Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Cognitive Performance and Sex Differences

NCT07256080 | Not Yet Recruiting

• 1 other identifier: 61351342/020-93
• Study Type: interventional
• Target: 60
• Locations: 0 countries
• Sites: N/A

Brief Summary

This study investigates the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on cognitive performance in healthy adults. The study uses a sham-controlled, cross-over design in which each participant receives both active taVNS and sham stimulation in separate sessions. Each participant completes both conditions (active and sham) in a randomized order using a crossover design. Cognitive performance will be assessed before and after each session using standardized tests. The study also explores whether males and females respond differently to taVNS, in order to identify potential sex-related differences in cognitive outcomes.

Conditions

Cognitive Assessment; Cognition; taVNS; Vagus Nerve Stimulation; Executive Functions; Healthy Participants; Neuromodulation; Sex Differences

Outcome Measures

Primary Outcomes (1)

• CogniFit Digital Battery

  Cognitive performance will be evaluated using the CogniFit digital cognitive battery, which assesses multiple cognitive domains including attention, working memory, executive functions, and processing speed. The battery will be administered once at baseline (Visit 1). It will be administered again immediately after Active stimulation in Visit 2 and immediately after Sham stimulation in Visit 3. Changes in cognitive scores between baseline and post-stimulation sessions will be compared to determine the acute cognitive effects of active vs. sham taVNS.

  Day 1 (Visit 1 baseline), Day 8 (Visit 2), and Day 15 (Visit 3) Cognitive testing will occur after stimulation on Day 8 and Day 15.

Secondary Outcomes (4)

• Heart Rate Variability (HRV)

  Day 8 (Visit 2): 5 minutes before stimulation and 5 minutes after stimulation. Day 15 (Visit 3): 5 minutes before stimulation and 5 minutes after stimulation.

• Perceived Stress Levels (PSS)

  Day 1 (Visit 1 baseline), Day 8 (Visit 2 after stimulation), and Day 15 (Visit 3 after stimulation).

• State and Trait Anxiety (STAI)

  Day 1 (Visit 1 baseline), Day 8 (Visit 2 after stimulation), and Day 15 (Visit 3 after stimulation).

• Self-Reported Side Effects

  Day 8 (Visit 2 after stimulation) and Day 15 (Visit 3 after stimulation)

Study Arms (2)

Active taVNS Stimulation

EXPERIMENTAL

Active taVNS will be applied bilaterally to the cymba conchae and tragus regions using the VaguStim device. Stimulation will follow standard parameters used in cognitive studies to minimize cardiac side effects. Parameters: biphasic waveform, 25 Hz frequency, 250 μs pulse width, and intensity individually adjusted below the sensory threshold (0.5-4 mA). Each session will last 20 minutes.

Device: Active taVNS

Sham Stimulation

SHAM COMPARATOR

For the sham condition, electrodes will be placed on the earlobe bilaterally, an area not innervated by the vagus nerve, using the same device and parameter settings but without delivering active stimulation. This setup controls for placebo effects.

Device: Sham Stimulation

Interventions

Active taVNS DEVICE

Active taVNS will be delivered bilaterally to the cymba conchae and tragus regions using the VaguStim device. Stimulation parameters follow cognitive-neuroscience standards to minimize cardiac side effects: biphasic waveform, 25 Hz frequency, 250 μs pulse width, and intensity individually adjusted below the sensory threshold (0.5-4 mA). Each stimulation session lasts 20 minutes. This intervention corresponds to the Active taVNS Stimulation arm.

Active taVNS Stimulation

Sham Stimulation DEVICE

Sham stimulation will be delivered using the same VaguStim device, but electrodes will be placed bilaterally on the earlobe, an area not innervated by the vagus nerve. Device parameters will be set to match the active condition, but no true vagus nerve stimulation is delivered. This procedure controls for placebo and participant expectancy effects. This intervention corresponds to the Sham Stimulation arm.

Sham Stimulation

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy young adults aged 18-30 years
• Ability to provide informed consent
• Right-handed participants (to reduce variability in cognitive performance)
• Normal or corrected-to-normal vision and hearing
• Female participants tested during the follicular phase of the menstrual cycle (days 5-10) to minimize hormonal effects on cognition and vagal tone

You may not qualify if:

• History of neurological or psychiatric disorders
• Cardiovascular disease
• Use of psychoactive medications
• Substance dependence, including alcohol, illicit drugs, or nicotine
• Pregnancy or breastfeeding
• Skin conditions or ear anomalies that interfere with electrode placement
• Metal implants in the head or neck region
• History of epilepsy or migraine

Sponsors & Collaborators

• Bahçeşehir University: lead

Study Officials

• Ali Veysel Ozden

  Bahçeşehir University

  STUDY CHAIR

Central Study Contacts

Yara A Skout

CONTACT

+905316766782; yaraskout@gmail.com

Ali Vesel Ozden Assistant Professor

CONTACT

00905065994233; aliveysel.ozden@bau.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: Participants will be blinded to whether they receive active or sham stimulation. Outcome measures (CogniFit, HRV, STAI, PSS) are automated or self-administered; outcome assessors will therefore be blinded to condition. The investigator applying stimulation will not be blinded due to device setup requirements.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal investigator

Study Record Dates

• First Submitted: November 18, 2025
• First Posted: December 1, 2025
• Study Start: December 1, 2025
• Primary Completion: April 1, 2026
• Study Completion: May 1, 2026
• Last Updated: December 1, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share