Accepted for Publication: November 15, 2012.
Published Online: April 15, 2013. doi:10.1001/jamaneurol.2013.1817
Author Contributions:Study concept and design: Dombroski and Schellenberg. Acquisition of data: Dombroski, Galasko, Mata, Zabetian, Craig, Oyanagi, and Schellenberg. Analysis and interpretation of data: Dombroski, Galasko, Zabetian, Garruto, and Schellenberg. Drafting of the manuscript: Dombroski, Galasko, and Schellenberg. Critical revision of the manuscript for important intellectual content: Dombroski, Mata, Zabetian, Craig, Garruto, Oyanagi, and Schellenberg. Obtained funding: Zabetian and Schellenberg. Administrative, technical, and material support: Craig, Garruto, Oyanagi, and Schellenberg. Study supervision: Zabetian and Schellenberg.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was supported by grants AG14382, P01-AG-017586, and R37 AG11762 from the National Institute on Aging and by grant R01 NS065070 from the National Institute of Neurological Disorders and Stroke.
Additional Contributions: We thank the individuals who participated in this study.