EEG-Based Brain-Computer Interface Using Visual Flicker Imagination for Assistive Communication System

Brain-computer interface (BCI) technology can be an alternative solution for people with severe disabilities who have lost their movement and communication abilities. This study proposes a self-paced paradigm using visual flicker imagination as an alternative modality for steady-state evoked potential (SSVEP)-based BCI systems during visual-fatigue periods. This study comprises two main parts. First, we propose a visual-stimulus pattern with sequential numbers to exhibit the responses and observe the electroencephalogram (EEG) features of visual flicker imagination in offline testing. We confirmed that EEG signals in the occipital and frontal areas responded to visual flicker imagination. Second, an EEG-based BCI was demonstrated for assistive-communication system control using visual flicker imagination. Two experiments were conducted to verify the efficiency of the proposed system. Twelve volunteers participated in the experiment. The results revealed that the proposed SSVEP method and algorithm yielded average classification accuracies of approximately 93.8% and 77.1% for SSVEP and visual flicker imagination in real-time processing, respectively. The visual flicker-imagination approach can be utilized for real-time EEG-based BCI systems and can further enhance the efficiency of conventional SSVEP-based BCI systems during visual fatigue. We plan to improve and verify the proposed BCI system for practical use to control augmentative and alternative communication for people with severe disabilities.