Clinical trials

This single-center randomized controlled cross-over trial aims to investigate the effect of transcutaneous auricular vagus nerve stimulation on upper gastrointestinal motility in healthy individuals. The primary aim of this study is to assess the impact of tVNS on gut motor function, with regards to its potential to induce phase III contractions in the upper GI tract. Secondary objectives include: * To study the effect of tVNS on other parameters characterizing upper GI motility such as the number of duodenal phase III contractions, gastric and duodenal phase MMCs, amplitude of antral contractions and motility index * To study the effect of tVNS on plasma levels of motilin and PP * To evaluate the effect of tVNS on parameters related to autonomic outflow, using a Shimmer3 GSR Sensor for heart rate variability and skin conductance. * To compare the results of the measurements of antroduodenal manometry with measurements of Gastric Alimetry Participants will undergo tVNS (applied to the cymba conchae of the left ear) alternating with sham stimulation (using a non-conducting electrode) in a blinded, pre-randomized fashion, using two 4-hour blocks during an 8-hour fasted antroduodenal manometry recording period. Optionally, participants may simultaneously also undergo body surface gastric mapping using the Gastric Alimetry system.

This single-center randomized controlled trial aims to investigate the efficacy of transcutaneous auricular vagus nerve stimulation in alleviating nausea in healthy adults. The primary aim of this study is to assess the efficacy of taVNS in reducing nausea in healthy adults subjected to nausea induction through intragastric lipid infusion, compared to sham stimulation, as measured by 0-100 Visual Analogue Scale (VAS) scores. The secondary objectives include evaluating the potential of taVNS to alleviate other gastrointestinal symptoms, such as abdominal pain, bloating, and fullness, as well as exploring its effects on the desire to eat, all measured using 0-100 VAS scores. Additionally, changes in autonomic parameters, plasma levels of ghrelin and motilin, and salivary cortisol will be evaluated. The relationship between the nausea response and affective symptoms, as well as personality traits, will also be explored. Participants will be randomly assigned to either the taVNS or the sham stimulation group, with the intervention administered for 30 minutes immediately following nausea induction through intragastric lipid infusion.