1. Department of Otolaryngology, Harvard Medical School; Boston Massachusetts U.S.A.
2. Massachusetts Eye and Ear Infirmary; Boston Massachusetts U.S.A.
3. Massachusetts General Hospital; Boston Massachusetts U.S.A.
4. Department of Infectious Diseases, Massachusetts General Hospital; Boston Massachusetts U.S.A.
5. Department of Radiology, Massachusetts Eye and Ear Infirmary; Boston Massachusetts U.S.A.
6. Department of Neurosurgery; Hospital of the University of Pennsylvania; Philadelphia Pennsylvania U.S.A.