The study is a randomized, double-blinded, sham-controlled, parallel group clinical trial, which will include participants with diabetes and gastrointestinal (GI) problems. These problems may be manifestations of diabetic autonomic neuropathy.~Participants are randomised to received either active non-invasive transcutaneous vagal nerve stimulation (tVNS) or inactive sham stimulation. The study period is divided in two phases. The first phase investigates the effects of short-term, high-intensity tVNS treatment on GI symptoms. The second phase investigates the effects of long-term, middle-intensity tVNS treatment. The primary outcome of both phases is subjective patient evaluation of GI symptoms by the use of validated questionnaires.~A third phase, conducted only on participants, who proved to be responsive to tVNS treatment, will investigate the acute endocrine and metabolic response to short-term tVNS in a randomised cross-over design.~Lastly, healthy volunteers will be included in a cross-sectional, descriptive study in order to provide a comparable baseline dataset.
The purpose of the DAN-VNS study is to investigate the effects of non-invasive vagal nerve stimulation on gastrointestinal symptoms such as nausea, vomiting, bloating, and diarrhea in people with diabetes.