1. Faculty of Medicine, Imperial College London, London, United Kingdom
2. Medizinische Hochschule Hannover - MHH, Hannover, Germany
3. Department of Neurology and Neurosurgery, National Institute of Health, Yerevan, Armenia
4. Department of Neurosurgery, Imperial College NHS Healthcare Trust, London, United Kingdom
5. Department of Neurosurgery, Charité – Universitätsmedizin Berlin, Berlin, Germany