An Efficient 3D Column-Only P300 Speller Paradigm Utilizing Few Numbers of Electrodes and Flashings for Practical BCI Implementation

The event related P300 potentials, positive waveforms in

electroencephalography (EEG) signals, are often utilized in brain computer interfaces

(BCI). Many studies have been carried out to improve the performance of P300

speller systems either by developing signal processing algorithms and

classifiers with different architectures or by designing new paradigms. In this study, a new paradigm is proposed for this

purpose. The proposed paradigm combines two remarkable properties of being a 3D

animation and utilizing column-only flashings as opposed to classical paradigms

which are based on row-column flashings in 2D manner. The new paradigm is

utilized in a traditional two-layer artificial neural networks model with a

single output neuron, and numerous experiments are conducted to evaluate and

compare the performance of the proposed paradigm with that of the classical

approach. The experimental results, including statistical significance tests,

are presented for single and multiple EEG electrode usage combinations in 1, 3

and 15 flashing repetitions to detect P300 waves as well as to recognize target

characters. Using the proposed paradigm, the best average classification

accuracy rates on the test data are improved from 89.97% to 93.90% (an

improvement of 4.36%) for 1 flashing, from 97.11% to 98.10% (an improvement of

1.01%) for 3 flashings and from 99.70% to 99.81% (an improvement of 0.11%) for

15 flashings when all electrodes, included in the study, are utilized. On the

other hand, the accuracy rates are improved by 9.69% for 1 flashing, 4.72% for

3 flashings and 1.73% for 15 flashings when the proposed paradigm is utilized

with a single EEG electrode (P8). It is observed that the proposed speller paradigm is

especially useful in BCI systems designed for few EEG electrodes usage, and

hence, it is more suitable for practical implementations. Moreover, all

participants, given a subjective test, declared that the proposed paradigm is

more user-friendly than classical ones.<o:p></o:p>