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.

Brain–computer interfacing in disorders of consciousness

“…Since then, a range of improvements has been proposed to the original interface [24][25][26] and the EEG signal processing techniques [27,28]. Recently, a large group study by Guger et al [29] reported that in 81 healthy users , 89% were able to successfully use a P3-based BCI for spelling, with accuracies of 80% and above.…”

Communication Impairment in ALS Patients Assessment and Treatment

“…The computer identifies the attended item as the intersection of the row and column that elicited the largest P300. The RCP has been tested in various configurations to achieve efficient communication that is practical for in-home use Lenhardt et al, 2008;; the paradigm itself has been modified (Guger et al, 2009;Hong et al, 2009;Martens et al, 2009;Salvaris & Sepulveda, 2009;Takano et al, 2009). Unfortunately, none of such alternative paradigms substantially improves P300-based BCI performance.…”

Exploring multiple protocols for a brain-computer interface mouse

“…Over the last few years there has been a healthy interest in trying to improve P300-based BCIs through modifications of the protocol used [1]- [3]. These modification come from trying to mitigate the temporal limitations of the P300 signal [1] or simply by observing the possible effects of the alterations to the visual makeup of the protocol [2], [3].…”

“…These modification come from trying to mitigate the temporal limitations of the P300 signal [1] or simply by observing the possible effects of the alterations to the visual makeup of the protocol [2], [3]. For example, in [3] a number of modifications were made to the visual properties of a P300 matrix speller, including, the size of the letters, the distance between the letters and the colours used.…”

“…Gonsalvez et al [4] explored the effects of the Target to Target Interval (TTI) on the P300 and found a direct correlation between TTIs and P300 amplitudes. Martens et al [1], Salvaris and Sepulveda [5] and Citi et al [6] explored the effects of very short TTIs in P300-based BCIs and concluded that temporally proximal target events are harder to detect than target events separated by greater temporal distance. Although the reason for this effect is not entirely clear, a possible explanation is repetition blindness and attentional blink [7].…”