DESENSITIZE-PD: Intestinal Levodopa + Entacapone Therapy (Lecigon®) to Support Dopaminergic Desensitization in PD

20 patients with idiopathic Parkinson's disease, who are planned to undergo intestinal L-Dopa + entacapone (Lecigon®) treatment will be included into this observational single-armed study. These patient will be observed for hyperdopaminergic complications and neuropsychiatric fluctuations postprocedure at 3, 6 and 12 months.

This study is planned as non-interventional observational single-armed study in patients that are planned to undergo intestinal L-Dopa + entacapone (Lecigon®) treatment as regular treatment choice outside the study protocol and under the accepted regulatory approval and indication criteria (according to German "Fachinformation Lecigon®"). Patients will be observed at the pre-interventional baseline (oral treatment, before treatment initiation with Lecigon®), 3-month, 6-month follow-up, and final 12-month follow-up. As primary interest, the investigator will analyze the contrast of the pre-interventional baseline and 12-month follow-up in terms of the Ardouin Behavioural Scale which evaluates the hyperdopaminergic complications and neuropsychiatric fluctuations in a semi-structured interview. As additional exploratory outcomes, the investigator will study the "Neuropsychiatric fluctuation scale", impulse control disorders with the "QUIP rating scale (QUIP-RS)". Moreover, the investigator will study apathy outcomes using the "Apathy Evaluation Scale" that mainly relates to the dopaminergic off-state. Outcomes of post-interventional apathy are particularly important, since i) they may coincide with hypodopaminergic off-states, and ii) since outcomes of postoperative apathy are a limitation of existing DBS therapy. Avoiding worsening of apathy might be a strength of intestinal L-Dopa therapy in this regard. Further, the investigator will study established measures of motor sensitization/de-sensitization in particular motor fluctuations and dyskinesia (MDS-UPDRS IV) and Unified Dyskinesia Rating Scale (UDysRS). For completeness, the investigator will characterize MDS-UPDRS III motor state in addition. Since dopaminergic desensitization occurs with considerable delay of rather weeks and months after changing oral to continuous treatment, the investigator expect a reduction of dopaminergic motor and neuropsychiatric complications within the first 6 months from introducing Lecigon® together with a stable course until final 12-month follow-up. The outcomes will be decided as contrast of the pre-interventional baseline (V0) in best oral treatment compared to 12 month follow-up of Lecigon® treatment.