title: Overlap and refractory effects in a brain-computer interface speller based on the visual P300 event-related potential.
abstract: We reveal the presence of refractory and overlap effects in the event-related potentials in visual P300 speller datasets, and we show their negative impact on the performance of the system. This finding has important implications for how to encode the letters that can be selected for communication. However, we show that such effects are dependent on stimulus parameters: an alternative stimulus type based on apparent motion suffers less from the refractory effects and leads to an improved letter prediction performance.
authors.affiliation: Empirical Inference Department, Max Planck Institute for Biological Cybernetics, Tübingen, Germany. smm.martens@gmail.com
authors.forename: S M M
authors.initials: SM
authors.lastname: Martens
authors.forename: N J
authors.initials: NJ
authors.lastname: Hill
authors.forename: J
authors.initials: J
authors.lastname: Farquhar
authors.forename: B
authors.initials: B
authors.lastname: Schölkopf
mesh_terms: D000465:Algorithms; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003198:Computer Simulation; D004569:Electroencephalography; D018913:Event-Related Potentials, P300; D006801:Humans; D008959:Models, Neurological; D010363:Pattern Recognition, Automated / Q000379:methods; D010775:Photic Stimulation; D012660:Semantics; D012815:Signal Processing, Computer-Assisted; D013647:Task Performance and Analysis; D014584:User-Computer Interface; D014956:Writing