TY - JOUR T1 - Rapid Communication with a "P300" Matrix Speller Using Electrocorticographic Signals (ECoG). JF - Front Neurosci Y1 - 2011 A1 - Peter Brunner A1 - A L Ritaccio A1 - Emrich, Joseph F A1 - H Bischof A1 - Gerwin Schalk KW - brain-computer interface KW - Electrocorticography KW - event-related potential KW - P300 KW - speller AB -

brain-computer interface (BCI) can provide a non-muscular communication channel to severely disabled people. One particular realization of a BCI is the P300 matrix speller that was originally described by Farwell and Donchin (1988). This speller uses event-related potentials (ERPs) that include the P300 ERP. All previous online studies of the P300 matrix speller used scalp-recorded electroencephalography (EEG) and were limited in their communication performance to only a few characters per minute. In our study, we investigated the feasibility of using electrocorticographic (ECoG) signals for online operation of the matrix speller, and determined associated spelling rates. We used the matrix speller that is implemented in the BCI2000 system. This speller used ECoG signals that were recorded from frontal, parietal, and occipital areas in one subject. This subject spelled a total of 444 characters in online experiments. The results showed that the subject sustained a rate of 17 characters/min (i.e., 69 bits/min), and achieved a peak rate of 22 characters/min (i.e., 113 bits/min). Detailed analysis of the results suggests that ERPs over visual areas (i.e., visual evoked potentials) contribute significantly to the performance of the matrix speller BCI system. Our results also point to potential reasons for the apparent advantages in spelling performance of ECoG compared to EEG. Thus, with additional verification in more subjects, these results may further extend the communication options for people with serious neuromuscular disabilities.

VL - 5 UR - http://www.ncbi.nlm.nih.gov/pubmed/21369351 ER -