Other form of BCIs includes hybrid versions, which combines paradigms such as P300, visual or audio to improve the accuracy and efficiency in BCI operations. SSVEP uses non-muscular communication channel and that makes it widely acceptable in brain–computer interface (BCI) applications, where it can support people with disabilities to control external application with multiple visual stimuli. Studies have also explored the application of SSVEP responses for infants in investigating visual acuity and cortical functions. Researchers have also explored SSVEP application in emotion and electrophysiological study to explore the face inversion effect and the N170 potential. SSVEP-based electroencephalogram (EEG) responses are used in medical diagnosis for investigating visual perceptions, user attention or brain responses to identify any symptoms or other medical conditions. SSVEP is widely used in academic and clinical research studies due to the minimal amount of training required and also as it allows a higher signal-to-noise ratio. SSVEP is a periodic response generated in the occipital region of the brain when the user focuses on a flashing visual stimulus and would have the same frequency as the presented visual stimulus. Steady-state visual evoked potential (SSVEP) is elicited in the brain when a user attentively gazes at a visual stimulus flashing at a constant frequency. This could pave the way for increased usage of SSVEP for practical applications. Electroencephalogram data was recorded with PWM duty-cycles of 50–95% generated by a precise custom-made light-emitting diode hardware and tested ten subjects responded that increasing duty-cycles had less visual strain for all the frequency values and the SSVEP exhibited a subject-independent peak response for duty-cycle of 85%. Here, the authors study the use of extremely high duty-cycles in the stimulus in the hope of solving these constraints. Various studies have suggested the usage of high frequencies of visual stimulus to reduce the visual fatigue for the user but this results in poor response performance. This combined with the difficulty in establishing precise pulse-width modulation (PWM) that results in poorer accuracy warrants the development of appropriate approach to solve these issues. However, one major impediment in using flashing visual stimulus to obtain SSVEP is eye fatigue that prevents continued long-term use preventing practical deployment. Steady-state visual evoked response (SSVEP) is widely used in visual-based diagnosis and applications such as brain–computer interfacing due to its high information transfer rate and the capability to activate commands through simple gaze control. IET Generation, Transmission & Distribution.
IET Cyber-Physical Systems: Theory & Applications.IET Collaborative Intelligent Manufacturing.CAAI Transactions on Intelligence Technology.
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