Accepted for Publication: August 21, 2013.
Published Online: December 16, 2013. doi:10.1001/jamaneurol.2013.4835.
Study concept and design: Premi, Padovani, Borroni.
Acquisition of data: Premi, Formenti, Gazzina, Archetti, Gasparotti, Borroni.
Analysis and interpretation of data: Premi, Formenti, Gazzina, Archetti, Padovani, Borroni.
Drafting of the manuscript: Premi, Formenti, Gazzina, Borroni.
Critical revision of the manuscript for important intellectual content: Premi, Archetti, Gasparotti, Padovani.
Statistical analysis: Premi, Formenti, Gazzina, Borroni.
Obtained funding: Borroni.
Administrative, technical, and material support: Archetti, Gasparotti, Padovani, Borroni.
Study supervision: Padovani, Borroni.
Conflict of Interest Disclosures: None reported.
Additional Contributions: We thank involved volunteers for participating in this study. Marco Bozzali, MD (Neuroimaging Laboratory, Santa Lucia Foundation, Rome, Italy), provided advice in neuroimaging procedures. No financial compensation was given.