1. Department of Neurosurgery, Clinical Neuroscience Centre, University Hospital Zurich and University of Zurich , 8091 Zurich , Switzerland
2. Department of Neurology, Clinical Neuroscience Centre, University Hospital Zurich and University of Zurich , 8091 Zurich , Switzerland
3. Division of Paediatric Neurosurgery, University Children's Hospital , 8032 Zurich , Switzerland