[1] Univ Washington, Sch Med, Dept Rehabil Med, 325 9th Ave,Box 359612, Seattle, WA 98104 USA
[2] Univ Washington, UW Multiple Sclerosis Ctr, Sch Med, Dept Neurol, 1536 N 115th St,McMurray Bldg,Suite 130, Seattle, WA 98133 USA
[3] Univ Washington, Sch Med, Dept Psychiat & Behav Sci, 1959 NE Pacific St,Box 356560, Seattle, WA 98195 USA