1. Radboud University Nijmegen Medical Center; Department of Neurology and Clinical Neurophysiology; PO Box 9101 c/o 920 KNF Nijmegen Netherlands 6500 HB
2. Radboud University Nijmegen Medical Center; Department of Neurology; PO Box 9101 Nijmegen Netherlands 6500 HB
3. National Hospital for Neurology and Neurosurgery; MRC Centre for Neuromuscular Disease; PO Box 114 Queen Square London UK WC1N 3BG