SLEEPDOUBLE-BLIND RANDOMIZED SHAM-CONTROLLED TRIAL2025

taVNS and chronic insomnia

Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) Improves Sleep Quality in Chronic Insomnia Disorder: A Double-Blind, Randomized, Sham-Controlled Trial

A double-blind, randomized, sham-controlled trial of 40 people with chronic insomnia disorder reported significantly greater improvements in sleep quality and insomnia severity with active taVNS than with sham stimulation after six weeks.

Evidence highlight 1: 40 participants
Evidence highlight 2: 30 minutes daily for six weeks
Evidence highlight 3: Active taVNS compared with sham

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IN PLAIN ENGLISH

What the trial examined.

The study compared active transcutaneous auricular vagus nerve stimulation with sham stimulation in people diagnosed with chronic insomnia disorder.

Participants used the assigned stimulation for 30 minutes each day over six weeks. Sleep quality measured with the Pittsburgh Sleep Quality Index, or PSQI, was the primary outcome.

The researchers also assessed insomnia severity, total sleep time, quality of life and adverse events.

STUDY DESIGN

Study at a glance.

Design: Double-blind, randomized, sham-controlled trial
Participants: 40 participants with chronic insomnia disorder
Comparison: Active taVNS compared with sham stimulation
Treatment period: Six weeks
Session schedule: 30 minutes daily
Primary outcome: Sleep quality measured with the Pittsburgh Sleep Quality Index (PSQI)
Secondary outcomes: Insomnia severity, total sleep time and quality of life
Objective sleep measurement: Fitbit wearable devices were used to obtain objective sleep measures
Analysis: Modified intention-to-treat analysis at six weeks

RESULTS

What the trial reported.

Lower PSQI and ISI scores indicate improvement in sleep quality and insomnia severity.

Sleep quality — PSQI

The active taVNS group showed a significantly greater reduction in PSQI scores than the sham group after six weeks.

Reported effect size: Cohen’s d: −1.21
p-value: p = 0.009

The reported effect size indicates a large difference between the groups, with lower PSQI scores favouring active taVNS.

Insomnia severity — ISI

The active taVNS group also showed a significantly greater improvement in insomnia severity than the sham group.

Active taVNS:: −7.6 points
Sham:: −4.25 points
Reported effect size: Cohen’s d: −0.75
p-value: p = 0.023

The result favoured active taVNS and represented a moderate to large difference between the groups.

Total sleep time

The study reported a significant increase in total sleep time with active taVNS compared with sham stimulation.

Reported effect size: Cohen’s d: 0.69
p-value: p = 0.019

Quality of life

Quality-of-life scores improved significantly more with active taVNS than with sham stimulation.

Reported effect size: Cohen’s d: 0.65
p-value: p = 0.047

SAFETY IN THE TRIAL

Reported adverse events.

The authors reported no significant adverse events during the six-week trial.

This safety finding relates to the participants, device, protocol and treatment period examined in this specific study.

STUDY CONTEXT

What to keep in mind.

A strong controlled design

The double-blind, randomized, sham-controlled design provides a controlled comparison between active and sham stimulation rather than relying only on changes from baseline.

A specific treatment protocol

Participants used the assigned stimulation for 30 minutes daily over six weeks. The findings belong to this studied protocol and should not automatically be assumed to apply to every stimulation schedule.

A small external study

The trial included 40 participants and did not evaluate the Neuvago device. Larger independent studies would help establish how widely the findings apply.

SOURCE DETAILS

Citation and original sources.

Yeom JW, Kim H, Park S, Yoon Y, Seo JY, Cho CH, Lee HJ. Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) Improves Sleep Quality in Chronic Insomnia Disorder: A Double-Blind, Randomized, Sham-Controlled Trial. Sleep Medicine. 2025;133:106579.

DOI: 10.1016/j.sleep.2025.106579
Open DOI record
PubMed: PMID 40398066
View on PubMed

The original paper remains the primary scientific source.

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