1. Veterans Affairs Rehabilitation Research and Development Service, National Center for Rehabilitative Auditory Research, VA Portland Health Care System, Portland, OR, USA,
2. Department of Otolaryngology—Head and Neck Surgery, Oregon Health and Science University, Portland, OR, USA,
3. GN Advanced Science, Glenview, IL, USA, and
4. Mental Health Service, VA Portland Health Care System, Portland, OR, USA