Noninvasive Graphene Brain-Computer Interface Integrating EEG Recording and Acoustic-Optical Stimulation for Rhythm...

Noninvasive wearable stimulation-acquisition integrated brain-computer interfaces (BCIs) have significant application value in neurological rehabilitation and health monitoring. However, their widespread adoption depends on the development of long-term, stable dry/semi-dry electrodes and lightweight hardware. In this study, a sodium-doped vertical graphene (Na-VG) electrode that utilized sweat and tissue fluids as electrolytes was developed. When applied with ultrapure water, an extremely low electrode-skin impedance of 4.22 ± 0.50 kΩ was detected at 10 Hz. The 20-channel EEG cap assembled with the Na-VG electrodes maintained a high α-rhythm response of 5.06-14.22 dB in the signal-to-noise ratio of whole-brain EEG signals during a 36-day stability evaluation. Furthermore, a wearable Na-VG headband BCI combining sound-light stimulation and EEG acquisition was developed. Healthy individuals wearing this system, under the coordinated intervention of 40 Hz differential-frequency sound stimulation and 10 Hz light stimulation, showed changes in the frequency and amplitude of the α-rhythm. This improvement increased the proportion of moderate-levels of the vigilance index, neural activity, heart rate, emotion, and arousal index to 84-100%, with a precision of 98.73%. These results provide novel long-term, lightweight strategies and matching software and hardware for the monitoring and noninvasive intervention of emotional and cognitive-related diseases.