PROJECT SUMMARY Cochlear implants (CI) are the standard of care for adults with sensorineural hearing loss that is beyond the therapeutic reach of hearing aids. Little is known about how current CI devices affect environmental sound recog- nition (ESR), a nonspeech outcome domain that is crucial for the safety, independence, and quality of life (QOL) for all CI users. Lacking robust evidence for how CIs affect ESR and the patient factors that influence ESR, hearing health professionals are limited in their ability to offer ESR rehabilitation and evidence-based counseling. This research study's investigators have found through pilot studies that ESR in postlingually deaf adults is significantly reduced and highly variable compared to normal hearing peers. Preliminary cross-sectional and longitudinal ESR assessments of environmental sounds presented in isolation ? in contrast to context-rich presentation of daily life ? have demonstrated that experienced adult CI users do not uniformly outperform CI candidates tested under best-aided conditions with hearing aids. The current study has two Specific Aims: (1) to longitudinally quantify change in ESR for postlingual adults using a novel context-rich ESR assessment to better approximate real-world everyday listening; and (2) to determine the relative contribution of ESR to CI-specific QOL as reported by CI users. It is hypothesized that (1) context- rich ESR will improve in adults following implantation, and (2) that ESR will contribute significantly to self-reported CI-specific QOL. To test these hypotheses, a prospective, longitudinal assessment of ESR and CI-specific QOL will be performed pre-CI through the first year of cochlear implantation in a sample of postlingual adults. The expected benefits of this study are that hearing health professionals will be able to (1) provide patients with evidence-based ESR predictions, (2) develop a more comprehensive understanding of the contributions of CI- specific QOL beyond speech perception, and (3) lay the groundwork for future ESR rehabilitation strategies for CI users who struggle in this important, overlooked CI outcome domain.