[1] Columbia Univ, Neurol Inst, New York, NY USA
[2] Massachusetts Gen Hosp, Dept Neurol, Healey Ctr ALS, Boston, MA 02114 USA
[3] Cedars Sinai Med Ctr, Dept Neurol, Los Angeles, CA 90048 USA
[4] Emory Univ, Sch Med, Dept Neurol, Atlanta, GA 30322 USA
[5] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21205 USA
[6] Washington Univ, Sch Med, Dept Neurol, St Louis, MO 63110 USA
[7] Barrow Neurol Inst, Phoenix, AZ 85013 USA
[8] Penn State Hlth Milton S Hershey Med Ctr, Neurol, Hershey, PA USA
[9] Univ Washington, Dept Neurol, Seattle, WA 98195 USA
[10] Duke Univ, Dept Neurol, Durham, NC USA