Detection of motor imagery of swallow EEG signals based on the dual-tree complex wavelet transform and adaptive model selection.
OBJECTIVE
Detection of motor imagery of hand/arm has been extensively studied for stroke rehabilitation. This paper firstly investigates the detection of motor imagery of swallow (MI-SW) and motor imagery of tongue protrusion (MI-Ton) in an attempt to find a novel solution for post-stroke dysphagia rehabilitation. Detection of MI-SW from a simple yet relevant modality such as MI-Ton is then investigated, motivated by the similarity in activation patterns between tongue movements and swallowing and there being fewer movement artifacts in performing tongue movements compared to swallowing.


METHODS
Novel features were extracted based on the coefficients of the dual-tree complex wavelet transform to build multiple training models for detecting MI-SW. The session-to-session classification accuracy was boosted by adaptively selecting the training model to maximize the ratio of between-classes distances versus within-class distances, using features of training and evaluation data.


RESULTS
Our proposed method yielded averaged cross-validation (CV) classification accuracies of 70.89% and 73.79% for MI-SW and MI-Ton for ten healthy subjects, which are significantly better than the results from existing methods. In addition, averaged CV accuracies of 66.40% and 70.24% for MI-SW and MI-Ton were obtained for one stroke patient, demonstrating the detectability of MI-SW and MI-Ton from the idle state. Furthermore, averaged session-to-session classification accuracies of 72.08% and 70% were achieved for ten healthy subjects and one stroke patient using the MI-Ton model.


CONCLUSIONS
These results and the subjectwise strong correlations in classification accuracies between MI-SW and MI-Ton demonstrated the feasibility of detecting MI-SW from MI-Ton models.
Institute for Infocomm Research, Agency for Science, Technology and Research (A*STAR), Singapore.
Huijuan
H
Yang
Cuntai
C
Guan
Karen Sui Geok
KS
Chua
See San
SS
Chok
Chuan Chu
CC
Wang
Phua Kok
PK
Soon
Christina Ka Yin
CK
Tang
Kai Keng
KK
Ang
D000328:Adult; D000465:Algorithms; D062207:Brain-Computer Interfaces; D003198:Computer Simulation; D003679:Deglutition; D003680:Deglutition Disorders / Q000209:etiology / Q000503:physiopathology* / Q000534:rehabilitation*; D004569:Electroencephalography / Q000379:methods; D019054:Evoked Potentials, Motor; D005240:Feasibility Studies; D025461:Feedback, Physiological; D005260:Female; D006801:Humans; D007092:Imagination; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009068:Movement; D058765:Neurofeedback / Q000379:methods*; D020521:Stroke / Q000150:complications / Q000503:physiopathology; D000071939:Stroke Rehabilitation; D013647:Task Performance and Analysis; D014584:User-Computer Interface; D058067:Wavelet Analysis