The effects of hearing loss and envelope processing on speech understanding in adverse acoustics during childhood

Abstract

Children with hearing loss (CHL) experience greater difficulty understanding speech in the presence of noise and reverberation relative to their normal hearing (CNH) peers despite provision of appropriate amplification. The fundamental frequency of voice (f0)—a salient temporal cuei—could play a significant role. However, the nature of deficits and its relationship with speech understanding are poorly understood. To this end, we evaluate the role of f0 encoding on speech perception abilities of CNH and CHL in the presence of noise and/or reverberation. In 14 CHL and 29 CNH, envelope following responses (EFRs) were elicited by vowels, modified to estimate f0 encoding in low (<1 kHz) and higher frequencies. Both groups demonstrated a frequency-dependent dichotomy in the disruption of f0 encoding– greater disruption at low frequencies due to noise and greater disruption at the high frequencies due to reverberation. In contrast to CNH, CHL demonstrated: (a) greater disruption of f0 encoding at low frequencies, particularly in the presence of reverberation, (b) a positive relationship between f0 encoding at low frequencies and speech discrimination. Together, these results provide evidence for the persistence of suprathreshold temporal processing deficits in children despite the provision of appropriate amplification to compensate for hearing loss.