A hybrid ERD/SSVEP BCI for continuous simultaneous two dimensional cursor control.

We introduce a new type of BCI for continuous simultaneous two dimensional cursor control. Users tried to control the vertical position of a virtual ball via ERD activity associated with imagined movement while simultaneously controlling horizontal position with SSVEP activity resulting from visual attention. Ten subjects participated in one offline and six online control sessions. The online sessions assessed subjective measures via questionnaires as well as objective measures. Subjects generally reported that the hybrid task combination was not especially difficult or annoying. Two subjects attained very good performance, while the remaining subjects did not. Training did not affect subjective or objective measures. Overall, results show that this new hybrid approach is viable for some users, and that substantial further research is needed to identify and optimize the best BCIs for each user.