Parkinson’s Disease is characterised by a progressive degeneration of dopaminergic neurons. Individual physiological conditions, such as stress, may play a role in the onset, the diversity in symptoms and the course of Parkinson’s Disease. This hypotheses is part of a longitudinal study by Sandra Eygelshoven, MSc., clinical psychologist at Zuyderland Medical Centre (formerly the Atrium-Orbis MC) et al. in cooperation with Groningen University. Patients’ stress levels have been registered during two years using a Daily Problems Checklist, online, in the webbrowser. Immediate, delayed and recognition memory were measured by using the 15 Word Learning Test (15 WLT) during the baseline and the follow-up assessments. Furthermore, the digital version of the Scopa-Cog battery, as well as the MAAS Concept Shifting Task (CST) and Letter-Digit Substitution Test (LDST) were used for measuring cognitive functioning. The Metrisquare DiagnoseIS software was used to administer these tests.