ClinicalTrials.gg
Enrolling by invitationNCT05826457NAPS2Updated May 13, 2026

North American Prodromal Synucleinopathy Consortium Stage 2

An observational study in REM Sleep Behavior Disorder, Parkinson Disease and Lewy Body Dementia, sponsored by Washington University School of Medicine. Enrolling by invitation at 9 sites in 2 countries. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-05-13.

Sponsored by Washington University School of Medicine · Observational

Study type
Observational
Model
Case-control
Time perspective
Prospective
Enrollment
500
Ages
18 Years and older
Sex
All
01

Study summary

This study will enroll participants with idiopathic REM sleep behavior disorder (RBD) and healthy controls for the purpose of preparing for a clinical trial of neuroprotective treatments against synucleinopathies.

Read the detailed description

REM sleep behavior disorder (RBD) is a disorder where people act out their dreams. People with RBD often, but not always, develop Parkinson's Disease, dementia with Lewy bodies, multiple system atrophy, or other neurodegenerative diseases of the synucleinopathy type.

The North American Prodromal Synucleinopathy Consortium Stage 2 (NAPS2) was formed with the purpose of enrolling participants with RBD, in anticipation of a future clinical trial of a neuroprotective trreatment against synucleinopathies. The NAPS Consortium will collect standardized clinical assessments, biofluids, and neuroimaging data. The RBD group will also undergo two overnight sleep studies. Some of this data will be used to develop biomarkers for synucleinopathies in the prodromal (presymptomatic) stage as well as a trial-ready registry of participants.

RBD group procedures include a clinical assessment, questionnaires, blood draw, neuroimaging (MRI and DaTscan), polysomnogram (sleep study), and optional lumbar puncture.

Control group procedures include a clinical assessment, questionnaires, blood draw, neuroimaging (MRI), and lumbar puncture.

02

Conditions studied

  • REM Sleep Behavior Disorder
  • Parkinson Disease
  • Lewy Body Dementia
  • Dementia With Lewy Bodies
  • Multiple System Atrophy
  • REM Sleep Parasomnias
03

In context

REM Sleep Behavior Disorder

101 studies on the registry are indexed under REM Sleep Behavior Disorder; 45 are open to participants now.

This study's planned enrollment of 500 is above the median of 119 across 48 observational studies indexed under REM Sleep Behavior Disorder.

Browse REM Sleep Behavior Disorder studies →

Lead sponsor

Washington University School of Medicine is the lead sponsor of 1,803 studies on the registry; 271 are open to participants now.

Of its 329 completed or terminated interventional studies of FDA-regulated products, 216 (66%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes
Sampling method
Non-probability sample

Study population

Idiopathic REM sleep behavior disorder, adults.

Eligibility criteria

Inclusion Criteria for RBD Group

  1. Polysomnogram-confirmed RBD by ICSD-3 criteria
  2. Capable of providing at time of study enrollment
  3. Age > 18 years

Exclusion Criteria for RBD Group

  1. Diagnosis of PD, dementia of any type, or MSA unless previous participant in NAPS1.
  2. Narcolepsy-associated RBD
  3. RBD secondary to any known cause except prodromal synucleinopathy.
  4. Participation in a clinical trial, except by specific permission by the Executive Committee
  5. In the opinion of the investigator, the individual has a uncontrolled medical condition that would impede safe completion of the study protocol

Inclusion Criteria for Control Group

  1. Ability to provide written consent
  2. Age > 18 years
  3. Must meet age, sex, and race matching criteria per the Data Management and Statistical core recommendations for the site
  4. Must be willing to undergo all testing procedures, including neuroimaging and lumbar puncture.
  5. Normal capacity to perform complex activities of daily living independently based on informant or physician report

Exclusion Criteria for Control Group

  1. History of dream enactment behavior to suggest RBD
  2. Parkinsonism, MSA, dementia, or mild cognitive impairment
  3. Active central nervous system, systemic, psychiatric condition or use of psychoactive medication that would adversely affect cognitive, neuropsychiatric, motor, or autonomic functioning.
  4. to complete MRI.
  5. Contraindications to lumbar puncture.
  6. Participation in a clinical trial, except by specific permission by the Executive Committee
  7. In the opinion of the investigator, the individual has a clinically significant uncontrolled medical condition that would impede safe completion of the study protocol
Terms in these criteria, in plain language(3)

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.

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.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

05

Study design

Observational model
Case-control
Time perspective
Prospective
Enrollment
500 participants (estimated)
Patient registry
No
Biospecimen retention
Samples with dna

Groups and cohorts

  • RBD group

    Clinical observation involving annual visits to a study site for up to 5 years.

  • control group

    Clinical observation involving annual visits to a study site for up to 5 years.

06

What researchers measure

Primary outcomes

  1. Prodromal Synucleinopathy Rating Scale

    Rating scale combining neurocognitive battery, motor, autonomic, olfaction, color vision functions. Global score range 0-3, with higher score indicating greater symptoms of synucleinopathy.

    Time frame: up to 5 years

07

Study locations

9 sites
08

References and documents

Publications

  • Boeve BF, Nie Y, Lu R, De La Cruz H, Avidan AY, Bliwise DL, Campbell MC, Criswell SR, Davis AA, Duff K, Elliott J, Ferman TJ, Fields JA, Forsberg LK, Gagnon JF, Howell M, Huddleston DE, Lim MM, Locke J, McCarter SJ, McLeland J, Miglis MG, Miyagawa T, Neilson LE, Nichols K, Pelletier A, Schenck CH, Louis EKS, Sum-Ping O, Trotti LM, Videnovic A, Xiong C, Postuma R, Ju YS; NAPS Consortium. The Prodromal Synucleinopathy Rating Scale: An Assessment in Patients With REM Sleep Behavior Disorder. Neurology. 2026 Jul 14;107(1):e218176. doi: 10.1212/WNL.0000000000218176. Epub 2026 Jun 16. PubMed 42302227 ↗
  • Lim MM, Neilson LE, Elliott JE, Hoang-Dang B, Locke JR, Cunningham H, Brewer J, Dennis L, Dovek L, Pelletier A, St Louis EK, McCarter SJ, Miyagawa T, Davis AA, McLeland JS, Criswell S, Howell MJ, Schenck CH, Avidan AY, Trotti LM, Bliwise DL, Huddleston DE, Videnovic A, Miglis MG, Sum-Ping O, Lee-Iannotti JK, Shprecher DR, Duff K, Ferman TJ, Campbell MC, Fields JA, Gagnon JF, Kotzbauer P, Singer W, Gan-Or Z, Ross OA, Kantarci K, Lowe VJ, Hu XP, Ehgoetz Martens KA, Hu MT, Xiong C, Postuma RB, Boeve BF, Ju YS; NAPS Consortium for RBD. The North American Prodromal Synucleinopathy study: protocol for a multi-site, longitudinal, observational study of idiopathic/isolated rapid eye movement sleep behavior disorder. Sleep Adv. 2026 Jan 19;7(1):zpag007. doi: 10.1093/sleepadvances/zpag007. eCollection 2026. PubMed 41725984 ↗

Individual participant data

Plan to share: Yes — De-identified subject level data will be shared upon approved data request. This project will develop a large database of potential neurocognitive, neuroimaging, genetic, and polysomnographic biomarkers in rapid eye movement sleep behavior disorder (RBD), as well as a biobank of blood, DNA, RNA, and cerebrospinal fluid. A large part of the clinical battery is the Uniform Dataset version 3, will be uploaded to the National Alzheimer's Coordinating Center (NACC). Biofluid samples will be banked at the National Cell Repository for Alzheimer's Disease (NCRAD). Genetic data will be submitted to the National Institute on Aging Genetics of Alzheimer's Disease Data Storage (NIAGADS). Brain MRI and DaTscan imaging data will be uploaded to the Laboratory of NeuroImaging (LONI). Polysomnogram data will be uploaded to the National Sleep Research Resource (NSRR).

Supporting information: Study protocol

Time frame: Updated datasets will be made available after completion of each semiannual data cleaning and data freeze. De-identified data will be available for at least the duration of the NAPS2 study.

Access criteria: The NAPS2 Administrative Core will receive, process, and track all requests for data/biospecimens. All requests will be reviewed and tracked per the current NAPS Data Access Policy (https://www.naps-rbd.org/resources at the bottom of the webpage) at the time of request. Approved requests will be filled using data that has been de-identified.

Data sharing details ↗ · www.naps-rbd.org

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on May 13, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05826457
Responsible party
Sponsor
First posted
Apr 24, 2023
Start date
Aug 12, 2022
Primary completion
May 1, 2027 (estimated)
Completion
May 1, 2028 (estimated)
Last update
May 13, 2026

Study contacts

Yo-El Ju, MD, MCSI
principal investigator · Washington University School of Medicine
Brad Boeve, MD
principal investigator · Mayo Clinic
Ron Postuma, MD
principal investigator · McGill University

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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