F J Rodríguez de Rivera1, H A Rambold2, E Díez-Tejedor3. 1. Department of Neurology, Hospital Universitario La Paz, Madrid, Spain. Electronic address: rodriguezderivera@yahoo.es. 2. Department of Neurology, County Hospitals of Altötting-Burghausen, University of Regensburg, Regensburg, Germany. 3. Department of Neurology, Hospital Universitario La Paz, Madrid, Spain.