[1] Department of Neurology,
[2] University of Muenster,undefined
[3] Albert-Schweitzer-Str. 33,undefined
[4] 48129 Muenster,undefined
[5] Germany,undefined
[6] Tel.: +49-2 51/8 34 81 93,undefined
[7] Fax: +49-2 51/8 34 81 81,undefined
[8] E-Mail: happes@uni-muenster.de,undefined
[9] Institute of Epidemiology and Social Medicine,undefined
[10] University of Muenster,undefined
[11] Germany,undefined