Binocularly incongruent, multifrequency-coded SSVEP in VR: feasibility and characteristics

Area of Science:

• Neuroscience
• Virtual Reality
• Brain-Computer Interfacing

Background:

• Steady-state visual evoked potentials (SSVEPs) are widely used in brain-computer interfaces (BCIs).
• Virtual reality (VR) integration with SSVEPs opens new avenues for clinical applications.
• Traditional SSVEP methods use congruent stimulation, while incongruent stimulation aims to enhance information transfer rates.

Purpose of the Study:

• To systematically investigate incongruent dual-, triple-, and quadruple-frequency-coded SSVEPs within a VR environment.
• To compare the performance of novel incongruent multifrequency SSVEP paradigms with traditional congruent SSVEP methods.
• To assess the potential of VR-based incongruent SSVEP for clinical applications, particularly in relation to binocular vision.

Main Methods:

• Development and testing of novel incongruent dual-, triple-, and quadruple-frequency-coded SSVEP paradigms in VR.
• Comparison of performance metrics between incongruent and congruent SSVEP stimulation methods.
• Analysis of summation and suppression effects in monocular versus binocular stimulation for both congruent and incongruent paradigms.

Main Results:

• Confirmed a summation effect for monocular versus binocular single-frequency congruent SSVEP stimulation.
• Observed a suppression effect for monocular versus binocular dual-frequency incongruent SSVEP stimulation.
• Demonstrated that binocular vision capabilities, when affected, can be signaled by incongruent SSVEP responses, suggesting potential for amblyopia detection.

Conclusions:

• VR-based binocularly incongruent SSVEP shows significant potential for BCI and clinical applications.
• The choice of SSVEP paradigm and decoder design is crucial for optimizing system performance and user comfort.
• Incongruent SSVEP paradigms may offer a novel approach to assessing binocular vision function within immersive environments.