1. Department of Neurology and Clinical Neurophysiology, University Hospital of North Norway , 9019 Tromsø , Norway
2. Department of Clinical Medicine, The Arctic University of Norway , 9019 Tromsø , Norway
3. Department of Medical Genetics, Telemark Hospital Trust , 3710 Skien , Norway
4. Department of Neurology and Clinical Neurophysiology, Medical Division, Akershus University Hospital , 1478 Lørenskog , Norway
5. Department of Anesthesiology, Vanderbilt University School of Medicine , Nashville, TN 37232 , USA
6. Sandvika Neurocenter , 1337 Sandvika , Norway
7. Department of Medical Genetics, Oslo University Hospital , 0450 Oslo , Norway
8. Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North-Norway , 9019 Tromsø , Norway