Assessment of Speech Discrimination Based on the Event-Related Potentials to the Visual Stimuli

Monitoring user states is one of the main applications in the e-Health field. This paper focuses on the assessment of speech discrimination for fitting the parameters of hearing aids using the electroencephalogram (EEG). The characteristic of our method is to utilize the event-related potentials (ERPs) to visual stimuli instead of the conventional auditory stimuli. A letter is played through a speaker as an initial auditory stimulus; then, the same letter is displayed on a screen as a following visual stimulus as a match condition (p = .50), and sometimes a different letter is displayed as a mismatch condition (p = .50). The participant then determines whether the two stimuli represent the same letter or not. The conventional evaluation focused on the evoked potentials just after the initial auditory stimuli. A larger component of late positive potential (LPP) is elicited when a participant detects the mismatch between the auditory and visual stimuli. These results suggest the possibility of assessing speech discrimination using EEG potentials.