[1] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21205 USA
[2] Mayo Clin, Dept Neurol, Rochester, MN USA
[3] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[4] Mayo Clin, Dept Radiol, Rochester, MN USA
[5] Wake Forest Sch Med, Dept Neurol, Winston Salem, NC USA
[6] Univ Minnesota, Div Epidemiol & Community Hlth, Sch Publ Hlth, Minneapolis, MN USA
[7] Univ Mississippi, Dept Med, Div Geriatr, Sch Med, Jackson, MS USA
[8] Wake Forest Sch Med, Div Publ Hlth Sci, Winston Salem, NC USA