The general goal of this project is to identify and compare factors that influence speech recognition in competing talker backgrounds by listeners with hearing loss. The project will emphasize factors known to promote perceptual segregation of competing sounds in normal hearing listeners with particular focus on sentence segregation based on differences in fundamental frequency (FO), vocal tract length, and speaking rate. Aim 1 is to determine the relations between speech recognition in multi-talker backgrounds and two non-speech measures of auditory function: frequency selectivity, and sequential stream segregation. The number of competing talkers will be varied in order to explore the interplay between peripheral and perceptual masking. Aim 2 is to quantify the contributions of differences in talker fundamental frequency, vocal tract length, and speaking rate to the perceptual segregation of talkers by listeners with hearing loss. Aim 3 is to do the same for listeners with simulated cochlear implants. The number of simulated implant channels and maximum modulation rate within channels will be varied to determine the relative contributions of spectral and temporal cues. It is hypothesized that temporal segregation cues based on talker differences in speaking rate will be the most effective segregation cue for people with hearing loss and simulated cochlear implants. Aim 4 is to determine the extent to which listeners with hearing loss can use fundamental frequency excursion range within a talker to segregate the speech of two talkers, and to evaluate the interaction of within- and between-talker cues. The identification of factors involved in the perception of speech in competing-talker backgrounds by listeners with hearing loss is needed to develop improved remediation strategies for hearing loss. These remediation strategies may include improved hearing aid and cochlear implant signal processing designed to preserve cues that enhance talker separation, therapeutic strategies to address specific perceptual deficits, and training approaches aimed at strengthening listeners' reliance on under-weighted cues to speech perception. [unreadable] [unreadable] [unreadable]