1. Duke Voice Care Center, Division of Otolaryngology–Head & Neck Surgery, Duke University Medical Center, Durham, North Carolina, USA
2. Division of Public Health & Study Design and Biostatistics Center, University of Utah, Salt Lake City, Utah, USA
3. Department of Communication Sciences and Disorders, and Division of Otolaryngology–Head & Neck Surgery (Adjunct), University of Utah, Salt Lake City, Utah, USA
4. Center for Outcomes Research, Department of Medicine, University of Illinois College of Medicine, Peoria, Illinois, USA
5. Department of Otolaryngology–Head & Neck Surgery, University of California, San Francisco, California, USA