Open AccessA novel approach of decoding EEG four-class motor imagery tasks via scout ESI and CNN
Author(s) -
Yimin Hou,
Zhou Lu,
Shuyue Jia,
Xiangmin Lun
Publication year - 2020
Publication title -
journal of neural engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.594
H-Index - 111
eISSN - 1741-2560
pISSN - 1741-2552
DOI - 10.1088/1741-2552/ab4af6
Subject(s) - fist , computer science , motor imagery , convolutional neural network , artificial intelligence , electroencephalography , morlet wavelet , pattern recognition (psychology) , classifier (uml) , brain–computer interface , decoding methods , wavelet transform , wavelet , discrete wavelet transform , algorithm , psychology , physiology , psychiatry , biology
Objective . To develop and implement a novel approach which combines the technique of scout EEG source imaging (ESI) with convolutional neural network (CNN) for the classification of motor imagery (MI) tasks. Approach . The technique of ESI uses a boundary element method (BEM) and weighted minimum norm estimation (WMNE) to solve the EEG forward and inverse problems, respectively. Ten scouts are then created within the motor cortex to select the region of interest (ROI). We extract features from the time series of scouts using a Morlet wavelet approach. Lastly, CNN is employed for classifying MI tasks. Main results . The overall mean accuracy on the Physionet database reaches 94.5% and the individual accuracy of each task reaches 95.3%, 93.3%, 93.6%, 96% for the left fist, right fist, both fists and both feet, correspondingly, validated using ten-fold cross validation. We report an increase of up to 14.4% for overall classification compared with the competitive results from the state-of-the-art MI classification methods. Then, we add four new subjects to verify the validity of the method and the overall mean accuracy is 92.5%. Furthermore, the global classifier was adapted to single subjects improving the overall mean accuracy to 94.54%. Significance . The combination of scout ESI and CNN enhances BCI performance of decoding EEG four-class MI tasks.