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 LDA, RBF MLP, SVM and KNN 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.