1 Department of Neurosurgery, Stanford University School of Medicine, Stanford, California.
2 Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.
3 Department of Neurology, Stanford University School of Medicine, Stanford, California.
4 Department of Anesthesia, Stanford University School of Medicine, Stanford, California.
5 Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California.
6 Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania; Department of Surgery, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania. Electronic address: casey.halpern@pennmedicine.upenn.edu.