Up till now, dopaminergic replacement is considered as the gold standard for the symptomatic treatment of motor symptoms in Parkinson's disease (PD). However, the intake, especially higher doses when taken for a longer duration, are associated with several side effects including response fluctuations. These fluctuations in medication response are often characterized by a wearing-OFF period, also defined as the recurrence of PD symptoms before a patient should take the next dose of medication. The duration of test sessions during research experiments (e.g. in the field of rehabilitation) can interfere with the period of the optimal therapeutic effect of dopaminergic medication, influencing outcomes of a study. Therefore, the objective of this project is to get more insight in the measurability of ON-OFF fluctuations by testing the applicability of a short and simple timed tapping task (TTT) on a smartphone in rehabilitation research studies. The assessment can be useful for future clinical studies in PD where a precise estimation of medication is indispensable for accurate research outcomes.

Inclusion Criteria:

• A diagnosis of PD, based on the UK Brain Bank Diagnostic Criteria
• Hoehn & Yahr stage I-III
• Mini Mental State Examination (MMSE) scores >24
• Right-handedness
• No other known disease or disorder that will interfere with the experiments