Day 1: Duodopa in individually optimised dose Day 2: 80% of optimised Duodopa dose + two tablets of entacapone at t=0 hours and at t= 6 hours Day 3: 80% of optimised Duodopa dose + two tablets of tolcapone at t=0 hours and at t= 6 hours Plasma samples for determination of levodopa concentrations will be taken every 30 minutes during 8 hours. Video recordings will be performed every 30 min during 8 hours, for later blinded assessments by 2-3 experts. Sequences will be in randomised order. Patient self-scores regarding mobility will be recorded, every 30 min during 8 hours.