[1] Univ Groningen, Dept Neurol, Univ Med Ctr Groningen, Wenckebach Inst,Sch Nursing & Hlth, NL-9700 RB Groningen, Netherlands
[2] Univ Groningen, Dept Hlth Sci, Grad Sch Hlth Res, Univ Med Ctr Groningen, NL-9700 RB Groningen, Netherlands
[3] Univ Groningen, Dept Oral Hlth & Clin Epidemiol, Univ Med Ctr Groningen, NL-9700 RB Groningen, Netherlands