Application of a single-flicker online SSVEP BCI for spatial navigation

Abstract

A promising approach for brain-computer interfaces (BCIs) employs the steady-state visual evoked potential (SSVEP) for extracting control information. Main advantages of these SSVEP BCIs are a simple and low-cost setup, little effort to adjust the system parameters to the user and comparatively high information transfer rates (ITR). However, traditional frequency-coded SSVEP BCIs require the user to gaze directly at the selected flicker stimulus, which is liable to cause fatigue or even photic epileptic seizures. The spatially coded SSVEP BCI we present in this article addresses this issue. It uses a single flicker stimulus that appears always in the extrafoveal field of view, yet it allows the user to control four control channels. We demonstrate the embedding of this novel SSVEP stimulation paradigm in the user interface of an online BCI for navigating a 2-dimensional computer game. Offline analysis of the training data reveals an average classification accuracy of 96.9±1.64%, corresponding to an information transfer rate of 30.1±1.8 bits/min. In online mode, the average classification accuracy reached 87.9±11.4%, which resulted in an ITR of 23.8±6.75 bits/min. We did not observe a strong relation between a subject’s offline and online performance. Analysis of the online performance over time shows that users can reliably control the new BCI paradigm with stable performance over at least 30 minutes of continuous operation.

Hybrid Brain-Computer Interface Systems: Approaches, Features, and Trends

“…All visual stimuli have properties like frequency, color, and contrast which affect SSVEP. Stimuli frequency can be divided into low (1-12 Hz), medium (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and high bands. Visual fatigues and false positives can occur at low frequency bands, whereas flash and pattern reversal stimuli can provoke epileptic seizures above low frequency bands.…”

“…SSVEP-based BCI using single flicker stimulus is coded spatially to control four channels for navigation of 2-D computer games. Control channels are coded by their spatial position rather than flickering frequency or phase which may provide alternative route toward a practical SSVEP BCI with reduced visual strain [26]. To reduce visual fatigue from traditional SSVEP using flickering lights, an equal-luminance, ring-shaped, red-green colored checkerboard paradigm is used which produces high SSVEP power around 15 Hz [27].…”

“…Sensorimotor rhythms (SMRs) are synchronized brain waves over sensorimotor cortex in three different frequency bands: μ (8-12 Hz), β (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and γ . EEG recording is mostly limited to μ and β bands.…”

Simultaneous Decoding of Eccentricity and Direction Information for a Single-Flicker SSVEP BCI

“…The phenomenon, known as the retinotopic mapping [11,12], has gained increasing interest in recent BCI studies. While pilot BCI studies have mainly focused on designing visual spatial patterns to increase possible BCI target numbers [13] or enhance the signal-to-noise ratio (SNR) of SSVEP [14], efforts have been devoted to decoding the spatial information embedded in SSVEP responses directly [15,16]. Unlike the traditional frequency-coded SSVEP BCI paradigm in which SSVEP responses were modulated by targets with different frequencies [3,9], it is feasible to design a spatially-coded SSVEP BCI by encoding responses by targets with different spatial locations.…”

A Novel Dual And Triple RSVP Paradigm For P300 Speller

“…Depending on the diverse types of components of EEG signal, BCI systems can be divided into steady state visually evoked potentials (SSVEP)-based (Chen et al , 2017) and event-related potentials (ERP)-based (Zhang et al , 2012) systems, the latter being our area of focus in this paper. Event-related potentials are the brain's response to an external stimulus or event.…”