Developing consensus among movement disorder specialists on clinical indicators for identification and management of advanced Parkinson's disease: a multi-country Delphi-panel approach

Background: Lack of a global consensus on the definition of advanced Parkinson's disease (APD) and considerations for timing of device-aided therapies may result in heterogeneity in care. Objectives: To reach consensus among movement disorder specialists regarding key patient characteristics indicating transition to APD and guiding appropriate use of device-aided therapies in the management of PD symptoms. Methods: A Delphi-panel approach was utilized to synthesize opinions of movement disorder specialists and build consensus. Results: A panel was comprised of movement disorder specialists from 10 European countries with extensive experience of treating PD patients (mean =24.8 +/- 7.2 years). Consensus on indicators of suspected APD and eligibility for device-aided therapies were based on motor symptoms, non-motor symptoms, and functional impairments. Key indicators of APD included: (i) motor-moderate troublesome motor fluctuations, >= 1 h of troublesome dyskinesia/day, >= 2 h "off" symptoms/day, and >= 5-times oral levodopa doses/day; (ii) non-motor-mild dementia, and non-transitory troublesome hallucinations; (iii) functional impairment-repeated falls despite optimal treatment, and difficulty with activities of daily living. Patients with good levodopa response, good cognition, and <70 years of age were deemed as good candidates for all three device-aided therapies. Patients with troublesome dyskinesia were considered good candidates for both levodopa-carbidopa intestinal gel and Deep Brain Stimulation (DBS). PD patients with levodopa-resistant tremor were considered good candidates for DBS. Conclusion: Identifying patients progressing to APD and suitable for device-aided therapies will enable general neurologists to assess the need for referral to movement disorder specialists and improve the quality of care and patient outcomes.