Abstract: 944 patients with Parkinson's disease were divided into two groups, 86 cases in young-onset Parkinson's disease (YOPD) group and 858 cases in regular Parkinson's disease (PD) group. Levodopa was used in 632 cases of PD. There were no significant differences concerning clinical types, family history, side effects of levodopa. There were no significant differences concerning modified Hoehn-Yahr (H-Y)scale during "off" state between YOPD group and PD group, while significant difference was found between YOPD group and PD group concerning modified Hoehn-Yahr (H-Y)scale during "on" state.

Key words: Parkinson's disease, levodopa, dyskinesia, on-off phenomena