[1] Harvard Med Sch, Dept Neurol, Boston, MA 02115 USA
[2] Massachusetts Gen Hosp, Boston, MA 02114 USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Dept Med & Pediat, Los Angeles, CA USA
[4] UCLA, Sch Nursing, Los Angeles, CA USA
[5] Kaiser Permanente Bernard J Tyson Sch Med, Dept Hlth Syst Sci, Pasadena, CA USA
[6] UCLA, Dept Med, David Geffen Sch Med, Los Angeles, CA USA
[7] UCLA, Dept Community Hlth Sci, Fielding Sch Publ Hlth, Los Angeles, CA USA