• Clinical Global Impression of Improvement (CGI-I) [ Time Frame: at Follow-up visit at 1, 3, 6, 9, 12 months ]
  hange of score from baseline at each follow-up visit (from 0=good health to 100=poor health).
• Parkinson Disease Questionnaire (PDQ-8) [ Time Frame: at baseline, Follow-up visit at 6,12 months ]
  hange of score from baseline at each follow-up visit (from 0=good health to 100=poor health).
• Unified Parkinson's Disease Rating Scale (UPDRS) [ Time Frame: at baseline, Follow-up visit at 6,12 months ]
  change from baseline at each follow-up visit for each of the 4 sections and for the total score (from 0=no disability to 199=total disability).
• Montreal Cognitive Assessment (MoCA) [ Time Frame: at baseline, Follow-up visit at 6,12 months ]
  change from baseline at each follow-up visit (30-point test; score >26 is normal).
• Patients' Global Impressions of Change (PGI-C) [ Time Frame: at Follow-up visit at 1, 3, 6, 9, 12 months ]
  Percentage of patients for each item at each follow-up visit (from 1=very much improved since the initiation of treatment to 7=very much worse since the initiation of treatment).

This will be a multinational, multicentre, prospective non-interventional study in elderly patients with PD. Approximately 100 patients with PD will be recruited by specialists from approximately 37 sites in European countries. The total enrolment period will be one year, and each patient will be followed for up to one year after enrolment.

PD patients with end-of-dose motor fluctuations suitable for additional treatment optimization will be included in the study and split into 2 cohorts:

• Cohort 1: 50 patients; standard of care (including L-DOPA) + starting opicapone
• Cohort 2: 50 patients; standard of care (including L-DOPA Data will be collected at baseline (date of enrolment), 1 month, 3 months, 6 months, 9 months, and 12 months after enrolment.

This non-interventional study does not recommend the use of any specific treatments. Use of opicapone and of standard of care are only driven by the physician's decision.

• Drug: Opicapone
  Capsules, oral use - 50 mg Use of opicapone is only driven by the physician's decision.
  Other Name: Ongentys
• Drug: Levodopa (L-DOPA) + Standard care
  Levodopa (immediate- or controlled-release) + Standard care. Use of Levodopa and standard of care are only driven by the physician's decision.

• Cohort 1
  Standard of care (including L-DOPA) + starting opicapone
  Interventions:

  • Drug: Opicapone
  • Drug: Levodopa (L-DOPA) + Standard care
• Cohort 2
  Standard of care (including L-DOPA)
  Intervention: Drug: Levodopa (L-DOPA) + Standard care

Inclusion Criteria:

• Patient or legally acceptable representative willing and able to provide informed consent as mandated by local regulation
• Patient with clinical diagnosis of idiopathic PD (excluding non-idiopathic PD: atypical Parkinsonism, secondary [acquired or symptomatic] Parkinsonism, Parkinson-plus syndrome)
• Patient with age >=75 years at enrolment
• Patient with end-of-dose motor fluctuations suitable for additional treatment optimization

Exclusion Criteria:

• Patient concurrently participating in any clinical trial
• Patient who used tolcapone or opicapone previously
• For the patient who starts opicapone: concomitant treatment with entacapone or tolcapone is not allowed
• Patient with any contraindications to Ongentys use
• Patient with any concomitant medical condition that could interfere with study assessments