1. Unit of Rehabilitation Medicine, IRCCS Istituto delle Scienze Neurologiche di Bologna, 40139 Bologna, Italy
2. Unit of Neurosurgery, IRCCS Istituto delle Scienze Neurologiche di Bologna, 40139 Bologna, Italy
3. Department of Neurosurgery, Mayo Clinic, Rochester, MN 55905, USA
4. Department of Neurosurgery, Hospital Universitario Fundación Santa Fé de Bogotá, Bogotá 220246, Cundinamarca, Colombia