1. Department of Neurosurgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland
2. Department of Neurology, The Johns Hopkins Medical Institutions, Baltimore, Maryland
3. Department of Emergency Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland
4. Department of Neurology, Mt. Sinai Hospital, New York, New York
5. Department of Neuroradiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland
6. Department of Neurosurgery, Mt. Sinai Hospital, New York, New York
7. Department of Neurosurgery, Medical College of Virginia, Richmond, Virginia
8. Department of Neurology, Columbia-Presbyterian Medical Center, New York, New York
9. Department of Neurology, University Hospital, Innsbruck, Austria