1. National Multiple Sclerosis Competence Centre; Department of Neurology; Haukeland University Hospital; Bergen; Norway
2. The Norwegian Multiple Sclerosis Registry; Department of Neurology; Haukeland University Hospital; Bergen; Norway
3. Department of Neurology; St. Olav University Hospital; Trondheim; Norway
4. Department of Neurology; University Hospital of North Norway; Tromsø; Norway
5. Department of Neurology; Oslo University Hospital Rikshospitalet; Oslo; Norway