SMR-Speller: A novel Brain-Computer Interface spell paradigm

P300-Speller is a typical Brain-Computer Interface (BCI) application, which aimed to construct a direct communication pathway between human brain and computer. Its performance declines as time goes by. And it can cause uncomfortable visual fatigue which makes it not adequate for longtime use. In this paper, we present a novel mental speller paradigm, Sensorimotor Rhythms Speller (SMR-Speller), in which four Motor Imagery (MI) potentials are translated into four move commands, respectively, to select symbols arranged in two cross-like layers. Symbols are distributed by the letters' use frequencies. The proposed mental speller can provide an enduring communication channel for people who are suffering severe neuromuscular disorders only through decoding their brain oscillations.