Using Combination of μ,β and γ Bands in Classification of EEG Signals

Introduction: In most BCI articles which aim to separate movement imaginations, μ and β frequency bands have been used. In this paper, the effect of presence and absence of γ band on performance improvement is discussed since movement imaginations affect γ frequency band as well. Methods: In this study we used data set 2a from BCI Competition IV. In this data set, 9 healthy subjects have performed left hand, right hand, foot and tongue movement imaginations. Time and frequency intervals are computed for each subject and then are classified using Common Spatial Pattern (CSP) as a feature extractor. Finally, data is classified by LDA1, RBF2 MLP3, SVM4and KNN 5 methods. In all experiments, accuracy rate of classification is computed using 4 fold validation method. Results: It is seen that most of the time, combination of μ,β and γ bands would have better performance than just using combination of μ and β bands or γ band alone. In general, the improvement rate of the average classification accuracy is computed 2.91%. Discussion: In this study, it is shown that using combination of μ, β and γ frequency bands provides more information than only using combination of μ and β in movement imagination separations.