1. Department of Neurosurgery, Mannheim University Hospital, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
2. Department of Rehabilitation, St Antonius Hospital, Nieuwegein, the Netherlands
3. Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands
4. Julius Center for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht University, Utrecht, the Netherlands