Gaze-independent BCI-spelling using rapid serial visual presentation (RSVP)

ObjectiveA Brain Computer Interface (BCI) speller is a communication device, which can be used by patients suffering from neurodegenerative diseases to select symbols in a computer application. For patients unable to overtly fixate the target symbol, it is crucial to develop a speller independent of gaze shifts. In the present online study, we investigated rapid serial visual presentation (RSVP) as a paradigm for mental typewriting.MethodsWe investigated the RSVP speller in three conditions, regarding the Stimulus Onset Asynchrony (SOA) and the use of color features. A vocabulary of 30 symbols was presented one-by-one in a pseudo random sequence at the same location of display.ResultsAll twelve participants were able to successfully operate the RSVP speller. The results show a mean online spelling rate of 1.43 symb/min and a mean symbol selection accuracy of 94.8% in the best condition.ConclusionWe conclude that the RSVP is a promising paradigm for BCI spelling and its performance is competitive with the fastest gaze-independent spellers in literature.SignificanceThe RSVP speller does not require gaze shifts towards different target locations and can be operated by non-spatial visual attention, therefore it can be considered as a valid paradigm in applications with patients for impaired oculo-motor control.

► Rapid serial visual presentation is exploited to implement an effective BCI speller that does not require any eye movements, in an online study.
► Selection of letters is performed intuitively by attending target letters in the stream of visual stimuli.
► The amplitude of the P3 component in a standard oddball recording was found to be a predictor of the spelling performance with the RSVP speller.