Program Director/Principal Investigator (Last, First, Middle): Gantz, Bruce J. PROJECT SUMMARY - OVERVIEW Hearing loss is a pervasive problem and, according to statistics from the NIDCD/NIH website, it is estimated that it affects nearly 37.5 million Americans aged 18 years and older. While remediation with hearing aids and cochlear implants has assisted those with moderate to profound loss, noise interferes with the ability to understand speech. Our research has identified the important advantage of combining acoustic+electric speech processing (A+E) to facilitate improved hearing in noise. Application of A+E processing has improved outcomes of cochlear implants in quiet and noise, but there is significant individual variability in outcome measures among subjects. To address these issues, this application requests continuation of the Iowa Cochlear Implant Clinical Research Center. In this proposal we will investigate hearing and auditory perception using studies that explore the mechanisms of electrical, acoustic, and A+E hearing from the auditory periphery to the cortex, including measures of cortical (re)organization and higher order language processing. Equally important, we also explore human ecology—factors in the person and in the environment that can mediate or impede successful communication and can be modified by A+E speech processing. Our overarching goal of this competitive renewal is to apply basic and cognitive neuroscience methodologies to assist us in addressing these fundamental questions about how individuals use both acoustic and electric auditory information. Four research projects, Human Ecology, Peripheral Electrophysiology, Central Auditory Integration and Cognitive Dynamics of Language Processing, an administrative and patient care/technical support cores are proposed. The overall objectives are to examine the impact that A+E processing function has on real-life socialization, cognition and quality of life issues, and to evaluate auditory processing from the periphery to cortical and higher level processing. We plan to study 200 newly implanted adult subjects with A+E hearing preservation implants, 50 subjects that use a hearing aid, 50 normal hearing subjects, and a combination of 300 previously implanted subjects with A+E, bimodal or single CIs that participate in our research registry. The four research projects are highly integrated and depend on data from each other to answer the experimental questions proposed.