Role of Slow Waves in the Progression of Neurodegeneration in Isolated REM Sleep Behavior Disorder

Overview

This study tests whether enhancing deep sleep with gentle sounds at night can slow progression in people with iRBD or early Parkinson's disease. Participants wear a sensor headband and headphones for 18 months. Four assessments including mobility, memory, imaging (PET/MRI), lumbar puncture, and blood tests are assessed.

Detailed description

Many people with REM sleep behavior disorder (iRBD) develop Parkinson's disease or similar conditions over the years. To date, there is no effective method to prevent this transition. Animal experiments and observational studies in patients and older adults indicate that deeper sleep is associated with a slower progression of brain changes. In this study, we are now investigating whether enhancement of deep sleep using sounds during sleep can influence the progressive brain changes in iRBD or early Parkinson's disease.

Participants wear a headband with sensors and headphones for 18 months, which plays gentle sounds during sleep to enhance deep sleep. In addition, four examinations are carried out, including tests of mobility, memory, imaging (PET/MRI), a lumbar puncture, and blood sampling. Two of the examinations will take place at the University Hospital of Zurich, and two more can also be carried out at home if desired.

The aim is to investigate whether enhancement of deep sleep can help slow the progression of iRBD or early-stage Parkinson's disease. The study is double-blind and controlled, which means that neither the participants nor the researchers know who is receiving the active treatment.

Interventions

• Device Tosoo Axora
  Phase Targeted Auditory Stimulation (PTAS) will be applied through integrated headphones with a portable EEG device when non-rapid-eye-movement (NREM) sleep is detected during the night.
• Device Tosoo Axora
  Auditory stimuli will be delivered during the night through integrated headphones with a portable EEG device in a non-PTAS manner.

Primary outcome measures

• Presynaptic Dopaminergic Integrity [Time frame: assessed at Baseline Visit and Closeout Visit (after 18 months)]

Secondary outcome measures (12)

• MDS-UPDRS Part III Score [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Purdue Pegboard Test Score [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Alternate Finger Tapping Test [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• UPDRS I.1 (subjective cognition) [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Montreal Cognitive Assessment (MoCA) Score [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout)]
• Trail Making Test Part A [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Trail Making Test Part B [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Digit Span Forward [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Digit Span backward [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Stroop Test [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Verbal Fluency - Semantic [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]
• Benton Judgment of Line Orientation (BJLO) [Time frame: assessed at each visit (Baseline, after 6 months, after 12 months, after 18 months (Closeout))]

Eligibility criteria

Inclusion criteria

• Signed informed consent
• Diagnosis of polysomnography-confirmed isolated REM Sleep Behavior Disorder (iRBD) based on international criteria (ICSD-3), combined with EITHER
• UPDRS III without action tremor ≥ 4 AND abnormal olfaction, OR
• diagnosis of PD along international criteria for less than 2 years

Further inclusion criteria are:

• no dopaminergic treatment and no foreseen start of such treatment during duration of the study
• ability to apply the intervention, alone or with help of a co-habitant, stable living situation
• sufficient language skills in German, French or Italian
• negative pregnancy test for women of child-bearing potential

Exclusion criteria

• Suspected or known non-compliance to other therapies
• current or recent participation in another clinical trial
• extended absences
• hearing impairment that prevents hearing the tones for auditory stimulation
• non-responder to auditory stimulation during screening
• clinically significant concomitant disease or unstable condition
• Apnea-Hypopnea-Index (AHI) > 15/h or under Continuous Positive Airway Pressure (CPAP) treatment
• Restless Legs Syndrome
• meeting criteria for diagnosis of atypical Parkinson syndrome
• diagnosis of Dementia or Montreal Cognitive Assessment (MoCA) < 24
• severe Depression or other psychiatric disorder
• regular use of benzodiazepines and other central nervous system depressant substances
• current or recent history within the last year of substance abuse disorders or chronic alcohol consumption
• recent or planned major surgery
• history of allergies and hypersensitivity relevant for electrode application or medication allergies
• additional exclusion criteria for PET imaging
• any criterion that may pose the participant at risk
• breastfeeding, intention to become pregnant, or unwillingness to use medically reliable contraception for women of child-bearing potential

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Triple blind

Primary purpose

Treatment

Study locations

Switzerland · 1 center

• University Hospital Zurich, Neurology Department — Zurich

Identifiers

NCT: NCT07355842 · SloW-iRBD · 2025-D0069

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗