Vagus Nerve Stimulation for Autonomic Nervous System Activity

Study Overview
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Brief Summary
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There are no generally accepted values for transcutaneous vagus nerve stimulation (taVSS application parameters (amplitude, frequency, intensity, duration, side) yet, therefore there are heterogeneous applications in studies. Although positive effects have been shown in different neurological, psychiatric and musculoskeletal diseases, taVSS treatment is not available yet. It is not clear which parameters are important in patient selection.In this study, it was aimed to investigate the change of taVSS effect in healthy individuals according to the level of autonomic nervous system activity before stimulation.

Detailed Description
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Healthy individuals between the ages of 18-45 without any disease will be included in the study. Male and female participants will be included in the study. Heart rate variability will be measured after participants are included in the study. A short 5-minute measurement will be made with the Polar H7 device, which can be measured with the belt attached to the chest. Heart Rate Variability measurement will be analyzed with the Kubios HRV program. Participants will be distributed to groups according to the SNS index and PNS index values obtained as a result of the Kubios analysis. According to the index scores obtained, the distribution of the groups will be made as <-2, between -2 and +2 and >2. Afterwards, 20 minutes of taVSS stimulation will be performed. As a vagus stimulation protocol, bilateral auricular stimulation and stimulation frequency of 10 Hz (Heartz), pulse width of 300 µs (microseconds) for 20 minutes, biphasic application will be given to each participant 2 times, with at least 48 hours between them.

Official Title
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Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Basic Autonomic Nervous System Activity

Conditions
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Autonomic Nervous System Imbalance

Intervention / Treatment
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* Device: Transcutaneous Vagus Nerve Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy participants between the ages of 18-45 will be included in the study. Exclusion Criteria: Having an acute or chronic disease, Having previously undergone transcutaneous vagus nerve stimulation, Not smoking or using alcohol, Being in the post-menopausal stage in women, Being in the post-andropausal period in men, Being on constant medication, In menstruating women, stimulation and heart rate assessment will be postponed to the next week.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Health Participants<br>Participants in this group will be measured heart rate variability before and after transcutaneous vagus nerve stimulation. | Device: Transcutaneous Vagus Nerve Stimulation<br>* As a vagus stimulation protocol, bilateral auricular stimulation and stimulation frequency of 10 Hz, pulse width of 300 µs, biphasic application for 20 minutes, each participant will be stimulated twice, with at least 48 hours between them.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart Rate Variability Parameters-Stress Index | Stress index which is a geometric measure of HRV reflecting cardiovascular system stress. High values of SI indicate reduced variability and high sympathetic cardiac activation. | 5 minutes (short measurement) measurement of heart rate variability | 
| Heart Rate Variability Parameters-RMSSD | RMSSD is a measure of short-term (beat-by-beat) variability. It equals the root mean square of successive differences. | 5 minutes (short measurement) measurement of heart rate variability | 
| Heart Rate Variability Parameters-LF (Low Frequency) | Power in the Low Frequency band of the HRV spectrum, often between 0.04 - 0.15 Hz, often reported in units of milliseconds-squared. | 5 minutes (short measurement) measurement of heart rate variability | 
| Heart Rate Variability Parameters-HF (High Frequency) | Power in the High Frequency band of the HRV spectrum, often between 0.15-0.40 Hz, often reported in units of milliseconds-squared. | 5 minutes (short measurement) measurement of heart rate variability | 
| Heart Rate Variability Parameters-LF/HF Ratio | LF/HF Ratio: A ratio of Low Frequency to High Frequency. | 5 minutes (short measurement) measurement of heart rate variability | 
| Heart Rate Variability Parameters-SNS Index | Sympathetic cardiac activity is known to 1) increase heart rate, 2) decrease HRV, reducing especially quick RSA related changes in RR interval, and 3) increase the ratio between lower frequency and higher frequency oscillations in HRV data | 5 minutes (short measurement) measurement of heart rate variability | 
| Heart Rate Variability Parameters-PNS Index | Parasympathetic cardiac activity is known to 1) decrease heart rate (i.e. increase the time interval between successive heart beats), 2) increase HRV via enhanced respiratory sinus arrhythmia (RSA) component (i.e. increasing the quick changes in RR interval linked to respiration - shortening of RR intervals during inhalation and lengthening of RR intervals during exhalation), and 3) decrease the ratio between lower frequency and higher frequency oscillations in HRV time series (i.e. increase the relative amount of quick RSA originated fluctuations in HRV compared to slower short-term fluctuations) | 5 minutes (short measurement) measurement of heart rate variability | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Autonomic Nervous Systems, Vagal Nerve Stimulation, Heart Rates