1. Berry Consultants Austin Texas USA
2. Department of Biostatistics Vanderbilt University Medical Center Nashville Tennessee USA
3. Biostatistics Center Massachusetts General Hospital Boston Massachusetts USA
4. Department of Medicine Harvard Medical School Boston Massachusetts USA
5. Department of Neurology Barrow Neurological Institute Phoenix Arizona USA
6. Sean M. Healey & AMG Center for ALS at Mass General, Department of Neurology Massachusetts General Hospital Boston Massachusetts USA
7. Department of Neurology Harvard Medical School Boston Massachusetts USA
8. Neurological Institute of New York Columbia University New York New York USA
9. Department of Physical Medicine and Rehabilitation Spaulding Rehabilitation Hospital Boston Massachusetts USA