1 From the Mellen Center for Multiple Sclerosis Treatment and Research (R.J.F.), Neurological Institute, Cleveland Clinic, OH; and Department of Statistics and Sanders Brown Center on Aging (R.J.K.), University of Kentucky, Lexington. foxr@ccf.org.
2 From the Mellen Center for Multiple Sclerosis Treatment and Research (R.J.F.), Neurological Institute, Cleveland Clinic, OH; and Department of Statistics and Sanders Brown Center on Aging (R.J.K.), University of Kentucky, Lexington.