Mu and beta rhythm modulations in motor imagery related post-stroke EEG: a study under BCI framework for post-stroke rehabilitation

Multiscale topological properties of functional brain networks during motor imagery after stroke

“…Beta rhythms during MI have been correlated to sensorimotor processes in healthy subjects (McFarland et al, 2000) and stroke patients (Gerloff et al, 2006). In the latter, the relative asymmetry between ipsilesional and contralesional hemispheres during contralateral MI and its relationship with functional motor impairment remain debated (Graziadio et al, 2012;Shahid et al, 2010). Here, the involvement of beta oscillatory activity is consistent with its function in the processing of overt and covert motor performance and corroborates previous observations of changes in EEG activity after stroke.…”

Research on Algorithm for Feature Extraction and Classification of Motor Imagery EEG Signals

“…As the wavelet db possesses excellent local characteristics in both time and frequency domains [11] , in this paper, wavelet db4 in the time length of 1s is selected as the wavelet function to carry out 4 From Figure3, it can be seen that during left hand motor imagination, obvious ERD/ERS occurs at the sample points of 600-700 in Channels C 3 and C 4 ; from Figure 4, it can be seen that during right hand motor imagination, obvious ERD/ERS occurs at the sample points of 700-800 in Channels C 3 and C 4 .…”

“…The research on BCI projects based on motor imagery EEG signals was firstly carried out by Pfurtscheller et al The result showed that, during unilateral limb movement or motor imagery, Event related desynchronization(ERD) was produced in the contralateral brain areas and event related synchronization (ERS) [2] was produced in the ipsilateral brain area. Specifically, during the experiment, the cerebral cortex where channels C 3 and C 4 were located represented the area of right and left hands motor imagery in the brain; during the motor imagery, ERD/ERS in the areas on both sides of the brain was symmetrical, i.e., during the right hand motor imagery, ERD occurred on the cerebral cortex for motor imagery in the left area of the brain while ERS occurred on the cerebral cortex in the right area of the brain; and vice versa. Further research showed that during the motor imagery, obvious ERD/ERS phenomenon occurred mainly within the frequencies of Rhythm μ (8-12Hz) and Rhythm β (18-24Hz) of the corresponding cerebral cortex for motor imagery in the contralateral brain areas, and at these time points, the energy in the frequencies of Rhythm μ and Rhythm β decreased (or increased) [3][4][5][6] .…”

“…Specifically, during the experiment, the cerebral cortex where channels C 3 and C 4 were located represented the area of right and left hands motor imagery in the brain; during the motor imagery, ERD/ERS in the areas on both sides of the brain was symmetrical, i.e., during the right hand motor imagery, ERD occurred on the cerebral cortex for motor imagery in the left area of the brain while ERS occurred on the cerebral cortex in the right area of the brain; and vice versa. Further research showed that during the motor imagery, obvious ERD/ERS phenomenon occurred mainly within the frequencies of Rhythm μ (8-12Hz) and Rhythm β (18-24Hz) of the corresponding cerebral cortex for motor imagery in the contralateral brain areas, and at these time points, the energy in the frequencies of Rhythm μ and Rhythm β decreased (or increased) [3][4][5][6] . A complete BCI system mainly includes acquisition, preprocessing, feature extraction, pattern recognition, control equipment and peripheral equipment for EEG signals [7] , among which feature extraction and pattern recognition are the most critical parts.…”

Classification of EEG signal from imagined writing using a combined Autoregressive model and multi-layer perceptron

“…The frequency that typically uses to record motor imagery activity is in the range of 8-30Hz which include Alpha/Mu rhythm at 8-13 Hz and Beta rhythm at 13-30Hz [5,6]. The Mu rhythm is usually used by researcher to design an application to control an activity using imagination [6].…”