A wavelet tool to discriminate imagery versus actual finger movements towards a brain-computer interface

Abstract

The present work explores the spatiotemporal aspects of the eventrelated desynchronization (ERD) and synchronization (ERS) during rhythmic finger tapping execution and imagery task. High resolution event related brain potentials were recorded to capture the brain activation underlying the motor execution and motor imagery. ERS and ERD were studied using a complex morlet wavelet decomposition of EEG responses. The results show similar patterns of beta ERD/ERS after the stimulus onset, for both the actual and imagery finger tapping task. This approach and results can be regarded as indicative evidences of a new strategy for recognizing imagined movements in EEG-based brain computer interface research. The long-term objective of this study is to create a multiposition brain controlled switch that is activated by signals that are measured directly from a human's brain. © Springer-Verlag Berlin Heidelberg 2006.