A Study of Auditory Speech Processing using Brainstem Evoked Responses under Quiet and Noisy Conditions

Abstract

This work investigates auditory speech processing through measurement of brainstem responses to the synthetic vowel /a/, and variants containing the first formant (F1) only or the second and third formants only, in quiet and in white background noise. The results show that the response at the fundamental frequency (F0) is more robust to noise than the response at F1. This study also provides an insight into the potential locations where the pitch of resolved and unresolved harmonics is extracted in the auditory system, and how the frequency regions dominated by resolved/unresolved harmonics contribute to the response at F0. Based on the results, a conceptual model of the neural processing underlying the generation of the electrophysiological response at F0 is proposed.