[1] Univ Miami, Miller Sch Med, Miami, FL 33136 USA
[2] Univ Copenhagen, Herlev, Denmark
[3] Karolinska Inst, Stockholm, Sweden
[4] Univ British Columbia, Vancouver, BC, Canada
[5] Univ Copenhagen, Herlev & Gentofte Hosp, Herlev, Denmark
[6] Univ Michigan, Ann Arbor, MI 48109 USA
[7] Natl Rehabil Hosp, The Plains, VA USA