Before revision:  Nonetheless, due to high intra- and inter-subject variabilities, many studies on decoding EEG were designed in a subject-specific manner by using calibration samples, with no much concern on its less practical, time-consuming, and data-hungry process. To tackle this problem, recent studies took advantage of transfer learning, especially using domain adaptation techniques .
After revision:  Nonetheless, due to high inter- and intrasubject variabilities are the points to be considered. Transfer learning, especially using domain adaptation techniques .