PROJECT SUMMARY/ABSTRACT Even with recent improvements in the early identification of hearing loss, children with mild bilateral hearing loss (MBHL) continue to experience significant delays in communication, social, and academic outcomes due to uncertainty about the benefits of hearing aids for this population. The lack of clinical protocols and tools that are sensitive to the listening needs of children with MBHL contribute to this uncertainty. Children with MBHL often perform like children with normal hearing on current clinical outcome measures. The goal of this proposal is to develop novel clinical protocols and tools that are sensitive to the challenges faced by children with MBHL. Current hearing-aid candidacy criteria based on the audiogram do not adequately quantify the effects of the child’s ear-canal acoustics and self-generated noise on their thresholds. Aim 1 of the proposal will be to develop audibility-based hearing-aid candidacy tools for children with MBHL that account for ear-canal acoustics and self-generated noise. Novel audiological assessment methods will allow for quantification of these factors and for the development of hearing-aid candidacy criteria based speech audibility that are not possible with current methods. Aim 2 of the proposal will be to validate clinical measures of speech recognition with speech maskers, reverberation, and overhearing that reflect real-world difficulties of children with MBHL. The reduction in audibility for low-intensity sounds is the main consequence of MBHL, which leads to difficulty segregating a target talker from a background talker, understanding speech in noise with reverberation, and problems with overhearing distant talkers. Clinical speech recognition tasks that reflect these specific listening challenges will be developed and validated. Aim 3 of the proposal will be to perform a clinical validation of a new test battery for hearing assessment, hearing-aid candidacy, and outcomes for children with MBHL. In collaboration with leading pediatric audiology centers around the U.S., the novel assessment and speech recognition measures will be used to validate these measures with a large clinical population of children with MBHL. The knowledge generated from this research will fundamentally improve the diagnosis and management of MBHL during childhood.