Robustness of the Farwell & Donchin BCI protocol to visual stimulus parameter changes

In this paper a number of visual modifications were carried out upon the Farwell & Donchin protocol. The effects of these modifications were studied both in the classification accuracy of the classifiers and the electrophysiological morphology of the P3 potential. The classifiers used were a support vector machine with a Gaussian kernel and a fisher linear discriminant. The electrophysiological aspects of the P3 potential studied were the amplitude and latency. The results indicate that although small fluctuations in the classifier accuracy were observed between the differing visual protocols, the relative changes were not statistically significant. This means that in this set of experiments the Farwell & Donchin has proved to be robust to visual stimulus parameter changes. The experiments also demonstrate the difficulties of using brain computer interfaces and the inconsistent results they often provide across subjects. Furthermore, the experiments have introduced some interesting changes to the visual layout of the Farwell & Donchin protocol.