Brain-Computer Interface Channel-Selection Strategy Based on Analysis of Event-Related Desynchronization Topography in Stroke Patients

Figure 5

Time-frequency graph and ERD topography during motor attempt for S2. (a) Unaffected band (left) movement: During the first to third second, the subject was in resting state. During the fourth to seventh second, the subject was conducting the required task. During the motor attempt of the unaffected left hand, apparent decline was identified in power spectral density on contralateral C4 compared with the resting state, based on Morlet Wavelet time-frequency analysis. (b) Affected band (right) movement: During the first to third second, the subject was in resting state. From the fourth to seventh second, the subject was required to conduct the motor attempt task. During the motor attempt of the paretic right hand, no apparent decline was found in power spectral density on contralateral C3 compared with resting state, based on Morlet Wavelet time-frequency analysis. Correspondingly, no ERD was shown in the ERD ratio-map.

(a)

(b)