1. Department of Neurology (R.F., J.A.R., H.O., A.V., S.O.-G., H.P.A., E.C.L., E.A.S.), University of Iowa Carver College of Medicine.
2. Department of Neurosurgery (J.A.R., S.O.-G., D.M.H., E.C.L., E.A.S.), University of Iowa Carver College of Medicine.
3. Department of Radiology (G.B., S.O.-G., C.D., E.A.S.), University of Iowa Carver College of Medicine.
4. Department of Epidemiology, University of Iowa College of Public Health (E.C.L.).