[1] Ann Arbor VA Healthcare Syst, VA Ctr Clin Management Res, Dept Vet Affairs, Ann Arbor, MI 48105 USA
[2] Univ Michigan, Dept Emergency Med, Ann Arbor, MI 48109 USA
[3] Univ Michigan, Dept Neurol, Ann Arbor, MI USA
[4] Duke Univ, Clin Trials Transformat Initiat, Durham, NC USA
[5] Fdn Interdisciplinary Motor Neuron Med, Metamora, MI USA
[6] Univ Michigan, Dept Pediat, Ann Arbor, MI 48109 USA