Effect of Stimulus Size in a Visual ERP-Based BCI under RSVP

Area of Science:

• Neuroscience
• Biomedical Engineering
• Human-Computer Interaction

Background:

• Event-related potential-based brain-computer interfaces (ERP-BCIs) are vital for individuals with motor impairments.
• Rapid serial visual presentation (RSVP) is a preferred gaze-independent paradigm for ERP-BCIs.
• The influence of stimulus size in RSVP for ERP-BCIs remains underexplored.

Purpose of the Study:

• To investigate the effect of stimulus size on ERP-BCI performance within the RSVP paradigm.
• To determine if stimulus size impacts the accuracy of gaze-independent ERP-BCIs.

Main Methods:

• Twelve participants completed an ERP-BCI task using RSVP with three distinct stimulus sizes: small (0.1 × 0.1 cm), medium (1.9 × 1.8 cm), and large (20.05 × 19.9 cm).
• A perceptual discrimination task was included to assess stimulus perception independent of BCI performance.

Main Results:

• Significant differences in accuracy were observed across stimulus sizes.
• Larger stimulus sizes resulted in demonstrably higher accuracy.
• Stimulus size did not affect performance in the perceptual discrimination task, indicating accurate perception across sizes.

Conclusions:

• Stimulus size is a critical factor influencing ERP-BCI performance under the RSVP paradigm.
• Optimizing stimulus size can enhance the efficacy of gaze-independent BCIs for users with ocular motility limitations.