  A brain-computer interface (BCI) based on electroencephalography (EEG) is a
promising technology for enhancing virtual reality (VR) applications-in
particular, for gaming. We focus on the so-called P300-BCI, a stable and
accurate BCI paradigm relying on the recognition of a positive event-related
potential (ERP) occurring in the EEG about 300 ms post-stimulation. We
implemented a basic version of such a BCI displayed on an ordinary and
affordable smartphone-based head-mounted VR device: that is, a mobile and
passive VR system (with no electronic components beyond the smartphone). The
mobile phone performed the stimuli presentation, EEG synchronization (tagging)
and feedback display. We compared the ERPs and the accuracy of the BCI on the
VR device with a traditional BCI running on a personal computer (PC). We also
evaluated the impact of subjective factors on the accuracy. The study was
within-subjects, with 21 participants and one session in each modality. No
significant difference in BCI accuracy was found between the PC and VR systems,
although the P200 ERP was significantly wider and larger in the VR system as
compared to the PC system.
