[1] Univ British Columbia, Dept Phys Med & Rehabil, Vancouver, BC V5Z 1M9, Canada
[2] Sahlgrens Acad, Inst Neurosci & Physiol, Gothenburg, Sweden
[3] VA Med Ctr, Dept Vet Affairs VA Rehabil Res & Dev Ctr Excelle, Spinal Cord Injudr Serv, Bronx, NY USA
[4] VA Med Ctr, Dept Vet Affairs VA Rehabil Res & Dev Ctr Excelle, Med Serv, Bronx, NY USA
[5] Rehabil Inst Chicago, Dept Phys Med & Rehabil, Chicago, IL 60611 USA
[6] Univ London Imperial Coll Sci Technol & Med, Fac Med, Neurovasc Med Unit, London SW7 2AZ, England
[7] UCL, Natl Hosp Neurol & Neurosurg, Inst Neurol, Auton Unit, London WC1E 6BT, England
[8] Thomas Jefferson Univ, Dept Rehabil Med, Philadelphia, PA 19107 USA