[1] Univ Bergen, Ctr Elderly & Nursing Home Med, Dept Global Publ Hlth & Primary Care, Arstadveien 17, N-5009 Bergen, Norway
[2] Univ Bergen, Dept Clin Med, Neuro SysMed, Jonas Vei 65, N-5021 Bergen, Norway
[3] Haukeland Univ Sjukehus, Helse Vest, Helse Bergen HF, Postboks 1400, N-5021 Bergen, Norway
[4] Voss Hosp, Dept Orthoped Surg, Sjukehusvegen 16, N-5704 Voss, Norway
[5] Haukeland Hosp, Dept Neurol, Haukelandsveien 22, N-2009 Bergen, Norway
[6] Haraldsplass Deaconess Hosp, Dept Internal Med, Ulriksdal 8, N-5009 Bergen, Norway
[7] Univ Politehn Bucuresti, Complex Syst Lab, Splaiul Independentei 313, Bucharest 060042, Romania