Brain Effect of Vagal Nerve Stimulation at Rest and Pain

  • STATUS
    Recruiting
  • days left to enroll
    34
  • participants needed
    30
  • sponsor
    Queen Mary University of London
Updated on 2 March 2022
Accepts healthy volunteers

Summary

Pain is a ubiquitous distressing sensory experience and is the most frequent symptom in numerous gastrointestinal disorders including inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Visceral pain is especially difficult to treat with conventional medications and new treatments are needed.

Recently, the relationship between autonomic nerve system (ANS) and pain has gathered attention because it could represent an effective treatment target for visceral pain. The parasympathetic nervous system (PNS), one of the two main branches of the ANS, is considered to play an important role for analgesia possibly due to vagal nerve-mediated activation of key brain areas implicated in descending analgesia of pain. Transcutaneous vagal nerve stimulation (tVNS) can non-invasively modulate vagal nerve and be expected as a new method to treat visceral pain. For example, the preliminary study showed that vagal nerve stimulation experimentally modulated cardiac vagal tone (CVT) and prevented the development of acid-induced oesophageal hyperalgesia.

Disturbances in ANS function have been reported not only in IBS patients but also in fibromyalgia and chronic pelvic pain syndrome. Many of these disorders have been associated with differences in brain structure and/or function as demonstrated by the use of structural and functional magnetic resonance imaging (fMRI). Of note, the investigators have recently shown that these differences in brain structure and function may be in part attributable to the aforementioned disturbance in ANS function, adding weight to the proposition that autonomic neuromodulation may be efficacious in pain disorders. For instance, in healthy participants the investigators have recently shown, using functional connectivity analysis, that higher resting parasympathetic CVT predicts the engagement of a subcortical functional network that is implicated in descending analgesia, thereby supporting the notion that vagal-mediated analgesia is achieved via descending inhibitory pathways1,4. Thus, tVNS seems a reasonable method to treat pain. However, to date, the precise real-time effect of tVNS on brain function, including during the processing of visceral pain is unknown.

Hence, the aims of this study are to investigate the real-time effect of tVNS compared to sham stimulus on brain activity whilst experiencing acute oesophageal pain, using fMRI in double-blind, randomised crossover study of tVNS vs sham stimulation in healthy subjects.

Description

Following informed written consent and screening questionnaires to characterize psychophysiological traits including personality and anxiety/depression inventory, each subject will have a nasogastric tube inserted with the attached distensible balloon positioned in the distal oesophagus. Painful oesophageal stimulation will be achieved by inflation of the balloon to a pain threshold pre-determined in each subject, defined as the point at which subject describes the transition from sensation to pain. The MR-safe tVNS probe will be attached to the neck for cervical vagal nerve-directed tVNS, and subjects will then be positioned in the MRI scanner. Real-time activity of the ANS will be monitored by heart rate variability as described in the previous study, which has been adapted for use in the MR-environment. All subjects will undergo MRI. For each visit, there will be two scanning periods. High-resolution structural imaging will first be required, and subsequently resting fMRI data will be acquired whilst subjects are asked to relax in the scanner, and their baseline autonomic tone is monitored, using validated methods of acquiring ANS data. This will illustrate a brain signature of real-time brain activity mapped to their parasympathetic tone.

Subjects will then be randomised to either the active-tVNS paradigm or sham and a second fMRI data acquisition will then be performed so as to acquire brain activity in conjunction with active and sham-tVNS. Following this, painful oesophageal stimulation will be repeated 20 times while active or sham tVNS continues. Following a two-week washout period, subjects will be crossed over and re-examined to receive the intervention they did not receive in visit 1.

Details
Condition Healthy Volunteer
Treatment active transcutaneous Vagal Nerve Stimulation (tVNS), sham transcutaneous Vagal Nerve Stimulation (tVNS)
Clinical Study IdentifierNCT04282226
SponsorQueen Mary University of London
Last Modified on2 March 2022

Eligibility

Yes No Not Sure

Inclusion Criteria

Healthy participants (defined as those without pre-existing medical comorbidity) from staff, students and the local population of Queen Mary, University of London and/or King's College London
Inclusion will be determined on the basis of availability. They should be able to attend the Denmark Hill King's College London Campus for 2 sessions
Women should be studied in the follicular phase of their menstrual cycle or taking oral contraceptives

Exclusion Criteria

Participants unable to provide informed consent
Participants with any systemic disease or medications that may influence the autonomic nervous system (e.g. beta-agonists or Parkinson's disease)
Pregnant or breastfeeding females
Participants unable to lie flat in the MRI scanner, suffer from claustrophobia or are unsuitable for MRI scanning due to contraindications, comorbidity or in situ metalwork
Current smokers
History of anxiety or depression, or hospital anxiety or depression score >8
History of drug or alcohol abuse
Patients who have cardiovascular condition problems
Patient with cochlear implants
Recent nasal trauma, base of skull fracture and/or facial surgery that would contraindicate insertion of a nasogastric tube
A positive urinary drugs screen
Head circumference exceeding the limits of the scanner
Not meeting any of the inclusion criteria above
Clear my responses

How to participate?

Step 1 Connect with a study center
What happens next?
  • You can expect the study team to contact you via email or phone in the next few days.
  • Sign up as volunteer  to help accelerate the development of new treatments and to get notified about similar trials.

You are contacting

Investigator Avatar

Primary Contact

site

Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

Learn more

If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

Learn more

Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

Learn more

Similar trials to consider

Loading...

Browse trials for

Not finding what you're looking for?

Every year hundreds of thousands of volunteers step forward to participate in research. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.

Sign up as volunteer

user name

Added by • 

 • 

Private

Reply by • Private
Loading...

Lorem ipsum dolor sit amet consectetur, adipisicing elit. Ipsa vel nobis alias. Quae eveniet velit voluptate quo doloribus maxime et dicta in sequi, corporis quod. Ea, dolor eius? Dolore, vel!

  The passcode will expire in None.
Loading...

No annotations made yet

Add a private note
  • abc Select a piece of text from the left.
  • Add notes visible only to you.
  • Send it to people through a passcode protected link.
Add a private note