Methods - Individuals with PD will be enrolled in the study in Aix-en-Provence, France (N = 60) and Lisbon, Portugal (N = 60). Their global motor disability and orofacial motor functions will be assessed with specific clinical rating scales, without (OFF) and with (ON) medical treatment. Two groups of 60 healthy age-matched volunteers will provide the reference for between-group comparisons. Along with the clinical examinations, several speech tasks will be recorded to obtain acoustic and perceptual measures. Self-evaluation questionnaires will be used to assess the psychosocial impact of dysarthria on quality of life.