A Flexible EEG Acquisition Headband With High Reliability and High Signal-to-Noise Ratio

To create a modern healthcare system, there is a desire to have easy access to electroencephalography (EEG) signals throughout daily life. EEG signals are weak and are susceptible to a variety of interferences, including electrode shifts and noise. Therefore, EEG signals need to be acquired at high resolution with very low noise and sampling frequencies in the range of hundreds of hertz. In our previous work, a head ring that could acquire EEG was proposed and used to acquire EEG signals during sleep cycles and different emotional states. However, no noise analysis or optimization comparisons have been undertaken. In this article, noise analysis is performed with optimization of the circuits based on the results. Then, the circuits are simulated using Pspice software to analyze the effect of the optimization measures on the noise suppression of the circuit. Further, blink signals are captured using OpenBCI, the original circuit, and the optimized circuit to analyze and compare the signal-to-noise ratios of the three circuits. In addition, the structure of the flexible electrode we used is described, and accelerated degradation experiments are performed comparing it with other electrodes. Experimental results show that the proposed circuit is temperature stable with a high signal-to-noise ratio, and the noise of the circuit can be further reduced by the circuit optimization measures. The proposed electrodes are reliable, superior to other commercially available electrodes made of other materials, and simple and low-cost to prepare. The proposed electrodes and circuits can be utilized in portable wearable bioelectricity acquisition devices.