[1] Univ Florida, Dept Emergency Med & Neurol Surg, Gainesville, FL 32608 USA
[2] Mayo Clin, Coll Med, Dept Emergency Med, Rochester, MN 55905 USA
[3] Univ Rochester, Med Ctr, Dept Neurosurg, Rochester, NY 14623 USA
[4] Mayo Clin, Dept Neurol, Rochester, MN 55905 USA