Health Related Quality of Life in LCIG Patients and LCIG Eligible Patients Continuing Oral Therapy

* Eligibility for LCIG according to current version of the Summary of Product Characteristics of LCIG of the respective country (Germany, Switzerland). * Decision to treat with LCIG or other medication made by the study physician prior to any decision to approach the patient to participate in this study. * Unchanged available combinations of PD medicinal treatment for at least one week prior to study inclusion. * Patient has given written informed consent.

* Contraindication to LCIG according to current version of the German SmPC or Swiss SmPC. * Contraindication to placement of intrajejunal PEG-J tube. * Current treatment with Deep Brain Stimulation (DBS), Apomorphine pump or LCIG * Severe dementia based on a Mini-Mental State Examination (MMSE) of \< 10 * Acute psychotic disorder (benign hallucinations or earlier psychotic episodes are not an exclusion criterion) * Depression with suicidal thoughts (earlier episodes of major depression are not an exclusion criterion) * History or presence of any condition that might interfere with absorption, distribution, metabolism, or excretion of LCIG * Drug or alcohol addiction (drug addiction: continuous or sporadic use of drugs without medical indication or with paradoxical medical indication or in inappropriate amounts. Addictive consumption of e.g. alcohol, cannabis, amphetamine, sniffing agents, cocaine, heroin, crack). Alcohol addiction male: \> 40 g/day; female: \> 30 g/day) * Illiteracy or insufficient language skills to complete the questionnaires