1. Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
2. Division of Emergency Medicine, Boston Children's Hospital, Boston, Massachusetts, USA.
3. School of Medicine, Boston University, Boston, Massachusetts, USA.
4. Duke University School of Medicine, Duke University Medical Center, Durham, North Carolina, USA.
5. Harvard Medical School, Boston, Massachusetts, USA.
6. Department of Neurology, Karolinska University Hospital, Stockholm, Sweden.