1. Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
2. Sean M. Healey & AMG Center for ALS & the Neurological Clinical Research Institute, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
3. Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
4. Department of Neurology, Washington University, St. Louis, MO, USA