1. Institute of Medical Psychology and Medical Sociology, University Medical Center Göttingen, Göttingen, Germany.
2. IDV-Datenanalyse und Versuchsplanung, Gauting, Germany.
3. Department of Neurosurgery, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium.
4. Department of Psychology and Logopedics, University of Helsinki, Helsinki, Finland.