1. Department of Neurology, St. Josef-Hospital/Ruhr-University Bochum, Gudrunstrasse 56, 44791 Bochum, Germany,
2. Department of Neurology, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
3. Department of Neurological and Psychiatric Sciences, University of Florence, viale Morgagni, 85, 50134 Florence, Italy
4. Department of Neurology, Institute of Experimental Neurology, Scientific Institute San Raffaele Vita, Salute University, Milan, Italy