[1] Univ Calif Los Angeles, Stroke Ctr, Dept Neurol, Los Angeles, CA 90095 USA
[2] Univ Calgary, Hotchkiss Brain Inst, Dept Clin Neurosci, Calgary, AB, Canada
[3] Univ Calif Los Angeles, Div Cardiol, Los Angeles, CA 90095 USA
[4] Michigan State Univ, Dept Epidemiol, E Lansing, MI 48824 USA
[5] Duke Univ, Clin Res Ctr, Durham, NC USA
[6] Massachusetts Gen Hosp, Dept Neurol, Boston, MA 02114 USA