SUSCEPTIBILITY TO AND RELEASE FROM MASKING IN INFANCY AND CHILDHOOD

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 DESCRIPTION (provided by applicant): Infants and children are at a disadvantage relative to adults when listening to speech in the presence of competing sounds. These developmental effects can be striking when the competing sounds are also speech, and are substantially larger for children with hearing loss than children with normal hearing. Despite growing awareness that infants and children spend the majority of their days in multi-talker environments, little is currently known about the specific factors that limit children's hearing in competing speech. In addition, it is unclear how hearing loss impacts children's ability to "hear out" a target talker when multiple people are speaking at the same time. The long-term goal of this project is to understand the maturation of hearing in complex acoustic environments that contain multiple sources of competing sounds. The proposed experiments will isolate factors that limit children's abilities to separate target from competing speech and will evaluate the extent to which speech-on-speech recognition improves for children with hearing loss when acoustic cues thought to promote sound segregation are provided. Aim 1 will evaluate the extent to which children capitalize on glimpses of improved signal-to-noise ratio (SNR), associated with masker fluctuations, to recognize target speech in a speech masker. It is hypothesized that children will benefit less from modulation than adults due to their reduced auditory experience. Aim 2 will evaluate the relative impact of listener factors such as age and degree of hearing loss on the development of speech-on-speech masking for children with congenital hearing loss. It is hypothesized that variable and/or degraded auditory experience as a result of hearing loss interferes with the maturation of perceptual processing abilities, such as those related to the segregation of target from background speech. Aim 3 will evaluate the practical consequences of enhancing acoustic cues thought to aid in the segregation of sounds for children with hearing loss. It is hypothesized that children with hearing loss benefit from the provision of these acoustic cues, provided that high-quality access is supported by their sensory system and hearing aids. The results of the proposed studies are expected to provide fundamental knowledge regarding the development of speech perception under adverse listening conditions from infancy to adulthood. Completion of the proposed experiments may also generate feasible intervention strategies that improve receptive communication outcomes for children with hearing loss.