1. University of Liège, Liege, Belgium
2. University Hospital of Liege, Liege, Belgium
3. Rehanova Neurorehabilitation Center, Cologne-Merheim, Germany
4. University Hospital of Cologne, Cologne, Germany
5. Institute of Neuroscience and Medicine, Research Centre Jülich, Jülich, Germany
6. Spaulding Rehabilitation Hospital and Harvard Medical School, Boston, MA, USA