A Study on RSVP Paradigm Based on Brain Computer Interface Across Subjects

Abstract

Most visual brain-computer interface (BCI) speller based on the event related potential (ERP) primarily use matrix layouts, and often need patients to complete spelling with moderate eye movement. The fundamental aim of our study is to enhance the perceptibility of target characters by introducing classical rapid serial visual presentation (RSVP) spellers that do not require any eye movement, thereby applying them to the paralyzed patients suffered from oculomotor nerve dysfunction, such as amyotrophic lateral sclerosis (ALS), spinal cord injury, stroke or muscular dystrophy. To test the feasibility of the proposed RSVP paradigm based-BCI, a series of symbols exploded quickly for 20 participants. The flash stimulus on time was 88 ms, and the off time was 22 ms. The effects of sequential letters on target induction with different colors were studied. The P300 component was locked on the target representation by time. The offline classification showed that the average accuracy of choosing the target symbol among 26 possibilities was as high as 90% and above. When calculating the accuracy across subjects under the condition of a certain sample size, the classification rate was changing, up to 68% with the increase of the number of subjects in the sample. The results showed that RSVP speller based-BCI is a promising new model and can be applied to patients with eye movement disorder.