[1] UCL Inst Neurol, Sobell Dept Motor Neurosci & Movement Disorders, London, England
[2] Univ Verona, Dipartimento Sci Neurol & Movimento, I-37100 Verona, Italy
[3] Univ Naples Federico II, Dept Neurol Sci, Naples, Italy
[4] Univ Salerno, Ctr Neurodegenerat Dis CEMAND, I-84100 Salerno, Italy