Dual-frequency steady-state visual evoked potential for brain computer interface

This study presents a new steady-state visual evoked potential (SSVEP) for brain computer interface (BCI) systems. The goal of this study is to increase the number of selections using fewer stimulation frequencies. This study analyzes the SSVEPs induced by six groups of light-emitting diodes (LEDs). The proposed method produces more selections than the number of stimulation frequencies through a suitable combination of dual frequencies for stimulation. Further, the six groups of LEDs are generated by four frequencies. The symmetric harmonic phenomena in this study helps increase recognition efficiency. This study tests seven subjects to verify the feasibility of the proposed method.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (108 K)Download as PowerPoint slideResearch highlights▶ Each flicker comprises two flashing LEDs with different flickering frequencies. ▶ The main frequencies are f1 and f2, and the symmetric harmonic frequency is fhs = 2f1 − f2. ▶ Another symmetric harmonic frequency is fhb = 2f2 − f1. ▶ The symmetric harmonic phenomenon helps increase the recognition efficiency.