Neural representation of consonant-vowel transition in individuals with cochlear hearing loss and auditory neuropathy spectrum disorder.

Abstract

Acoustic change complex (ACC) is an evoked potential recorded in response to subtle change(s) in the continuing stimuli. It is assumed that poor speech perception can be due to poor encoding of consonant-vowel (CV) transition in cochlear hearing loss (CHL) and auditory neuropathy spectrum disorder (ANSD). The present study aims to investigate the use of ACC as an objective tool to study neural representation of CV transition in individuals with ANSD, CHL, and normal hearing (NH). The study consisted of three groups of population (NH, ANSD, and CHL) in the age range of 18-40years. ACC was recorded for naturally produced CV stimulus /sa/ of 380ms in duration, which consists consonant (150ms) and vowel (230ms) using Biologic Navigator pro 7.2.1. The result showed significantly prolonged latencies of ACC in individuals with ANSD compared to NH. The current study also showed significantly prolonged latency and significantly lower peak-to-peak amplitude in individuals with ANSD compared to CHL. The interesting finding of the present study was significantly better peak-to-peak amplitude for CHL compared to NH. Whereas, there was no significant difference between NH and CHL for latencies measures. Poor neural synchronization in individuals with ANSD could be the reason of poor neural representation of CV transition in present study. The outcome of the present study showed poor neural representation of CV transition in individuals with ANSD compared to CHL and NH. Current study also showed better encoding of CV transition in individuals with CHL compared to ANSD.