title: Abnormal neuronal response to rectal and anal stimuli in patients with idiopathic fecal incontinence.
abstract: BACKGROUND
  The pathophysiology behind idiopathic fecal incontinence (IFI) is poorly understood. We hypothesized abnormal sensory pathways along the brain-gut axis as a key player in this disease, reflected in cortical evoked potentials (CEP) from mechanical stimuli of the rectum and the anal canal.
  
  
  METHODS
  CEPs were recorded during repeated rapid balloon distensions of the rectum and anal canal in 19 women with IFI (mean age: 60 ± 14, mean Wexner score: 14.7 ± 2.9) and in 19 healthy women (mean age: 56 ± 11, mean Wexner score: 1.1 ± 1.3). Latencies, amplitudes and topography of CEPs elicited by rectal distension were compared between the groups. CEPs from both rectal and anal distensions were examined using spectral band analysis of single sweeps determining the relative amplitude of five spectral bands as a proxy of neuronal processing.
  
  
  RESULTS
  Compared to controls IFI patients had prolonged latency of CEPs from rectal distension by up to 27% (p < 0.001) while amplitudes and topography were similar (all p > 0.7 and all p > 0.23). Spectral analysis of CEPs from rectal distensions showed no difference (all p > 0.1) between groups. However, analysis of CEPs following distension of the anal canal resulted in abnormally low activity in beta (8-12 Hz; p < 0.001) band and high activity in the gamma (32-70 Hz; p = 0.04) band in patients.
  
  
  CONCLUSIONS
  IFI seems to be associated with impaired ano-rectal sensory functions in both the afferent fibers to the brain and the cortical processing of anal sensory pathways. This may play a central role for the pathogenesis of IFI.
authors.affiliation: Department of Surgery P, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Haas
authors.affiliation: Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Brock
authors.affiliation: Neurogastroenterology Unit, Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Krogh
authors.affiliation: Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Gram
authors.affiliation: Department of Surgery P, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Lundby
authors.affiliation: Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
authors.forename: A M
authors.initials: AM
authors.lastname: Drewes
authors.affiliation: Department of Surgery P, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Laurberg
mesh_terms: D000368:Aged; D001003:Anal Canal / Q000503:physiopathology*; D005071:Evoked Potentials / Q000502:physiology; D005242:Fecal Incontinence / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D010812:Physical Stimulation; D012007:Rectum / Q000503:physiopathology*; D012684:Sensory Thresholds / Q000502:physiology
keywords: anal canal; electroencephalography; evoked brain potentials; idiopathic fecal incontinence