Transauricular Vagal Nerve Stimulation; Functional Dyspepsia and Gastroparesis

Effects of Transauricular Vagal Nerve Stimulation on Electrogastrography (EGG) and Heart Rate Variability (HRV) in Healthy Subjects, Functional Dyspepsia, and Gastroparesis

The goal of this study is to establish parameters of gastric myoelectrical activity and heart rate variability in healthy human subjects and compare and contrast them to those with gastroparesis and functional dyspepsia, at baseline and following taVNS.

This is a prospective pilot study assessing the relationship of electrogastrography and heart rate variability, with transauricular stimulation of the vagal nerve in healthy subjects compared to gastroparesis and functional dyspepsia patients. The investigators plan to recruit a total of 60 patients: 20 healthy volunteers, 20 gastroparesis, and 20 functional dyspepsia patients. Participants will undergo two testing sessions in which electrogastrography (EGG) and heart rate variability (HRV) will be measured using electrodes following transauricular vagal nerve stimulation (tAVNS) at various frequencies.

Inclusion Criteria:

1. Male or female.
2. Age 18-85 years.
3. Healthy volunteer or established diagnosis of idiopathic, diabetic, or postsurgical gastroparesis and functional dyspepsia.
4. Patient is capable of giving informed consent.
5. Patient is on stable doses of other medications for gastroparesis or functional dyspepsia for preceding 4 weeks prior to enrollment (including cholinergics, anti-cholinergics, dopamine and serotonin receptor agonists/antagonists, motility agents, neuromodulators, herbals).

Exclusion Criteria:

1. Any diagnosis of systemic autonomic dysfunction.
2. Use of narcotic, anticholinergic, cholinergic, or promotility medications in preceding 2 weeks of study.
3. Enteric feeding tubes.
4. Parenteral nutrition.
5. Severe disease flare requiring hospitalization or ER visits within 3 months of study.
6. Untreated depression or suicidal thoughts.
7. Pregnant/breastfeeding women.
8. History of gastric pacemaker implantation.
9. Implantable electronic devices (i.e. cardiac pacemakers)
10. Extrinsic myopathy/neuropathy
11. Vagal nerve injury.
12. High risk cardiac arrhythmias (high grade AV block, atrial fibrillation, atrial flutter).
13. GERD.
14. History of dumping syndrome.
15. History of rapid gastric emptying.
16. Severe allergy to skin adhesives.
17. Concurrent enrollment in other clinical trials.