seen in the comparison among the left (eyes closed), middle (eyes open), and right maps.…”

“…Initially, a positive linear relationship was observed between the exponent and intercept. Figure 3(b) illustrates a nearly positive linear correlation between the exponent and offset across various task modes and tDCS stimulations, consistent with previous research [26,31]. Subsequently, the study provided evidence of an increase in brain state arousals due to tDCS-based neural modulation.…”

“…This shift in parameters, associated with frequency energies, indicates a decrease in low-frequency energy and an increase in high-frequency energy, suggesting enhanced brain arousal. Additionally, compared to sham tDCS, anodal tDCS more significantly reduced fractal parameter values, highlighting its superior effectiveness as a neural modulation pattern, in line with earlier research [31].…”

“…On the first day, participants sequentially underwent eyes-open (120 s), eyes-closed (120 s), SSVEP stimulation (6 minutes×2 blocks), and tDCS (21 minutes) tasks, with EEG data collection at each stage. Subjects received tDCS stimulation for 21 minutes, and this setting had similarities to a previous research [31]. Initially, participants focused on a central white fixation cross on a black screen.…”