CognitionNCT07897175
Effects of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) on Cognition, Dual-Task Performance, and Interoceptive Accuracy
A study testing taVNS 30 Hz and taVNS 100 Hz in people with Cognition and Healthy Volunteers, run by Toros University at 1 site in Turkey (Türkiye).
Trial summary
This study aims to determine the simultaneous effects of transcutaneous auricular vagus nerve stimulation (taVNS) at two frequencies (30 Hz and 100 Hz) compared to sham stimulation on cognitive functions, dual-task performance, and interoceptive accuracy in healthy adults. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Cognition, Healthy Volunteers
- What is being tested?
- taVNS 30 Hz and taVNS 100 Hz
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 54 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Nov 2026to 1 May 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 1. Age 18-45 years 2. Mini-Mental State Examination (MMSE) score >24 3. Willing to participate; signed written informed consent 4. No uncorrected vision problems (glasses or contact lenses acceptable) 5. No communication difficulties; native Turkish speaker
Who cannot join
- 1. Cardiovascular disease or history (arrhythmia, conduction block, hypertension, cardiac diagnosis) 2. Any implanted electronic device or metal implant in the head/neck (pacemaker, cochlear implant, ventricular shunt, etc.) 3. Neurological disease or history of neurological procedures (epilepsy, stroke, TIA, migraine, brain surgery, progressive neurological disease) 4. Psychiatric diagnosis (schizophrenia, bipolar disorder, major depressive disorder, OCD, etc.) 5. History of vagotomy or prior vagus nerve stimulation 6. Current use of medications affecting the autonomic or central nervous system (beta-blockers, antiarrhythmics, antidepressants, antiepileptics, sedatives, etc.) 7. Systemic disease affecting autonomic function (diabetes, etc.) 8. Local conditions at stimulation site: acute tinnitus, ear or facial pain, ear trauma, skin lesion or infection, anatomical anomaly, or ear piercing at stimulation site 9. Chronic or acute musculoskeletal pain (neck/low back pain, fibromyalgia, joint disease, etc.) 10. Pregnancy or breastfeeding 11. Alcohol or substance use disorder 12. Concurrent enrollment in another interventional study 13. Vigorous physical exercise within 24 hours before assessment 14. Inability to understand or adhere to study protocol
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Toros University 45 Evler Campus
Mersin, 33140
Ece EKİCİ, Msc, +905300733826, ekiciece@gmail.com
About this study
Official title: Simultaneous Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Cognitive Functions, Dual-Task Performance, and Interoceptive Accuracy: A Double-Blind, Sham-Controlled, Randomized Parallel-Group Study
This study aims to determine the simultaneous effects of transcutaneous auricular vagus nerve stimulation (taVNS) at two frequencies (30 Hz and 100 Hz) compared to sham stimulation on cognitive functions, dual-task performance, and interoceptive accuracy in healthy adults. taVNS non-invasively activates vagal afferent fibers through electrical stimulation of the outer ear (cymba conchae and tragus), which are exclusively innervated by the auricular branch of the vagus nerve. Its proposed mechanism involves activation of the locus coeruleus-norepinephrine system and insular/prefrontal projections, providing a putative neurobiological basis for cognitive modulation. Ninety healthy volunteers (18-45 years) will be randomly assigned to one of three parallel groups: sham taVNS (n=30), active 30 Hz taVNS (n=30), or active 100 Hz taVNS (n=30). Each participant completes two sessions separated by one week: Session 1 (baseline, no stimulation) and Session 2 (experimental, stimulation active). Assessments include dual-task cost (3-Meter Tandem Walk Test with serial subtraction), executive function (Stroop Test), processing speed (Deary-Liewald Reaction Time Task), interoceptive accuracy (Heartbeat Counting Task), and heart rate variability (Polar H10). Sleep quality (PSQI), depression (BDI), physical activity (IPAQ-SF), and fatigue (Chalder Fatigue Scale) are measured at baseline as potential moderators. This is the first double-blind, sham-controlled study to simultaneously evaluate the effects of taVNS on these three constructs within a single experimental design, and the comparative frequency analysis (30 Hz vs 100 Hz) will contribute to parameter optimization for taVNS applications.
Read the detailed description
BACKGROUND AND RATIONALE The vagus nerve (cranial nerve X) is the longest and most widely distributed component of the parasympathetic nervous system. The auricular branch of the vagus nerve innervates specific anatomical regions of the outer ear, particularly the cymba conchae. Transcutaneous auricular vagus nerve stimulation (taVNS) leverages this anatomy to non-invasively activate vagal afferents without surgical implantation. The core mechanism involves projections from stimulated vagal afferents to the nucleus tractus solitarius (NTS), with subsequent signal relay to the locus coeruleus-norepinephrine (LC-NE) system, nucleus raphe, insula, and prefrontal cortex. A meta-analysis of 19 studies reported a small but statistically significant effect of taVNS on overall cognitive performance (weighted effect size = 0.21), with significant effects particularly for executive functions. No published study has simultaneously evaluated taVNS effects on cognitive function, dual-task performance, and interoceptive accuracy within the same design. STUDY DESIGN Single-center, prospective, double-blind, parallel-group, sham-controlled randomized trial. Participants are randomized via a web-based tool to one of three groups (1:1:1). Double blinding is achieved by keeping both the participant and the outcome assessor blinded to group allocation; stimulation is administered by a separate researcher not involved in assessments. The CONSORT checklist will be followed. PROTOCOL Session 1 (Baseline): Cognitive function (Stroop, Deary-Liewald), dual-task performance (3-Meter Tandem Walk Test), interoceptive accuracy (Heartbeat Counting Task), and HRV (Polar H10) are assessed without stimulation. Baseline questionnaires (PSQI, BDI, IPAQ-SF, Chalder) and MMSE screening are also administered. Session 2 (Experimental, 1 week later): The same outcome measures are re-assessed during active or sham taVNS administration. Within-group change (Δ = Session 2 - Session 1) and between-group comparisons (ΔSham vs. Δ30 Hz vs. Δ100 Hz) are the primary analyses. STIMULATION PARAMETERS Device: Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement: bilateral cymba conchae and tragus. Pulse width: 250 µs. Mode: continuous. Intensity: perceptible but sub-pain threshold. Groups: Sham (same electrode placement, no current); 30 Hz active; 100 Hz active. OUTCOME MEASURES Primary outcomes assessed at both sessions: (1) Dual-Task Cost (%) on 3-Meter Tandem Walk Test with serial subtraction by 3s; (2) Stroop effect (response time and accuracy); (3) Simple and Choice Reaction Time (Deary-Liewald Task); (4) Interoceptive Accuracy Score (Heartbeat Counting Task - 25, 35, 45-second intervals; Schandry 1981 formula). Secondary outcome assessed at both sessions: Heart Rate Variability (1-min resting Polar H10 recording). Baseline-only assessments: Pittsburgh Sleep Quality Index, Beck Depression Inventory, IPAQ-Short Form, Chalder Fatigue Scale, Mini-Mental State Examination (screening criterion). STATISTICAL ANALYSIS Two-way repeated-measures ANOVA (within-between interaction) for primary analysis; Bonferroni-corrected post-hoc comparisons. Effect sizes reported as partial eta squared (η²). Multiple linear regression to identify moderators of taVNS response. Analyses conducted in IBM SPSS Statistics v27.
- Conditions
- Cognition, Healthy Volunteers
- Being tested
- Sham Stimulation, taVNS 30 Hz, taVNS 100 Hz
- Keywords
- transcutaneous auricular vagus nerve stimulation;, cognitive function, heartbeat counting task, reaction time
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sham StimulationDevice
Sham transcutaneous auricular vagus nerve stimulation delivered via Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement is identical to active groups: bilateral cymba conchae and tragus using custom-sized auricular electrodes (small/medium/large). The device is switched on and electrodes are positioned in the same manner, but no electrical current is delivered. Session duration and all procedural steps are identical to active arms to maintain blinding. Participants are not informed of group allocation. The outcome assessor is blinded to group assignment throughout the study.
taVNS 30 HzDevice
Active transcutaneous auricular vagus nerve stimulation at 30 Hz delivered via Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement: bilateral cymba conchae and tragus using custom-sized auricular electrodes (small/medium/large). Parameters: frequency 30 Hz, pulse width 250 µs, continuous mode, current intensity individually titrated to a perceptible but sub-pain threshold. Stimulation is applied online (throughout the experimental session) during all outcome assessments. The outcome assessor is blinded to group allocation; stimulation is administered by a separate researcher not involved in assessments.
taVNS 100 HzDevice
Active transcutaneous auricular vagus nerve stimulation at 100 Hz delivered via Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement: bilateral cymba conchae and tragus using custom-sized auricular electrodes (small/medium/large). Parameters: frequency 100 Hz, pulse width 250 µs, continuous mode, current intensity individually titrated to a perceptible but sub-pain threshold. Stimulation is applied online (throughout the experimental session) during all outcome assessments. The outcome assessor is blinded to group allocation; stimulation is administered by a separate researcher not involved in assessments.
| Study group | Role | What they receive |
|---|---|---|
| Sham taVNS | Sham comparator | Participants receive sham stimulation via Vagustim® device with the same bilateral electrode placement at cymba conchae and tragus, but with no electrical current delivered. Electrode placement and session duration are identical to active groups Receives: Device: Sham Stimulation |
| Active taVNS - 30 Hz | Experimental | Participants receive active transcutaneous auricular vagus nerve stimulation at 30 Hz via Vagustim® device, bilaterally applied to cymba conchae and tragus, at sub-pain perceptible intensity, throughout the experimental session. Receives: Device: taVNS 30 Hz |
| Active taVNS - 100 Hz | Experimental | Participants receive active transcutaneous auricular vagus nerve stimulation at 100 Hz via Vagustim® device, bilaterally applied to cymba conchae and tragus, at sub-pain perceptible intensity, throughout the experimental session. Receives: Device: taVNS 100 Hz |
What is being measured
The primary outcome is the main question the study is designed to answer.
Dual-Task Cost on 3-Meter Tandem Walk Test
Dual-Task Cost (DTC, %) quantifies the decrement in tandem walking performance when simultaneously performing serial subtraction (counting backward by 3s from a 3-digit number). DTC (%) = [(single-task time - dual-task time) / single-task time] × 100. Higher DTC indicates greater cognitive-motor interference.
Measured: Session 1 (Baseline, no stimulation) and Session 2 (1 week later, during taVNS or sham)
Stroop test
Executive function assessed via Stroop Test (Stroop Anchor Form). The Stroop effect is the difference in response time and accuracy between the color-word incongruent and congruent conditions, reflecting inhibitory control capacity.
Measured: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Simple and Choice Reaction Time - Deary-Liewald Task
Processing speed assessed using the Deary-Liewald Reaction Time Task administered via psytoolkit.org. Two conditions: Simple Reaction Time (SRT: respond to single stimulus appearing on blue background) and Choice Reaction Time (CRT: respond to one of four stimuli with the corresponding key). Inter-stimulus interval randomized between 1-3 seconds.
Measured: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Heartbeat Counting Task Score (Interoceptive Accuracy)
Objective interoceptive accuracy assessed using the Schandry (1981) Heartbeat Counting Task. Participants silently count their own heartbeats during 25-, 35-, and 45-second intervals without external cues. Reported counts are compared with actual heart rate recorded via Polar H10 sensor. Accuracy score = 1 - [Σ(|reported - actual| / actual)] / 3. Scores range 0-1; higher scores indicate greater interoceptive accuracy.
Measured: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Secondary outcomes (1)
Resting Heart Rate Variability
HRV assessed as an index of autonomic nervous system regulation using Polar H10 heart rate sensor (Polar Electro Oy, Kempele, Finland) synchronized via Bluetooth with the "ECG Analysis for Polar H10" smartphone application. Participants rest in a supported seated position for 1 minute after sensor calibration. Time-domain and frequency-domain HRV indices extracted.
Measured: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Oct 2026
- Study start1 Nov 2026 (estimated)
- Primary completion1 Mar 2027 (estimated)
- Study completion1 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for CognitionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 54 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Toros University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ece Ekici, Toros University
- Investigators
- Öznur TUNCA, PhD, Study chair, Hacettepe University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07897175
- Sponsor's protocol ID
- TorosU-EE-1
- Status last verified
- Oct 2026
- First submitted
- 19 Oct 2026
- Last updated
- 27 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Simultaneous Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Cognitive Functions, Dual-Task Performance, and Interoceptive Accuracy: A Double-Blind, Sham-Controlled, Randomized Parallel-Group Study
- ClinicalTrials.gov ID
- NCT07897175
- Acronym / sponsor ID
- TorosU-EE-1
- Conditions
- Cognition, Healthy Volunteers
- Keywords
- transcutaneous auricular vagus nerve stimulation;, cognitive function, heartbeat counting task, reaction time
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 54 participants (estimated)
- Lead sponsor
- Toros UniversityUniversity, hospital or other
- Study start
- 1 Nov 2026 (estimated)
- Primary completion
- 1 Mar 2027 (estimated)
- Study completion
- 1 May 2027 (estimated)
- First posted
- 27 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to determine the simultaneous effects of transcutaneous auricular vagus nerve stimulation (taVNS) at two frequencies (30 Hz and 100 Hz) compared to sham stimulation on cognitive functions, dual-task performance, and interoceptive accuracy in healthy adults. taVNS non-invasively activates vagal afferent fibers through electrical stimulation of the outer ear (cymba conchae and tragus), which are exclusively innervated by the auricular branch of the vagus nerve. Its proposed mechanism involves activation of the locus coeruleus-norepinephrine system and insular/prefrontal projections, providing a putative neurobiological basis for cognitive modulation. Ninety healthy volunteers (18-45 years) will be randomly assigned to one of three parallel groups: sham taVNS (n=30), active 30 Hz taVNS (n=30), or active 100 Hz taVNS (n=30). Each participant completes two sessions separated by one week: Session 1 (baseline, no stimulation) and Session 2 (experimental, stimulation active). Assessments include dual-task cost (3-Meter Tandem Walk Test with serial subtraction), executive function (Stroop Test), processing speed (Deary-Liewald Reaction Time Task), interoceptive accuracy (Heartbeat Counting Task), and heart rate variability (Polar H10). Sleep quality (PSQI), depression (BDI), physical activity (IPAQ-SF), and fatigue (Chalder Fatigue Scale) are measured at baseline as potential moderators. This is the first double-blind, sham-controlled study to simultaneously evaluate the effects of taVNS on these three constructs within a single experimental design, and the comparative frequency analysis (30 Hz vs 100 Hz) will contribute to parameter optimization for taVNS applications.
Detailed description
BACKGROUND AND RATIONALE The vagus nerve (cranial nerve X) is the longest and most widely distributed component of the parasympathetic nervous system. The auricular branch of the vagus nerve innervates specific anatomical regions of the outer ear, particularly the cymba conchae. Transcutaneous auricular vagus nerve stimulation (taVNS) leverages this anatomy to non-invasively activate vagal afferents without surgical implantation. The core mechanism involves projections from stimulated vagal afferents to the nucleus tractus solitarius (NTS), with subsequent signal relay to the locus coeruleus-norepinephrine (LC-NE) system, nucleus raphe, insula, and prefrontal cortex. A meta-analysis of 19 studies reported a small but statistically significant effect of taVNS on overall cognitive performance (weighted effect size = 0.21), with significant effects particularly for executive functions. No published study has simultaneously evaluated taVNS effects on cognitive function, dual-task performance, and interoceptive accuracy within the same design. STUDY DESIGN Single-center, prospective, double-blind, parallel-group, sham-controlled randomized trial. Participants are randomized via a web-based tool to one of three groups (1:1:1). Double blinding is achieved by keeping both the participant and the outcome assessor blinded to group allocation; stimulation is administered by a separate researcher not involved in assessments. The CONSORT checklist will be followed. PROTOCOL Session 1 (Baseline): Cognitive function (Stroop, Deary-Liewald), dual-task performance (3-Meter Tandem Walk Test), interoceptive accuracy (Heartbeat Counting Task), and HRV (Polar H10) are assessed without stimulation. Baseline questionnaires (PSQI, BDI, IPAQ-SF, Chalder) and MMSE screening are also administered. Session 2 (Experimental, 1 week later): The same outcome measures are re-assessed during active or sham taVNS administration. Within-group change (Δ = Session 2 - Session 1) and between-group comparisons (ΔSham vs. Δ30 Hz vs. Δ100 Hz) are the primary analyses. STIMULATION PARAMETERS Device: Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement: bilateral cymba conchae and tragus. Pulse width: 250 µs. Mode: continuous. Intensity: perceptible but sub-pain threshold. Groups: Sham (same electrode placement, no current); 30 Hz active; 100 Hz active. OUTCOME MEASURES Primary outcomes assessed at both sessions: (1) Dual-Task Cost (%) on 3-Meter Tandem Walk Test with serial subtraction by 3s; (2) Stroop effect (response time and accuracy); (3) Simple and Choice Reaction Time (Deary-Liewald Task); (4) Interoceptive Accuracy Score (Heartbeat Counting Task - 25, 35, 45-second intervals; Schandry 1981 formula). Secondary outcome assessed at both sessions: Heart Rate Variability (1-min resting Polar H10 recording). Baseline-only assessments: Pittsburgh Sleep Quality Index, Beck Depression Inventory, IPAQ-Short Form, Chalder Fatigue Scale, Mini-Mental State Examination (screening criterion). STATISTICAL ANALYSIS Two-way repeated-measures ANOVA (within-between interaction) for primary analysis; Bonferroni-corrected post-hoc comparisons. Effect sizes reported as partial eta squared (η²). Multiple linear regression to identify moderators of taVNS response. Analyses conducted in IBM SPSS Statistics v27.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Sham taVNS | Sham comparator | Device: Sham StimulationParticipants receive sham stimulation via Vagustim® device with the same bilateral electrode placement at cymba conchae and tragus, but with no electrical current delivered. Electrode placement and session duration are identical to active groups |
| Active taVNS - 30 Hz | Experimental | Device: taVNS 30 HzParticipants receive active transcutaneous auricular vagus nerve stimulation at 30 Hz via Vagustim® device, bilaterally applied to cymba conchae and tragus, at sub-pain perceptible intensity, throughout the experimental session. |
| Active taVNS - 100 Hz | Experimental | Device: taVNS 100 HzParticipants receive active transcutaneous auricular vagus nerve stimulation at 100 Hz via Vagustim® device, bilaterally applied to cymba conchae and tragus, at sub-pain perceptible intensity, throughout the experimental session. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- 1. Age 18-45 years 2. Mini-Mental State Examination (MMSE) score >24 3. Willing to participate; signed written informed consent 4. No uncorrected vision problems (glasses or contact lenses acceptable) 5. No communication difficulties; native Turkish speaker
Key exclusion criteria (1 listed)
- 1. Cardiovascular disease or history (arrhythmia, conduction block, hypertension, cardiac diagnosis) 2. Any implanted electronic device or metal implant in the head/neck (pacemaker, cochlear implant, ventricular shunt, etc.) 3. Neurological disease or history of neurological procedures (epilepsy, stroke, TIA, migraine, brain surgery, progressive neurological disease) 4. Psychiatric diagnosis (schizophrenia, bipolar disorder, major depressive disorder, OCD, etc.) 5. History of vagotomy or prior vagus nerve stimulation 6. Current use of medications affecting the autonomic or central nervous system (beta-blockers, antiarrhythmics, antidepressants, antiepileptics, sedatives, etc.) 7. Systemic disease affecting autonomic function (diabetes, etc.) 8. Local conditions at stimulation site: acute tinnitus, ear or facial pain, ear trauma, skin lesion or infection, anatomical anomaly, or ear piercing at stimulation site 9. Chronic or acute musculoskeletal pain (neck/low back pain, fibromyalgia, joint disease, etc.) 10. Pregnancy or breastfeeding 11. Alcohol or substance use disorder 12. Concurrent enrollment in another interventional study 13. Vigorous physical exercise within 24 hours before assessment 14. Inability to understand or adhere to study protocol
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Sham StimulationSham transcutaneous auricular vagus nerve stimulation delivered via Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement is identical to active groups: bilateral cymba conchae and tragus using custom-sized auricular electrodes (small/medium/large). The device is switched on and electrodes are positioned in the same manner, but no electrical current is delivered. Session duration and all procedural steps are identical to active arms to maintain blinding. Participants are not informed of group allocation. The outcome assessor is blinded to group assignment throughout the study. | Device | Sham taVNS |
| taVNS 30 HzActive transcutaneous auricular vagus nerve stimulation at 30 Hz delivered via Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement: bilateral cymba conchae and tragus using custom-sized auricular electrodes (small/medium/large). Parameters: frequency 30 Hz, pulse width 250 µs, continuous mode, current intensity individually titrated to a perceptible but sub-pain threshold. Stimulation is applied online (throughout the experimental session) during all outcome assessments. The outcome assessor is blinded to group allocation; stimulation is administered by a separate researcher not involved in assessments. | Device | Active taVNS - 30 Hz |
| taVNS 100 HzActive transcutaneous auricular vagus nerve stimulation at 100 Hz delivered via Vagustim® non-invasive stimulation device (CE No: 2460; Vagustim Health Technologies Inc., Turkey). Electrode placement: bilateral cymba conchae and tragus using custom-sized auricular electrodes (small/medium/large). Parameters: frequency 100 Hz, pulse width 250 µs, continuous mode, current intensity individually titrated to a perceptible but sub-pain threshold. Stimulation is applied online (throughout the experimental session) during all outcome assessments. The outcome assessor is blinded to group allocation; stimulation is administered by a separate researcher not involved in assessments. | Device | Active taVNS - 100 Hz |
Primary outcome
Dual-Task Cost on 3-Meter Tandem Walk Test
Time frame: Session 1 (Baseline, no stimulation) and Session 2 (1 week later, during taVNS or sham)
Dual-Task Cost (DTC, %) quantifies the decrement in tandem walking performance when simultaneously performing serial subtraction (counting backward by 3s from a 3-digit number). DTC (%) = [(single-task time - dual-task time) / single-task time] × 100. Higher DTC indicates greater cognitive-motor interference.
Stroop test
Time frame: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Executive function assessed via Stroop Test (Stroop Anchor Form). The Stroop effect is the difference in response time and accuracy between the color-word incongruent and congruent conditions, reflecting inhibitory control capacity.
Simple and Choice Reaction Time - Deary-Liewald Task
Time frame: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Processing speed assessed using the Deary-Liewald Reaction Time Task administered via psytoolkit.org. Two conditions: Simple Reaction Time (SRT: respond to single stimulus appearing on blue background) and Choice Reaction Time (CRT: respond to one of four stimuli with the corresponding key). Inter-stimulus interval randomized between 1-3 seconds.
Heartbeat Counting Task Score (Interoceptive Accuracy)
Time frame: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Objective interoceptive accuracy assessed using the Schandry (1981) Heartbeat Counting Task. Participants silently count their own heartbeats during 25-, 35-, and 45-second intervals without external cues. Reported counts are compared with actual heart rate recorded via Polar H10 sensor. Accuracy score = 1 - [Σ(|reported - actual| / actual)] / 3. Scores range 0-1; higher scores indicate greater interoceptive accuracy.
1 secondary outcome
Resting Heart Rate Variability
Time frame: Session 1 (Baseline) and Session 2 (1 week later, during taVNS or sham)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Öznur TUNCA, PhD study chair
Hacettepe University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing taVNS 30 Hz and taVNS 100 Hz in people with Cognition and Healthy Volunteers, run by Toros University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 27 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ece EKİCİ, MSc (+905300733826, ekiciece@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Dual-Task Cost on 3-Meter Tandem Walk Test (time frame: Session 1 (Baseline, no stimulation) and Session 2 (1 week later, during taVNS or sham)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Oct 2026.