1. Medical College of Georgia and Augusta VA Medical Center, Department of Neurology, 1120 15th Street Augusta, GA 30904, USA
2. Henry Ford Hospital, Department of Neurology, 2799 West Grand Blvd., Detroit, MI 48202, USA
3. Stanford University School of Medicine, Department of Neurosurgery, R281, 300 Pasteur Drive, Stanford, CA, 94305, USA
4. University of Pittsburgh, Department of Neurological Surgery, Suite B-400, UPMC, 200 Lothrop Street Pittsburgh, PA 15213, USA