Study on the effects of brightness contrast on steady-state motion visual evoked potential

Traditional steady - state visual evoked potential (SSVEP) using light flicker stimulation may easy cause visual fatigue with a consequent reduction of recognition accuracy. In the previous study, we proposed a steady - state motion visual evoked potential (SSMVEP) brain - computer interface (BCI) method. A black - white ring - shaped checkerboard was used as the visual stimulus paradigm in this study. The movement patterns of the checkerboard included contraction and expansion. Based on the signal-to-noise ratio (SNR), recognition accuracy and anti-fatigue properties, the effects of black-white brightness contrast on the brain response were investigated. Experimental results indicated that when the contrast ratio was the highest, it could obtain higher recognition accuracy and SNR, yet it was easy to cause visual fatigue. When the contrast was the lowest, the sensitivity of the eyes against flicker reduced to the lowest, and it could reduce visual fatigue. However the recognition accuracy and SNR were low. In contrast, the appropriate contrast could guarantee high SNR and recognition accuracy, and as much as possible to reduce the visual fatigue.