A P300 event-related potential brain-computer interface (BCI): the effects of matrix size and inter stimulus interval on performance.

TitleA P300 event-related potential brain-computer interface (BCI): the effects of matrix size and inter stimulus interval on performance.
Publication TypeJournal Article
Year of Publication2006
AuthorsSellers, EW, Krusienski, DJ, McFarland, DJ, Vaughan, TM, Wolpaw, JR
JournalBiological psychology
Volume73
Pagination242–252
Date Published10/2006
ISSN0301-0511
KeywordsAmyotrophic Lateral Sclerosis, brain-computer interface, electroencephalogram, event-related potentials, P300, Rehabilitation
Abstract

We describe a study designed to assess properties of a P300 brain-computer interface (BCI). The BCI presents the user with a matrix containing letters and numbers. The user attends to a character to be communicated and the rows and columns of the matrix briefly intensify. Each time the attended character is intensified it serves as a rare event in an oddball sequence and it elicits a P300 response. The BCI works by detecting which character elicited a P300 response. We manipulated the size of the character matrix (either 3 x 3 or 6 x 6) and the duration of the inter stimulus interval (ISI) between intensifications (either 175 or 350 ms). Online accuracy was highest for the 3 x 3 matrix 175-ms ISI condition, while bit rate was highest for the 6 x 6 matrix 175-ms ISI condition. Average accuracy in the best condition for each subject was 88%. P300 amplitude was significantly greater for the attended stimulus and for the 6 x 6 matrix. This work demonstrates that matrix size and ISI are important variables to consider when optimizing a BCI system for individual users and that a P300-BCI can be used for effective communication.

URLhttp://www.ncbi.nlm.nih.gov/pubmed/16860920
DOI10.1016/j.biopsycho.2006.04.007