Rapid balloon distension as a tool to study cortical processing of visceral sensations and pain D. LELIC,* T. D. NISSEN, † C. BROCK,* Q. AZIZ‡ & A. M. DREWES*, †, § *Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark †Department of Clinical Medicine, Aalborg University, Aalborg, Denmark ‡Centre for Digestive Diseases, Blizard Institute, The Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK §Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark Key Messages  Rapid balloon distention is a more physiological-like stimulus to study central processing of visceral discomfort and pain compared to its electrical alternative. However, its validity is not known.  Reliability of EPs evoked by rapid balloon distension in the rectum was investigated.  Within- and between days reproducibility was assessed in terms of latencies and amplitudes of the cortical evoked potential global field power, topography, and underlying brain networks in 18 healthy volunteers.  Cortical evoked potentials following rectal rapid balloon distension were reliable for all the parameters. Abstract Background The processing of discomfort and pain in the central nervous system is normally studied with experimental methods, but it is mandatory that they are reliable over time to ensure that any interven- tions will result in valid results. We investigated reliability of rapid balloon distension in the rectum to elicit cortical evoked potentials (CEPs) to study the reliability of central processing of visceral sensa- tion and discomfort/pain. Methods Eighteen healthy volunteers had two series of rectal balloon disten- sions performed on two separate days. Individualized balloon pressure, corresponding to pain detection threshold or to the maximum possible distension (30 psi), was used. Within- and between days reliability was measured in terms of amplitudes and latencies of the CEP global field power, topogra- phy and underlying brain networks. Key Results There were two prominent peaks in the CEP record- ings at mean latencies of 157 and 322 ms. There were no differences in latencies or amplitudes (p = 0.3) and they passed the Bland–Altman test for reproduc- ibility. There were no differences in topographies (p > 0.7). Brain source connectivity revealed the cingulate-operculum network as the most consistent network within and between subjects. There were no differences in the location of brain sources in this network (p = 0.9) and the source coordinates were reproducible. Finally, the cingulate source generally had higher strength than operculum source (p < 0.001). Conclusions & Inferences A reliable method to study central mechanisms underlying visceral sensation and pain was established. The method may improve our understanding of visceral pain and could be an objective method for studying efficacy of analgesics on visceral pain. Keywords cortical evoked potentials, rapid balloon distension, reliability, source localization, visceral pain. Address for Correspondence Dina Lelic, MSc, PhD, Mech-Sense, Department of Gastroenterology and Hepatology, Mølleparkvej 4, Aalborg University Hospital, Aalborg DK-9000, Denmark. Tel: +45 97663524; fax: +45 99326507; e-mail: dl@mech-sense.com Received: 29 September 2014 Accepted for publication: 27 February 2015 © 2015 John Wiley & Sons Ltd 832 Neurogastroenterol Motil (2015) 27, 832–840 doi: 10.1111/nmo.12557 Neurogastroenterology & Motility