GeoSpell: an alternative P300-based speller interface towards no eye gaze required

The speller based on the N by N matrix is the most commonly used approach for text writing in a P300-based Brain Computer Interface. This study presents an alternative P300 speller interface, GeoSpell (Geometric Speller), where stimuli are delivered in a covert attention modality and thus not require eye gaze control. Moreover, the GeoSpell interface allows to avoid the problem of the adjacent stimuli interference that is instead present in the P300-matrix approach. A performances comparison between the two interfaces showed a comparable classification accuracy.