Reference Signal Effects on Task Discrimination Algorithms for EEG-based BCIs

O. Falzon and K.P. Camilleri (Malta)


Electroencephalography, Brain-Computer Interface, Reference Electrode Standardization Technique


The reference signal in EEG recordings can affect features such as signal energy, phase synchrony and coherence, acquired from the EEG data [1–3]. In this study we investigate the influence of referencing methods on the performance of task discrimination techniques used in BCIs. Together with more commonly used referencing methods we also consider the reference electrode stan dardization technique developed by Yao [4]. We perform tests on simulated as well as real EEG data. In particular, we use band power estimates, the method of common spatial patterns, and the phase-locking value, to determine the influence of the various referencing possibilities on classification rates for the discrimination of motor imagery tasks. The results obtained suggest that the phase synchronization measure is more sensitive to the choice of reference when compared to the band power estimates and the method of CSP. For the phase synchronization measure, references that attempt to reproduce a zero reference scalp voltage give the best performance.

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