1. VA Portland Health Care System, National Center for Rehabilitative Auditory Research, Portland, Oregon, USA
2. Department of Otolaryngology, Head and Neck Surgery, Oregon Health and Science University, Portland, Oregon, USA
3. Hearing and Balance Research Program James H. Quillen VA Medical Center, Mountain Home, Tennessee, USA
4. Department of Audiology and Speech Language Pathology, East Tennessee State University, Johnson City, Tennessee, USA
5. Boys Town National Research Hospital, Omaha, Nebraska, USA
6. Department of Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, MD, and Johns Hopkins Cochlear Center for Hearing and Public Health, Johns Hopkins University, Baltimore, Maryland, USA.