Discriminating three motor imagery states of the same joint for brain-computer interface

PeerJ. 2021 Aug 24:9:e12027. doi: 10.7717/peerj.12027. eCollection 2021.


The classification of electroencephalography (EEG) induced by the same joint is one of the major challenges for brain-computer interface (BCI) systems. In this paper, we propose a new framework, which includes two parts, feature extraction and classification. Based on local mean decomposition (LMD), cloud model, and common spatial pattern (CSP), a feature extraction method called LMD-CSP is proposed to extract distinguishable features. In order to improve the classification results multi-objective grey wolf optimization twin support vector machine (MOGWO-TWSVM) is applied to discriminate the extracted features. We evaluated the performance of the proposed framework on our laboratory data sets with three motor imagery (MI) tasks of the same joint (shoulder abduction, extension, and flexion), and the average classification accuracy was 91.27%. Further comparison with several widely used methods showed that the proposed method had better performance in feature extraction and pattern classification. Overall, this study can be used for developing high-performance BCI systems, enabling individuals to control external devices intuitively and naturally.

Keywords: Brain-computer interface; Cloud model; Common spatial pattern; Local mean decomposition; Motor imagery; Multi-objective grey wolf optimizer; Twin support vector machine.

Grants and funding

This work was supported by the National Natural Science Foundation of China (No.31772059), the Northeast Electric Power University (BSJXM-201521), and the Jilin City Science and Technology Bureau (20166012). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.