1 Department of Geriatric Psychiatry (TF, PH), LVR-Hospital Cologne, German Sport University Cologne, Institute of Movement and Sport Gerontology, Cologne, Germany. Electronic address: t.fleiner@dshs-koeln.de.
2 Department of Electrical, Electronic, and Information Engineering (SM), University of Bologna, "Guglielmo Marconi," Bologna, Italy.
3 Department of Geriatric Psychiatry (TF, PH), LVR-Hospital Cologne, German Sport University Cologne, Institute of Movement and Sport Gerontology, Cologne, Germany.
4 Institute of Movement and Sport Gerontology (TF, WZ), German Sport University Cologne, Cologne, Germany.