1 Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland 2Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 1777, 70211, Kuopio, Finland 3Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB, Canada T2N 1N4 4Department of Biomedical Engineering, Eindhoven University of Technology, P.O. B...