PET-MRI of Reward System in Parkinson's Disease With RBD (NCT07213219) | Clinical Trial Compass
Not Yet RecruitingNot Applicable
PET-MRI of Reward System in Parkinson's Disease With RBD
France44 participantsStarted 2026-01-01
Plain-language summary
Impulse control disorders (ICDs) are frequently observed in Parkinson's disease (PD) and can have a major functional impact on the quality of life of both the patient and their entourage. The primary risk factor for the emergence of ICDs in PD is long-term dopaminergic treatment, but other risk factors, such as rapid eye movement sleep behavior disorder (RBD), have recently been identified. The mechanisms leading to ICDs in PD remain debated, but it has been shown that the dopaminergic mesocorticolimbic pathways play a key role in reward, learning, and reinforcement processes, as well as in the regulation of impulsivity. PET studies using \[11C\]raclopride, a tracer that allows evaluation of the postsynaptic availability of dopamine D2/D3 receptors, have demonstrated abnormal sensitization of the mesocorticolimbic dopaminergic system (the reward system), particularly in the ventral striatum, in Parkinson's patients with ICDs when presented with appetitive stimuli or during gambling tasks. However, this has never been studied in patients with and without RBD. Parkinson's patients with RBD may present greater impairment of mesocorticolimbic pathways than those without RBD, particularly abnormal sensitization and postsynaptic modifications of the dopaminergic system, which could predispose patients to the emergence of ICDs when exposed to dopaminergic agonists. Confirming a particular pattern of denervation in Parkinson's patients with RBD that may favor the emergence of ICDs constitutes a personalized medicine approach with a readily identifiable risk marker in routine clinical practice and offers the possibility of adapting the management of these patients.
The main objective of this study is to investigate the availability of D2 dopaminergic receptors in subcortical structures (particularly the mesocorticolimbic system) in patients with idiopathic Parkinson's disease, depending on the presence or absence of RBD
Who can participate
Age range
45 Years – 80 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Patients aged 45 to 80 years
* Patients diagnosed with idiopathic Parkinson's disease (PD) according to the Movement Disorder Society criteria
* Disease duration between 3 and 7 years
* Patients receiving chronic dopaminergic treatment including levodopa for at least one year to avoid tolerance issues during acute levodopa administration
* Ability to cooperate and understand, allowing strict compliance with the conditions set forth in the protocol
* Patients affiliated with or beneficiaries of a social security system
* Volunteer patients capable of providing informed consent to participate in the research
Exclusion Criteria:
* Patients suffering from neurological disorders other than idiopathic Parkinson's disease (PD)
* Patients with severe depression (Beck Depression Inventory \\\[20\] (BDI) score \> 30), apathy (Starkstein scale \\\[21\] score ≥ 14), cognitive impairment (Montreal Cognitive Assessment \\\[MoCA\] \\\[22\] score \< 25), or impulse control disorders (QUIP - Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease \\\[23\], score ≥ 1)
* Patients with severe motor symptoms: patients with an MDS-UPDRS III score \> 45 will be excluded to avoid severe discomfort or interfering tremor (tremor item ≥ 3 in any body part) in the OFF state during PET-MRI acquisition. Patients with severe dyskinesias will also be excluded due to technical issues related to movement
* Patients under guardianship, curatorship, deprived of liberty, …
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1This trial is specifically comparing Parkinson's patients who have REM sleep behavior disorder (RBD) with those who don't — does my diagnosis fall into one of those two groups, and would that affect whether this study is even relevant to my situation?
2The study uses a PET-MRI scan with a radioactive tracer called [¹¹C]raclopride to measure dopamine activity in the brain's reward system — what does that involve practically, and are there any risks from the radiation exposure or the tracer itself that I should weigh?
3Since the trial is listed as 'not yet recruiting,' how long might it be before it actually opens, and given where my Parkinson's is right now, does it make more sense to focus on treatment options available to me today rather than waiting?
4The scan is done 'off treatment,' which I understand means stopping my Parkinson's medications before the imaging — is that safe for me specifically, and how long would I need to go without my medication?
5This trial seems to be focused on understanding the disease better rather than testing a new treatment — can you help me understand whether participating would offer me any direct medical benefit, or is this primarily a research contribution that might help future patients?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
[¹¹C]raclopride binding potential (BP, unitless) measured with PET-MRI in mesocorticolimbic brain structures between participants with and without RBD, off treatment.
Timeframe: During MRI exploration (3 months after inclusion visit)