1. From the Department of Rehabilitation Medicine (A.V.M., M.P., I.v.d.P., E.L.), Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht and the Rehabilitation Center De Hoogstraat, Utrecht, The Netherlands; the Department of Methodology and Statistics (C.M.), Utrecht University, Utrecht, The Netherlands; and the Institute of Neuroscience and Physiology (G.F.-W.), Sahlrenska Academy and Göteborg University, Göteborg, Sweden.