Highly Interactive Brain–Computer Interface Based on Flicker-Free Steady-State Motion Visual Evoked Potential
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Paper
Link: https://www.nature.com/articles/s41598-018-24008-8
Year: 2018
Summary
- hypothesis is that the motion checkerboard stimulation method would keep uniform brightness at all local areas that delivered pure motion stimuli and that motion blur would be further reduced with a high-refresh-rate display to elicit SSMVEPs with a single frequency
Contributions and Distinctions from Previous Works
- continuous high-intensity contrast changes are very uncomfortable and unfriendly to users and will cause visual fatigue easily
Methods
- ring-shaped motion checkerboard patterns with oscillating expansion and contraction motions
Results
- evoked “single fundamental peak” responses after signal processing without harmonic and subharmonic peaks - more stimulation frequencies could thus be selected to elicit more responding fundamental peaks without overlap with harmonic peaks
- response amplitude reached the highest when the stimulation frequency was 7 Hz to 13 Hz and then dropped as the stimulation frequency increased or decreased
- each trial lasted 2–3.5 s, including 0.5 s for gaze shifting, average 94% accuracy with CCA
- stimulation of FF-SSMVEPs was much more comfortable than the stimulation of SSVEPs, mainly because they did not feel any eye irritation, good performance for a long period of time
- SSMVEP paradigm remained stable when the contrast of the stimulus changed. In contrast, SSVEPs can be significantly affected by ambient light: the depth of contrast modulation of stimulation targets decreases when the luminance of ambient light increases.