1. Department of Neurology; University Medical Center Groningen; University of Groningen; Groningen the Netherlands
2. Department of Neurology; Ommelander Hospital Group; Delfzijl the Netherlands
3. Department of Neurology; Safarik University; Kosice Slovakia
4. Department of Neurology; University Hospital L. Pasteur; Kosice Slovakia
5. Department of Health Sciences; Community and Occupational Medicine; University Medical Center Groningen; Groningen the Netherlands
6. Department of Neuroscience; University Medical Center Groningen; Groningen the Netherlands