 Eligible participants, who participated in the ADAGIO trial and who sign an approved informed consent form, will be enrolled into the study at their original study locations. participants who have stopped rasagiline therapy and in the opinion of the investigator will gain clinical benefit from restarting treatment can also be considered for enrollment in the Core follow-up study period. Use of any other anti-PD treatment is permitted as deemed necessary by the treating physician according to the participants clinical status. 