Improving the performance of P300 BCI system using different methods

Abstract

A brain–computer interface (BCI) can be used for people with severe physical disabilities such as ALS, or amyotrophic lateral sclerosis. BCI can allow these individuals to communicate again by creating a new communication channel directly from the brain to an output device. BCI technology can allow paralyzed people to share their intent with others, and thereby demonstrate that direct communication from the brain to the external world is possible, and that it might serve useful functions. In this paper, we propose a system to exploit the P300 signal in the brain, a positive deflection in event-related potentials. The P300 signal can be incorporated into a spelling device. BCI systems include machine learning algorithms (MLA). Their performance depends on the feature extraction and classification techniques employed. This work discusses the performance of different machine learning algorithms. First, a preprocessing step is introduced to the subjects to extract the important features before applying the machine learning algorithms. The presented algorithms are linear discriminant analysis (LDA I and LDA II), support vector machine (SVM I, SVM II, SVM III, and SVM IV), linear regression (LREG), and Bayesian linear discriminant analysis (BLDA). It is found that BLDA and SVMIV classifiers yield the highest performance for both subjects considered in our study.