SLEEPRANDOMIZED SHAM-CONTROLLED CLINICAL TRIAL2024

taVNS and chronic insomnia

Transcutaneous Auricular Vagus Nerve Stimulation for Chronic Insomnia Disorder: A Randomized Clinical Trial

In a randomized sham-controlled clinical trial of 72 adults with chronic insomnia, the studied taVNS protocol produced a 4.2-point greater improvement in PSQI sleep-quality scores than sham at week 8. The difference exceeded the study’s prespecified 2.5-point threshold for clinical importance.

Evidence highlight 1: 72 participants
Evidence highlight 2: 4.2-point greater PSQI improvement than sham
Evidence highlight 3: 69.4% responder rate with active taVNS

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IN PLAIN ENGLISH

What the trial examined.

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

Participants used the assigned stimulation for 30 minutes twice daily, five consecutive days per week, over eight weeks. The primary outcome was change in sleep quality measured with the Pittsburgh Sleep Quality Index, or PSQI.

The researchers also assessed insomnia severity, mental health, daytime sleepiness, fatigue and safety. Participants were followed for a total of 20 weeks.

STUDY DESIGN

Study at a glance.

Design: Single-centre, parallel-group, randomized sham-controlled clinical trial
Participants randomized: 72 adults with chronic insomnia disorder
Groups: 36 active taVNS and 36 sham taVNS
Completion: 68 participants completed the eight-week intervention and follow-up
Treatment schedule: 30 minutes twice daily, five consecutive days per week, for eight weeks
Follow-up: Twelve weeks after treatment, for a total study period of 20 weeks
Primary outcome: Change in Pittsburgh Sleep Quality Index score at week 8
Clinically important threshold: 2.5 points for the between-group PSQI difference
Secondary outcomes: Insomnia severity, depression, anxiety, daytime sleepiness and fatigue
Blinding: Participants, outcome assessors and statisticians were blinded to treatment assignment
Analysis: Intention-to-treat and per-protocol analyses
Trial registration: ChiCTR2100051319

RESULTS

What the trial reported.

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

Sleep quality at week 8

Active taVNS: PSQI change: −8.2 points
Sham: PSQI change: −3.9 points
Between-group result: 4.2-point greater improvement with active taVNS
Confidence interval: 95% confidence interval: 2.6 to 5.9 points greater improvement
p-value: p < 0.001
Effect size: Cohen’s d: 1.2

The between-group difference exceeded the study’s prespecified 2.5-point threshold for clinical importance.

PSQI responder rate at week 8

Active taVNS: 69.4%
Sham: 27.8%
Between-group difference: 41.6 percentage points
p-value: p < 0.001

A responder was defined as a participant with at least a 50% reduction from baseline in PSQI score.

Insomnia severity at week 8

Active taVNS: ISI change: −10.6 points
Sham: ISI change: −5.9 points
Between-group result: 4.7-point greater improvement with active taVNS
Confidence interval: 95% confidence interval: 2.3 to 7.1 points greater improvement
p-value: p < 0.001
Effect size: Cohen’s d: 0.9

Results at week 20

The between-group difference in PSQI remained 4.5 points in favour of active taVNS at week 20.

Active taVNS: Responder rate: 72.2%
Sham: Responder rate: 22.2%
p-value: p < 0.001

The study reported that the sleep-quality difference between the groups remained present through the 20-week study period.

SAFETY IN THE TRIAL

Reported adverse events.

Active taVNS: 5 participants — 13.9%
Sham: 4 participants — 11.1%

The study found no statistically significant difference in the proportion of participants reporting adverse events between active and sham stimulation.

The most commonly reported stimulation-related event was slight temporary clamping pain at the outer ear.

STUDY CONTEXT

What to keep in mind.

A controlled comparison

The randomized sham-controlled design allowed the outcomes reported with active stimulation to be compared with a sham condition rather than with baseline change alone.

A specific treatment protocol

The trial used 30-minute sessions twice daily, five consecutive days per week, for eight weeks. The findings belong to this studied protocol and should not automatically be assumed to apply to every stimulation schedule.

A single-centre external study

The study was conducted at one centre with 72 participants and did not evaluate the Neuvago device. Larger multicentre studies are needed to establish how widely the findings apply.

SOURCE DETAILS

Citation and original sources.

Zhang S, Zhao Y, Qin Z, et al. Transcutaneous Auricular Vagus Nerve Stimulation for Chronic Insomnia Disorder: A Randomized Clinical Trial. JAMA Network Open. 2024;7(12):e2451217.

DOI: 10.1001/jamanetworkopen.2024.51217
Open DOI record
PubMed: PMID 39680406
View on PubMed
Trial registration: ChiCTR2100051319

The original paper remains the primary scientific source.

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