[1] Mayo Clin, Coll Med, Dept Neurol, 200 First St SW, Rochester, MN 55905 USA
[2] Mayo Clin, Ctr Multiple Sclerosis & Autoimmune Neurol, Rochester, MN 55905 USA
[3] Mayo Clin, Coll Med, Dept Neurol, Rochester, MN USA
[4] Mayo Clin, Coll Med, Dept Lab Med & Pathol, Rochester, MN USA
[5] Mayo Clin, Coll Med, Dept Quantitat Hlth Sci, Rochester, MN USA