[1] Univ Hosp Kiel, Dept Neurol, Div Pain Res & Therapy, Kiel, Germany
[2] Schon Clin Rendsburg, Dept Psychiat Psychotherapy & Psychosomat, Rendsburg, Germany
[3] StatConsult GmbH, Magdeburg, Germany
[4] Benedictus Hosp Tutzing & Feldafing, Dept Anaesthesiol Crit Care Med & Pain Med, Pain Ctr Lake Starnberg, Feldafing, Germany
[5] Tech Univ Munich, Dept Neurol, Klinikum Rechts Isar, Munich, Germany
[6] Univ Klinikum Schleswig Holstein, Klin Neurol, Sekt Neurol Schmerzforsch & Therapie, Campus Kiel,Arnold Heller Str 3,Haus D, D-24105 Kiel, Germany