Leveraging textured flickers: a leap toward practical, visually comfortable, and high-performance dry EEG code-VEP...

Area of Science:

• Neuroscience
• Biomedical Engineering
• Human-Computer Interaction

Background:

• Traditional reactive brain-computer interfaces (BCIs) often use repetitive visual stimuli, leading to user discomfort and reduced attention.
• There is a need for more comfortable and efficient visual stimuli for BCI applications.

Purpose of the Study:

• To introduce novel visual stimuli for augmented response (StAR) using Gabor or Ricker patches to optimize foveal neural response and minimize peripheral distraction.
• To evaluate the performance and user experience of StAR stimuli compared to traditional plain flickers in a BCI paradigm.

Main Methods:

• A factorial design study with 24 participants using an 8-dry electrode EEG system.
• Participants focused on target flickers presented in three formats: plain, Gabor-based, and Ricker-based, within a five-class visually evoked potentials paradigm.
• Subjective ratings and accuracy metrics were collected, followed by an online implementation for validation.

Main Results:

• Gabor and Ricker stimuli were rated as visually comfortable and nearly invisible in peripheral vision.
• Higher accuracy was achieved with Gabor (93.6%) and Ricker (96.3%) stimuli using only 88s of calibration data, compared to plain flickers (65.6%).
• Online implementation demonstrated high accuracies (97.5% cued, 94.3% asynchronous) with a mean decoding time of 1.68s.

Conclusions:

• Gabor and Ricker stimuli offer a visually unobtrusive and highly accurate alternative for BCI applications.
• The integration of these stimuli with gel-free, low-density EEG technology enhances BCI accessibility and efficiency.
• This research paves the way for expanding BCI applications beyond laboratory settings.