  This study provides a comprehensive test of the head-related impulse response
(HRIR) to an auditory spatial speller brain-computer interface (BCI) paradigm,
including a comparison with a conventional virtual headphone-based spatial
auditory modality. Five BCI-naive users participated in an experiment based on
five Japanese vowels. The auditory evoked potentials obtained produced
encouragingly good and stable P300-responses in online BCI experiments. Our
case study indicates that the auditory HRIR spatial sound paradigm reproduced
with headphones could be a viable alternative to established multi-loudspeaker
surround sound BCI-speller applications.
