Accepted for Publication: July 15, 2013.
Published Online: October 7, 2013. doi:10.1001/jamaneurol.2013.4354.
Study concept and design: Hocker, Tian, Li, Steckelberg, Rabinstein.
Acquisition of data: Hocker, Tian, Li.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Hocker, Tian, Li.
Critical revision of the manuscript for important intellectual content: Hocker, Tian, Steckelberg, Mandrekar, Rabinstein.
Statistical analysis: Hocker, Tian, Li, Mandrekar.
Study supervision: Steckelberg, Rabinstein.
Conflict of Interest Disclosures: None reported.