Using Mental Shadowing Tasks to Improve the Sound-Evoked Potential of EEG in the Design of an Auditory Brain–Computer Interface

Abstract

This study proposed an auditory stimulation protocol based on Shadowing Tasks to improve the sound-evoked potential in an EEG and the efficiency of an auditory brain–computer interface system. We use stories as auditory stimulation to enhance users’ motivation and presented the sound stimuli via headphones to enable the user to concentrate better on the keywords in the stories. The protocol presents target stimuli with an oddball P300 paradigm. To decline mental workload, we shift the usual Shadowing Tasks paradigm: Instead of loudly repeating the auditory target stimuli, we ask subjects to echo the target stimuli mentally as it occurs. Twenty-four healthy participants, not one of whom underwent a BCI use or training phase before the experimental procedure, ran twenty trials each. We analyzed the effect of the auditory stimulation based on the Shadowing Tasks theory with the performance of the auditory BCI system. We also evaluated the judgment effectiveness of the three ERPs components (N2P3, P300, and N200) from five chosen electrodes. The best average accuracy of post-analysis was 78.96%. Using component N2P3 to distinguish between target and non-target can improve the efficiency of the auditory BCI system and give it good practicality. We intend to persist in this study and involve the protocol in an aBCI-based home care system (HCS) for target patients to provide daily assistance.