1. Roessingh Research and Development, Enschede, the Netherlands
2. Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands
3. Department of Biosystems and Signals, University of Twente, Enschede, the Netherlands
4. Eskilstuna Kommun Vård-och omsorgsförvaltningen, Eskilstuna, Sweden
5. National Foundation for the Elderly, Bunnik, the Netherlands
6. terzStiftung, Berlingen, Switzerland
7. Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois, USA