1. G Verheyden, PT, is Research Assistant, Department of Rehabilitation Sciences, Katholieke Universiteit Leuven, Tervuursevest 101, 3001 Leuven, Belgium
2. G Nuyens, PT, PhD, is Research Physiotherapist, Department of Rehabilitation Sciences, Katholieke Universiteit Leuven, and Physiotherapist, National Multiple Sclerosis Center, Melsbroek, Belgium
3. A Nieuwboer, PT, PhD, is Professor, Department of Rehabilitation Sciences, Katholieke Universiteit Leuven
4. P Van Asch, PT, is Head of Physiotherapy, National Multiple Sclerosis Center, Melsbroek
5. P Ketelaer, MD, is former Medical Director, National Multiple Sclerosis Center, Melsbroek
6. W De Weerdt, PT, PhD, is Professor, Department of Rehabilitation Sciences, Katholieke Universiteit Leuven