1. Clinical and Developmental Neuropsychology, University of Groningen, Groningen, The Netherlands
2. Royal Dutch Visio, Centre of Expertise for Blind and Partially Sighted People, Huizen, The Netherlands
3. Department of Neurology, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
4. MS Centrum Noord Nederland, Groningen, The Netherlands
5. Department of Neurology, Martini Hospital Groningen, Groningen, The Netherlands