[1] Johns Hopkins Univ, Johns Hopkins Med Inst, Dept Neurol, Brain Injury Outcomes Div, Baltimore, MD 21287 USA
[2] Johns Hopkins Univ, Johns Hopkins Med Inst, Dept Neurol, Neurosci Crit Care Div, Baltimore, MD 21287 USA
[3] Heidelberg Univ, Dept Neurol, D-6900 Heidelberg, Germany