This paper discusses the hybrid brain-computer interface (BCI), which combines multiple neuroimaging modalities to enhance the reliability and efficiency of BCI systems.
Pfurtscheller, G., Allison, B. Z., Bauernfeind, G., Brunner, C., Solis Escalante, T., Scherer, R., Birbaumer, N. P. (2010). The hybrid BCI. Frontiers in Neuroscience, 4, 3. doi: 10.3389/fnpro.2010.00003