1. C. Besta National Neurological Institute, Milan
2. Neurological Department, S. Gerardo Hospital, Monza
3. Service of Neurology, Pieve di Coriano
4. Neurological Department, Policlinico S. Pietro, Ponte S. Pietro
5. Neurological Department, Ospedali Riuniti, Bergamo
6. Neurological Department, S. Paolo Hospital, Milan, Italy