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Frequency-Dependent Effects of Auricular Vagus Nerve Stimulation on Autonomic and Cardiovascular Parameters

ConditionsVagus Nerve StimulationAutonomic Nervous SystemHeart RateBlood PressureRespirationHealthy Volunteers
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-30
SponsorSEFA HAKTAN HATIK

About this trial

This randomized, sham-controlled, crossover study investigates the acute autonomic effects of transcutaneous cervical vagus nerve stimulation (tcVNS) applied at five different frequencies (0 Hz/sham, 10 Hz, 25 Hz, 50 Hz, 100 Hz) in healthy adults. The primary objective is to determine how stimulation frequency modulates heart rate variability (HRV), blood pressure, and respiratory rate. The study aims to establish a frequency-specific dose-response model using validated physiological measurements.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

18-30 years

Healthy (self-reported)

No cardiovascular, neurological, metabolic or psychiatric disorders

No regular medication affecting autonomic function

Disqualifiers

Pregnancy

Cardiac arrhythmia

Hypertension or hypotension

Chronic respiratory disorders

Trial design

Design model

Crossover

Treatments tested in this trial

  • Pulsetto FIT™ - Sham tcVNS

    Device

    The Pulsetto FIT™ device is placed bilaterally on the cervical region (posterior margin of the sternocleidomastoid muscle). In the sham condition, the device displays normal operational lights but delivers no electrical stimulation (0 Hz; inactive mode). This condition is used for blinding and as the control comparator. Dose: 10 minutes

  • Pulsetto FIT™ - tcVNS 10 Hz

    Device

    Bilateral transcutaneous cervical vagus nerve stimulation delivered via the Pulsetto FIT™ device at 10 Hz, 250 µs pulse width. Current intensity adjusted to a mild, non-painful tingling sensation, individualized for each participant. Dose: 10 minutes

  • Pulsetto FIT™ - tcVNS 25 Hz

    Device

    Bilateral tcVNS using the Pulsetto FIT™ device at 25 Hz, 250 µs pulse width. Stimulation intensity set at a comfortable sensory level. Dose: 10 minutes

  • Pulsetto FIT™ - tcVNS 50 Hz

    Device

    Bilateral cervical vagus nerve stimulation via Pulsetto FIT™ at 50 Hz, 250 µs pulse width. Intensity adjusted to a tolerable sensory level without discomfort. Dose: 10 minutes

  • Pulsetto FIT™ - tcVNS 100 Hz

    Device

    Bilateral tcVNS delivered with the Pulsetto FIT™ device at 100 Hz, 250 µs pulse width. Highest stimulation frequency used in this protocol; current intensity individualized per participant comfort. Dose: 10 minutes

Treatment groups

36 Participants
are divided into 5 treatment groups
Group A: 1 - Sham (0 Hz)Sham comparator 1 intervention
Group B: 2 - 10 Hz tcVNSExperimental treatment 1 intervention
Group C: 3 - tcVNS 25 HzExperimental treatment 1 intervention
Group D: 4 - tcVNS 50 HzExperimental treatment 1 intervention
Group E: 5 - tcVNS 100 HzExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

Heart Rate Variability (HRV) Changes (ΔRMSSD, ΔHF, ΔLF/HF)

HRV is recorded using a validated high-resolution heart rate monitor (Polar H10) during a 5-minute resting baseline (T0) and a 5-minute post-stimulation period (T2). The following time- and frequency-domain parameters are analyzed: RMSSD, HF (ms²), and LF/HF ratio. Artefact correction is performed using standard HRV processing methods. Acute autonomic response is quantified by calculating change scores (Δ = post-pre) for each stimulation frequency.

Time frame
Pre- vs Post-stimulation (5-min segments)(5-minute baseline, 5-minute stimulation, 5-minute post period)

Secondary outcomes

1

Blood Pressure (SBP, DBP, MAP)

Two readings are taken at each time point from the right arm with a validated automatic sphygmomanometer, and the average systolic, diastolic, and mean arterial pressure values are used for analysis. Changes are calculated as post-pre (Δ values) to assess the acute physiological effect of each stimulation frequency..

Time frame
Pre- vs Post-stimulation (5-minute baseline, 5-minute stimulation, 5-minute post period)
2

Respiratory Rate (breaths per minute)

Respiratory rate is assessed by video-based thoracoabdominal motion tracking at baseline (T0) and after stimulation (T2). Videos are analyzed using Kinovea motion-tracking software, and a 1-minute stable segment is used to determine breaths per minute by counting inspiratory peaks. Respiratory changes are expressed as Δ values (post-pre) to account for individual differences and improve HRV interpretability.Respiratory rate is assessed by video-based thoracoabdominal motion tracking at baseline (T0) and after stimulation (T2). Videos are analyzed using Kinovea motion-tracking software, and a 1-minute stable segment is used to determine breaths per minute by counting inspiratory peaks. Respiratory changes are expressed as Δ values (post-pre) to account for individual differences and improve HRV interpretability.

Time frame
Pre- vs Post-stimulation (5-minute video segments) (5-minute baseline, 5-minute stimulation, 5-minute post period)
3

Discomfort Level (Visual Analog Scale, 0-10)

Participants report their perceived discomfort level at baseline (T0) and immediately after stimulation (T2) using a 0-10 Visual Analog Scale (VAS). The scale captures any sensory discomfort associated with tcVNS. Changes are calculated by subtracting the pre-stimulation score from the post-stimulation score (ΔVAS).

Time frame
Pre- vs Post-stimulation (5-minute baseline, 5-minute stimulation, 5-minute post period)

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

SEFA HAKTAN HATIK

Lead sponsor

Sinop University

Sponsor institution

Source ClinicalTrials.gov

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