[1] Institute of Clinical Neurology,
[2] University of Bologna Medical School,undefined
[3] Via U. Foscolo 7,undefined
[4] I-40123 Bologna,undefined
[5] Italy,undefined
[6] e-mail: pmontagn@neuro.unibo.it,undefined
[7] Tel.: +39-051-6442179,undefined
[8] Fax: +39-051-6442165,undefined