 This translational study is a monocentric Randomized Controlled Trial RCT. The investigators will recruit 40 PD patients from the early Hoehn Yahr stages. Patients will be randomly allocated to an experimental group writing training and a control group stretch- and relaxation training. All patients will receive the same frequency and duration of intervention. After the training period, patients will be followed up for another 6 weeks. Patients will be tested in the ON-phase of the medication cycle at 3 occasions: before T1 and after training T2 and after a 6-week retention period T3. At T1 T2 participants will be tested at the behavioral neural level. At T3 participants will only be tested at the behavioral level. 