1 DUMC 3403, Department of Neurology, Duke University, Durham, NC 27710, USA. Electronic address: lisa.hobsonwebb@duke.edu.
2 Institute of Neurology, Catholic University of Sacred Heart, Largo A. Gemelli 8, Rome, Italy; Don Carlo Gnocchi Onlus Foundation, Piazzale Morandi 6, Milan, Italy. Electronic address: lpadua@rm.unicatt.it.