Title: Impact of electrode positions and harmonic frequency components in SSVEP-based BCIs

Authors: S. Xing; A.J. McDaid; S.Q. Xie

Addresses: Mechatronics Group, Department of Mechanical Engineering, The University of Auckland, Private Bag 92019, Auckland, New Zealand ' Mechatronics Group, Department of Mechanical Engineering, The University of Auckland, Private Bag 92019, Auckland, New Zealand ' Mechatronics Group, Department of Mechanical Engineering, The University of Auckland, Private Bag 92019, Auckland, New Zealand

Abstract: Steady state visual evoked potential (SSVEP) based brain computer interfaces (BCIs) have been recognised as having major potential to be used practically in everyday daily life as they typically outperform more traditional BCIs in terms of detection accuracy and information transfer rates. It is also essential to improve the ease of use such as reducing the number of necessary electrodes without decreasing speed or accuracy. This study investigated the extent to which electrode positions, derivation methods, and harmonics will affect the performance of a SSVEP-based BCI. A pilot study was carried out on a 4-class SSVEP-based BCI with six healthy subjects. Detection accuracy increased from 63.75 ± 5.62% (mean ± SD) with monopolar derivation to 89.42 ± 5.58% with two-channel bipolar derivation using only harmonic H1. The significantly improved detection accuracy with two electrodes implies that it is possible to achieve high classification accuracy with a very low number of electrodes.

Keywords: electroencephalograms; EEG signals; steady state visual evoked potential; SSVEP; electrode positions; harmonic frequency; BCI; brain-computer interface; derivation methods; harmonics; detection accuracy; classification accuracy.

DOI: 10.1504/IJISTA.2015.074079

International Journal of Intelligent Systems Technologies and Applications, 2015 Vol.14 No.2, pp.168 - 184

Received: 29 Jan 2015
Accepted: 27 Oct 2015
Published online: 06 Jan 2016 *

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