Temporal and Spatial Parameters Dynamics of SSVEP During Long-Term Low-Frequency LED-Stimulation: Pilot Study

Brain-computer interface technology is becoming increasingly common. However, there is a problem of stability of such systems during long-term use. The most stable highspeed interfaces include steady-state visual evoked potential interfaces. However, despite the relative stability of the interfaces, they are affected by the habituation effect and, on the other hand, by the steady-state visual evoked potentials amplification. This study proposes to evaluate the steady-state visual evoked potentials amplitude dynamics during prolonged stimulation with a flash pattern of 50 s or 100 s with frequencies of 9, 11, 13, and 15 Hz on healthy subjects. Based on the results obtained, it was concluded that there was no pronounced enhancement or suppression of steady-state visual evoked potentials relative to the alpha-rhythm over time. However, the graphs in the time-frequency area shows the steady-state visual evoked potentials amplitude bursts at short intervals of time. Topographic maps of the steady-state visual evoked potentials distribution on the scalp surface show the activity occurring in the parietal and central regions at different times. The application of the steady-state visual evoked potentials sources spatial separation method using common spatial pattern filtering is also demonstrated.