1. Department of Neurology, Sleep Disorders Division, Vanderbilt University School of Medicine, Nashville, TN
2. Department of Oral and Maxillofacial Surgery, Vanderbilt University School of Medicine, Nashville, TN
3. Departments of Neurology and Otolaryngology, University of Michigan, Ann Arbor, MI
4. Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN