Developmental hearing loss in conjunction with early life stress: Perceptual deficits and central auditory correlates

Abstract

In children with otitis media, the conductive hearing loss (CHL) accompanying infection is a risk factor for later problems with speech perception. These perceptual deficits can persist long after auditory thresholds return to normal, suggesting they may be mediated by changes within the central auditory system. Using animal models of developmental CHL, we have demonstrated perceptual deficits for several temporally-varying signals that comprise speech. Furthermore, these perceptual deficits are correlated with impaired encoding in auditory cortex, indicating that central changes emerge from early auditory deprivation. In our transient developmental CHL model, which mimics the intermittent bouts of hearing loss experienced by children with otitis media, deficits are much alleviated by adulthood. However, early-life stress (ELS) has been described as an additional risk factor for speech problems arising from otitis media. Our data indicate that ELS alone induces deficits in the perception of temporally varying signals. Furthermore, animals experiencing both early transient CHL and ELS have perceptual deficits lasting into adulthood, the magnitude of which is greater than the sum of the individual deficits. These results raise the possibility that early life stress, alone or in conjunction with early CHL, may adverely impact speech perception in humans.