An approximation approach for rendering visual flickers in SSVEP-based BCI using monitor refresh rate

Area of Science:

• Neuroscience
• Biomedical Engineering
• Human-Computer Interaction

Background:

• Steady-state visual evoked potential (SSVEP)-based brain-computer interfaces (BCIs) offer direct brain-computer communication.
• Conventional SSVEP stimulus presentation is limited by monitor refresh rates, restricting the number of usable frequencies.
• An alternative approximation approach using variable on/off frames has been proposed.

Purpose of the Study:

• To directly compare the performance of SSVEPs elicited by a conventional constant period stimulus approach versus an approximation approach.
• To evaluate amplitude, signal-to-noise ratio (SNR), and target identification accuracy.
• To assess performance across different monitor refresh rates (75Hz and 120Hz).

Main Methods:

• Comparison of SSVEPs elicited by two stimulus presentation methods: constant period and approximation.
• Measurement of SSVEP amplitude and SNR.
• Evaluation of target identification accuracy.
• Experiments conducted using monitors with 75Hz and 120Hz refresh rates.

Main Results:

• SSVEPs elicited by the approximation approach demonstrated performance largely comparable to the conventional constant period approach.
• No significant differences in amplitude, SNR, or accuracy were consistently observed between the two methods across tested refresh rates.
• The approximation approach shows potential as a viable alternative for SSVEP-based BCI stimulus presentation.

Conclusions:

• The approximation approach for SSVEP stimulus presentation is a viable alternative to the conventional method.
• This method offers comparable performance in terms of SSVEP amplitude, SNR, and target identification accuracy.
• The findings support the use of the approximation approach in developing practical SSVEP-based BCIs.