title: Rapid balloon distension as a tool to study cortical processing of visceral sensations and pain.
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 interventions 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 sensation and discomfort/pain.
  
  
  METHODS
  Eighteen healthy volunteers had two series of rectal balloon distensions 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, topography and underlying brain networks.
  
  
  RESULTS
  There were two prominent peaks in the CEP recordings 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 reproducibility. 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
  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.
authors.affiliation: Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: D
authors.initials: D
authors.lastname: Lelic
authors.affiliation: Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: T D
authors.initials: TD
authors.lastname: Nissen
authors.affiliation: Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Brock
authors.affiliation: 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.
authors.forename: Q
authors.initials: Q
authors.lastname: Aziz
authors.affiliation: Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.|Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: A M
authors.initials: AM
authors.lastname: Drewes
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004106:Dilatation / Q000379:methods*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D017288:Pain Threshold / Q000502:physiology; D012007:Rectum / Q000502:physiology*; D015203:Reproducibility of Results; D012677:Sensation / Q000502:physiology*; D059265:Visceral Pain; D055815:Young Adult
keywords: cortical evoked potentials; rapid balloon distension; reliability; source localization; visceral pain