Inclusion Criteria (patients):  Subject is included in the Personalized Parkinson Project and has already participated in all baseline measurements (this means that inclusion and exclusion criteria of the Personalized Parkinson Project have already been fulfilled) Subject has completed the Informed Consent Form, as approved by the Ethics Committee  Exclusion Criteria (patients):  Subject is not taking dopaminergic medication  Inclusion Criteria (healthy controls):  Subject is at least 40 years old Subject can read and understand Dutch Subject has completed the Informed Consent Form, as approved by the Ethics Committee Subject is willing, competent, and able to comply with all aspects of the protocol, including follow-up schedule.  Exclusion Criteria (healthy controls):  Subject has no co-morbidities that would negatively influence the interpretability of results from a comparison with PD patients (e.g. other neurodegenerative diseases or mental health disorders)