VIBRANT-IBD: Brain Effects of Non-Invasive Vagus Nerve Stimulation in IBD Remission

The VIBRANT-IBD study is a pilot, prospective, single-arm feasibility study designed to investigate the neuropsychological and neurofunctional effects of non-invasive vagus nerve stimulation (nVNS) in adults with inflammatory bowel disease (IBD) who are in clinical remission. The study focuses on individuals diagnosed with Crohn's disease or ulcerative colitis and aims to explore the relationship between vagal neuromodulation, brain functional connectivity, emotional functioning, stress regulation, fatigue, and quality of life. Approximately 15 adult participants will be recruited from a gastroenterology outpatient clinic and hospital department. Participants will undergo a 28-day intervention using the Nurosym device, a non-invasive auricular vagus nerve stimulation system. The stimulation will be self-administered daily following standardised instructions after participant training. The intervention involves stimulation of the auricular branch of the vagus nerve at the tragus area of the ear using mild electrical impulses. Stimulation will deliver at a frequency of 25 Hz with a pulse width of 250 µs. Stimulation intensity will be individually adjusted to a comfortable, clearly perceptible, non-painful level following standardized participant training. The total stimulation time will be 1.5 hours per day. The study aims to evaluate preliminary effects of this intervention, the feasibility, and acceptability in individuals with IBD in remission. Each participant will complete two magnetic resonance imaging sessions: one before the intervention and one after the 28-day stimulation period. MRI examinations will be performed using a 3T Magnetom Vida scanner equipped with a 64-channel head coil. The imaging protocol will include structural and functional neuroimaging assessments. Structural MRI will include standard anatomical imaging, high-resolution three-dimensional T1-weighted magnetisation-prepared rapid acquisition gradient echo (3D MPRAGE), diffusion-weighted imaging (DWI), and non-contrast MR angiography using the time-of-flight (TOF) technique. Functional magnetic resonance imaging (rs-fMRI) will be performed during resting-state conditions using T2-weighted Gradient Echo Echo-Planar Imaging (EPI) sequences to assess functional brain connectivity and neural networks. Participants will also complete a set of standardised psychological questionnaires before and after the intervention. These measures will assess anxiety (DASS-21), depression (DASS-21), stress (DASS-21), fatigue (IBD-F), resilience (RS14), interoceptive awareness (Brief MAIA-2), and quality of life (WHOQoL BREF). In addition, study-specific questionnaires developed for the project will evaluate, e.g., disease-related concerns, fear of relapse, stress-related gastrointestinal symptoms, and daily functioning. Post-intervention assessments will additionally examine treatment adherence, usability, and acceptability of the stimulation device, perceived therapeutic effects, and potential side effects. Optional qualitative interviews will also be conducted with interested participants to explore personal experiences related to living with IBD and using vagus nerve stimulation therapy. The primary objective of the study is to explore changes in brain functional connectivity following non-invasive vagus nerve stimulation in adults with IBD in remission. Secondary objectives are to evaluate the feasibility and safety of the intervention and to assess psychological outcomes, including associations between neuroimaging findings and psychological measures. The study may contribute to a better understanding of brain-gut interactions and the potential role of neuromodulation as a supportive non-pharmacological intervention in IBD.