Older Adults Without Any Specific Clinical ConditiontVNS_olderNCT07292623
Effects of Transcutaneous Vagus Nerve Stimulation in Older Adults
A study testing Active location tVNS in people with Older Adults Without Any Specific Clinical Condition and Autonomic Nervous System Imbalance, run by Universidade da Coruña at 1 site in Spain.
Trial summary
The autonomic nervous system consists of two branches, the sympathetic and the parasympathetic, which must work in balance. Its functioning can be measured indirectly by heart rate variability, which is the time between heartbeats, which is not constant. Read more about this study
- Who is it for?
- Ages 65 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Older Adults Without Any Specific Clinical Condition, Autonomic Nervous System Imbalance, Transcutaneous Vagus Nerve Stimulation
- What is being tested?
- Active location tVNS
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 12 participants
- Where
- 1 siteSpain
- Study dates
- 19 Dec 2025to 12 Feb 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 65 to 80 years
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- Non-smokers aged 65 to 80, with BMI from 18.5 to less than 30, who consider themselves healthy and are able to maintain their balance for at least 1 minute without assistance, living in A Coruña (Spain), with a 50% allocation to each sex
Who cannot join
- systolic blood pressure above 160 mm Hg and diastolic blood pressure above 100 mm Hg,
- previous vagotomy, history of syncope in the last two years, or lack of reliable reading in heart rate variability
- presence of chronic pain (migraine, back, neck, shoulder, etc.) or being diagnosed with or receiving treatment for malignant, cardiovascular disease (excluding hyperlipidaemia and hypercholesterolaemia), respiratory, neurological or autonomic, metabolic (e.g. diabetes), osteoarticular of autoimmune origin (e.g. arthritis), psychiatric or history of treatment with antidepressants or anxiolytics
- impaired cognitive level
- presence of any contraindication or difficulty in applying TENS: pacemaker, defibrillator or any implanted electronic device, apprehension of electric current, burns or irritated skin or allergic reaction or any alteration in the area that prevents the electrode from being placed on the left ear;
- previous application of electrical stimulation to the ear
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of Transcutaneous Stimulation of the Auricular Branch of the Vagus Nerve in Older Adults
The autonomic nervous system consists of two branches, the sympathetic and the parasympathetic, which must work in balance. Its functioning can be measured indirectly by heart rate variability, which is the time between heartbeats, which is not constant. The more it varies, the greater the role of the parasympathetic branch, and vice versa. However, with age, an imbalance can occur and the parasympathetic branch can play a lesser role, resulting in less heart rate variability (the times between heartbeats become more similar).
The aim of this study is to know if electrical stimulation in the ear can improve the balance between the two branches of the autonomic nervous system in older adults, comparing two different locations of application. The main questions to answer are:
Does applying electrical stimulation to a specific area of the ear improve the balance of the autonomic nervous system? Does it also help improve hand tremors, balance, concentration, saliva production, and voice quality?
Read the detailed description
Electrical stimulation (ES) of the nervous system, also denominated as neuromodulation, has been investigated for diverse conditions as cardiovascular diseases, chronic pain and psychiatric conditions. It is unknown which locations and parameters can be more effective and better tolerated. The transcutaneous ES is a non-invasive technique which has fewer side-effects than subcutaneous vagus nerve stimulation.
The aim of this study is to analyze the acute effects of transcutaneous ES on autonomic nervous modulation by heart rate variability (HRV) and heart frequency (HF) in older adults who perceive themselves as healthy, comparing two different locations for the ES, before and after a battery of motor, cognitive and other tests.. In addition, the tolerance to the current and the side-effects will be compared.
Once the participants have given their informed consent and had been checked for exclusion criteria, are invited to an experimental session. Subjects will be advised to refrain from caffeine or alcohol for 12 h and vigorous exercise for at least 24h prior to the intervention. The volunteers will be randomized by sex to begin with one of two electrode locations: cymba concha and cavum concha at the left ear (active session); or scapha and lobule at the left ear (sham-session). These two interventions will be denominated as Transcutaneous Vagus Electrical Nerve Stimulation (t-VNS) and Sham Transcutaneous Vagus Electrical Nerve Stimulation (sham t-VNS). Allocation concealment, stratified by sex, will be ensured as the person will choose a piece of paper with the assignment coded with numbers (real/placebo) from a bag containing all the coded options that only the person applying the stimulation will see and understand (coded) The stimulation location will be wiped down with alcohol and the minimum intensity, at which the stimulus is perceived, will be registered. Subsequently, the intensity will be increased until reaching the discomfort threshold, and then decreased to a strong but well-tolerated sensation.
At the beginning of the intervention, the different tests will be explained to the participant, the chest strap will be placed, its synchronisation with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a belt.
After 10 minutes, the pre-stimulation assessment will be carried out. At the beginning of each session, participants will be allowed to try each one to familiarise themselves with it. At the end of the session, the stimulation will be applied and the variables will be measured in the same order during the actual electrical stimulation or placebo, as appropriate.
The second session will be performed in the same way, but using the application not used in the previous session (placebo or active, as appropriate).
The participants will be asked upon completion of the session their presumed group assignment.
Adverse effects will be checked at the end of each session, and again 48 h after.
- Conditions
- Older Adults Without Any Specific Clinical Condition, Autonomic Nervous System Imbalance, Transcutaneous Vagus Nerve Stimulation
- Being tested
- Active location tVNS, Sham Comparator
- Keywords
- Transcutaneous Electric Nerve Stimulation, Vagus Nerve, Ear Auricle, Heart Rate, Aged, Voice, Saliva, Postural Balance, Tremor, Executive Function
- Medical subject headings
- Tremor
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Active location tVNSDevice
Also called tVNS, aVNS, auricular vagus nerve stimulation, Active tVNS
The tVNS will be performed at 20 Hz and 200 microseconds, in the area innervated by the auricular branch of the vagus nerve (cymba concha and concha) in the active location.
The intensity will be set above the sensory threshold (intense tingling sensation) but below the level of discomfort. The TENS will be set to 27 seconds of working time, with a 3-second ramp-up and 90 seconds off. It will last until the end of the last HRV test.
Sham ComparatorDevice
Also called Sham tVNS, sham aVNS, Sham auricular vagus nerve stimulation
The tVNS will be performed at 20 Hz and 200 microseconds, in the area not innervated by by the auricular branch of the vagus nerve (scapha) for sham TENS.
The intensity will be set above the sensory threshold (intense tingling sensation) but below the level of discomfort. The TENS will be set to 27 seconds of working time, with a 3-second ramp-up and 90 seconds off. It will last until the end of the last HRV test.
| Study group | Role | What they receive |
|---|---|---|
| Active tVNS | Active comparator | While acclimatization of the participant (10 minutes) the different tests will be explained, the chest strap will be placed, its synchronization with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a fanny pack.
The pre-stimulation assessment will be carried out (from 10 to 40 minutes after initiating the session). Participants will be allowed to try each one to familiarize themselves with it. All the tests will be performed (tremor, saliva, Flanker, balance, voice, Heart Rate Variability- HRV). At the end of this first part, the stimulation will be applied at the left ear in the area innervated by the vagus nerve (concha and cymba concha),and all the variables will be measured again in the same order during the actual electrical stimulation, after a new HRV measurement (from 45 to 75´). Then, the last HRV measurement will be taken and the participant will be asked about tolerance, the occurrence of adverse effects, and blinding. Receives: Device: Active location tVNS |
| Sham tVNS | Sham comparator | At the beginning, the different tests will be explained, the chest strap will be placed, its synchronization with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a fanny pack.
Next, the pre-stimulation assessment will be carried out. Participants will be allowed to try each one to familiarize themselves with it. All the tests will be performed (tremor, saliva, Flanker, balance, voice, Heart Rate Variability- HRV). At the end of this first part, the stimulation will be applied at the left ear in the area not innervated by the vagus nerve (scapha) and all the variables will be measured in the same order during the sham electrical stimulation, after a new HRV measurement. Then, the last HRV measurement will be taken and the participant will be asked about tolerance, the occurrence of adverse effects, and blinding. Receives: Device: Sham Comparator |
What is being measured
The primary outcome is the main question the study is designed to answer.
HRV
Heart Rate Variability (HRV) using Kubios app and H10 polar heart rate monitor chest strap, in periods of 5 minutes:
- Frequency domain; ratio LF/HF power will be calculated along with normalised LF/HF where baseline values will set to 1; Low frequency (LF, referred to HRV frequency band 0.04-0.15 Hz); High frequency (HF = HRV frequency band 0.15-0.4 Hz); absolute powers of LF, and HF bands (ms2); normalized power (powers of LF and HF bands in normalised units, %)
- Time domain: RR (mean values of RR intervals in ms) ; SDNN (Standard deviation of RR intervals); RMSSD (Root mean square of successive RR interval differences, in ms)
- Non-linear methods: the poincaré plot short term variability (SD1, ms); the poincaré plot long term variability (SD2, ms).
- Global measures: Stress Index (SI), square root of Baevsky's stress index; Parasympathetic nervous system (PNS) index
Measured: Change from pre-tVNS (baseline= post initial battery of tests, about minute 35 after initiating the session) and during tVNS (post second battery of tests, 5 minutes before the end of the session, about minute 70)
Secondary outcomes (8)
HRV
Heart Rate Variability (HRV) using Kubios app and H10 polar heart rate monitor chest strap in periods of 5 minutes:
- Frequency domain; ratio LF/HF power will be calculated along with normalised LF/HF where baseline values will set to 1; Low frequency (LF, referred to HRV frequency band 0.04-0.15 Hz); High frequency (HF = HRV frequency band 0.15-0.4 Hz); absolute powers of LF, and HF bands (ms2); normalized power (powers of LF and HF bands in normalised units, %)
- Time domain: RR (mean values of RR intervals in ms) ; SDNN (Standard deviation of RR intervals); RMSSD (Root mean square of successive RR interval differences, in ms)
- Non-linear methods: the poincaré plot short term variability (SD1, ms); the poincaré plot long term variability (SD2, ms).
- Global measures: Stress Index (SI), square root of Baevsky's stress index; Parasympathetic nervous system (PNS) index; Sympathetic nervous system (SNS) index
- Mean heart rate (beats/min)
- ECG derived respiration (breaths/min)
Measured: Change from pre-tVNS (baseline = post initial battery of tests, about minute 35 after initiating the session) and initial tVNS (5 minutes after setting the intensity of tVNS, about 45 minutes after initiating the session)
Hand tremor
The tremor in both hands will be measured with the app (G-Sensor Logger) for a minute, using a mobile phone secured to each hand (both hands)
Measured: Change from pre-tVNS (baseline= initial battery of tests, about minute 10 to 15 after initiating the session) and during tVNS (post = second battery of tests, about 50 to 55 minutes after after setting the intensity of tVNS)
Salive
To measure salivation, a dry cloth will be placed in the mouth and weighed after 2 minutes without swallowing to estimate the volume of saliva produced.
Measured: Change from pre-tVNS (baseline= initial battery of tests, from minute 15 to 20 after initiating the session) and during tVNS (post second battery of tests, about 55 to 60 minutes after after setting the intensity of tVNS)
Flanker test
The Flanker test is designed to assess selective attention and inhibitory function, deciding the direction of a central row, flanked by nontarget stimuli, which can be congruent (matching the target) or incongruent (opposite to the target). It will be done with both arms.
Measured: Change from pre-tVNS (baseline= initial battery of tests, about 20 minutes after initiating the session) and during tVNS (post second battery of tests = 60 minutes after initiating the session)
Balance test
For balance, a baropodometric platform will be used and the centre of pressure area (mm), the ellipse area (mm2), the speed (mm/s)and the displacements in the axes of space (mm) will be measured, with eyes open and eyes closed, twice on each occasion
Measured: Change from pre-tVNS (baseline= post initial battery of tests, from minute 25) and during tVNS (post second battery of tests = from minute 65)
Voice
The PRAAT software will be used to test the voice twice, when sustaining till 10 seconds the vowel "a" and when reading a text at their usual volume. The intensity, the fundamental frequency (F0), the jitter and shimmer parameters and the HNR (Harmonic to Noise Ratio) will be measured
Measured: Change from pre-tVNS (baseline= post initial battery of tests, from minute 35) and during tVNS (post second battery of tests = from minute 75 after initiating the session)
Tolerance
The level of tolerance of the entire stimulation (by electrical stimulation, by electrodes, or by both) will be measured on a VAS scale from 0 (no discomfort at all) to 10 (the discomfort would have prevented me from finishing the session)
Measured: Immediately after the intervention (around the 80th minute after the start of the session)
Adverse effects
A questionnaire will be used to test the presence, severity, persistence and causality of ear pain, headache, tingling, itching, redness, irritation, pressure, dizziness, nausea, vertigo, fatigue, vertigo, palpitations, tinnitus, unpleasant feeling, other
Measured: Immediately after the intervention, and after 48 hours of ending it
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Dec 2025
- Study start19 Dec 2025
- Primary completion10 Feb 2026
- Study completion12 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Older Adults Without Any Specific Clinical ConditionStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- All participants will undergo both conditions, placebo and real location, in a randomly assigned order. Placebo stimulation will be performed in a different location, using the same electrical parameters. The second session will be performed in the same way, but using the application not used in the previous session (placebo or active, as appropriate). Each session will follow this order: 10 minutes (min) of acclimatization, connection of equipment and checking that the chest band is working; 10 to 35 min performance of the first set of tests; from 35 to 40 min measurement of heart rate variability (HRV); 40-45 min, searching for the highest intensity tolerated without discomfort- initiation of transcutaneous vagus nerve stimulation (sham or active tVNS); 45-50 min, HRV; from 50 to 75´ new performance of the set of tests with tVNS; 75-80 min final HRV; 80 min- tolerance, adverse effects (and 48 h after), blinding
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidade da Coruña
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Alicia Martínez Rodríguez, Universidade da Coruña
- Investigators
- Alicia Martínez-Rodríguez, Lecturer, Principal investigator, Universidade da Coruña (University of A Coruna)Olalla Bello, Lecturer, Principal investigator, Universidade da Coruña (University of A Coruna)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07292623
- Sponsor's protocol ID
- 2025/295_I
- Acronym
- tVNS_older
- Status last verified
- Dec 2025
- First submitted
- 29 Nov 2025
- Last updated
- 2 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The IPD that underlie results included in the publication will be shared in Zenodo, with a description of the codes and needed information to understand it
Study at a glance
From the registry record, last updated by the sponsor on 2 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Transcutaneous Stimulation of the Auricular Branch of the Vagus Nerve in Older Adults
- ClinicalTrials.gov ID
- NCT07292623
- Acronym / sponsor ID
- tVNS_older / 2025/295_I
- Conditions
- Older Adults Without Any Specific Clinical Condition, Autonomic Nervous System Imbalance, Transcutaneous Vagus Nerve Stimulation
- Keywords
- Transcutaneous Electric Nerve Stimulation, Vagus Nerve, Ear Auricle, Heart Rate, Aged, Voice, Saliva, Postural Balance
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- Universidade da CoruñaUniversity, hospital or other
- Study start
- 19 Dec 2025 (actual)
- Primary completion
- 10 Feb 2026 (actual)
- Study completion
- 12 Feb 2026 (actual)
- First posted
- 18 Dec 2025 (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.
The autonomic nervous system consists of two branches, the sympathetic and the parasympathetic, which must work in balance. Its functioning can be measured indirectly by heart rate variability, which is the time between heartbeats, which is not constant. The more it varies, the greater the role of the parasympathetic branch, and vice versa. However, with age, an imbalance can occur and the parasympathetic branch can play a lesser role, resulting in less heart rate variability (the times between heartbeats become more similar).
The aim of this study is to know if electrical stimulation in the ear can improve the balance between the two branches of the autonomic nervous system in older adults, comparing two different locations of application. The main questions to answer are:
Does applying electrical stimulation to a specific area of the ear improve the balance of the autonomic nervous system? Does it also help improve hand tremors, balance, concentration, saliva production, and voice quality?
Detailed description
Electrical stimulation (ES) of the nervous system, also denominated as neuromodulation, has been investigated for diverse conditions as cardiovascular diseases, chronic pain and psychiatric conditions. It is unknown which locations and parameters can be more effective and better tolerated. The transcutaneous ES is a non-invasive technique which has fewer side-effects than subcutaneous vagus nerve stimulation.
The aim of this study is to analyze the acute effects of transcutaneous ES on autonomic nervous modulation by heart rate variability (HRV) and heart frequency (HF) in older adults who perceive themselves as healthy, comparing two different locations for the ES, before and after a battery of motor, cognitive and other tests.. In addition, the tolerance to the current and the side-effects will be compared.
Once the participants have given their informed consent and had been checked for exclusion criteria, are invited to an experimental session. Subjects will be advised to refrain from caffeine or alcohol for 12 h and vigorous exercise for at least 24h prior to the intervention. The volunteers will be randomized by sex to begin with one of two electrode locations: cymba concha and cavum concha at the left ear (active session); or scapha and lobule at the left ear (sham-session). These two interventions will be denominated as Transcutaneous Vagus Electrical Nerve Stimulation (t-VNS) and Sham Transcutaneous Vagus Electrical Nerve Stimulation (sham t-VNS). Allocation concealment, stratified by sex, will be ensured as the person will choose a piece of paper with the assignment coded with numbers (real/placebo) from a bag containing all the coded options that only the person applying the stimulation will see and understand (coded) The stimulation location will be wiped down with alcohol and the minimum intensity, at which the stimulus is perceived, will be registered. Subsequently, the intensity will be increased until reaching the discomfort threshold, and then decreased to a strong but well-tolerated sensation.
At the beginning of the intervention, the different tests will be explained to the participant, the chest strap will be placed, its synchronisation with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a belt.
After 10 minutes, the pre-stimulation assessment will be carried out. At the beginning of each session, participants will be allowed to try each one to familiarise themselves with it. At the end of the session, the stimulation will be applied and the variables will be measured in the same order during the actual electrical stimulation or placebo, as appropriate.
The second session will be performed in the same way, but using the application not used in the previous session (placebo or active, as appropriate).
The participants will be asked upon completion of the session their presumed group assignment.
Adverse effects will be checked at the end of each session, and again 48 h after.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- All participants will undergo both conditions, placebo and real location, in a randomly assigned order. Placebo stimulation will be performed in a different location, using the same electrical parameters. The second session will be performed in the same way, but using the application not used in the previous session (placebo or active, as appropriate). Each session will follow this order: 10 minutes (min) of acclimatization, connection of equipment and checking that the chest band is working; 10 to 35 min performance of the first set of tests; from 35 to 40 min measurement of heart rate variability (HRV); 40-45 min, searching for the highest intensity tolerated without discomfort- initiation of transcutaneous vagus nerve stimulation (sham or active tVNS); 45-50 min, HRV; from 50 to 75´ new performance of the set of tests with tVNS; 75-80 min final HRV; 80 min- tolerance, adverse effects (and 48 h after), blinding
| Arm | Type | Receives |
|---|---|---|
| Active tVNS | Active comparator | Device: Active location tVNSWhile acclimatization of the participant (10 minutes) the different tests will be explained, the chest strap will be placed, its synchronization with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a fanny pack. The pre-stimulation assessment will be carried out (from 10 to 40 minutes after initiating the session). Participants will be allowed to try each one to familiarize themselves with it. All the tests will be performed (tremor, saliva, Flanker, balance, voice, Heart Rate Variability- HRV). At the end of this first part, the stimulation will be applied at the left ear in the area innervated by the vagus nerve (concha and cymba concha),and all the variables will be measured again in the same order during the actual electrical stimulation, after a new HRV measurement (from 45 to 75´). Then, the last HRV measurement will be taken and the participant will be asked about tolerance, the occurrence of adverse effects, and blinding. |
| Sham tVNS | Sham comparator | Device: Sham ComparatorAt the beginning, the different tests will be explained, the chest strap will be placed, its synchronization with the HRV measurement system will be checked, and the TENS equipment will be placed on the waist using a fanny pack. Next, the pre-stimulation assessment will be carried out. Participants will be allowed to try each one to familiarize themselves with it. All the tests will be performed (tremor, saliva, Flanker, balance, voice, Heart Rate Variability- HRV). At the end of this first part, the stimulation will be applied at the left ear in the area not innervated by the vagus nerve (scapha) and all the variables will be measured in the same order during the sham electrical stimulation, after a new HRV measurement. Then, the last HRV measurement will be taken and the participant will be asked about tolerance, the occurrence of adverse effects, and blinding. |
Who may qualify
- Ages
- 65 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (1 listed)
- Non-smokers aged 65 to 80, with BMI from 18.5 to less than 30, who consider themselves healthy and are able to maintain their balance for at least 1 minute without assistance, living in A Coruña (Spain), with a 50% allocation to each sex
Key exclusion criteria (6 listed)
- systolic blood pressure above 160 mm Hg and diastolic blood pressure above 100 mm Hg,
- previous vagotomy, history of syncope in the last two years, or lack of reliable reading in heart rate variability
- presence of chronic pain (migraine, back, neck, shoulder, etc.) or being diagnosed with or receiving treatment for malignant, cardiovascular disease (excluding hyperlipidaemia and hypercholesterolaemia), respiratory, neurological or autonomic, metabolic (e.g. diabetes), osteoarticular of autoimmune origin (e.g. arthritis), psychiatric or history of treatment with antidepressants or anxiolytics
- impaired cognitive level
- presence of any contraindication or difficulty in applying TENS: pacemaker, defibrillator or any implanted electronic device, apprehension of electric current, burns or irritated skin or allergic reaction or any alteration in the area that prevents the electrode from being placed on the left ear;
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 |
|---|---|---|
| Active location tVNSAlso: tVNS, aVNS, auricular vagus nerve stimulation, Active tVNSThe tVNS will be performed at 20 Hz and 200 microseconds, in the area innervated by the auricular branch of the vagus nerve (cymba concha and concha) in the active location. The intensity will be set above the sensory threshold (intense tingling sensation) but below the level of discomfort. The TENS will be set to 27 seconds of working time, with a 3-second ramp-up and 90 seconds off. It will last until the end of the last HRV test. | Device | Active tVNS |
| Sham ComparatorAlso: Sham tVNS, sham aVNS, Sham auricular vagus nerve stimulationThe tVNS will be performed at 20 Hz and 200 microseconds, in the area not innervated by by the auricular branch of the vagus nerve (scapha) for sham TENS. The intensity will be set above the sensory threshold (intense tingling sensation) but below the level of discomfort. The TENS will be set to 27 seconds of working time, with a 3-second ramp-up and 90 seconds off. It will last until the end of the last HRV test. | Device | Sham tVNS |
Primary outcome
HRV
Time frame: Change from pre-tVNS (baseline= post initial battery of tests, about minute 35 after initiating the session) and during tVNS (post second battery of tests, 5 minutes before the end of the session, about minute 70)
Heart Rate Variability (HRV) using Kubios app and H10 polar heart rate monitor chest strap, in periods of 5 minutes: * Frequency domain; ratio LF/HF power will be calculated along with normalised LF/HF where baseline values will set to 1; Low frequency (LF, referred to HRV frequency band 0.04-0.15 Hz); High frequency (HF = HRV frequency band 0.15-0.4 Hz); absolute powers of LF, and HF bands (ms2); normalized power (powers of LF and HF bands in normalised units, %) * Time domain: RR (mean values of RR intervals in ms) ; SDNN (Standard deviation of RR intervals); RMSSD (Root mean square of successive RR interval differences, in ms) * Non-linear methods: the poincaré plot short term variability (SD1, ms); the poincaré plot long term variability (SD2, ms). * Global measures: Stress Index (SI), square root of Baevsky's stress index; Parasympathetic nervous system (PNS) index
8 secondary outcomes
HRV
Time frame: Change from pre-tVNS (baseline = post initial battery of tests, about minute 35 after initiating the session) and initial tVNS (5 minutes after setting the intensity of tVNS, about 45 minutes after initiating the session)
Hand tremor
Time frame: Change from pre-tVNS (baseline= initial battery of tests, about minute 10 to 15 after initiating the session) and during tVNS (post = second battery of tests, about 50 to 55 minutes after after setting the intensity of tVNS)
Salive
Time frame: Change from pre-tVNS (baseline= initial battery of tests, from minute 15 to 20 after initiating the session) and during tVNS (post second battery of tests, about 55 to 60 minutes after after setting the intensity of tVNS)
Flanker test
Time frame: Change from pre-tVNS (baseline= initial battery of tests, about 20 minutes after initiating the session) and during tVNS (post second battery of tests = 60 minutes after initiating the session)
Balance test
Time frame: Change from pre-tVNS (baseline= post initial battery of tests, from minute 25) and during tVNS (post second battery of tests = from minute 65)
Voice
Time frame: Change from pre-tVNS (baseline= post initial battery of tests, from minute 35) and during tVNS (post second battery of tests = from minute 75 after initiating the session)
Tolerance
Time frame: Immediately after the intervention (around the 80th minute after the start of the session)
Adverse effects
Time frame: Immediately after the intervention, and after 48 hours of ending it
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Mar 2026.
- Individual participant dataSharing planned: Yes. The IPD that underlie results included in the publication will be shared in Zenodo, with a description of the codes and needed information to understand it
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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. This study is not recruiting at the moment.
Alicia Martínez-Rodríguez, Lecturer principal investigator
Universidade da Coruña (University of A Coruna)
Olalla Bello, Lecturer principal investigator
Universidade da Coruña (University of A Coruna)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Active location tVNS in people with Older Adults Without Any Specific Clinical Condition and Autonomic Nervous System Imbalance, run by Universidade da Coruña at 1 site in Spain.
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 6 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: finished, as of the sponsor's last update on 2 Mar 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 Spain. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
HRV (time frame: Change from pre-tVNS (baseline= post initial battery of tests, about minute 35 after initiating the session) and during tVNS (post second battery of tests, 5 minutes before the end of the session, about minute 70)). 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 2 Mar 2026; AzTrials last refreshed its copy on 7 Nov 2026.