Before revision: Almost all EEG-based brain-computer interfaces (BCIs) need some labeled subject-specific data to calibrate a new subject, as neural responses are different across subjects to even the same stimulus. So, a major challenge in developing high-performance and user-friendly BCIs is to cope with such individual differences so that the calibration can be reduced or even completely eliminated.
After revision: Almost all EEG-based brain-computer interfaces (BCIs) : how to cope with individual differences so that the calibration can be reduced or even completely eliminated.