1. Department of Otolaryngology University of Pittsburgh Pittsburgh Pennsylvania U.S.A.
2. Veteran's Affairs Pittsburgh Healthcare System Pittsburgh Pennsylvania U.S.A.
3. Department of Otolaryngology Thomas Jefferson University Philadelphia Pennsylvania U.S.A.
4. A.T. Still University Medical School Kirksville Missouri U.S.A.
5. Division of Pulmonology, Allergy, Critical Care, and Sleep Medicine University of Pittsburgh Pittsburgh Pennsylvania U.S.A.
6. Department of Otolaryngology University of Pennsylvania Philadelphia Pennsylvania U.S.A.