Effects of Transcutaneous Vagus Nerve Stimulation on Emotion Regulation and Executive Functioning in Prader-Willi Syndrome

Summary

The STIM-PRADER study aims to assess the effectiveness of auricular vagal neuromodulation therapy (aVNT) on emotional, behavioral, and cognitive domains impaired in Prader-Willi Syndrome (PWS). Currently, no treatment exists that addresses the multiple alterations associated with this rare neurodevelopmental disorder that significantly impact patients and their families. We will investigate the effects of daily, four-hour aVNT stimulation over a nine-month period on (a) emotion regulation, including assessing the persistence of effects following stimulation; (b) executive functions, including inhibition, flexibility, planning, and updating information in memory; (c) hyperphagia; (d) depression; (e) quality of life; (e) and the threshold at which effects on these dimensions can be observed.

We will conduct a longitudinal multicenter parallel randomized controlled single-blind exploratory trial. Twenty-four adults with PWS and 24 caregivers will be randomly assigned to receive either active or sham stimulation under identical conditions (four hours per day, seven days per week over nine months). The primary outcome, focusing on emotional control, will be assessed every two weeks for both participants and caregivers. Secondary outcomes (executive functions, hyperphagia, depression, and quality of life) will be measured at four time points: pre-intervention, at three months, six months, and at nine months.

As this is the first multicenter randomized controlled trial investigating the effects of aVNT as a treatment in PWS patients, we anticipate witnessing improved emotional regulation and reduced eating disorders, along with enhancements in executive functions and quality of life in the active stimulation group. The findings from this project could support the development of broader therapeutic approaches for other conditions in which behavioral disorders and emotional processing deficits affect patients and their caregivers.

Conditions

• Prader-Willi Syndrome

Interventions

DEVICE

Auricular vagal neuromodulation therapy (aVNT)

The aVNT device used in our study (Parasym ®) consists of a small portable unit connected to stimulation electrodes placed on the left ear. These electrodes deliver painless electrical microcurrents through the skin to stimulate the auricular branch of the vagus nerve (ABVN). The device parameters will be defined in accordance with the recommendations for use of the Parasym ® device and the pilot studies: frequency of 25 Hz, pulse width of 250 µS, and an intensity of 1 mA to 36 mA. Stimulation sessions will last for four hours each day, each of which can be divided into two sessions and conducted over a period of nine months. Patients will adjust the intensity at each session according to their comfort level, starting with a gradual increase until they feel a slight tingling sensation, followed by a decrease until discomfort disappears completely. Stimulation should take place during a relaxing activity but not should not take place during sleep, meals or major physical activity.

DEVICE

Sham Auricular vagal neuromodulation therapy (aVNT)

The sham stimulation control condition will be performed using the same aVNT Parasym® device under similar conditions (four hours a day, seven days a week, for nine months) but with a different location (without afferent vagus nerve fibers) or a control condition integrated into the device.

Sponsors & Collaborators

• John Bost Foundation

  collaborator UNKNOWN

• University Hospital, Bordeaux

  collaborator OTHER

• Hendaye hospital

  collaborator UNKNOWN

• Groupe Hospitalier Pitie-Salpetriere

  collaborator OTHER

• University Hospital, Toulouse

  collaborator OTHER

• Prader-Willi Syndrome Association

  collaborator OTHER

• University of Bordeaux

  lead OTHER

Principal Investigators

• Virginie Postal, PhD · University of Bordeaux

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-11-22

Primary Completion

2026-03-30

Completion

2026-03-30

Countries

• France

Study Locations