A New P300 No Eye-gaze based Interface: GeoSpell

Brain Computer Interface (BCI) is an alternative communication system which allows users to send commands and/or messages toward the outside not crossing the normal output channels of the brain, but conveying these outputs from the human brain to a computer (Wolpaw et al., 2002). In an EEG-based BCI messages are obtained from brain activity. This study presents a novel P300 based Brain Computer Interface requiring no eye gaze, and so usable in covert attention status, called GeoSpell (Geometric Speller). GeoSpell performances have been compared with those obtained by the subjects with the standard 6 by 6 P300 Speller (P3Speller) matrix which depends on eye gaze (Farwell and Donchin, 1988). A NASA Task Load Index (TLX) workload assessment was employed to provide a subjective rating about the task’s workload and satisfaction with respect to both the interfaces (NASA Human Performance Research Group 1987). Results shown comparable workload values for P3Speller and Geospell; this result has an important impact in term of efficiency and satisfaction for the use of the BCI devices. Geospell interface has shown an accuracy comparable with the P3Speller one but with a lower bit-rate.