OBJECTIVE: The aim of this study was to examine the temporal stability of event-related desynchronization/synchronization (ERD/S) patterns over several sessions as a function of mental task, frequency band, brain region and time interval during the imagery period. METHODS: Nine volunteers participated in four sessions within 2 weeks of multi-channel EEG recordings. They performed seven mental tasks (i.e. mental rotation, word association, auditory imagery, mental subtraction, spatial navigation, imagery of familiar faces, motor imagery) during 7-s imagery periods. Cronbach's alpha coefficients were calculated over sessions to evaluate the stability of ERD/S values. RESULTS: The word association, mental subtraction and spatial navigation task showed highest stability. Cronbach's alpha coefficients were highest in the alpha bands (7-10, 10-13 Hz), poorer in the beta bands (13-20, 20-30 Hz) and poorest in the theta band (4-7 Hz). In the majority of tasks, the first time interval and posterior left regions showed highest stability and strongest ERD in the alpha and beta bands. CONCLUSION: Stability of ERD/S is strongly dependent on the specific task and differs between time intervals of the imagery period. Furthermore, stability was related to ERD in the alpha and beta bands. SIGNIFICANCE: The reliability of brain activation patterns is highly relevant for brain-computer interface developments.
OBJECTIVE: The aim of this study was to examine the temporal stability of event-related desynchronization/synchronization (ERD/S) patterns over several sessions as a function of mental task, frequency band, brain region and time interval during the imagery period. METHODS: Nine volunteers participated in four sessions within 2 weeks of multi-channel EEG recordings. They performed seven mental tasks (i.e. mental rotation, word association, auditory imagery, mental subtraction, spatial navigation, imagery of familiar faces, motor imagery) during 7-s imagery periods. Cronbach's alpha coefficients were calculated over sessions to evaluate the stability of ERD/S values. RESULTS: The word association, mental subtraction and spatial navigation task showed highest stability. Cronbach's alpha coefficients were highest in the alpha bands (7-10, 10-13 Hz), poorer in the beta bands (13-20, 20-30 Hz) and poorest in the theta band (4-7 Hz). In the majority of tasks, the first time interval and posterior left regions showed highest stability and strongest ERD in the alpha and beta bands. CONCLUSION: Stability of ERD/S is strongly dependent on the specific task and differs between time intervals of the imagery period. Furthermore, stability was related to ERD in the alpha and beta bands. SIGNIFICANCE: The reliability of brain activation patterns is highly relevant for brain-computer interface developments.
Authors: Svenja Espenhahn; Archy O de Berker; Bernadette C M van Wijk; Holly E Rossiter; Nick S Ward Journal: Neuroimage Date: 2016-12-10 Impact factor: 6.556