Brain-Computer Interface: Usability Evaluation of Different P300 Speller Configurations: A Preliminary Study

Brain-Computer Interface (BCI) is particularly relevant as a new way to interact with the outside world for disabled people. Based on P300 event-related potentials (ERPs) BCIs have been frequently used for communication purposes, being the first P300-based BCI paradigm developed by Farwell and Donchin for visual speller._P300-BCI speller studies require a significant attentional demand during sustained long times which could represent fatigue and feeling of increasing workload. The evaluation of workload while using P300-BCI speller requires taking into account the cognitive, emotional and physical state of participant during task. This would help to improve usability of the system. The objective of the study is to evaluate, through objective and subjective measures, three different size of speller in order to analyze effectiveness, cognitive load and user comfort. Three healthy subjects took part in the experiment. The preliminary results suggest that speller size can have different effects on user performance and represent important workload for subjects.