1From the Department of Physical Medicine and Rehabilitation, Northwestern University Medical School, (E.J.R., S.A.D.), the Rehabilitation Institute of Chicago, (E.J.R., S.A.D.), the Illinois Institute of Technology, (C.M.), Chicago, Illinois, Tucson Veterans Center, Tucson, Arizona (K.M.), University of Chicago, Pritzker School of Medicine, Chicago, Illinois (W.W.S.).