No changes have been made since the original submission. Project Summary The overarching theme of this K23 application is to develop a research program with the aim of improving outcomes for children with hearing loss (HL) and to further my career as a clinician-scientist. In order to develop a career as a clinician scientist, together with my mentors, we have developed a training program that includes three goals: 1) utilizing evoked potential responses to develop a biomarker of infant speech discrimination, 2) learning techniques to establish predictive validity, and 3) in-depth training in longitudinal statistical analysis. This training will be accomplished through mentorship, didactic course work, and a research project. This research project was developed due to the considerable variation in speech and language outcomes in children with HL. While many gains have been made since the beginning of newborn hearing screenings, there is still significant work that needs to be done to optimally fit amplification in infants with HL, to decrease the gap in listening and spoken language abilities between normal hearing and hard-of- hearing children. Behavioral techniques such as a conditioned head turn are available to assess speech discrimination in infants. These techniques, however, are limited both by a minimum age limit and by impracticality for the large group of infants with secondary disabilities. Development of a biomarker for infant speech discrimination would significantly impact the 3 out of 1000 infants per year identified with permanent HL. As a first step, this application seeks to validate a biomarker of infant speech perception that can be measured shortly after the fitting of amplification, using an event-related potential known as the mismatch response/negativity (MMR/N). Our longitudinal study design will allow examine the relationship of MMR/N (measured at 3 months) with behavioral speech perception (measured at 9 months), and later language abilities (measured at 16, 24, and 30 months). The proposed research will advance MMR/N approaches in infants with HL and determine if MMR/N can be used as a measure of speech discrimination in this population. The central hypothesis of this proposal is that MMR/N, measured at 3 months of age, will be a related to language abilities 30 months of age. The research training provided by the K23 funding mechanism will allow me to widen my knowledge base in auditory evoked potentials as a model for biomarker development, learn new approaches to establishing validity between two different measures, including longitudinal follow-up, as well as develop an independent line of research. The ultimate goal of this research and training program is to prepare the PI for a career as a sustainably funded clinician-scientist who focuses on the need for translational research linking mechanisms of infant speech perception to evidence based clinical practice.