[1] Department of Neurology,
[2] University Hospital Gasthuisberg,undefined
[3] University of Leuven,undefined
[4] School of Medicine,undefined
[5] Herestraat 49,undefined
[6] B-3000 Leuven,undefined
[7] Belgium Tel.: +32-16-34-42-80 Fax: +32-16-34-42-85 e-mail: Wim.robberecht@uz.kuleuven.ac.be,undefined