1. Neurological Clinical Research Institute, Massachusetts General Hospital, Boston, MA, United States
2. Harry J. Hoenselaar ALS Clinic, Henry Ford University, Detroit, MI United States
3. SLUCare ALS Clinic, Washington University, St Louis,MO, United States
4. Providence Portland Medical Center, Providence Brain and Spine Institute, Portland, OR, United States
5. Norman Fixel Institute for Neurological Diseases,University of Florida, Gainesville, FL,United States
6. Neuromuscular and ALS Clinic, Virginia Commonwealth University, Richmond, VA, United States
7. U.O. Riabilitazione Specialistica Neurologica, Istituti Clinici Scientifici Maugeri IRCCS, Milano, Italy
8. Neuromuscular Omnicentre, Milano, Italy
9. MDA/ALS Center of Hope, Temple University, Philadelphia, PA, United States
10. Les Turner ALS Center, Northwestern University, Chicago, IL, United States
11. Biostatistics, Harvard Medical School, Boston, MA, United States
12. Neurology, University of Minnesota, Minneapolis, MN, United States
13. Neurology, Marquette University, Milwaukee, WI, United States and
14. Neurology, Harvard Medical School, Boston, MA, United States