1. Amyotrophic Lateral Sclerosis Center of Oregon and Electrodiagnostic Laboratory, and Neuromuscular Disease Program, Oregon Health and Science University, Portland, OR, USA
2. Department of Neurology, Muscular Dystrophy Association/Amyotrophic Lateral Sclerosis Center and Electrodiagnostic Laboratory, University of Washington Medical Center, Seattle, WA, USA
3. Muscular Dystrophy Association/Amyotrophic Lateral Sclerosis Center, University of Washington Medical Center, Seattle, WA, USA,