An observational study in REM Sleep Behavior Disorder, Synucleinopathies and Parkinson's Disease (PD), sponsored by Danish Research Centre for Magnetic Resonance. Recruiting at 1 site in Denmark. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Danish Research Centre for Magnetic Resonance · Observational
Comprehensive characterization of early-stage Parkinson's disease in patients with REM sleep behavior disorder
Parkinson's disease (PD) is the fastest-growing neurodegenerative disorder worldwide, significantly affecting quality of life and causing substantial social and economic burdens. Currently, treatments for Parkinson's disease primarily manage symptoms through medication and lifestyle changes but cannot stop disease progression. By the time Parkinson's disease is diagnosed, substantial nerve-cell loss has already occurred in specific brain areas. Identifying early signs of PD before symptoms fully develop is essential for improving future treatment strategies.
This research project aims to deeply understand the earliest stages of Parkinson's disease by studying patients with REM sleep behavior disorder (RBD). RBD is a condition characterized by unusual movements or behaviors during dream sleep, caused by nerve-cell loss in the brainstem. Importantly, more than 80% of individuals with RBD eventually develop Parkinson's disease or related conditions, such as Dementia with Lewy Bodies or Multiple System Atrophy.
Study Goals:
Our study will examine multiple potential biomarkers (measurable indicators) that could help identify early stages of Parkinson's disease. These include:
Together, these extensive assessments will provide a detailed understanding of how Parkinson's disease begins and progresses. This knowledge can greatly improve early diagnosis, allowing earlier and potentially more effective treatments for individuals at high risk.
Study Design:
The investigators will recruit:
THe investigation team have a complete, detailed plan and will begin collecting data as soon as ethical approval is granted.
Main Hypotheses:
Although our extensive data will allow many analyses, the investigation team specifically predict:
Impact:
This study will significantly enhance early detection of Parkinson's disease, paving the way for personalized medical approaches and potentially more effective treatments. Conducted by a multidisciplinary team of experts in brain imaging, sleep medicine, autonomic function, and protein aggregation, this research supports Denmark's leadership in precision clinical imaging and aligns closely with hospital research strategies aimed at understanding and treating chronic diseases. Ultimately, our goal is to improve personalized patient care for Parkinson's disease in the future.
101 studies on the registry are indexed under REM Sleep Behavior Disorder; 45 are open to participants now.
This study's planned enrollment of 100 is below the median of 119 across 48 observational studies indexed under REM Sleep Behavior Disorder.
Browse REM Sleep Behavior Disorder studies →Danish Research Centre for Magnetic Resonance is the lead sponsor of 14 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
We have 2 groups; Subjects diagnosed with REM-sleep behaviour disorder via polysomnography Healthy, age- and gendermatched controls.
Our RBD-group will be recruited via an ongoing cohort at a different site (Danish center for sleep medicine), where subjects diagnosed with RBD via polysomnography will be asked to also participate in our cohort, should they fulfill our inclusion criteria.
Controls will be recruited via our own institutions webpage, as well as advertisements on other danish websites such as trialtree.dk.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Both groups - The ability to give
For RBD-group
For Healthy controls
- Age matched to RBD-group
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Control participants without known major psychiatric or neurological disease.
Subjects diagnosed with RBD via polysomnography.
Structural disintegraiton of the Locus Coeruleus
One of the main hypotheses is that there will be a strutural pattern of disintegration in the Locus Coeruleus (LC) in our RBD-cohort when compared to controls. This will be seen as a change in neuromelanin Contrast-to-Noise-Ratio (CNR) in the LC. We expect this pattern to have a caudo-rostral gradient, as other studies have shown in subjects with Parkinson's Disease.
Time frame: Baseline
Differences in neuromelanin-CNR in the Substantia Nigra pars Compacta in RBD-subjects compared to controls
As with the Locus Coeruleus, it is expected to see altered neuromelanin signal from the SNc in RBD subjects compared to controls
Time frame: Baseline
Motor-task performance
The investigators expect to see group-level differences in motor-task performance with an in-house designed motor-test battery, validated before being put into use.
Time frame: Baseline
Cognitive test performance
The investigators expect to see group-level differences in cognitive test performance, tested with particular tests from the CANTAB-battery, between RBD-subjects and controls, with controls performing better..
Time frame: Baseline
Resting-state EEG
Preliminary data from another study (Manuscript under review) at our site has shown that the aperiodic part of resting-state EEG is able to clearly separate subjects with clinically established Parkinson's Disease from controls. We will test whether this also holds true in the prodromal RBD-state using a short resting-state EEG recording.
Time frame: Baseline
Correlation between LC and autonomic dysfunction.
Loss of LC-CNR will positively correlate with increased burden of autonomic symptoms in RBD-subjects.
Time frame: Baseline
Autonomic, sympathic responses to arousing stimuli
Autonomic responses (Pupil dilation, skin conductance) to arousing stimuli will be changed in RBD-subjects compared to controls, correlating with lowered LC-CNR
Time frame: Baseline
Cardiac sympathetic measures
Cardiac sympathetic nervous function, measures using MIBG-SPECT will be changed in RBD-subjects compared to controls, and correlate positively to the degree of cellular degeneration in the LC.
Time frame: Baseline
Longitudinal outcomes
At follow up, subjects with more progressive cognitive deficits measured via MOCA and CANTAB are hypothesized to show more pronounced change in rostral LC-CNR.
Time frame: Through study completion, an average of 1 year
Longitudinal outcomes
Conversion rates to clinical ɑ-syn (PD, MSA, DLB) will be higher in subjects showing peripheral ɑ-synuclein pathology in blood and/or skin.
Time frame: Through study completion, an average of 1 year
Longitudinal outcomes
Subjects converting to DLB will display more rostral change in LC-CNR than subjects converting to other ɑ-syn.
Time frame: Through study completion, an average of 1 year
Plan to share: Undecided — The pseudonymized data can only be shared with a formal Data Processing Agreement and a formal approval by the Danish Data Protection agency in line with the requirements of the European General Data Protection Regulation. If complete anonymization can be achieved, individual data will be shared openly after study completion.
Started Feb 2026 (actual). Primary completion is estimated for Jun 2028, 28 months after the start.
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Danish Research Centre for Magnetic Resonance