Communication for patients with disorders of consciousness with a vibro-tactile P300 brain-computer interface

In this publication we present a novel P300 speller that could be used for communication with DOC patients. The stimulation for the P300 is done tactile on seven different body locations. Test on four healthy users have been done and resulted in an average accuracy of 95% when answering simple "yes" versus "no" questions. We further implemented a statistical test, that provides additionally a so called zero-class. If the classification result "yes" or "no" is rather uncertain, and therefore maybe wrong, the speller provides the so called zero-class as output. The answer is therefore considered ambiguous. After adding the zero-class calculations to the analysis of the same data, the percentage of correct answers decreased from 95% to 87.5%, but with the big advantage of no single wrong classification.