Knee OsteoarthritisNCT05625178
Effects of Vagus Nerve Stimulation on Central Pain Sensitivity & Parasympathetic Function in Knee Osteoarthritis
A study testing Transcutaneous vagus nerve stimulation in people with Knee Osteoarthritis and Central Pain Syndrome, run by University of Texas, El Paso at 1 site in United States.
Trial summary
The goal of this clinical trial is to test the feasibility and effectiveness of transcutaneous vagus nerve stimulation (tVNS) to the ear on pain and autonomic function in people with knee osteoarthritis (OA). Read more about this study
- Who is it for?
- Ages 45 to 90 years
- Conditions the study is for
- Knee Osteoarthritis, Central Pain Syndrome
- What is being tested?
- Transcutaneous vagus nerve stimulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Dec 2022to 8 Jun 2023
- 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 45 to 90 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- chronic knee pain consistent with a clinical osteoarthritis diagnosis, which does not require radiographic evidence (age ≥ 45 years, activity-related knee pain, and no knee morning stiffness lasting >30 minutes)
- knee pain ≥ 3 months
- average pain intensity ≥ 4 on a scale from 0 to 10
- knee pain as the chief complaint
- able to understand English
Who cannot join
- current skin disease of the left ear interfering with the application of the auricular electrode for stimulation(eczema, urticarial lesion, skin infection, external otitis, etc.)
- auditory canal not adapted to the application of the ear electrode
- known history of cardiac rhythm disturbances or atrioventricular block > 1st degree, conduction disturbances
- recurrent vagal syncope
- history of vagotomy
- use of other medical devices electrically active (pacemaker, transcutaneous electrical nerve stimulation, etc)
Show all 11Show fewer
- serious and uncontrolled concomitant disease, including cardiovascular, nervous system, pulmonary, renal, hepatic, endocrine, gastrointestinal, epileptic disease or malignant diseases
- pregnant or breastfeeding woman
- numbness or sensation loss on the body sites for pain measurements (i.e., the wrist, knee, the forearm)
- any intervention procedures for knee pain in the past 3 months
- age less than 45 years old
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Texas at El Paso
El Paso, Texas, 79968
About this study
Official title: Investigating Effects of Auricular Vagus Nerve Stimulation on Central Pain Mechanisms, Autonomic Function, and Pain Severity in People With Knee Osteoarthritis
The goal of this clinical trial is to test the feasibility and effectiveness of transcutaneous vagus nerve stimulation (tVNS) to the ear on pain and autonomic function in people with knee osteoarthritis (OA). The main questions it aims to answer are: 1) whether tVNS is feasible to be used in people with knee OA; 2) whether tVNS demonstrates the trend in improving knee pain; and 3) whether tVNS has physiological effects on autonomic function (e.g., parasympathetic function) and pain perception in the central nervous system such as brain (i.e., central pain mechanisms). Participants will be asked to complete a battery of self-reported questionnaires about their demographic and behavioral information, ethnicity, pain, sleep, psychological/emotional symptoms. Subsequently, participants will complete baseline assessment where investigators will assess their knee pain severity, central pain sensitivity, and heart rate variability (a measurement for autonomic function). Then participants will receive a 60-minute tVNS. Investigators will redo the same assessment as baseline assessment after tVNS intervention to see the degree of knee pain, central pain sensitivity, and autonomic function changes. At the end of the study, investigators will assess their satisfaction level with the tVNS intervention and the feasibility of the intervention (e.g., completion rate, side effects).
- Conditions
- Knee Osteoarthritis, Central Pain Syndrome
- Being tested
- Transcutaneous vagus nerve stimulation
- Medical subject headings
- Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Transcutaneous vagus nerve stimulationDevice
tVNS will be performed by the application of an auricular electrode placed at the cymba concha of the left ear. The auricular electrode containing the anode will be applied with a conductive gel without prior disinfection. Once the electrode fits the cymba concha comfortably, the participant will lie down or take a position that is comfortable for them. Once in position, investigators initiate tVNS for 60 minutes with a below-discomfort-threshold intensity with 25 Hz and pulse width 250 uS. The electrical parameters will be modified accordingly to keep the below-discomfort threshold during the intervention.
| Study group | Role | What they receive |
|---|---|---|
| tVNS group | Experimental | This will be a single-arm study where all study participants will receive transcutaneous vagus nerve stimulation (tVNS) at the cymba concha of the left ear for 60 minutes. The tVNS parameters will be a below-discomfort-threshold intensity with 25 Hz and a pulse width of 250 uS. Receives: Device: Transcutaneous vagus nerve stimulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Pressure Pain Threshold
Pressure pain thresholds (PPT) will be assessed at the wrist and patellae. PPT being assessed at a remote body site (e.g., wrist) is to measure central pain sensitivity while PPT being assessed at the location of pain (i.e., knee, patellae) is to assess peripheral pain sensitivity with or without central pain sensitivity. PPT will be assessed using a handheld pressure algometer with 1 cm2 rubber tip. PPT will be defined as the point at which the participant verbally indicated that the pressure first changed to slight pain. A lower PPT value (Kgf) represents greater pain sensitivity. PPT will be assessed 3 times at each location and averaged. Changes in PPT between immediately after tVNS and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Measured: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Change in Conditioned Pain Modulation
Conditioned pain modulation (CPM) evaluates the adequacy of the descending pain modulatory pathways, which contributes to central pain sensitivity. Investigators will assess CPM using PPT as the test stimulus (PPT1) at the wrist as described above, with forearm ischemia using a blood pressure cuff as the conditioning stimulus. Briefly, the blood pressure cuff applied to the contralateral arm will be inflated to 10mm Hg above systolic pressure. The participant will be then instructed to perform hand grip squeezes until pain of at least 4/10 occurs in the contralateral arm. PPT will be then reassessed at the wrist 3 times and averaged (PPT2). Percent efficiency of CPM (%CPM) was computed as PPT2/PPT1, multiplied by 100; %CPM ≤ 100 indicates inefficient CPM. Changes in %CPM between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Measured: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Change in Temporal Summation
Temporal summation (TS) is a sensitive measurement of central pain sensitivity. Investigators will assess TS using a standard set of weighted probes from 64-512 mN. Participants will rate the pain experienced by each successive weighted probe being touched on the skin of the wrist until a pain rating of ≥ 4/10 is achieved. The selected probe will be then applied at a frequency of 1 Hz for 10 seconds on the wrist. Participants will provide a pain rating at the completion of the train of 10 stimulations and 15 seconds post-stimulation. TS will be defined as the difference between the highest post-stimulation pain rating and the initial pain rating. A post-stimulation pain rating greater than the initial pain rating will be considered to be reflective of an increase in central pain sensitivity. Changes in TS between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Measured: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Change in Parasympathetic Function
Investigators will assess changes in parasympathetic function before and immediately after- and 15 minutes after tVNS intervention. Heart rate variability (HRV), a measurement of autonomic function, will be assessed at baseline and after tVNS intervention using a wearable and wireless heart rate monitor. Investigators will have participants lie supine for 5 mins in each assessment to collect heart rate variability parameters such as high frequency and high-frequency/low-frequency ratio that is specific to activity in parasympathetic nervous system function.
Measured: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Change in knee pain
Investigators will assess changes in knee pain before (baseline), immediately after- and 15 minutes after tVNS intervention using a 0-10 numeric rating scale where 0 indicates no knee pain and 10 indicates the worst knee pain. Changes in knee pain between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Measured: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Change in and The Western Ontario McMaster Universities Osteoarthritis Index
Investigators will assess changes in knee pain before (baseline), immediately after- and 15 minutes after tVNS intervention using The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). WOMAC knee pain scale ranges 0-20 with 5 questions assessing knee pain in different contexts such as knee pain during walking and pain during standing. Each question has a score of 0-4. A greater WOMAC score represents greater knee pain. Change in WOMAC score between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Measured: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Safety about tVNS intervention
Investigators will assess safety by evaluating the intervention completion rate, determined by the number of participants who completed the intervention divided by the number of participants enrolled. If there is any adverse/side effect, the types of such events will be documented.
Measured: At the end of the study visit
Satisfaction Level
At the end of the study visit, investigators will assess the satisfaction level with tVNS intervention using the 8-item Client Satisfaction Questionnaire. The questionnaire asks about the satisfaction level regarding the new intervention using 8 questions. Each question has a 1-4 score where 1 indicates poor, and 4 indicates high satisfaction level.
Measured: At the end of the study visit
Secondary outcomes (5)
Pain catastrophizing scale (PCS)
The Pain Catastrophizing Scale is a validated 13-item scale with questions related to catastrophizing behavior. The total score is 52 with higher scores indicating greater catastrophic thoughts.
Measured: Immediately before tVNS intervention
Fear avoidance belief questionnaire (FABQ)
The Fear-Avoidance Belief Questionnaire categorizes these traits using items related to fear about physical and work activities. A total score is 96 with 16 questions. Each item is scored from 0 to 6 with a higher number indicating increased fear of activity or work.
Measured: Immediately before tVNS intervention
Pittsburgh sleep quality index (PSQI)
The Pittsburgh Sleep Quality Index (PSQI) is a self-reported questionnaire. PSQI contains 19 individual items, creating seven components that produce one global score, ranging from 0 to 21. A score of 0-4 indicates the absence of sleep problems, while scores 5 and higher indicate poor sleep quality.
Measured: Immediately before tVNS intervention
Hospital anxiety and depression scale (HADS)
HADS contains seven questions about anxiety and seven questions about depression, with a 0-3 score for each question. Higher scores indicate greater anxiety and depression.
Measured: Immediately before tVNS intervention
Ethnic Identity (Multigroup Ethnic Identity Measure (MEIM)
MEIM contains 12 questions to assess the extent to which individuals have an ethnic identity. Each question has a 1-4 score where 1 indicates poor ethnic identity and 4 indicates strong ethnic identity. Higher scores indicate that the individual has stronger feelings of belonging to the ethnic group with which he/she identified.
Measured: Immediately before tVNS intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Nov 2022
- Study start15 Dec 2022
- Primary completion3 Jun 2023
- Study completion8 Jun 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Knee OsteoarthritisStudies 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
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Texas, El Paso
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05625178
- Sponsor's protocol ID
- 1966880-1
- Status last verified
- Mar 2025
- First submitted
- 18 Oct 2022
- Last updated
- 2 Apr 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Publications
Aoyagi K, Rivas E, Shababi R, Edwards R, LaValley M, Lechuga J, Napadow V, Neogi T. Safety and preliminary efficacy of transcutaneous auricular vagus nerve stimulation on chronic knee pain: A pilot trial. Osteoarthr Cartil Open. 2024 Nov 23;7(1):100545. doi: 10.1016/j.ocarto.2024.100545. eCollection 2025 Mar.
PubMed 39687279
Study at a glance
From the registry record, last updated by the sponsor on 2 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigating Effects of Auricular Vagus Nerve Stimulation on Central Pain Mechanisms, Autonomic Function, and Pain Severity in People With Knee Osteoarthritis
- ClinicalTrials.gov ID
- NCT05625178
- Acronym / sponsor ID
- 1966880-1
- Conditions
- Knee Osteoarthritis, Central Pain Syndrome
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- University of Texas, El PasoUniversity, hospital or other
- Study start
- 15 Dec 2022 (actual)
- Primary completion
- 3 Jun 2023 (actual)
- Study completion
- 8 Jun 2023 (actual)
- First posted
- 22 Nov 2022 (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 goal of this clinical trial is to test the feasibility and effectiveness of transcutaneous vagus nerve stimulation (tVNS) to the ear on pain and autonomic function in people with knee osteoarthritis (OA). The main questions it aims to answer are: 1) whether tVNS is feasible to be used in people with knee OA; 2) whether tVNS demonstrates the trend in improving knee pain; and 3) whether tVNS has physiological effects on autonomic function (e.g., parasympathetic function) and pain perception in the central nervous system such as brain (i.e., central pain mechanisms). Participants will be asked to complete a battery of self-reported questionnaires about their demographic and behavioral information, ethnicity, pain, sleep, psychological/emotional symptoms. Subsequently, participants will complete baseline assessment where investigators will assess their knee pain severity, central pain sensitivity, and heart rate variability (a measurement for autonomic function). Then participants will receive a 60-minute tVNS. Investigators will redo the same assessment as baseline assessment after tVNS intervention to see the degree of knee pain, central pain sensitivity, and autonomic function changes. At the end of the study, investigators will assess their satisfaction level with the tVNS intervention and the feasibility of the intervention (e.g., completion rate, side effects).
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| tVNS group | Experimental | Device: Transcutaneous vagus nerve stimulationThis will be a single-arm study where all study participants will receive transcutaneous vagus nerve stimulation (tVNS) at the cymba concha of the left ear for 60 minutes. The tVNS parameters will be a below-discomfort-threshold intensity with 25 Hz and a pulse width of 250 uS. |
Who may qualify
- Ages
- 45 to 90 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- chronic knee pain consistent with a clinical osteoarthritis diagnosis, which does not require radiographic evidence (age ≥ 45 years, activity-related knee pain, and no knee morning stiffness lasting >30 minutes)
- knee pain ≥ 3 months
- average pain intensity ≥ 4 on a scale from 0 to 10
- knee pain as the chief complaint
- able to understand English
Key exclusion criteria (11 listed)
- current skin disease of the left ear interfering with the application of the auricular electrode for stimulation(eczema, urticarial lesion, skin infection, external otitis, etc.)
- auditory canal not adapted to the application of the ear electrode
- known history of cardiac rhythm disturbances or atrioventricular block > 1st degree, conduction disturbances
- recurrent vagal syncope
- history of vagotomy
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 |
|---|---|---|
| Transcutaneous vagus nerve stimulationtVNS will be performed by the application of an auricular electrode placed at the cymba concha of the left ear. The auricular electrode containing the anode will be applied with a conductive gel without prior disinfection. Once the electrode fits the cymba concha comfortably, the participant will lie down or take a position that is comfortable for them. Once in position, investigators initiate tVNS for 60 minutes with a below-discomfort-threshold intensity with 25 Hz and pulse width 250 uS. The electrical parameters will be modified accordingly to keep the below-discomfort threshold during the intervention. | Device | tVNS group |
Primary outcome
Change in Pressure Pain Threshold
Time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Pressure pain thresholds (PPT) will be assessed at the wrist and patellae. PPT being assessed at a remote body site (e.g., wrist) is to measure central pain sensitivity while PPT being assessed at the location of pain (i.e., knee, patellae) is to assess peripheral pain sensitivity with or without central pain sensitivity. PPT will be assessed using a handheld pressure algometer with 1 cm2 rubber tip. PPT will be defined as the point at which the participant verbally indicated that the pressure first changed to slight pain. A lower PPT value (Kgf) represents greater pain sensitivity. PPT will be assessed 3 times at each location and averaged. Changes in PPT between immediately after tVNS and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Change in Conditioned Pain Modulation
Time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Conditioned pain modulation (CPM) evaluates the adequacy of the descending pain modulatory pathways, which contributes to central pain sensitivity. Investigators will assess CPM using PPT as the test stimulus (PPT1) at the wrist as described above, with forearm ischemia using a blood pressure cuff as the conditioning stimulus. Briefly, the blood pressure cuff applied to the contralateral arm will be inflated to 10mm Hg above systolic pressure. The participant will be then instructed to perform hand grip squeezes until pain of at least 4/10 occurs in the contralateral arm. PPT will be then reassessed at the wrist 3 times and averaged (PPT2). Percent efficiency of CPM (%CPM) was computed as PPT2/PPT1, multiplied by 100; %CPM ≤ 100 indicates inefficient CPM. Changes in %CPM between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Change in Temporal Summation
Time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Temporal summation (TS) is a sensitive measurement of central pain sensitivity. Investigators will assess TS using a standard set of weighted probes from 64-512 mN. Participants will rate the pain experienced by each successive weighted probe being touched on the skin of the wrist until a pain rating of ≥ 4/10 is achieved. The selected probe will be then applied at a frequency of 1 Hz for 10 seconds on the wrist. Participants will provide a pain rating at the completion of the train of 10 stimulations and 15 seconds post-stimulation. TS will be defined as the difference between the highest post-stimulation pain rating and the initial pain rating. A post-stimulation pain rating greater than the initial pain rating will be considered to be reflective of an increase in central pain sensitivity. Changes in TS between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Change in Parasympathetic Function
Time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Investigators will assess changes in parasympathetic function before and immediately after- and 15 minutes after tVNS intervention. Heart rate variability (HRV), a measurement of autonomic function, will be assessed at baseline and after tVNS intervention using a wearable and wireless heart rate monitor. Investigators will have participants lie supine for 5 mins in each assessment to collect heart rate variability parameters such as high frequency and high-frequency/low-frequency ratio that is specific to activity in parasympathetic nervous system function.
Change in knee pain
Time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Investigators will assess changes in knee pain before (baseline), immediately after- and 15 minutes after tVNS intervention using a 0-10 numeric rating scale where 0 indicates no knee pain and 10 indicates the worst knee pain. Changes in knee pain between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Change in and The Western Ontario McMaster Universities Osteoarthritis Index
Time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention
Investigators will assess changes in knee pain before (baseline), immediately after- and 15 minutes after tVNS intervention using The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). WOMAC knee pain scale ranges 0-20 with 5 questions assessing knee pain in different contexts such as knee pain during walking and pain during standing. Each question has a score of 0-4. A greater WOMAC score represents greater knee pain. Change in WOMAC score between immediately after tVNS intervention and baseline and between 15 minutes after tVNS intervention and baseline will be used for analysis.
Safety about tVNS intervention
Time frame: At the end of the study visit
Investigators will assess safety by evaluating the intervention completion rate, determined by the number of participants who completed the intervention divided by the number of participants enrolled. If there is any adverse/side effect, the types of such events will be documented.
Satisfaction Level
Time frame: At the end of the study visit
At the end of the study visit, investigators will assess the satisfaction level with tVNS intervention using the 8-item Client Satisfaction Questionnaire. The questionnaire asks about the satisfaction level regarding the new intervention using 8 questions. Each question has a 1-4 score where 1 indicates poor, and 4 indicates high satisfaction level.
5 secondary outcomes
Pain catastrophizing scale (PCS)
Time frame: Immediately before tVNS intervention
Fear avoidance belief questionnaire (FABQ)
Time frame: Immediately before tVNS intervention
Pittsburgh sleep quality index (PSQI)
Time frame: Immediately before tVNS intervention
Hospital anxiety and depression scale (HADS)
Time frame: Immediately before tVNS intervention
Ethnic Identity (Multigroup Ethnic Identity Measure (MEIM)
Time frame: Immediately before tVNS intervention
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 Apr 2025.
- Derived from this study: PubMed 39687279Aoyagi K, Rivas E, Shababi R, Edwards R, LaValley M, Lechuga J, Napadow V, Neogi T. Safety and preliminary efficacy of transcutaneous auricular vagus nerve stimulation on chronic knee pain: A pilot trial. Osteoarthr Cartil Open. 2024 Nov 23;7(1):100545. doi: 10.1016/j.ocarto.2024.100545. eCollection 2025 Mar.
- 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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Transcutaneous vagus nerve stimulation in people with Knee Osteoarthritis and Central Pain Syndrome, run by University of Texas, El Paso at 1 site in United States.
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 5 inclusion and 11 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 Apr 2025. 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 United States. 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. 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?
Change in Pressure Pain Threshold (time frame: Same day assessment with 3 data points: baseline, immediately after- and 15 minutes after tVNS intervention). The study lists 8 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05625178, which also lists 1 linked publication.
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 Apr 2025.