Evaluation of Different Types of Stimuli in a ERP-Based Brain-Computer Interface Speller under RSVP.

Abstract

Rapid Serial Visual Presentation (RSVP) is currently one of the most suitable gaze-independent paradigms to control a visual brain-computer interface based on event related potentials (ERP-BCI) by patients with a lack of ocular motility. However, gaze-independent paradigms have not been studied as closely as gaze-dependent ones in reference to the type of stimuli presented. Under gaze-dependent paradigms, faces have been shown to be the most appropriate stimuli, especially when they are red. Therefore, the aim of the present work is to evaluate whether these results of the color of faces as visual stimuli also has an impact on ERP-BCI performance under the RSVP paradigm. In this preliminary study, six participants tested the ERP-BCI under RSVP using four different conditions for a speller application: letters, blue faces, red faces, and green faces. These preliminary results showed non-significant differences in accuracy or information transfer rate. The present work therefore shows that, unlike under gaze-dependent paradigms, the stimulus type has no impact on the performance of an ERP-BCI under RSVP. This finding should be considered in future ERP-BCI proposals aimed at users who need gaze-independent systems.