1 From the Department of Neurology (A.B.S.), Massachusetts General Hospital, Boston; and the Department of Neurology (W.L.), Nationwide Children's Hospital, Columbus, OH. asinghal@mgh.harvard.edu.
2 From the Department of Neurology (A.B.S.), Massachusetts General Hospital, Boston; and the Department of Neurology (W.L.), Nationwide Children's Hospital, Columbus, OH.