Patterned visual stimuli for enhancement of SSVEP-based BCI performance

Steady-state visual evoked potential (SSVEP) signals are weak and buried in noise. The signal-to-noise ratio (SNR) of SSVEPs is correlated with attention, and its enhancement contributes to the increase of the speed and accuracy of SSVEP-based brain-computer interfaces (BCIs). Therefore, in this paper it is proposed the use of patterns on the flickers not only to enhance the SNR but also to motivate the subjects and to boost the information-transfer rate (ITR). Experiments have shown an average increase of 43.6% of the SNR resulting in an increase of about 17.0% of the ITR, comparing to the traditional visual stimulator.