Psychophysical Responses Comparison in Spatial Visual, Audiovisual, and   Auditory BCI-Spelling Paradigms
  The paper presents a pilot study conducted with spatial visual, audiovisual and auditory brain-computer-interface (BCI) based speller paradigms. The psychophysical experiments are conducted with healthy subjects in order to evaluate a difficulty and a possible response accuracy variability. We also present preliminary EEG results in offline BCI mode. The obtained results validate a thesis, that spatial auditory only paradigm performs as good as the traditional visual and audiovisual speller BCI tasks. 
Moonjeong Chang, Nozomu Nishikawa, Zhenyu Cai, Shoji Makino, and   Tomasz M. Rutkowski
cs.HC q-bio.NC