Spatial auditory BCI paradigm based on real and virtual sound image generation

This paper presents a novel concept of spatial auditory brain-computer interface utilizing real and virtual sound images. We report results obtained from psychophysical and EEG experiments with nine subjects utilizing a novel method of spatial real or virtual sound images as spatial auditory brain computer interface (BCI) cues. Real spatial sound sources result in better behavioral and BCI response classification accuracies, yet a direct comparison of partial results in a mixed experiment confirms the usability of the virtual sound images for the spatial auditory BCI. Additionally, we compare stepwise linear discriminant analysis (SWLDA) and support vector machine (SVM) classifiers in a single sequence BCI experiment. The interesting point of the mixed usage of real and virtual spatial sound images in a single experiment is that both stimuli types generate distinct event related potential (ERP) response patterns allowing for their separate classification. This discovery is the strongest point of the reported research and it brings the possibility to create new spatial auditory BCI paradigms.