In Alvisi et al. (2018), the present affiliations of the following authors will be added:Cristina Tassorelli, Silvano Cristina, and Giorgio Sandrini:Department of Neurorehabilitation, IRCCS Mondino Foundation, Pavia, ItalyArmando Perrotta and Francesco PierelliIRCSS fondazione Don Carlo Gnocchi, Rome, Italy