VEP-Based Brain-Computer Interfaces: Time, Frequency, and Code Modulations

We described the three stimulus modulation approaches used in current VEP based BCIs: time modulation (t-VEP), frequency modulation (f-VEP), and pseudorandom code modulation (c-VEP). We then carried out a detailed comparison of system performance between an f-VEP BCI and a c-VEP BCI. The results show that an f-VEP BCI has the advantage of little or no training and simple system configuration, while the c-VEP based BCI has a higher communication speed. The stimulus modulation design is the crux of VEP based BCI systems. In future work, other stimulus modulation techniques, such as various multiple access methods used in communication systems, may be used to improve BCI performance. © 2006 IEEE.