1 Department of Geriatrics, Neurosciences and Orthopaedics, Università Cattolica del Sacro Cuore, Rome, Italy; Don Carlo Gnocchi Onlus Foundation, Milan, Italy. Electronic address: luca.padua@unicatt.it.
2 Don Carlo Gnocchi Onlus Foundation, Milan, Italy; Board of Physical Medicine and Rehabilitation, Department of Orthopaedic Science, "Sapienza" University, Rome, Italy.
3 Department of Geriatrics, Neurosciences and Orthopaedics, Università Cattolica del Sacro Cuore, Rome, Italy.
4 Don Carlo Gnocchi Onlus Foundation, Milan, Italy.
5 Institute of Neurology, Policlinico A. Gemelli Foundation University Hospital, Rome, Italy.
6 Department of Neurology, Duke University, Durham, NC, USA.