Skip to main content
Kent Academic Repository

The cost of space independence in P300-BCI spellers.

Chennu, Srivas, Alsufyani, Abdulmajeed, Filetti, Marco, Owen, Adrian, Bowman, Howard (2013) The cost of space independence in P300-BCI spellers. Journal of NeuroEngineering and Rehabilitation, 10 (82). pp. 1-13. ISSN 1743-0003. (doi:10.1186/1743-0003-10-82) (KAR id:34935)


Background: Though non-invasive EEG-based Brain Computer Interfaces (BCI) have been researched extensively over the last two decades, most designs require control of spatial attention and/or gaze on the part of the user.

Methods: In healthy adults, we compared the offline performance of a space-independent P300-based BCI for spelling words using Rapid Serial Visual Presentation (RSVP), to the well-known space-dependent Matrix P300 speller.

Results: EEG classifiability with the RSVP speller was as good as with the Matrix speller. While the Matrix speller’s performance was significantly reliant on early, gaze-dependent Visual Evoked Potentials (VEPs), the RSVP speller depended only on the space-independent P300b. However, there was a cost to true spatial independence: the RSVP

speller was less efficient in terms of spelling speed.

Conclusions: The advantage of space independence in the RSVP speller was concomitant with a marked reduction in spelling efficiency. Nevertheless, with key improvements to the RSVP design, truly space-independent BCIs could approach efficiencies on par with the Matrix speller. With sufficiently high letter spelling rates fused with predictive

language modelling, they would be viable for potential applications with patients unable to direct overt visual gaze or covert attentional focus.

Item Type: Article
DOI/Identification number: 10.1186/1743-0003-10-82
Uncontrolled keywords: RSVP Speller BCI, Matrix P300 Speller BCI, Space-independence, Gaze-independence, Rapid serial visual presentation.
Subjects: Q Science > Q Science (General)
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Computing
Depositing User: Howard Bowman
Date Deposited: 06 Aug 2013 11:23 UTC
Last Modified: 16 Nov 2021 10:12 UTC
Resource URI: (The current URI for this page, for reference purposes)

University of Kent Author Information

  • Depositors only (login required):

Total unique views for this document in KAR since July 2020. For more details click on the image.