Changes in mu and beta amplitude of the EEG during upper limb movement correlate with motor impairment and structural damage in subacute stroke

Objective: Mu and beta EEG oscillations show typical desynchronization patterns during movement. The aim of the current study was to assess whether in sub-acute stroke patients the magnitude of movement-related desynchronization reflects the extent of residual motor ability in the paretic upper limb. Methods: EEG and EMG data were recorded from 14 first-event stroke patients during repeated wrist extension movements of the paretic upper limb. Residual motor ability was assessed by the Fugl Meyer and Box and Blocks standardized clinical tests. Normalized lesion data was analyzed using the MEDx software. Results: The magnitude of event-related de-synchronization (ERD) of the high-mu and low-beta bands of the EEG, measured over the affected hemisphere, correlated significantly with (a) residual motor function in the paretic upper limb as measured by standard clinical tests; (b) the magnitude of EMG recorded from the paretic upper limb during wrist extension; and (c) the total hemispheric volume loss (negative correlation). Conclusion: The magnitude of high-mu and low-beta ERD recorded from the lesioned hemisphere of subacute stroke patients correlates with residual motor ability in the paretic upper limb. Significance: Measures derived from quantitative EEG analysis may play an important role in neurorehabilitation clinical practice.