A Grating Based High-Frequency Motion Stimulus Paradigm for Steady-State Motion Visual Evoked Potentials

Objective: This paper proposes a novel type of stimulus in the shape of sinusoidal gratings displayed with an imperceptibly high-frequency motion. The stimulus has been designed for use in BCI (Brain Computer Interface) applications that employ visually evoked potentials (VEPs) in an effort to mitigate discomfort associated with VEPs. The stimuli set included traditional VEP stimuli, already established in the literature, allowing comparative analyses. We conducted analyses of signal distinction measures by calculating the signal-to-noise ratio and the classification performance of its evoked potentials. Methods: Fourteen participants were seated in a dimly lit room facing a display. Participants' fixation on the central stimulus was controlled by means of a desktop eye tracker. Participants attended a flicker-based steady-state VEP (SSVEP) task, a motion-based steady-state-motion VEP (SSMVEP) task, and the novel stimulus task (the imperceptible grating SSMVEP). Participants were asked to complete behavioral fatigue scale tasks. Results: A significant effect of stimulus type was observed, accompanied by insignificant differences in prediction accuracy. Partially significant task effects were obtained in fatigue scale tasks. Conclusion: The study revealed that the imperceptible grating SSMVEP stimulus successfully evoked SSMVEP responses within acceptable margins in the related cortical regions. This novel stimulus contributes to BCI research by providing an imperceptible interface, improving already established stimuli design in the SSVEP and the SSMVEP literature. Significance: The present paper provides a novel SSMVEP stimulus type that may inform the future design of effective VEP-based BCI paradigms that allow seamless interaction with computer interfaces.