1. Vanderbilt Voice Center, Department of Otolaryngology; Nashville Tennessee
2. Division of Epidemiology, Department of Medicine; Vanderbilt University Medical Center; Nashville Tennessee
3. Saint Louis University School of Medicine; St. Louis Missouri
4. Vanderbilt University; Nashville Tennessee
5. Division of Otolaryngology, Wisconsin Surgical Outcomes Research, Department of Surgery; University of Wisconsin; Madison Wisconsin U.S.A.