[1] Uppsala Univ, Dept Clin Neurophysiol, Inst Neurosci, Uppsala, Sweden
[2] George Washington Univ, Dept Neurol, Washington, DC 20052 USA
[3] Univ Calif Davis, Sch Med, Dept Neurol, Davis, CA 95616 USA
[4] Univ Miami, Miller Sch Med, Dept Neurol, Miami, FL 33136 USA